1986 vf500f valve and tappet adjusting screw damage

I picked up an 86 vf500f that had been in storage for about 10 years. the bike has 32,000 miles on it and after a good carb cleaning, seemed to run pretty good. I was having some issues with idle and low end power and found out the intake boots were cracked. I ordered some new boots and figured I better check the valve lash because it was a little noisy.

When I got in to start making some adjustments I noticed one of the exhaust valve adjusting screws was missing the area that pushes on the valve :disturbed: and the top of the valve was mashed a bit. is it going to be OK if I just replace the valve adjusting screw? I really don't have the time to tear the head off of this thing to replace the valve, if they are available. anybody have any experiences with this?

Thanks,
Tim

 

This is a common failure and I am sorry to say there is now easy fix, you will need to remove the head and have the valve replaced.....all of them really.

 

ugh... What would happen if I just replaced the tappet screw? I am not too excited about tearing the head off of this bike...

I am surprised how good the bike ran with the valve in it's current state.

 

The valve will eventually fail and drop into the cylinder. This would be bad. You are lucky you caught it when you did.

 

When you say replace all of them, what do you mean exactly? What usually gives first, the valve or the adjusting screw?

 

how long do you think the valve would last if I just replaced the adjuster?

 

vf500 valves

they are wore out...all need replaced,,a real pain in the butt to change heads and find a head gasket..hopefully its a front jug not the rear,easier to do I redid one with a dropped valve and a wiped cam..worked or find another head from a low mileage engine..Gregg in ohio

 

it is the rear, I found OEM valves on line. I have not opened up the front cylinders yet. would it be easier to pull the head with the engine removed or would that be too much hassle just to remove the head.

What a pain! why does a simple valve adjust have to turn into a full rebuild! I should have known better than to open it but I am glad I found out about it now and not on a long trip...

Thanks,
Tim

 

You need to check the heads of the other valves. Honda were aware of this issue and issued a bodge fix which involved a hardened steel cap to fit over the head of the valve stem. These are unobtainable now so not an option for you I am afraid. If the other valves are not mashed and you are prepared to risk it then just replace the screw adjuster of the one in the picture. Then keeps the revs down...
Ultimately you will be better off replacing the valve with the mashed head but new valves are very hard to come by. The other valves if OK are best left alone in my opinion. LIke you said the bike was running OK so fix what was broken and ride it.

 

Thanks Jeremy,
I may just do that, I am having a hard time finding head gaskets. I would hate to tear it open and not be able to put it back together...

I work as a machinist and I could clean up the current adjusting screw, it would allow a larger area that will be pushing on the valve so it will hopefully not push through.

The bike was given to me so I wont be out much either way. unless it drops a valve, then it would be costly to repair and would probably turn the bike into a parts bike

 

Does anybody have the specs of the hardened caps that would go on the valve stems? I used to work as a toolmaker and still have access to the shop and tool steels.

cap material, hardness and dimensions...

 

if you ever figure this out, count me in for about 16

 

Me too...

 

Like others, I'm going to say that replacing the valve would be a lot less work, and far safer, then trying to salvage it. Seriously, the last thing you want is for that valve to drop when you're running hard in a fast corner... even the quickest of clutch disengagements will often not be enough to keep it on the road, let alone on two wheels.

Just my 2 cents worth...

 

After imagining the valve dropping and the damage it will cause I have decided to replace the valve. Just a bit too scary for me...

Can I pull the rear head with out dropping the engine?

Thanks for all the advice

Tim

 

where????

 

http://www.bikebandit.com/1986-honda-interceptor-500-vf500f/o/m151673?a=1#sch544429

Does anybody have any experience making head gaskets for these bikes? I saw the templates and I will have a template when I pull the old one off. curious about materials. I have seen copper gaskets. I also saw a guy on youtube that used regular head gasket material and formed fire rings out of stainless foil.

 

there are a couple on ebay

 

Complete gasket kit for the 500 http://www.athenaparts.com/eng/products/view/6450/complete-gaskets-kit around $200 US for everything.