Shovel top end

Well boys, I am planning to tear into the top end of my '77 shovel motor. The reason being is that there is smoke coming out of the rear pipe every time I start or restart the bike. (The motor has about 2000 miles on it since the so-called "rebuild":gah. No smoke afterwards, just for a second after I start it up each time. The rear plug stays oil fouled, so I change it fairly often for now. Tattoo thinks it may just be the valve seals, but I won't know for sure until I get everything off and have a looksee. I am going to attempt to do this work myself in my shop.

Questions I'd like to ask are: should I do both cylinders? And, what parts should I have on hand before beginning so I don't have to wait around for parts. I'm thinking at least a copper head gasket set, new valve seals, and new rocker box gaskets. Anything else?

Also, what's a good way to clean carbon off the valves, pistons, etc.

Thanks guys, and as always, thanks for your valuable insights and advice. Josh

What you describe (barring any other symtoms) is almost always indicative of valve seals in any four stroke engine. Head gasket leaking into cyl would have pressure building up in crankcase. Rings would almost always smoke. I would lay money on a valve guide leak. That being the case, just the problem head gets yanked. Jmo

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one thing about it with a v-twin you can do front or rear see how it does and then do the other if needed

Yep...if only one smokes...fix one...might want to add intake and exhaust gaskets to your list....I'd price a top end gasket kit,if it doesn't cost a lot more...sure doesn't hurt to have a few extra gaskets hanging around:chopper:

I spoke with Tattoo today and he says he would do both heads. But I'm from the school that says: if it ain't broke, don't fix it. And you guys say the same thing, so that's settled.

He recommended using brake cleaner and a bit of elbow grease with an old rag or a scotchguard scrubby to remove carbon deposits off the piston and combustion chamber and valves.

I'm going to do a bit of research and see what I can find out about valve guides and seals on big twin engines.

proper way to clean back side and face side of valve is as follows tape off valve stems with masking tape so as not to mar the smooth finish of stem and loose the guide size , GLASS BEAD THE VALVES . NO WIRE WHEEL NO SCOTCH BRITE . OR JUST WASH THEM WITH PURPLE CLEANER AND SOAP AND WATER . do one head at a time and place them back in the same seats and make sure you relap them tells ya if the guide and seat is true . if the motor did not smoke when it was new it should not have smoked 200 miles later . if the head had positive contact seals on the guides and is now smoking check to make sure you dont have a guide going south with too much clearence . dial indicate valve stem to guide and look up spec . if its loose your just gonna keep putting seals in . when valves are clean you can polish the stems that makes for a very good smooth surface for the seal to ride on and allows you to feel for any small burrs on the stem that might be causeing seal faluire as well . i chaulk them up on my lathe and hit them with 3.000 wet paper and then some polish for a smooth finish on stems only. its only four valves and well worth it .

So... do them both and do them right would be your recommendation BP??Which does make sense...if a jobs worth doing,it's worth doing right and completely one time only....

well its only one more set of gaskets and all the rest of the motor is apart at this point so why not just pull the other head off the jug . he will be real pissed of if he has to pull it back apart again . to do the other head . just my opinion but what do i know :rant:

:roflmao:Well buddy...we know what you know...There ya go Joshbob...do it right,do it once....

ONE more thing to check on a shovel that has to do with guide and seal area if there is any tdc lift on a cam change .THE GUIDE MUST BE TURNED DOWN FOR CLEARENCE OF THE RETAINER FOR THE VALVE SPRNG. cause for the added lift will cut the seal . the guides are tall on the shovel motor some guys dont turn them down enough and at full lift the retainer crashes against the seal and destroys the top of the seal.

i would love to do bike stuff but even i sent my chit to kirby . all my stuff is set up and table indicated for full size chevy heads i can stone the seats for him hell i would do it for nothing ! but in all honesty i dont want to reset my seat and guide machine . kirby can do the guide work if needed hell aint nothing but a thing for him to put liners in there if he is still running cast stuff . he can set them up for two thousands clearence and the valve job will last for ever he has a nice serdi to lay down the seats real nice and pick up flow like mad that shovel will run real nice with a serdi valve job !

Been there, done that. If I ship the heads to him (not Kirby - but my "rebuilder") I'm not sure he'll do a good job, considering what I've gone though already with this motor. My warranty has expired anyway.

And no, the rear pipe didn't start smoking until about 1000 miles or so. But I had issues with leaking gaskets and seals and a blown head gasket after just a few miles. The cam seal still weeps a bit onto my rear exhaust pipe after replacing twice. The oil comes out of the hole where the coil wire exits the cone.

check the cam support bushing and or bearing may have to much play allowing for the cam to walk up and down causeing seal faliure.

I'm not having to top off the oil. It's just a puff of smoke when I start it. Will continue to change the plug as needed until winter.

Thanks for all the advice, BP. I will look into this cam business as well this winter. Since I changed the seal the last time, it's not leaking nearly as bad as it did before. I remember feeling a little ridge on the shaft right where the seal goes.

I'm wondering what it would cost to have someone go through the motor and check everything. Probably more than I could spare, I'm sure. I have had some success with my own motor work, but not always. There are only so many things I can do. I spent $4500 on this motor and I think it should have been done better than it was. It looks good on the outside, but the inside is a whole different story.