Top End Rebuild Question

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jd48792

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After numerous attempts to get the carbs clean so my 1989 would run without the choke, I finally did a compression check. The compression ranged from 60 to 120. I guess it wasn't the carbs after all.

Now the engine is out and the rear head is off. Every exhaust valve so far has a couple of small chunks of what look like cloth stuck to the seat. I've no idea what caused the problem since the bike wasn't running when I bought it (disintegrated air filter or some dolt left a rag in the intake?). But I'll be lapping the valves and replacing the seals just to be sure before I button it back up.

My question: Which of the gaskets and o-rings can I safely reuse? Any other parts that should routinely be replaced? [I realize I'll need to replace shims after lapping.]
 
I think anyone who is a competent mechanic will tell you the same thing: "as-long as you're in there, replace 'em." That refers to the gaskets, valve seals and O-rings.
 

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Replace everything. Your there anyway.....might as well do it right.

I figured that would be the answer. Since the pain in my wallet keeps growing every time I price another part for this thing, I was hoping for better news.

Funny how the idea of "do it right" depends on what brand bike you have. Many of the gaskets on my other bikes (Guzzi, Harley, and even some British gaskets) were designed to be reused. But it seems that everything I touch on the Vmax needs to be replaced and the cost is two- to four- times higher.
 
I think anyone who is a competent mechanic will tell you the same thing: "as-long as you're in there, replace 'em." That refers to the gaskets, valve seals and O-rings.

So what is that white stuff in the last photo?
 
The money you would save by reusing gaskets would seem like no bargain if you had to tear it down to fix a leak..
 
The money you would save by reusing gaskets would seem like no bargain if you had to tear it down to fix a leak..

I wasn't trying to cut corners. I just hoped that some of these things, especially the rubber gaskets, were intended to be reused - like the rubber valve cover gaskets on my Moto Guzzi which have now been off and back on five times with no issues.
 
I figured that would be the answer. Since the pain in my wallet keeps growing every time I price another part for this thing, I was hoping for better news.

Funny how the idea of "do it right" depends on what brand bike you have. Many of the gaskets on my other bikes (Guzzi, Harley, and even some British gaskets) were designed to be reused. But it seems that everything I touch on the Vmax needs to be replaced and the cost is two- to four- times higher.

True, but look at it this way, once its done......its done. Take for instance the valves. If I remember correctly they need to be done about every 26000 miles, but a lot of people have said that the valves didnt need to be done. (They were still within spec) My 07 has 48000 miles on it, and still going strong, and Bill has 132000 on his original 85. The Vmax really is a bike with a great engine, that will go 100000 miles.
 
The smegma is crystallized material I removed from the head's cooling jacket while I was doing the overhaul of the head. The previous owner said it ran very well performance-wise, but could run a 'bit hot' and I think I found out why.

So what is that white stuff in the last photo?
 
In the pic w/the valve-lapping tool, you can see the material coating the cooling passage in clumps.

With the surfaced head you can see the cleared water passages.

I sure do miss being able to edit posts. :confused2:
 
Valve cover gaskets CAN be reused if you wish.

Inspect them carefully for tiny cracks. Seems the ones on the older bikes hold up better than the newer ones. I already replaced them on my '06. If there are any signs of cracks, buy new. Considering the amount of time it takes to replace valve cover gaskets I would buy new but, that is your call.

Don't reuse the head gaskets.

Not sure what else you're into but that should be it for a head job.

I know you need to pull the stator insert but that gasket is reusable as well as the O-ring.

Sent from my SM-G930V using Tapatalk
 
Head gasket and exhaust header gaskets definitely, valve stem seals probably particularly if there is any sign of hardening but I would try re-using the cam cover seal provided it is still flexible and in good visual condition. A light smear of silicon sealer around the half moons would be prudent.
Re-use the can cover bolt seals.
 

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