carb #1 leaking, oil burning

If it's broken or just needs tweaked

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DammitDan
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Re: carb #1 leaking, oil burning

Postby DammitDan » Wed Oct 04, 2006 5:36 pm

frankinstyn wrote:1) How do I remove the rocker arms?

2) How do I compress the springs?

3) Should I replace the springs and keepers while I have them off?

4) I will need to regap all the valve clearances when I'm done right? This is a solid lifter head?


You remove the rocker arms when you take off the head cover. The CB650 has four main top end pieces from bottom to top... The jugs, the head, the head cover (camshaft cover), and the valve covers. The head cover is held on with 22 small 8mm bolts.

You can the springs off with a trick my local shop mechanic taught me. Take a long 15mm socket, put it on the spring retainer, and hit the socket with a sharp accurate pop from a hammer. Just watch for the keepers, cause they'll go shooting off into your garage if you're not careful. Getting everything back together is going to be difficult if the head is still on the bike, as the only tool that I know of only works with the head removed. But I'm sure you can jerry rig something if you really don't want to take the head off.

I wouldn't worry about replacing the springs or the retainer, or even the keepers. Just be careful not to mix anything up when you take it all apart.

And yes, you'll need to re-gap the valves when you're all done. But now's a good time to learn! I'm not sure what a solid lifter head is, but if you mean it's all one piece (rocker arms attached to the tappets) then no.

frankinstyn
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Postby frankinstyn » Wed Oct 04, 2006 7:56 pm

Ibsen wrote:If you are planning on replacing the valve stem seals, the first thing you will need is a workshop manual. A Clymer manual will be fine:

http://www.repairmanual.com/catalog/M336

I also posted a few pics when I had the cylinder head off and replaced the cam chain tensioner:

viewtopic.php?t=74

And Volker posted this:

viewtopic.php?t=52


I have the manual. The problem is it only guides you through replacing the valve spring seals with the head removed. I'm looking at replacing the spring seals without removing the head.
Is the above comment is complete idiotic or ignorant please attribute it to the alchohol.

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nickjtc
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Postby nickjtc » Wed Oct 04, 2006 10:33 pm

Apparently there are all kinds of creative ways of doing this (none of which I confess that I have done myself), including stuffing a length of cord into the combustion chamber, or using compressed air, so that when the piston is moved up to tdc on the appropriate stroke the valves are kept closed, thereby relieving the tension on the springs, etc, etc, etc.
.....to be myself, a pattern for others.

1979 CB650
1971 Norton Commando
1968 CB175

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Volker_P
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e: carb #1 leaking, oil burning

Postby Volker_P » Thu Oct 05, 2006 1:47 am

you don't find it in the manual as the procedure is not standard and also provides the risk of damage. You will have to plug the chain opening and open oil channels and makes sure nothing gets in. So you will have to work very carefully.
The rocker arms are fixed to the cylinder head cover. This means after removal of this cover, camshaft and valves are accessible. Chain and camshaft can stay in place. (see Ibsens great photos) Use the opportunity to check your camshaft chain tension directly. If you now manage to keep the valves open (by e.g compressed air), you can replace the valve stem seals without further disassemble of the engine. There is no need to replace springs or holders as long as they are allright.
I would recommend to release the loaded valves for head cover removal, but anyway you should adjust the valves after re-mounting of the head cover.
The head cover 1.2m long O-Ring usally can be reused if it is not really got hard. Important point is to get everything clean and tighten the bolts stepwise in a crisscross pattern (given in the manual) with a small enough torque wrench. Everything else will end up in helicoil action and/or leaking. Final torque is not so important, 8-9Nm may be sufficient after 4-5 steps using the correct pattern. The black coin-like rubber seals may be inserted with a bit sealant in case they o not look that elastic any more and you don't get replacement in time.
I never tried it with the engine and head in place but I would guess you need good nerves for the two inner exhaust valves.

Your floater bowl valves still seem leaking as you have fuel in your airbox. Unhappy circumstances may cause burning your CB down from that, so consider to fix it in time.

Ibsen: I guess there is one "Z" too much in your signature? :wink:

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Ibsen
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Postby Ibsen » Thu Oct 05, 2006 8:09 am

This is how the valve seals are replaced on a car engine by using comressed air:

http://thunkgeek.com/?p=96

http://www.rrbew.co.uk/FeatureHtms/F-OilSeals.htm

frankinstyn
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Postby frankinstyn » Thu Oct 05, 2006 9:27 am

Thanks to all then. I just remembered about the two inner cylinders and don't have good nerves. I'll just have to break down and remove the head. This is definetely a job I want to do myself though. All shops have quoted me over $500 and seeing as I am a diesel mechanic I suppose I could bridge over to gas engines this once and save a dime. I guess I could do a write-up on it when I do the job huh?

Those two links above are great though. Exactly what I needed to motivate me to stop being so lazy. If someone with absolutely to experience in mechanic work can not only do this well but also devise a cheaper method (air that is) to do it then I really have no excuse.
Is the above comment is complete idiotic or ignorant please attribute it to the alchohol.


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