Shim questions - SOCALSPORTBIKES.ORG

Sembalap · 06-18-2017, 05:46 PM

When you choose valve shim, do you go for looser or tighter shim? And why?

Pearl zx6 · 06-19-2017, 06:57 AM

If I had to, I would go on the loose side. Why? Because Its just safer to go that route, Usually the tolerances get tighter

You can always buy the thicker shim and remove material so you can have it in the middle of the range.

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rgbeard · 06-19-2017, 07:34 AM

+1

The clearance gaps decrease over time so slightly looser would be better than slightly tighter, given that both numbers are within spec.

Sembalap · 06-20-2017, 07:46 PM

Thanks! So aim for the looser.
But isn't removing the material means you're losing the heat treated surface which will effect shim's durability?

rgbeard · 06-20-2017, 10:28 PM

Quote:

Originally Posted by Sembalap

Thanks! So aim for the looser.
But isn't removing the material means you're losing the heat treated surface which will effect shim's durability?

Am I reading this correctly?

You don't shave the shim. You replace the shim with one that's a different thickness.

Pearl zx6 · 06-21-2017, 07:33 AM

Quote:

Originally Posted by Sembalap

Thanks! So aim for the looser.
But isn't removing the material means you're losing the heat treated surface which will effect shim's durability?

What bike are you working on and what are your measurements right now.

I doubt valve shims are heat treated but I'm not 100% sure..... darn! I'm going to have to do some reading now lol.

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Sembalap · 06-21-2017, 08:14 PM

Quote:

Originally Posted by rgbeard

Am I reading this correctly?

You don't shave the shim. You replace the shim with one that's a different thickness.

You are. It's all Pearl's fault lol.

Working on d675

Aphex · 06-22-2017, 07:08 AM

Quote:

Originally Posted by Sembalap

You are. It's all Pearl's fault lol.

Working on d675

Shims are cheap (a lot cheaper than an engine rebuild). Find the diameter of your shims and order up a hotcams shim kit so you dont have to play to swap game at a dealer.

Also F sanding down shims, that may have worked in the 70's on air cooled engines with looser tolerances but I wouldn't do it.

Pearl zx6 · 08:45 PM

Wait. I didn't say that shaving down his shims should be his first option. I answered the original question then I implied doing what I've done with a few of my shims.

Sometimes you are stuck in a range that almost put you at the limit an either direction. Shims are usually sold in 0.05mm intervals

Example if your clearance should be between 0.15mm and 0.24mm and your measument is 0.12mm you can either get a clearance of 0.17mm or 0.22mm witch puts you only to .02mm of the limit in either direction. So In this scenario I suggested he goes with shim that will net him the looser setting.

I just bought the thicker shim, took it to a machine shop had them remove .01mm off each side witch gave me a gap of .20mm. That almost puts me right in the middle of the range. I had a few shims modified and from what I have read since this thread started there isn't any special heat treating on the shims. I've had the modified shims in there for 2 track seasons, I check them once a year and I haven't seen any abnormal wear in the shims nor the buckets so in my case it's working out.

Wrote this on my phone, sorry for all the errors.

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06-18-2017, 05:46 PM	#1
Sembalap Senior Member Join Date: Jul 2013 Feedback Rating: (0) Posts: 370	Shim questions When you choose valve shim, do you go for looser or tighter shim? And why?

06-19-2017, 07:34 AM	#3
rgbeard Forum Supporter Senior Member Join Date: Jan 2013 Location: Ensenada, MX and Phoenix, AZ Feedback Rating: (0) Posts: 3,693 Experience: 10+ years Trackdays: 10+ Bike(s): 2001 Speed Triple 2001 Triumph Trophy 2003 GSXR 1000 Member Garage	+1 The clearance gaps decrease over time so slightly looser would be better than slightly tighter, given that both numbers are within spec.
	__________________ My name is Rusty. I'm a fan of things that ride, fly and drive. IBA: 63413

06-22-2017, 08:05 PM	#9
Pearl zx6 Still Slow Join Date: May 2013 Location: Los Angeles Feedback Rating: (0) Posts: 2,738 Bike(s): Zx6r Zx6r Zx6r Hopefully another zx6r	Wait. I didn't say that shaving down his shims should be his first option. I answered the original question then I implied doing what I've done with a few of my shims. Sometimes you are stuck in a range that almost put you at the limit an either direction. Shims are usually sold in 0.05mm intervals Example if your clearance should be between 0.15mm and 0.24mm and your measument is 0.12mm you can either get a clearance of 0.17mm or 0.22mm witch puts you only to .02mm of the limit in either direction. So In this scenario I suggested he goes with shim that will net him the looser setting. I just bought the thicker shim, took it to a machine shop had them remove .01mm off each side witch gave me a gap of .20mm. That almost puts me right in the middle of the range. I had a few shims modified and from what I have read since this thread started there isn't any special heat treating on the shims. I've had the modified shims in there for 2 track seasons, I check them once a year and I haven't seen any abnormal wear in the shims nor the buckets so in my case it's working out. Wrote this on my phone, sorry for all the errors. Sent from my SM-G928T using Tapatalk
	Last edited by Pearl zx6; 06-22-2017 at 08:45 PM.

06-19-2017, 06:57 AM	#2
Pearl zx6 Still Slow Join Date: May 2013 Location: Los Angeles Feedback Rating: (0) Posts: 2,738 Bike(s): Zx6r Zx6r Zx6r Hopefully another zx6r	If I had to, I would go on the loose side. Why? Because Its just safer to go that route, Usually the tolerances get tighter You can always buy the thicker shim and remove material so you can have it in the middle of the range. Sent from my SM-G928T using Tapatalk

06-20-2017, 07:46 PM	#4
Sembalap Senior Member Join Date: Jul 2013 Feedback Rating: (0) Posts: 370	Thanks! So aim for the looser. But isn't removing the material means you're losing the heat treated surface which will effect shim's durability?