Valve Clearance Guide

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Haydn
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Re: Valve Clearance Guide

Post by Haydn » Sat Jun 22, 2013 4:03 pm

Quick question. Ive checked the valve clearances on the rear today. This is what I found.

Cylinder 1

Inlet

0.20 - 0.18

Exhaust

0.30 - 0.33


Cylinder 3

Inlet

0.21 - 0.19

Exhaust

0.30 - 0.31

Now i thought the clearances would get smaller as the engine wears so why are all mine either on the upper tolerance or too large?? It has been a track bike for many years raced in Formula 400, would anyone have done this intentionally?

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Haydn

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Re: Valve Clearance Guide

Post by CMSMJ1 » Sat Jun 22, 2013 4:14 pm

yes - the HRC manual has the clearances set pretty loose..though the exhausts on yours are bloody loose! I bet it is a noisy mofo.
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Re: Valve Clearance Guide

Post by Haydn » Sat Jun 22, 2013 4:25 pm

That's the strange thing, it isn't particularly noisy, sounds really well. I'm only checking as I had the carbs off. The tolerance is obviously there for a reason so is it worth re shimming to bring it in, the engine is spotless inside with no signs of wear due to loose clearances. I did check the clearance between cam and rocker and they are all bang on so I think somebody may have set the clearances that way in the past.

The HRC tolerances are:

0.15-0.20 for inlet. Making it 0.01 over on cylinder 3.
0.25-0.30 for exhaust. Which makes it 0.03 over on cylinder 1.

Appreciate your input

Haydn

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Re: Valve Clearance Guide

Post by porndoguk » Sat Jun 22, 2013 10:59 pm

Carbon build up on the valve seats will cause the loosening/increase in clearance
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Re: Valve Clearance Guide

Post by Haydn » Sat Jun 22, 2013 11:33 pm

The bike has been running excessively rich for some time so that may have contributed to it.

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Re: Valve Clearance Guide

Post by CMSMJ1 » Sun Jun 23, 2013 8:21 am

Haydn wrote:That's the strange thing, it isn't particularly noisy, sounds really well. I'm only checking as I had the carbs off. The tolerance is obviously there for a reason so is it worth re shimming to bring it in, the engine is spotless inside with no signs of wear due to loose clearances. I did check the clearance between cam and rocker and they are all bang on so I think somebody may have set the clearances that way in the past.

The HRC tolerances are:

0.15-0.20 for inlet. Making it 0.01 over on cylinder 3.
0.25-0.30 for exhaust. Which makes it 0.03 over on cylinder 1.

Appreciate your input

Haydn

You surely mean the finger and the shim? :ugeek:
IMPERATOR REX ANGLORUM

The V4 is the law..

NC30 - No9 > My old mate
2005 ZX10 C1H - smashed it to death @Jerez :(
NC30 - Trackbike...again :)

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Re: Valve Clearance Guide

Post by Haydn » Sun Jun 23, 2013 1:16 pm

You've read that wrong. You didn't read the post before. I also checked between the cam and rocker after just out of curiosity, I thought the previous owner may of been mistaken by the Haynes manual photo and set the valve clearances between the rocker and cam. The measurements all came within the tolerances so I was suspicious thats all.

Thanks for the help
Haydn

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Re: Valve Clearance Guide

Post by hawk2993 » Wed Sep 18, 2013 3:41 pm

Does one have to replace the crankcase O-ring? I read in the haynes' that a new one must be used

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Re: Valve Clearance Guide

Post by Cammo » Wed Sep 25, 2013 1:20 am

hawk2993 wrote:Does one have to replace the crankcase O-ring? I read in the haynes' that a new one must be used
You mean the timing inspection cover o-ring? Probably not absolutely necessary if yours looks fine.

Personally though I would replace it as it could be 20+ years old and it's only a few bucks new: http://www.davidsilverspares.co.uk/part ... mber_6957/
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Re: Valve Clearance Guide

Post by bizzle3 » Wed Oct 23, 2013 12:29 pm

hi
First of all thank you viper for this detailed guide it looks simple enough to do, my question is, excuse me if i missed it in previous post (ive been through all 18 pages) what to do if your valve clearances do not match up? some people have addressed this issue but nobody has said anything about the procedure to rectify this? im worried my exhaust valve are out. :|


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