Dyno test

[yorkie_chris]

Me thinks I'll take the SV to a dyno tomorrow...

See this post for details of whats on/in the bike at the moment:
http://forums.sv650.org/showpost.php?p=1376760&postcount=1

Anybody want to guess what it'll make? (derestricted for the purpose of seeing how close the fuelling is to correct)

Or want to put any bets on whether my guess at the jetting is correct?

[phizog]

I'll guess 72-3 :)

[chunkytfg]

dynapro dyno 65ish

dynojet dyno 69ish

After all it is only a carby with a end can, needles and effectively no filter

[plowsie]

pot luck..........................71

[yorkie_chris]

After all it is only a carby with a end can, needles and effectively no filter

Micron system on there too.

It's booked in for Saturday on a dynojet

[dizzyblonde]

decided dodgy back tyre n snow not fer you......hehehe softie

[yorkie_chris]

No they won't have me till saturday, I'm off up to robs now to get a proper back tyre.

And where's your bike? Oh in the shed I hear... Now who's a softy? :-P

[dizzyblonde]

can't put a six yr old off school on the back..... thats my excuse anyway

[chunkytfg]

Micron system on there too.

It's booked in for Saturday on a dynojet


~In that case my figure are probably about right instead of flatteringly high!!:p

[micky t]

i had mine on the dyno at cresent open day and got 71 , all completly standard

[Robw#70]

It'll make a bit less than a std bike with a can, but worse in the midrange and a bit boggy low down

[yorkie_chris]

Could you elaborate on why?

[Robw#70]

The open filter will cause turbulance, making it 'gulp' for air at lower rpm when the throttle is opened and because it will flow more you'll end up with larger main jets making the jump between circuits bigger making part throttle poor.

What have you done to the filter?
Just cut the filter bit off leaving the lid and snorkel, doesn't flow much more as the size of the hole/tube limits the airflow so all you've done is allowed c**p in to the engine for no gain.
If you cut the bottom off the filter leaving the top, they'll be a bit of stand-off between the carbs loosing some midrange, again big jets where the midrange will suffer.
Cutting the middle of the lid out of a std filter is prob the best of the worst, but i'd say your 152's aren't big enough.

[yorkie_chris]

http://www.geocities.com/catpoopman/snork6.jpg

Like that

It feels better than it did, however the backside dyno isn't the most reliable thing in the world, so we'll see what happens saturday

[chunkytfg]

i had mine on the dyno at cresent open day and got 71 , all completly standard


did they then turn round and tell you that for the price of a race can and filter they could have it up to 200bhp or were they just taking the **** with your dyno figures?:brilsmurf::p

[zadar]

it does not matter what you have for filters,even if you got none,it will run good and gain power if tunned right.

[SV650Racer]

it does not matter what you have for filters,even if you got none,it will run good and gain power if tunned right.


not always. Unless of course your relying on the ultra reliable butt dyno:smt115

[micky t]

nope they didnt even mention that one chunky, just gave me the print out?

still gonna put a new can on it anyway,just so it looks nice

[yorkie_chris]

They're taking the pizzle mate, they must have decided that customers are very happy when they see big numbers :rolleyes:


Just got back from jordans with mine, dynojet 250 dyno and they sounded like they knew what they're on about. Were sound with me.

Anyway, its running lean. Robw#70, have a pint for being right :-P

Got some more jets, 157.5's, and will put these in and take it back on Wednesday, wondered why it felt a little gutless, max torque is only 52 Nm. :rolleyes:

http://photos-600.ll.facebook.com/photos-ll-sf2p/v168/78/86/574581600/n574581600_543403_3301.jpg

[SV650Racer]

cant read the figures but is that about 65bhp?. Its measured DIN too so thats quite low considering its also measured on the dynojet dyno.

Most carbies we see on a dynapro range between 62 for poor and 71.5 in minitwin spec, IE system and filter.

How many miles on the bike?.

[yorkie_chris]

66bhp, DIN CF of 1.03

18k miles

[Dangerous Dave]

Not bad for what you have done to the SV, I have seen worse with a Micron system. Sort out the lean running and it will feel much better to ride.

[yorkie_chris]

You reckon the 157's will be close?
(152.5 at the mo, mikuni sizes)

[Lissa]

[QUOTE=yorkie_chris;1379026]


wondered why it felt a little gutless, max torque is only 52 Nm. :rolleyes:

QUOTE]


http://i76.photobucket.com/albums/j5/Lissasv650/torque.jpg

At least there is room for improvement;)

[yorkie_chris]

Yup 38 lbf ft, converted it to Nm out of habit lol

Feels alright down low


Now to crack open another can of worms, who tunes to the A/f ratios?
Heard various things, none of them reliable and none of them agreeing with each other!

[SV650Racer]

Yup 38 lbf ft, converted it to Nm out of habit lol

Feels alright down low


Now to crack open another can of worms, who tunes to the A/f ratios?
Heard various things, none of them reliable and none of them agreeing with each other!

Well you dont want it running too lean thats for sure.

Getting the fueling, IE A/F spot on i would think would a good plan;).

How else would you tune it?. Butt dyno?:mrgreen: I dont think Butt dyno's are all that reliable especially after Xmas...mines running a bit rich at the moment..so gawd knows what some peoples will be like!:smt103:smt103:cool:

[Dangerous Dave]

I think so, your 157's will be closer than the 152.5's. Can't remember off hand what I had when I used a Micron, it was no good when I upgraded though, I'll have a dig through the doc's when I get home.

[yorkie_chris]

The arguement I've heard against says that the A/f out of the exhaust doesn't tell you whats actually going on in the cylinders, or whats going on in each cylinder, so its better to just tune for best power by experimenting.

This is jsut what I've heard, using the AF makes sense to me but wondering what everyone elses thoughts are.

[SV650Racer]

The arguement I've heard against says that the A/f out of the exhaust doesn't tell you whats actually going on in the cylinders, or whats going on in each cylinder, so its better to just tune for best power by experimenting.

This is jsut what I've heard, using the AF makes sense to me but wondering what everyone elses thoughts are.

Mostly wrong.

Ideally you need the A/F to be between 12.5 and 13.5 also taking into consideration what is happening to the power curve.

There is no point having maximum power yet the bike running lean running the risk of detonation or over heating.

You also need to consider other affects which can take place when the bike is actually ridden especially at high speed, have on the A/F ratio. This is why having someone experienced doing the fueling helps.

A/F ratios are there for a reason and not just to make your bit of A4 look pretty;)

[yorkie_chris]

Mostly wrong.

The wonders of getting tuning info on google :-P

[SV650Racer]

The wonders of getting tuning info on google :-P

LOL. Treat the internet 98% of the time as the equviliant of reading The Sunday Sport and you will be fine:D:cool:

[Lissa]

This is our A/F

http://i76.photobucket.com/albums/j5/Lissasv650/ratio.jpg

As you can see, much more even than yours.

[r4ce_e3nd]

The A/F is much too high with yours! Take care for detonation!
If you get the A/F right (+-13) you will earn more bhp, that's for sure. But if you can do it on your own? I doubt it!
Just bring you bike to a experienced tuner and let him do the job. It will cost you more but it will be done perfect and you will have a nice running SV, like we do. ;)

[yorkie_chris]

Just put the 157 mains in, seems to rev a little freer if that means anything.

Will go for a spin in an hour or so and let you know how it feels.


Taking it to the tuners, letting them dyno it and then making changes myself.
Can't see the point of, or afford to pay somebody £50 an hour to take the carbs off for me.

[Dangerous Dave]

Taking it to the tuners, letting them dyno it and then making changes myself.
Can't see the point of, or afford to pay somebody £50 an hour to take the carbs off for me.

Agreed, the only thing I never did myself was bore out the engine. If you don't feel confident to do any DIY work yourself then it is best to get a professional to do it, plus there is a warranty of such if it goes wrong!

A Haynes manual is an excellent start for any newbies...

[yorkie_chris]

So far this bit of messing around has cost me
Micron pipes ... £40
Bits for repairing my fuel can £25
New air filter £17 (?)
Jets £10 ish

If I'd paid somebody to make those changes then it would have been a fortune, and completely pointless, the thing I like about the SV is there's loads of decent performance to be had (not just engine, suspension) for not a great deal of money, i.e gixxer front ends, rear shocks from other bikes...

[SV650Racer]

So far this bit of messing around has cost me
Micron pipes ... £40
Bits for repairing my fuel can £25
New air filter £17 (?)
Jets £10 ish

If I'd paid somebody to make those changes then it would have been a fortune, and completely pointless, the thing I like about the SV is there's loads of decent performance to be had (not just engine, suspension) for not a great deal of money, i.e gixxer front ends, rear shocks from other bikes...

Kwel.

Although most still wont or cant manage taking carbs off letting alone changing jetting. Even being married to Steve and having watched him work on bikes for years i only touch under supervision:smt103..even then i still get told off:cool:

[yorkie_chris]

Seems to be one of those things, you're either inclined towards messing about or not.
I've never been able to leave anything alone for long hehe, except my 125, mods on that were fairly pointless. :p

[Robw#70]

So far this bit of messing around has cost me
Micron pipes ... £40
Bits for repairing my fuel can £25
New air filter £17 (?)
Jets £10 ish

If I'd paid somebody to make those changes then it would have been a fortune, and completely pointless, the thing I like about the SV is there's loads of decent performance to be had (not just engine, suspension) for not a great deal of money, i.e gixxer front ends, rear shocks from other bikes...

What about the 2 or more powerchecks?
If the 157's are wrong (ran 175's with a bmc) then your already down £90 or so as well as the back and forth trying things, 2 1/2hrs on the dyno's £125 job done in an afternoon, giving you more time to fiddle with other bits of the bike...or even ride it!

[zadar]

Seems to be one of those things, you're either inclined towards messing about or not.
I've never been able to leave anything alone for long hehe, except my 125, mods on that were fairly pointless. :p
what filter do you have?

[chunkytfg]

Kwel.

Although most still wont or cant manage taking carbs off letting alone changing jetting. Even being married to Steve and having watched him work on bikes for years i only touch under supervision:smt103..even then i still get told off:cool:

Well after watching you work on them for 2 years i can see why:p:p:smt056[-o<:mrgreen::mrgreen::mrgreen::mrgreen:

[r4ce_e3nd]

So far this bit of messing around has cost me
Micron pipes ... £40
Bits for repairing my fuel can £25
New air filter £17 (?)
Jets £10 ish

If I'd paid somebody to make those changes then it would have been a fortune, and completely pointless, the thing I like about the SV is there's loads of decent performance to be had (not just engine, suspension) for not a great deal of money, i.e gixxer front ends, rear shocks from other bikes...
You do not have to pay for the dynoruns?

[northwind]

Heh, I'm glad I sat on the fence when you were asking about jet sizes :) I still can't think in Mikuni and I don't like the Micron, so I'd probably have given you total rubbish.

Did you ever try the stumble test I told you about? (ie, ride at constant throttle in 3rd at 5000 and 6000rpm, open throttle fast, see what happens)- if it stumbles dramatically and loses power, it's a reasonable indicator for fairly undersized mains, taken along with other indications of course. Change jets and compare. It's easier to jet up from lean than it is to jet down from rich IMO, the lean symptoms are more dramatic to me at least. Jetting by riding can be fairly effective but it's so open to changes in circumstances and interpretation, this is more replicable.

That's one of the main tricks I use, combined with general butt dyno work, and I've never been more than one main jet size off (except when the bike was being kneecapped by the Renegade filter anyway, when I used the recommended settings and it was as rich as creosote). I did make a complete and total bo****s of the low end fuelling last time, to be fair :mrgreen: It'd be quite possible to mistake an over-lean needle setting for undersized jets if you tried this by itself, mind.

Having said that, I don't know if the restriction would affect this, never rode a restricted SV.

Incidentally, I put a desnorkelled filter into mine a while back out of curiousity... It ran fairly rich since I never bothered to rejet for it (it's got a BMC RS and 180 DJ mains, if memory serves), and it was a bit wooly and slower to respond throughout, but it didn't have any major issues, still perfectly ridable. I didn't dyno it naturally but it certainly didn't drastically lack for anything, I could have been happy enough with it.

<Grandpa Northwind gathers the kids around and opens the story book>

This is The YPE Butt Dyno Story, a cautionary tale ;)... One of the times I was having mine run at YPE, as I arrived a guy with a GSXR of some sort was just paying up for a remap for a new system etc. He rode off, happy as larry, but just as I was about to leave he turned up again, absolutely fuming. "You've messed it all up, it's got no top end!"

So, YPE Man comes out to have a word, and after a bit shows him the before and after runs, and finds a run for a fairly stock GSXR too. GSXR Man had been riding around with it really lean in the mids and low highs, and the midrange was completely knackered- but the peak wasn't too bad, and when it got out of the huge hole in the mids it felt more powerful than it was, as the change in power was so abrupt. After the remap, it was making more power up top and the hole in the mids was gone- but it felt weaker as the big change was gone.

What the butt dyno reads isn't total power, it's contrast. A peaky 60bhp actually feels like it's more outright powerful than a linear 60bhp even though it's far less useful, because the linear curve never has that big exciting jump in power.

<Grandpa Northwind closes the story book>

[yorkie_chris]

Did try the stumble test, it didn't actually stumble as such, just hesitated before starting to pull.

Going to go out for a spin later after food, will try again now it's got the 157 mains in.

Theres a nice long straight up on't moors so going to do a full throttle plug chop and see what it's doing that way.

[Robw#70]

Did try the stumble test, it didn't actually stumble as such, just hesitated before starting to pull.



:confused: :smt104 :confused: :rolleyes: :confused: :smt104 :confused: :smt075

[yorkie_chris]

No need to take the pi$$, it felt lean, it hesitated, the wording northwind used was:
"if it stumbles dramatically and loses power,"
It didn't lose power, it just hesitated, why the shock at that?

Maybe I've misinterpreted/misunderstood something, but I'm not a professional tuner, so bash someone else on the head with a stick, or at least take the pi$$ AND tell me where I'm going wrong!



The filter is stock, but with the snorkel/trumpet thing in the middle of it cut out.

The dyno runs are £20 each, and I go past there anyway so it's not that much of a waste of time.

[Berlin]

hes·i·tate http://cache.lexico.com/g/d/premium.gif http://cache.lexico.com/dictionary/graphics/luna/thinsp.pnghttp://cache.lexico.com/g/d/speaker.gif (https://secure.reference.com/premium/login.html?rd=2&u=http%3A%2F%2Fdictionary.reference.com%2Fbrowse%2 Fhesitate)/ˈhɛzhttp://cache.lexico.com/dictionary/graphics/luna/thinsp.pngɪˌteɪt/Pronunciation Key - Show Spelled Pronunciation[hez-i-teyt]Pronunciation Key - Show IPA Pronunciation
–verb (used without object), -tat·ed, -tat·ing.
1) To Stumble due to incorrect jetting
2) To be reluctant or wait to act.

:D

[zadar]

The filter is stock, but with the snorkel/trumpet thing in the middle of it cut out.


that graph looks weird for what you got.I think something else is wrong,not main jet size.
maybe air in UK :),we all run around 150-155 mains with that set up around here.
any intake leaks?air box sealing on boots?

[yorkie_chris]

OK OK stupid comment by me. I know what I meant!

In future I'll double check the wording to avoid :smt075 :p

[yorkie_chris]

any intake leaks?air box sealing on boots?

I'll have another check round it see if there's anything obvious.

[zadar]

you need to check with bike running.spray mist of water or carb cleaner around area.your idle will change if there is leak.

[yorkie_chris]

Now I'm quite embarrassed...

The cap over the vacuum spigot's split, thought it felt brittle when I put it on.
8-[

Will put the 152.5's back in and see if thats cured the stumble, would anybody do anything different?

(btw now I've sealed the vacuum spigot up and rebalanced them spraying carb cleaner round doesn't change the idle)

[zadar]

Now I'm quite embarrassed...

The cap over the vacuum spigot's split, thought it felt brittle when I put it on.
8-[

Will put the 152.5's back in and see if thats cured the stumble, would anybody do anything different?

(btw now I've sealed the vacuum spigot up and rebalanced them spraying carb cleaner round doesn't change the idle)
sounds like good plan to me :)

[SV650Racer]

A stumble can also be rich running;). If butt dyno's worked i could have saved myself £13k on a dyno. Although i might have had a hard time convincing customers that we were setting their A/F up by feel:cool:

Oh and Chunks...less of that!. Remember gaskets..Snett?...!!!!!!!!!!!!..oh I still have Nickies cooler bag BTW.

[zadar]

A stumble can also be rich running;). If butt dyno's worked i could have saved myself £13k on a dyno.
it worked really good for us born before dyno era :D

[northwind]

A stumble can also be rich running;).

Yup, that's why I tune up from lean ;) But it's easier to use a dyno, if it wasn't for the fact I like doing the work myself I'd just have handed the bike and a handful of jets over to YPE and said "Make it go faster". Or in fact, I'd probably have left it standard now I think of it.

The butt dyno can be very accurate, just like a bad dyno operator can be useless, it's just a question of skill. But I think a lot of butt dynos desperately need calibrating ;)

[yorkie_chris]

Probably mine, since this is the first road bike I've tried to jet :smt043


Just got back from a bit of a test run up and down the road, and whacking the throttle open at 3k in 3rd gives pretty much instant response.
Also a lot smoother throughout the rev range.

What next?

[SV650Racer]

Probably mine, since this is the first road bike I've tried to jet :smt043


Just got back from a bit of a test run up and down the road, and whacking the throttle open at 3k in 3rd gives pretty much instant response.
Also a lot smoother throughout the rev range.

What next?

Cool. So now get an A/F run done to make sure and off you go\\:D/

Butt dyno and reliable doesnt even exist. Call it guess work from feel. Trouble is even though it may be free...for £20 or so its cheaper than a toasted engine and ensures you definatly do have a bike thats performing how it should. Which IMHO i think it worth its weight in gold:cool:

[yorkie_chris]

Booked in for another run Wednesday lunchtime, not really much idea how it feels, it feels stronger, but then agian I know I'm expecting/hoping it to. So I discount that.

From another test ride, it pulls instantly from 3k as I said above, but theres another definite increase in power at 5k. Does this say anything to anyone? Or is this normal?

(my carburetion was wierd before when stock except for a slipon, big flatspot at 5.5k, so I don't know what standard feels like)

[zadar]

From another test ride, it pulls instantly from 3k as I said above, but theres another definite increase in power at 5k. Does this say anything to anyone? Or is this normal?

yes,it is normal.there is dip in power around there and hard to tune it out without changing cams,carbs....

[Robw#70]

it worked really good for us born before dyno era :D

But there was lead in the fuel then so plug chops actually meant something:shaking:

[zadar]

there are still many ways to do it.
btw.I don't do plug chops.
ps.dyno does not replicate what happens when you ride.so,even dyno is not that perfect as they make it sound.it is just tool to do it easier and more accurate in shorter time.

[chunkytfg]

A stumble can also be rich running;). If butt dyno's worked i could have saved myself £13k on a dyno. Although i might have had a hard time convincing customers that we were setting their A/F up by feel:cool:

Oh and Chunks...less of that!. Remember gaskets..Snett?...!!!!!!!!!!!!..oh I still have Nickies cooler bag BTW.


Yes I do remember if i'm honest though the fact i only managed 3 corners before falling off on the 4th was far worse!!!

[yorkie_chris]

http://photos-c.ak.facebook.com/photos-ak-sctm/v184/78/86/574581600/n574581600_556178_7784.jpg

Now what's going on?

The 157's apparently STILL too small, so a bit of duct tape over about 1/4 of the air filter gave this run.
Dyno guy said thats fuelling pretty well, its a sight closer than it was before anyway!

However, despite much better fuelling and restriction in the airbox not #that# much more significant than before its now making 10bhp less.

Ignition miss or something?

[yorkie_chris]

Oh yeah the dyno feller advised me to check for something disturbed when taking the carbs off, and could hear it popping on the dyno run, so suspects ignition trouble. Going to pull it in bits later and check my wiring.

[northwind]

For ease of comparison:

http://photos-600.ll.facebook.com/photos-ll-sf2p/v168/78/86/574581600/n574581600_543403_3301.jpg

[northwind]

And no, I don't know what's causing it. The curve's bumpy as all hell up top though.

[yorkie_chris]

Bumpy yes, but I was hoping for tuning to improve the thing not lose 10hp :p

[zadar]

assuming nothing is wrong with your carbs or around them try 160 and drop needle down.

[yorkie_chris]

I don't think there is, it was fine on saturday just lean.

Do you think its just jetting thats the trouble? Or is something else going on as the dyno guy thought?

54bhp seems naff to me especially since the fuelling looks OK, also much better than before and less power ???
I'm confused.

[r4ce_e3nd]

Do you feel the loss of power?

[yorkie_chris]

Well no, but before that it was really lean, hesitant and snatchy, so its an improvement over that.

[zadar]

I don't think there is, it was fine on saturday just lean.

Do you think its just jetting thats the trouble? Or is something else going on as the dyno guy thought?

54bhp seems naff to me especially since the fuelling looks OK, also much better than before and less power ???
I'm confused.
graph looks like within workable range,just to rich in lower part and little lean on top.
to lean will hesitate or surge,to rich will feel soft/not pulling hard.
all circuits in carbs overlap so it is important to get all of them right,fuel level,pilot,air jet,mixture,needle,main.
lower needle couple notches and bump main to 160 and try.you probably want to put 15 pilot in there.

[yorkie_chris]

I'm still confused as to how its lost power since getting the fuelling much closer to correct.

Just had a look and another squirt round with carb cleaner, I think it's sealed, and taking the air filter off shows that both sliders are lifting normally.

[r4ce_e3nd]

Well no, but before that it was really lean, hesitant and snatchy, so its an improvement over that.
Then my question is, how can you 'tune' your bike when you don't feel the loss of 10bhp?!?

[yorkie_chris]

Because it's gone from being really bad with the hesitation, to comparitively smoother. Before the bigger mains and taping part of the filter it was all over the place due to the surging, so felt really crap and slow, despite having 10bhp more. My ars is not a calibrated instrument.

I'm new to tuning bikes, never played around with this sort of thing seriously before now, I'll get it in the end....

[yorkie_chris]

Just had a look round everything, dropped the needle slightly as per zadars advice, also had a general look round the ignition system, one of the plug caps had high resistance so swapped it.
Will go see if theres any change when I've had me tea.

This DIY tuning lark is all well and good, but you get really sick of taking the carbs off.

[northwind]

Think of it as practice :)

Oh aye, don't entirely rule out dyno error, apart from the high end bumping that's a fairly tidy curve, so it's always possible that it's just an under-reading run.

[yorkie_chris]

Indeed, I had considered that, and low tyre pressure causing losses.

But, just checked the pressures, and theyre spot on. And, it was popping a bit during the run.

[yorkie_chris]

OK update after giving it a couple of proper kickings.

When it's been ragged a bit, it goes really weak in the mids, but better on top, which sort of confirms that the top end is a tad lean, and I'm just in the process of dropping the needles a tad more.

The only thing which is strange is it'll sometimes idle really badly, its set to 1400 rpm, but when its been ragged a bit it'll rise to 2k, when used in traffic (right when good power comes in handy...) it'll idle really badly, popping and farting, dropping to 1000 revs or less, when you blip the throttle it sort of coughs before it revs, and it sometimes cuts out. Very annoying.

[zadar]

did you change pilot jet?if not try it.

[northwind]

UK bikes have 17.5 as stock

[zadar]

I know.and different needle :)
I would try one up/down.
and mixture screw.

[northwind]

Damn it, i thought I knew something you didn't :(

[yorkie_chris]

Dropped the needle another notch, and it seems a little better today, but haven't had it up to full temperature, will see tomorrow what its like hot.

Is it normal for the idle speed to differ so drastically?

I'm pondering getting a DJ kit (or other) to give me a selection of jets to play with.

[northwind]

What sizes do you think you need? I should have an assortment from about 146 through to 180 due to... Well, poorly thought out jet purchases :mad:

[yorkie_chris]

No idea, I've been thinking in mikuni sizes, currently on 157.5 main, which is too small.

Running slightly lean on top even with a third of the filter taped over

[zadar]

Running slightly lean on top even with a third of the filter taped over
you having to many weird problems,you sure all is good with your carbs?
if I was you I would borrow set from somebody just to try.
tight valve can also give you weird idle.

[yorkie_chris]

Will have next week (don't tell dizzyblonde :-P)

Checked them over though, the sliders are moving about fine, there is no air leak round the throttle shaft (no excess play and doesn't react to being sprayed with carb cleaner) About the only thing I haven't checked is float level. Jet's are not loose. They balance normally, valves were in spec 4k miles ago. What else to check?
Did choke plungers again today, cleaned and greased, they weren't bad, but I thought it worth a go.

Oh yes, had a test light on the ignition wires and wiggled lots of cables and stuff and couldn't find a fault.
Coils and HT system all in spec too.

[Robw#70]

is the throttle linkage all free? they get sticky on the rear carb where the balance adjuster is, which when your taking them on/off get knocked, sticking open a bit, you set idle with it stuck and when it frees off the idle changes

[yorkie_chris]

Had them off last night, and my usual practice is to clean them off and give them a shot of dry lube, all seemed to be working as normal.

The idle only changes when it gets hot, a bit I could understand but 500rpm difference seems excessive.

Will see how it does at proper optemp today.

[ritchy31]

Hi all!
My bike has slotted needles (like yours in UK I think)
What is the stock setting for the E-clip?

Mine was in the 2nd slot starting from the top.I don't know if it is the original setting....I can' find this info on the tech manual.

FYI, I'm rejeting my french SV650 2002. Here is my actual config:
Cam swap/Full yosh system/desnorkel stock filter/155 mains/ 3rd slot on stock needles/2.5 turns out for the idle richness with 17 stock pilots.

Run great on top, not too bad but not perfect in the midrange and on low revs.


Cheers

[pod]

From what Ive read there is no point in cutting the lid on the air filter unless you have a full exhaust system upgrade like an M4 not a slip on to stock pipes.
The clever wee men at Suzuki put that bit in the middle for a reason, it has sexy bell mouth and a divergent splitter cone, wonderful engineering, giving laminar non turbulent air flows and helping the carb get steady conditions.I dont think they would have bothered if a great big hole was all that was needed.
Before I did any more dyno runs Id get a new filter and then try a back to back run with each type fitted, my moneys on the stock filter.

The increase in idle speed is strange and would suggest weakness of the idle circuit or an air leak somewhere (carb mounts?). Messing with needle height makes no difference to idling.,
My stock carbs, filter and pipe (Cagiva Raptor) make over 40 ft/ lbs and 76 hp(rear wheel), only mods are cam swap (K3 and exhaust). One dyno run showed all was AOK, no air fuel weirdness, the YPE op reckoned one size up on the MJ might help but wasnt really needed .

On old Brit bikes like my BSA 650 , removin the air filter or a louder pipe generally meant going up +10 on the main jet size (increments were 5), the fine +2.5 increments on the Mik are good for fine tuning but take a lot of sneaking up on for the ideal setting. Try a 160 and see if that makes it better at the top end.

I disagree with sneaking up from lean, thats one way to melt pistons if left in that condition. Ok for an afternoons trial though, in general too rich is safer than too lean.

Cheers
Pod

[Dangerous Dave]

The clever wee men at Suzuki put that bit in the middle for a reason, it has sexy bell mouth and a divergent splitter cone, wonderful engineering, giving laminar non turbulent air flows and helping the carb get steady conditions.
It was put there for noise emission tests, just like the bit of foam on the bottom of the tank.

As for the de-snorkeling, yes you are right it is not worth doing if you run with the standard downpipes in any manner (slip-on, renegade system).

Bear in mind this is an old thread, and I am sure Chris knows what he is doing.

[yorkie_chris]

So. Turbulence.

Why is air going through a tiny 1/4" slot going to be less turbulent than air going through a slot roughly 2" by 4", the air velocity is going to be huge with the snorkel, this tends to create power loss. By this logic even the BMC SP's and the like should flow worse than standard.

Have been running it with maybe a third of the filter mouth taped over to make it rideable, recently replaced the carbs, added BMC RS filter and 160 mains. It does feel a lot stronger and has been seen to indicate 125 ish on a private road, 2up. (no idea of wind direction, held 110 all day though)

Need to get a dyno run done and some other stuff, but hey de ho it runs alright.

[ritchy31]

So,
What is the stock setting for the E-clip?

[Dangerous Dave]

If you are still restricted Chris I advise you switch back to the OEM filter, overall the SV runs better on this when restricted.

[pod]

This link talks about snorkelectomy/ air filters.
http://www.geocities.com/catpoopman/sv650_snorkel.html
It suggests that the stock filter is best unless you have a full system.
It specifically mentions 5-7K probs with an opened up filter.

If your bike pulls 110 all day it cant be far off.

I did once cut out the top of the filter but then I read the link above and didnt bother fitting it, I dont want any more noise/hassle and the 1/4"slot is still more open area than both valves of one cylinder combined.
High inlet tract air velocities aid low speed carburation, smaller ported inlet tracts nearly always give better low speed torque.
I realise you are after more top end , so this isnt an issue.
My money is still on the stock filter .

Best of luck,
Pod

[fastdruid]

This link talks about snorkelectomy/ air filters.
http://www.geocities.com/catpoopman/sv650_snorkel.html
It suggests that the stock filter is best unless you have a full system.
It specifically mentions 5-7K probs with an opened up filter.


FWIW my SV is giving just over 70 rw hp[1] with the std suzuki air filter/airbox, no jetting changes (apart from needles were 'shimmed') and a full exhaust[2][3].

I considered the snorkeldectomy but thought that it wasn't worth the risk as it was sweet enough anyway. :)

http://www.fastdruid.co.uk/temp/thumbs/640x480DSC03108.JPG

Druid

[1] On a dyna pro
[2] Akrapovic downpipes/scorpion end can.
[3] Although tank is spacered up and foam underneath removed.