Help with Valves

  • Thread starter Thread starter boulevard
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boulevard

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Hey guys I am new here but recommended to the forum by the previous owner of my motorcycle. He says this is the best place to find help and other motorcycle fanatics ; )

I am fixing a 74 CL 360. I just got the top end tore down to find that the intake and exhaust valves on 1 cylinder are bent. Exhaust was bareley bent allowing me to remove it from the valve guide. The intake valve is stuck in the valve guide.

So here are the questions:
1. Should I just beat it through the valve guide with a hammer and small screw driver then replace the valve guide?

2. Once I remove the valve. . .How do you replace the valve guide.. . . seems like it is stuck in there. Do you bore it out or something.

3. Once I have replaced the valve guide do I need to do anything to the seat other than "lapping it in"

4. Should I just send it off and have the work done? Expensive? I don't know of anyone who does that kind of work. I live in Birmingham Alabama.

Thanks for your time. Any help is appreciated.
 
Your questions indicate clearly two things:

[list type=decimal]
[*]You don't have a service manual, or are not consulting it.
You need the help of a machine shop.
[*]
[/list]

DO NOT attempt to just lap new valves to the old seat. Have a machine shop do it. It's precision work that have neither the tools nor the skills to tackle. Most independent bike shops either know how to do valves and guides, or have a machine shop they send them out to. Make some phone calls to motorcycle shops. Not all automotive machine shops want to be bothered with motorcycle engine work, so you will have to do a little legwork to find a place.

There is no reason to fuck up what might be a perfectly good valve guide by pounding a bad valve through it. Have a machine shop fix it for you.
 
Oh, and if you have to replace a valve guide, it still has to be done by a machine shop, because the guide has to be reamed to fit the valve stem.
 
THanks for the fast reply!!!!!! I have a manual that a friend is mailing me . . . . thought I would tear it down while I waited.

I just got off the phone with a guy in portland oregon that does valve work (Schumman Motor Works) I think I am going to send it to him.

I am curious as to what caused this problem in the first place.
 
Bent valves can be caused by a timing chain that has slipped, valves hanging up in the guide and then getting hit by the piston, or overreving.
 
In my limited experience.. I side with Alpha (as I usually do when I read his posts). I watched a little bit about how they cut valves and valve seats.. its a very precise operation.. not something you are going to do with a hand drill. I am starting to notice that if you need a hammer to do something... you are probably doing it wrong and should consult someone with the right tools to do the job.
 
I just did this myself to my 360, had to replace broken valve guides and drive them in, they need to be reamed. It's a relatively easy job even with a standard drill and some cutting lube but you NEED the right tools and parts.

I can give more details if you need
 
AlphaDogChoppers said:
Bent valves can be caused by a timing chain that has slipped, valves hanging up in the guide and then getting hit by the piston, or overreving.
Click to expand...

On engines with rocker arms, it's also possible to get the arm wedged on the inside of the valve rather than having the tappet resting on top of the stem. When you torque down the valve cover, it bends the valves. This is what I did when I bent mine.
 
Finnigan said:
I just did this myself to my 360, had to replace broken valve guides and drive them in, they need to be reamed. It's a relatively easy job even with a standard drill and some cutting lube but you NEED the right tools and parts.

I can give more details if you need
Click to expand...

But you still need the machine shop to re-machine the seat as it has to be perfectly concentric to the guide or it won't seal. Who's to say the guide didn't go in perfectly straight or the hole in the guide is slightly askew in the new one vs the original one. We're talking very small numbers that the naked eye can't measure or basic hand tools too. Over .001" runout on a metal to metal seal will cause problems. Send it to a trusted automotive or powersports machine shop
 
Mucho thanks guys! I think I will send it off. I love doing things myself but I don't have the tools. In the meantime I am going to be reading up on posts . . . . Lot to learn before I start putting this thing back together.
 
Haha yah i guess thats an odd thing to hear, i'm finding more and more evidence that the engine had a catastrophic failure at one point in its previous existence
 
I had the exact same issue with my CB360, and in my case it was because the PO broke the chain tensioner bolt, so the chain stretched, and the pistons kissed the valves. Some details are in my build thread, linked in my sig. The HD timing chain I got from Boretech is a nice piece of insurance against this happening again.

In my case, I got a nice spare complete head for about $40 shipped. You might want to look into going that route - you could always have your original head fixed up as a spare. They show up on ebay, and also over on hondatwins.net.

Good luck with your build!
 
Good call I will check that site for another head. Thanks for the help

Boulevard
 
Crap! I already sent my head to Portland for a rebuild. I wouldn't mind having an extra but I can't spend much money because the valve job is costing 250....more than I want to spend

Boulevard
 
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