SV1000 throttle body balancing

[Mark_h]

Dear engine Gurus

My K3 SV1000 is running a bit lumpier than normal. I plan to give it an oil and plug change and give the airfiler (BMC) a good clean but it feels like my old 650 did when the carbs were out of balance.

symptoms:-
1. Sounds rougher than normal on tick-over
2. Bit more vibey at revs (incl bit of mirror vibration that I never used to get although this may just mean the mirrirs need looking at)
3. Occasionally if I've been riding "progressively" then do something slow like a tight turn in 1st <3000 rpm then it will sometimes give a bit of a cough which is not fun halfway round a tight hairpin!
4. Still starts immedaitely hot or cold
5. Still goes like a train

So... I thought I'd have a go at balancing the throttle bodies. Question is will normal carb balance gauges do the job or do I need something different for the injection bodies. Secondly am I setting myself up for a world of pain doing this or is it fairly straightforward?

Few newbie questions:-
1. Typically just how hard is it to get the test point covers off? as usual service manual says "remove covers" does not mention "snap spiggots, pout boiling water to attempt to soften, go get special v.expensive widget to remove thingy, skin knuckles, ping bits down throttle bodies into engine etc etc etc
2. If you are going to extend them to make it easier next time, where is the recommended place to extend them to?
3. Would you usually leave all the sensors etc connected to the airbox or does that just mean the airbox gets in the way?
4. Anything else you did first time that you realised was daft and found a much better way to do it next time.

thanks in advance,
Mark

[Sid Squid]

Originally Posted by Mark_h

give a bit of a cough

It's an SV1000 - has yours only just done this? - they all do it now and again.

Originally Posted by Mark_h

Question is will normal carb balance gauges do the job or do I need something different for the injection bodies?

Nothing different is required - a vacuum gauge is a vacuum gauge.

Originally Posted by Mark_h

Secondly am I setting myself up for a world of pain doing this or is it fairly straightforward?

No, it's pretty easy.

Originally Posted by Mark_h

1. Typically just how hard is it to get the test point covers off?

Dead easy, give them a twist and off they come.

Originally Posted by Mark_h

2. If you are going to extend them to make it easier next time, where is the recommended place to extend them to?

Not needed.

Originally Posted by Mark_h

3. Would you usually leave all the sensors etc connected to the airbox or does that just mean the airbox gets in the way?

The balance screw can be reached without removing the airbox.

Originally Posted by Mark_h

4. Anything else you did first time that you realised was daft and found a much better way to do it next time.

No, it's all very straightforward.

Things to know: The TPS is on the rear throttle body, the tickover stop is on the front, so when you adjust the balance the TPS setting *might* change, and often you'll find the tickover has moved a bit too, so you'll have to reset that, which means the TPS might just move a bit again, so...

You get the picture I'm sure.

[Mark_h]

Cheers Sid.

As for the cough, it used to do it once in a while now it seems to be more often. May just benefit from a service. Tickover has never been as low as it should (c1500 won't drop to 1200) be so guess something is amiss in that general area anyway.

[Mark_h]

Well.........

Managed to borrow a carbtune balancer.

Rear body spigot was easy to get off as it has a connector for the scottoiler.
Front body spigot blank was another story. Unfortunately I do not posses the jointless two dimensional fingers required to get at it. The rubber seemed to be bonded to the spigot and the circlip was still there so guess it's probably not moved for the last 30,000 miles and had no intention of doing so today. Eventually got it off.

With airbox filter etc back on at tick over the rear was pulling about twice the front. Balanced it up and got them more or less equal. Should have then stopped. however .........

Decided to see what is happening further up the rev band. They were miles out. Twiddled both adjusters some more and got what I decided was the best compromise between being similar at tickover (never been able to get it lower than 1500) and still evenish at about 5k.

Took it out for a test ride. Definitely a lot smoother at low revs and when opening the throttle from closed. The 3k "shudder" seems to have gone too. Not sure if it's got as much poke as it did or may just be because it's now a lot smoother so feels less "urgent"

I've added some extenders to the spigots so I can re-twiddle by just lifting the tank next time and disconnect the gauges without burning myself.

The question I'm left with is should I have attempted to balance at tickover and revs or should I just have done the low end? And why does my tickover not drop below 1500? Have wound the tickover adjuster right in and given loads of slack on the cables. About the only thing left is the stops on the throttle bodies that the manual says never ever mess with! May just be that the open BMC filter with no airbox lid gets so much air in that the do not touch screw needs to be touched.

It may sound silly, but why does it matter that you idle 300 rpm over the recommended level?

Oh, and if I were to purchase a vacuum gauge, can a 2 point gauge be used to balance an IL4 (if I ever get one!), or would it require a 4-dial job?

Sorry, two different enquiries, probably requiring two different people to answer!
Attack of idle curiosity!

[Mark_h]

Originally Posted by carternd

It may sound silly, but why does it matter that you idle 300 rpm over the recommended level?

The Idle does not really matter but may be an indication that something else is wrong

Originally Posted by carternd

Oh, and if I were to purchase a vacuum gauge, can a 2 point gauge be used to balance an IL4 (if I ever get one!), or would it require a 4-dial job?
!

You can as it just means you balance two at a time. 4 would be simpler but it can be done with 2. Busters have a really cheap set on offer. don't know if they are much good but I think they are £22 for a pair and £35 for four.

Hopefully out for a spin this morning so can see if it's better or worse overall than when I started

Originally Posted by Mark_h

The Idle does not really matter but may be an indication that something else is wrong



You can as it just means you balance two at a time. 4 would be simpler but it can be done with 2. Busters have a really cheap set on offer. don't know if they are much good but I think they are £22 for a pair and £35 for four.

Hopefully out for a spin this morning so can see if it's better or worse overall than when I started

Cheers, just what I was after! BTW, just saw the blue bit at the bottom of your post, maybe the induction kit and exhaust affect your idle speed. I assume you've already thought of that but just in case...

[ian505050]

i have an sv1000s 2003 with 9000 miles and mine has the exact same symptoms. It occasionally at 3000 rmp will missfire/splutter/cough ect...... just for a milli second. Mainley does it in 1st or second gear. at low speed.

I have just lived with it.

I recentley changed oil/filter to see if it helped but no change.

gonna fit some new plugs today to see if that helps, gonna try iridium

[Mark_h]

Originally Posted by ian505050

i have an sv1000s 2003 with 9000 miles and mine has the exact same symptoms. It occasionally at 3000 rmp will missfire/splutter/cough ect...... just for a milli second. Mainley does it in 1st or second gear. at low speed.

I have just lived with it.

I recentley changed oil/filter to see if it helped but no change.

gonna fit some new plugs today to see if that helps, gonna try iridium

Just got back from a nice early morning 60 miler. So much smoother than it used to be. Especially from a closed throttle, none of that hesitation, shudder, woosh; just straight into the woosh.

In general feels less viby too but that may all be in my head.

Tickover sounds less like a gallop. Not sure if that's a good thing but it's certainly a different thing.

Jury's still out on peak power though, will need to wait until my mate with his blade comes out to play and then I'l get a better measure.

If you have access to a vacuum tester and a bit of patience then it's worth givign it a go, just make a note of what you moved so you can put it all back if you really make a hash of it.

[yorkie_chris]

Just buy the 4 pot gauges for a 4 pot bike... balancing 4 pots with 2 gauges is biggest PITA I have had working on stuff.