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Valve Clearances Measured (all tight) - next step advice reqd

3K views 7 replies 5 participants last post by  kwaka10r 
#1 · (Edited)
History:

Bike was an ex Formula Extreme racebike last raced in 2010 with a apparently refreshed engine for the next season. I bought the bike in 2011 & have only really been using it again the past 18 months – it is now fully converted back to a road bike. The engine had $7000 of work done to it (unknown besides the fact it was blueprinted) & no doubt the valve clearance were set on the tight side for best power.


Have just checked my valves clearances & found them to be either at the limit of their allowances (on the tight side) or beyond the allowance (again on the tight side) – check out my results below.

Intake Valve Service Tolerances: 0.08 - 0.18mm
Exhaust Valve Service Tolerances: 0.18 - 0.28mm



I really only use the bike for commuting this winter with max sustained speeds of 60mph (100kph) however need to sort it out in any case. Can anyone tell me if they has been any likely damage suffered from the exhaust valves being too tight? The engine has been under very light load the last 10,000 miles so not too much gases or heat being rejected by it & the compression is largely ok except for 1 cylinder being a little lower that the others but only by 5% (I will recheck the compression after I put the bike back together after the shim measuring.)
All the plugs were looking on the lean side with plugs 1 & 4 looking slightly whiter that the centre pair - makes sense if the exhaust valves were too tight on this side too.

Cylinder 1


Cylinder 2


Cylinder 3


Cylinder 4



Also can anyone recommend a place to get shims cheap seeing as I will be needing to do all 16 of them by the looks of things!
 
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#4 ·
Wow, kinda like driving a Nascar Car to work and back!

Did you really mean this statement, is the 10mph a typo?
"I really only use the bike for commuting this winter with max sustained speeds of 10mph (100kph) "

Either way, good luck with it, and nice that you're getting so deep with it as to check the valve clearances, etc.
Hopefully, you have great skills in defensive driving to keep you safe on the road.
 
#5 ·
Yeah the 10mph is a typo - should read 60mph (100kph) [I'll fix the original post now...]

I don't don anything even remotely noteworthy speed wise on the commute so no fear form me doing something silly & I have 15 years of biking commuting under my belt so if the skills are there by now then they never will be! Have to replace the clutch also (slipping) & torque up the head bearings too but otherwise she's in pretty good nick mechaically.

I bought the bike for several reasons 5 years ago knowing full we it was an ex-race bike:

- I was a weekend warrior & used to tear up the hills
- I always tinker with bikes & thought buying a worked bike would save me time/money in the long run
- The fairings were pristine & the engine/suspension had just been re-built
- The bike was fully register-able on the road
- It had low kms & was cheaper than a similar age roadbike
- I had lots & lots of goodies (Ohlins race suspension & steering damper, Akra full Tiianium race Exhaust, rear sets & blueprinted engine)

The bike got a set of Dymag CA5 wheels a few years ago & Braking Wavey Disks too. It's a bit of a crime not using the the way it was designed to be used but can't be helped for now.
 
#6 ·
Hi Kenny,

Didn't see the clearances that you measured. Just the service manual specs. How tight are the tight ones?

Was it a superstock or superbike?

I recommend you don't use Hotcams shims. OEM only. Suzuki seem to list 0.05mm increments only, though they are available in 0.025 increments. You can use Honda shims which are listed at 0.025mm increments.

You may not need 16 shims. Sometimes some swapping around can get you to where you need to be.
 
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