Valve Clearance Guide

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CMSMJ1
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Re: Valve Clearance Guide

Post by CMSMJ1 » Wed Oct 23, 2013 7:16 pm

^ you change the shims...
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 scubasteve » Tue Nov 26, 2013 6:55 pm

bizzle3 wrote: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. :|
The arm that holds the shim in place slides to the side to gain access to it if you need to replace it. I used a magnet pen to remove it as it sits in a recess and can be tricky to get out. Best to put something down to block any passages into the engine like a few rags or foil I believe has been suggested before incase you drop the shim. Last thing you want is a shim dropping into your motor.
Bikes don't leak oil, they mark their territory.

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Re: Valve Clearance Guide

Post by GeeTee » Sun Jan 26, 2014 3:21 am

I've been checking the shims on my NC30 today, and got similar results to Haydn (post #95)in that the inlets aren't far out, but the exhausts are all near top limit or over. One of the rear pots is at 0.31 on both exhausts. Mines also been used for several years as a track bike, and possibly a bit choked up judging by the sooty plugs. Question is do I adjust the shims on all the loose valves, only for them to close up prematurely after some hard track use. The shims really are a pain in the arse to check/swap, and don't want to face having to it again anytime soon. Speedo had just over 30,000km showing which if accurate isn't that high for an NC30 lump. Oil looks pretty clean too so hopefully it's had some servicing done.

Oh and I'm another one with a seized in timing cover. I rounded the 17mm hex off trying to get it undone today, so had to use a rod down plughole to find TDC, and turn engine over using back wheel. I'm going to try a full hex sochet to see if that shifts it, but guess it's been overtightened by some idiot in the past :x

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Re: Valve Clearance Guide

Post by GeeTee » Wed Feb 12, 2014 10:20 am

After chatting to Rick Oliver on the phone I decided to adjust 2 inlets and 4 exhausts shims that were outside HRC specs. I'll leave the rest until it's had a bit of on track thrashing, and recheck them later in the year to see if anything has changed. Those front outer exhaust valve shims were a bitch to get at... must have taken me a dozen attempts to get them back in. The rebuild is making good progress now :grin:

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Re: Valve Clearance Guide

Post by carpman » Mon Apr 14, 2014 10:17 pm

While my carbs are getting checked over I used this guide to check my clearances but I checked for my gap between the rocker arm and the cam does this make a differance ?

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Re: Valve Clearance Guide

Post by EvanTate » Tue Nov 04, 2014 2:22 am

Pics seem to have disappeared on the NC24 guide on page 14. Is it just me or what? Does anybody have them saved still?

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Re: Valve Clearance Guide

Post by LightAndFast » Fri Aug 07, 2015 11:56 am

Do you think a metric feeler gauge that goes up in 0.05mm increments is going to be accurate enough?

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Re: Valve Clearance Guide

Post by LightAndFast » Mon Aug 10, 2015 9:40 am

The bike is a UK NC30.

Finally managed to check the valve clearances. The only ones that are out are front right cylinder, one inlet 0.20mm and one outlet also 0.20mm. They are only just out so I think I will leave them. All the CAM shaft lobes look perfect, no markes at all.

I found the front CAM cover very difficult to get off and could not position it back on. How do you get it past the wiring loom?

Is carburettor cleaner good do clean the gasket and mating surfaces?

Does grease keep the gasket in the groove while the cover is moved into position? Mine is quite a loose fit in the groove. I guess any grease will do.

Lower radiator looks really bad. I will search this site to see what the options are.

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Re: Valve Clearance Guide - Help!!!!!!!!!!!!!!!!!!!!!!!!!!!

Post by The Novice » Wed Nov 14, 2018 1:09 pm

crofty7 wrote:
Mon Jul 13, 2009 7:54 pm
I have made a fatal error when checking the valve clearances! :oops:

My father :wanker: , sorry dad ;) , decided to help me with the valve clearances and told me to remove the shims so I could get them exchanged for new ones. However, the engine had been manually cranked over so the arm things were pushed into the washer on top of the valve and got stuck. This has occurred on ten valves :Puke: , I had to prise the arm thingy out as it was stuck fast.

Now I’m not sure if any of the valves have been damaged due to cranking the engine over (by hand). When I put a new shim in and re-checked the valve clearance it was huge suggesting that the valve has not returned to its original position.

Anyone done this before, or am I the only dumb f**k to do this? So pissed off, this is a steep learning curve for a novice. Any help will greatly be appreciated. :pray: If not then its off to the mechanic which will cost ££££££££££££££££££££££££££££££££'s
I have just started to refurb an nc30 I have owned for about 6 years, that has been neglected (by me). In doing it, I am upgrading most of the front end and whilst the forks are off and the rads and the carbs - it seemed an excellent opportunity to measure the valve clearances. I did it on an nc23 years ago and thought it would be nice n easy.

Thinking it was easy - I appear to have made 2 fundamental errors.
1. I used Haynes and misunderstood so I have measured the gap between the cam and arm - so I need to redo it all again. No biggie but extremely annoying when I only get about an hour a day to work on the bike in a cold shed due to work and family commitments.
2. When I found this handy reference guide and read through, I realised I actually did the same as referred to in the above quote. I have removed all the shims. the engine has been manually cranked and the rocker arms have wedged in the washer (where the shims go). I wasn't at all concerned about this as I can just prise them back up relatively easily but then I read the above.

Is this really a concern? I have 16 shims on my workbench at home that i now need to reinsert to measure properly, however i just want to check if what i have done - other than possibly being a silly thing to do - is an issue i need to resolve before i start measuring again.

Surely with the shims removed, the valves just remain seated when the engine is manually cranked to the relevant timing marks.

3. One last question - can i just check (if my method is wrong) how you are supposed to remove all the shims and swap them about without cranking the engine manually to get the clearance required (between cam and rocker arm) to enable you to slide the rocker arms over?

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Re: Valve Clearance Guide

Post by CMSMJ1 » Wed Nov 14, 2018 2:14 pm

ref 1: - We've all done it..

ref 2 and 3: I have a bag of shims acquired over the years so I can measure and replace most of them at point of fiddle. if you do not have any spares then my advice would be to measure and replace and then do the figuring out of swaps to make the clearances decent. Then, replace the ones you need to. Don't get them all out at once.

Ballache and slow, but saves the issues of getting the followers stuck or shims lost.

I would aim for slightly larger than slightly tighter too - just think of that poor valve trying to get away from that big old piston swooshing up the bore! another nth of clearance, on that big over-rev might make the difference...
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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