Initial suspension setup - help

To be fair, not only is the GIXER shock not much longer than the stock shock, but why the hell are you putting a stock SV shock in?

For racing purposes you want the rear lifted as high as possible, this will not only make it steer sharper, but give you that o-so-valuable and needed ground clearance

Bearing in mind you can't use dogbones, I'd hate to race an SV with stock shock, you would be grounding out at every turn!!

It's a seriously bad move putting a stock shock in it ... I have a curvy, so have used a ZX6 shock, not a GIXER one, but it's the same idea and it is notably better than the stock SV shock ...

As other have said, tyre pressures (although this tends to make the front sluggish) and new bike syndrome ... also have you checked the forks and yokes for straightness???

[flymo]

Originally Posted by Blue_SV650S

To be fair, not only is the GIXER shock not much longer than the stock shock, but why the hell are you putting a stock SV shock in?

For racing purposes you want the rear lifted as high as possible, this will not only make it steer sharper, but give you that o-so-valuable and needed ground clearance

Bearing in mind you can't use dogbones, I'd hate to race an SV with stock shock, you would be grounding out at every turn!!

It's a seriously bad move putting a stock shock in it ... I have a curvy, so have used a ZX6 shock, not a GIXER one, but it's the same idea and it is notably better than the stock SV shock ...

As other have said, tyre pressures (although this tends to make the front sluggish) and new bike syndrome ... also have you checked the forks and yokes for straightness???

Blue, the only reason I'm going to try a stock shock for size is to compare against the K4 1000 shock to elliminate that as an issue. More to settle my mind really. The forks and yokes seem fine but I'm going to strip the font and take another look.

I've looked the frame over visually too and I cant see any evidence of damage or creasing.

I think I'll also take a side on photo of the bike to post here to see if it looks strange.

Originally Posted by flymo_racer

Blue, the only reason I'm going to try a stock shock for size is to compare against the K4 1000 shock to elliminate that as an issue. More to settle my mind really. The forks and yokes seem fine but I'm going to strip the font and take another look.

I've looked the frame over visually too and I cant see any evidence of damage or creasing.

I think I'll also take a side on photo of the bike to post here to see if it looks strange.

03-04 SV650 330mm 430# <<<==== stock 2nd gen...05 should be the same

03-04 GSXR1000 332.5mm 480#

Dude, it is 2.5mm longer ... if you are lucky that is going to equate to ~6mm at the saddle i.e. f-all ... and at 15mph in a carpark, its not like it is doing much dynamically ... the shock isn't your problem

[flymo]

Originally Posted by Blue_SV650S

03-04 SV650 330mm 430# <<<==== stock 2nd gen...05 should be the same

03-04 GSXR1000 332.5mm 480#

Dude, it is 2.5mm longer ... that if you are lucky that is going to equate to ~6mm at the saddle i.e. f-all ... and at 15mph in a carpark, its not like it is doing much dynamically ... the shock isn't your problem

I think you are right, I'm not disagreeing. Its a puzzler this one. I need a more extensive test ride to get a firm opinion so I'll give this a better try at the weekend. Cant really do much until my front brakes are sorted so will get that finished tonight. Just needs filling and bleeding.

Not really that comfortable about raggin along to test my suspension with no brakes

[flymo]

ok, I think my heart rate is coming back to normal. I have a beer in my hand and I'm a little happier.

Stripped and refitted the swing arm, a couple of the bearings were a touch sticky so re-greased everything. Nice and smooth now. Stripped, regreased and rebuilt the headstock. Think the steering stem nut may have been a little loose, but not much.

Checked the tyres earlier today, set them to road pressures for now, front was a little low but then its a while since they've been checked so now worries there. Come to test ride it again tonight and .....holy crap, I could barely turn a corner without fear of falling off the damn thing again. Got it back into the garage and started to examine the wheels further. After some 10 mins of real close up examination it seems I have a faulty front tyre valve. Front tyre pressure dropped from 36psi to 20 in the space of three hours!

Jacked it back up to 36 psi and took it out before it had a chance to leak.....bingo. back in business.

Sounds stupid but the tyre felt real firm and not at all squashy. but the pressure gauge doesnt lie. What a pain in the ass that was.

To satisfy my curiosity I let the pressure down to 30, felt a little dodgy, then 25 , not much change, then 20......woah! that last 5psi seems to be the point where the handling totally collapses.

Originally Posted by flymo_racer

...

To satisfy my curiosity I let the pressure down to 30, felt a little dodgy, then 25 , not much change, then 20......woah! that last 5psi seems to be the point where the handling totally collapses.

Its prolly the sort of pressure where the tyre wall starts to fold/deform proper as it isn't supported by the air?!!?

At least you have it sorted now

[flymo]

Originally Posted by Blue_SV650S

Its prolly the sort of pressure where the tyre wall starts to fold/deform proper as it isn't supported by the air?!!?

At least you have it sorted now

Yeah, this is a big relief. Thanks everybody for all the ideas and help, sometimes you get so buried in a problem that you need a fresh mind on it.

I ordered the Ohlins shock anyway, not as a method of sorting this problem but just because RobW's advice was that I'm really wasting my time with the GIXER shock on the track. I was going to get one later in the year so what the hell, its on the way now.

On the upside, when doing the brakes last night I think thats the quickest and easiest brake bleed I've ever done, from bone dry it only took 20mins or so to get it nice and firm ....ooo errrr.

I think it depends on how competitive you want to be ? if you want to be at the sharp end you need a race shock. It also depends on experience, as a rookie its less important ? as you are NOT a rookie, and presumably your FZR had a race shock? I think you?d get frustrated with not having a race shock.

If you are going to get one, indeed it makes sense to get one now!!

The rationale I used to use just before a big spend was this ..

?Will it potentially save me from an off?? .. offs are expensive and can be painful. You soon get your money back if you avoid an off ..

Secondly, I am going to spend ~?750 on this weekend .. why scrimp and effectively waste that as I have not got this bit ..

Always worked for stuff that was <?500!! Unfortunately full race systems (~?1000 for a 4cylinder bike) and race rads were >?500 (they are about ?1300) and therefore hard to convince myself I needed ? and so expensive it mean that if I had them then I couldn?t afford to do the actual racing anyway, so what was the point!?!

Unfortunately that has always meant I have never had a truly competitive bike and that has always eaten me up inside ?

[flymo]

Originally Posted by Blue_SV650S

I think it depends on how competitive you want to be ? if you want to be at the sharp end you need a race shock. It also depends on experience, as a rookie its less important ? as you are NOT a rookie, and presumably your FZR had a race shock? I think you?d get frustrated with not having a race shock.

If you are going to get one, indeed it makes sense to get one now!!

The rationale I used to use just before a big spend was this ..

?Will it potentially save me from an off?? .. offs are expensive and can be painful. You soon get your money back if you avoid an off ..

Secondly, I am going to spend ~?750 on this weekend .. why scrimp and effectively waste that as I have not got this bit ..

Always worked for stuff that was <?500!! Unfortunately full race systems (~?1000 for a 4cylinder bike) and race rads were >?500 (they are about ?1300) and therefore hard to convince myself I needed ? and so expensive it mean that if I had them then I couldn?t afford to do the actual racing anyway, so what was the point!?!

Unfortunately that has always meant I have never had a truly competitive bike and that has always eaten me up inside ?

yeah its a tough call. I did use a Maxton race rear on the FZR and it was seriously light years better than the stock one it replaced.

The good thing that attracted me to the mini-twins class though is that some of the silly money can be avoided such as serious engine upgrades. Yeah I've spent alot prepping this bike but its all up front cost that I shouldnt have to respend for at least a few years worth of racing. I'm not sure there is anything left for me to upgrade within the rules so off to a good start so far. The only thing I havent bothered with up to now is a steering damper. Now that I'm happier with the bike again I can live with that.

In the formula 400 class there were lads spending ?1800 on a balanced and lightened crank shaft! for gods sake! I just wasnt prepared to spend that kind of money.

Fingers crossed then it should be a good season. I was fighting for top three positions on the FZR with a seriously underpowered engine compared to the other guys, had a couple of wins on it too. Pretty annoying though when you fight your way to the front then some guy passes you on the straight with 20mph advantage.

Originally Posted by flymo_racer

...

I 'hear that'

What annoys me about the minitwin regs is that it only lets people get expensive power ... like you can't do the wire chop TRE mod and/or chop up your OE filter to improve flow and/or install a inlet cam on your exhast but you can (and therefore need to if you want to be at the sharp end!) get a full titanium race system and a BMC race filter and buy full set of pointy cams ... including DYNO time and labor ?1500-?2000?? I could have got similar results from the former for a tenth of that!