Valve Clearance Guide

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viper_biker
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Valve Clearance Guide

Post by viper_biker » Mon Jul 07, 2008 11:38 am

THE WORDs AND PICTURES BELOW ARE MY OWN WORK AND NOT ENDORSED BY 400 GREYBIKE. IF YOU USE THIS GUID AND YOU DAMAGE YOUR ENGINE NEITHER THE SITE NOR MYSELF ARE RESPONSIBLE. IT IS TO BE USED AS A VIEW ONLY DOCUMENT AND IF YOU ARE CARRYING OUT THE SAME WORK THEN YOU ALONE ARE RESPONSIBLE FOR YOUR ACTIONS.

IF YOU DON'T KNOW WHAT YOU ARE DOING THEN PAY TO GET IT DONE


This will be added to along with other guides. Remember, if this has been of any help, why not donate a few quid to the running of the site, thank you.

Firstly this is what you'll need,
- Ratchet with a 10mm, 14mm and 17mm socket,
- Feeler gauge that can measure between 0.12mm-0.18mm and 0.21mm-0.27mm
- And possibly a flat headed screwdriver to carefully help you separate the cylinder head from the block.

OK, so you will need to strip pretty much all of the bike (this is where the dealer gets you in labour costs). So,
- Bodywork off
- Tank, airbox, carbs out
- Top radiator off (or dropped to allow you access to the front head)

(If you don't know how to do any of the above please consult the Haynes manual)

Your bike should now look like this (pic is from an '89 NC30 I re-built last year [:D])

Image

Now for the fun stuff. First of all remove the 4 bolts that holds the head in place. They are 10mm hex head screws,

Image

Once removed carefully use a flat head screw driver to prise off the cam cover. Once off it will now look like this,

Image

Looks scary don't it. Don't be scared, if you're lucky you'll not need to replace any of the shims. Next up is to remove the Timing Hole Cap. A 17mm socket will sort that out to allow you access to the Timing nut adjuster thingy (a very technical term, 'I will not buy this record, it is scratched' [:D])

Image

Next up you'll need the 14mm socket to turn the engine over.

Image

Turn until you get both of these marks lined up. T1 and the mark on the casing, and the other 2 lines to match on the top of the cam shaft.

Image

And

Image

The hard work is behind you now. Next up is to check the gap between the shim and the camshaft (the long rod that has egg shaped things on it) When the lines are the same as the above pics you are then free to check the gap on cylinder no. 1 (rear left when sitting on the bike). There are 4 valves/shims per cylinder (and there are 4 cylinders making the bike, yes you guessed it, 16 valve [:D]) that need checking now. The front 2 are known as inlet valves and the rear 2 are exhaust valves. The tolerance for all the inlet valves on the bike are 0.12mm-0.18mm so take out your feeler gauge and check it now. If it is within tolerance a gauge should fit in like so.

Image

And the rear should be between 0.21mm-0.27mm and should fit like so,

Image

Once you know what the gap is please use the following page to write it down for future reference.

Image

Once you have Cylinder no. 1's gap it's then time to do cyliner no. 3 (this is the one to the right of no. 1. Turn the Timing nut again until you get back to T1 again and the cam shaft will now line up in the opposite way to the way it did on cylinder no. 1.

Image

Once you are at this stage you can then start to check the clearance on cylinder no. 3. Again the front 2 are the inlet valves and the rear are exhaust valves and the tolerances are still 0.12mm-0.18mm on the inlet valves and 0.21-mm-0.27mm on the exhaust valves. The following pics look the same as the ones above but believe me, thay are from cylinder no. 3. If you look really close you'll notice that.

Inlet valves

Image

Exhaust valves

Image
Ducati 916, not worth a carrott

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Re: Valve Clearance Guide

Post by spooky » Wed Jul 09, 2008 1:20 am

Anyone have this info for an nc24 by any chance? Please!!!
\That wee smilie can drink some Guinness. No wonder he's yellow.

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Re: Valve Clearance Guide

Post by Malc » Wed Jul 09, 2008 8:00 am

Nice useful info, but it would be better if the terminology inaccuracies were fixed. For example -

"... carefully help you separate the cylinder head from the block" should say
"... carefully help you separate the camshaft cover from the cylinder head"

"First of all remove the 4 bolts that holds the head in place" should say
"First of all remove the 4 bolts that holds the camshaft cover in place"

Sorry to be picky, but when I started to read it my first thought was "Why on earth is he removing cylinder heads!?" :ugeek:

PS - I find a gentle tap with a soft faced mallet is usually plenty to break the seal between cover and head - no need to lever it with a screwdriver :shock:

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Re: Valve Clearance Guide

Post by Lasse » Wed Jul 09, 2008 9:48 am

After removing the four bolts, gently place a screwdriver in one of the holes and twist lightly, loose.

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Re: Valve Clearance Guide

Post by viper_biker » Wed Jul 09, 2008 11:03 am

Everyones a critic LOL

When this was written I had just stripped and re-built a bike, did the valve clearances and added a washer to the needles and drilled the slides along with taking in the region of 100 pictures or so then proceeded to write this so my brain was in full function. Also, I did this about 2 years ago but I will go back over it and amend accordingly, thanks for your input.
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Re: Valve Clearance Guide

Post by dix » Thu Jul 17, 2008 1:10 am

:mrgreen: looks a good guide to me i will be using it for sure!

manythanks viper dood ;) 8-)

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Re: Valve Clearance Guide

Post by Lasse » Sun Jul 27, 2008 2:48 pm

Maybe edit the post to use the new picture feature?

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Re: Valve Clearance Guide

Post by Kevbarlas » Tue Jul 29, 2008 10:55 pm

Thats a good write up you done.

What exactly does having wrong valve clearances do? like, will this make a noticeable difference?

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Re: Valve Clearance Guide

Post by Lasse » Tue Jul 29, 2008 10:59 pm

Kevbarlas wrote:Thats a good write up you done.

What exactly does having wrong valve clearances do? like, will this make a noticeable difference?
If you are considering skipping checking the valve clearances, dont.

Burnt valves, poor running, loud valve train, not good things I promise you.

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Re: Valve Clearance Guide

Post by monkeywithaplan » Fri Aug 08, 2008 10:11 pm

Lasse wrote:
Kevbarlas wrote:Thats a good write up you done.

What exactly does having wrong valve clearances do? like, will this make a noticeable difference?
If you are considering skipping checking the valve clearances, dont.

Burnt valves, poor running, loud valve train, not good things I promise you.
agreed. think of it compared to wiping your arse with a thorny bush, or perhaps a cactus. it will only end in tears :cry:
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