Valve Clearance Guide

[viper_biker]

Click the links and look at the pics in the first post, that'll give you an idea.

[mattydrvf]

when your doing cylinders 2+4 do you need to turn the engine over so that the mark on the crank case lines up with the t2 mark. only asking this because when i line it up with t1 the marks on the end of the crank shaft do not line up with the marks on the engine, but do line up when i use t2. please help.

[crofty7]

mattydrvf

For cylinders 1 & 3 you line up the marks on the cylinder (either facing away from it or to it) with T1 on the crank case.

For cylinders 2 & 4 you use T2 on the crank case.

I have a haynes manual that gives you the exact sequence that you need to check the clearances in if you need any more info.

I've just done mine and need 10 new shims Still waiting for Rick Oliver to get back to me with prices.

[crofty7]

I have made a fatal error when checking the valve clearances!

My father , 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 , 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. If not then its off to the mechanic which will cost ££££££££££££££££££££££££££££££££'s

[viper_biker]

Crofty, sorry to hear your plight, but all is not lost. You have not bent valves from what you have done, what it does suggest though is that you have the incorrect clearances measured. This task is not a 'novice' task and you can actually damage your bike if you've done it wrong, maybe even terminal. If you can, put the clearances to the best tolerance and give it to a mechanic who knows what he'd doing.

Did you at any time take the cams out off the bike? If not then you have nothing to worry about, just let a pro do it.

[CMSMJ1]

You should be able to give the valves a teeny weeny little tap and make sure the collets are seated and the springs are straight. If it comes to it, taking a head off is doable and as long as you have a spare gasket you can sort it out and check the valves too.

What kind of clearances are you getting btw?

[crofty7]

When i first checked the clearance on one of the inlet valves on cylinder 1 i could not push a 0.1 gauge into the gap. The shim taken out was 2.35mm so i opted for a 1.90mm shim to see if that worked. However, after cranking the engine over as described before and placing the new 1.90mm shim in, the new clearance was over 0.3. This was when i realised something drastic had gone wrong! I should note that the bike has not been started since being stripped, which was when i bought it, it has only been cranked over by hand.

I did take the cams off and lightly tap the top of the spring to see if this re-positioned the valve and the collets, but it didn't work. I refitted the cams as they came off ie with the marker at TDC.

I guess the mechanic will have to remove the cylinder head and strip all the valves to make sure they are not damaged and then re-build the head, and then check the clearances

[micpec]

@viper_biker and others: I'd like to know what kind of grease you use to put the new correct shim back in the NC-engine?

In the Haynes manual I read that a dab of 50%-50% of molybdenum dishulphide grease (MoS2) would be of correct use. But most common Moly grease are sold with less than <5% MoS2 content.

Any suggestions?

[viper_biker]

I've always used lithium based grease. Only a little smudge on the end of a screwdriver, but I'd also do an oil change after a clearance change.

[micpec]

When looking in the NC30 manual of Honda I see there are several symbols:



Basicly they recommended to use MoS2 paste in a higher % molybdenum disulphide, such as the Honda Moly 45 (only sold in USA) or even Honda Moly 60...last one is Honda part no. 08734-0001.

Edit: I bought a can with <2,5% MoS2 but based on the spec sheet I returned it to the shop. Instead I ordered the Honda Moly 60 at the Honda shop. The guy asked me where I got the specific Honda part no. Eerhmmm.....google