Four Wheel Forum

No luck. The right-hand cylinder is smoking obviously more than the left. I had a look inside the cylinder, and there's a layer of carbon sludge on the piston crown.
Oil blow-by gets worse with increased throttle. I think I'll have to do a ring job on it.

Any tips on removing the head/cylinder without having to take off the flywheel & dynamo?

You obviously haven't seen my famous engine disassembly thread! Shame! Haha get over to this section. http://fourwheelforum.com/showthread.php?t=86

I'm suspicious of the valve guides more than the piston rings. You could pop the head off and replace those and just remove all the carbon from the head which would cost you little money. And at the same time when you are putting it back on you could adjust the valves. Having the cylinders machined and putting in new rings would cost a good chunk of change and might require pistons, wrist pins and clips. Not to mention it's more technical work than you might be comfortable with but we could walk you through it if you want to tackle it all.. as long as you could take pictures so we could see what's going on in there.

If it were mine and I was on a budget that's the order I would proceed with.

Smithers wrote:You obviously haven't seen my famous engine disassembly thread! Shame! Haha get over to this section. http://fourwheelforum.com/showthread.php?t=86

I'm suspicious of the valve guides more than the piston rings. You could pop the head off and replace those and just remove all the carbon from the head which would cost you little money. And at the same time when you are putting it back on you could adjust the valves. Having the cylinders machined and putting in new rings would cost a good chunk of change and might require pistons, wrist pins and clips. Not to mention it's more technical work than you might be comfortable with but we could walk you through it if you want to tackle it all.. as long as you could take pictures so we could see what's going on in there.

If it were mine and I was on a budget that's the order I would proceed with.

Well, if the head's coming off, I can check it anyways. That's a great guide you've put together!
Regarding valve guides - If I recall correctly, you install them by heading the head up in the oven, is that right? Also, do you have to get the guides machined first?

Checked compression today... approx. 150 PSI on both cylinders.
Looks like my winter project will be pulling the head.
Just got the tires for my learner bike (Yamaha SR185), so my next budget item is getting them mounted.

comp_wiz101 wrote:Checked compression today... approx. 150 PSI on both cylinders.
Looks like my winter project will be pulling the head.
Just got the tires for my learner bike (Yamaha SR185), so my next budget item is getting them mounted.

If it wasn't smoking before you laid it up for the winter and you have good compression, check that you don't have to much oil in it.

Sam.

Sam Green wrote:If it wasn't smoking before you laid it up for the winter and you have good compression, check that you don't have to much oil in it.

Sam.

In the crankcase, you mean? Wouldn't it smoke in both cylinders?

Done.

I premixed the seafoam in a jerrycan according to the bottle before I gassed up.
Since then, though, I swapped it out for fresh gas.
I always store the bike on the center stand, but I have no idea if the PO ever had the head off. I suppose it couldn't hurt to check the head bolts. Any tips on checking the torque with a normal wrench?

Jetblackchemist wrote:How much seafoam did you put in the tank? It's going to keep smoking and burning off until that's run it's course.

If there's oil in that pipe it's gonna smoke until that is burned off or taken off and cleaned out. Sitting during storage on the side stand, will cause the oil level to sit higher on that side, to seep and creep while sitting. If you have a center stand; make sure you use it when storing, to keep the oil level in the bike level.

If it keeps producing a lot of oil into the exhaust pipe then yeah you have problems; check the torques on your head bolts, if you or someone else ever had it off...it's a good idea to re-seat them after about a week when things settle; this goes for side covers too. New gaskets plus vibration equals a re-torque. This is especially important in a bike whom's head holds the weight of the engine constantly pulling down; this weight will try to separate the gaskets, if you don't re-torque them.

Done.

It's interesting how far a thread can go regarding some smoke coming from an old two cylinder engine. I agree with Sam that putting the bike away for the season did not cause an issue.

Remember, the bike is 45+years old. It was built in the day of leaded gas. No doubt it has some valve seat and/or guide wear. I say put some "Bardal" (bad spelling) "No Smoke" in the crankcase and enjoy the bike. It's not like it is a daily rider or transporting the family. Getting bogged down with torque detail, machine shops, trial and error along with a wide variety of advice makes a mountain out of a mole hill. Bottom line cure? Bore the cylinders and fit pistons & rings. Valve guides, new valves and cut valve seats. Machine the head/cylinder surfaces and put it all back together.

Then the cure can kill the motor...Correct compression, like new combustion and watch the crankshaft bearings take a crap...

Its a cool old bike. Take it for joy rides, park and talk with people who like the bike. Bike burns oil....well don't look back (except for traffic)

Spokes wrote:It's interesting how far a thread can go regarding some smoke coming from an old two cylinder engine. I agree with Sam that putting the bike away for the season did not cause an issue.

Remember, the bike is 45+years old. It was built in the day of leaded gas. No doubt it has some valve seat and/or guide wear. I say put some "Bardal" (bad spelling) "No Smoke" in the crankcase and enjoy the bike. It's not like it is a daily rider or transporting the family. Getting bogged down with torque detail, machine shops, trial and error along with a wide variety of advice makes a mountain out of a mole hill. Bottom line cure? Bore the cylinders and fit pistons & rings. Valve guides, new valves and cut valve seats. Machine the head/cylinder surfaces and put it all back together.

Then the cure can kill the motor...Correct compression, like new combustion and watch the crankshaft bearings take a crap...

Its a cool old bike. Take it for joy rides, park and talk with people who like the bike. Bike burns oil....well don't look back (except for traffic)

Oddly, it already pumps up to 150 PSI on both cyls - isn't spec 130PSI minimum?

Sooo... in some.. lateral thinking... I had a close look at the head. Oil appears to be seeping into the exhaust pipe (gasket is MIA). The tach-side cam cover didn't seem to be tightened down enough, and the oil MAY have been coming from there so I snugged it down and cleaned out oil from the exhaust pipe & muffler...
The thick blue smoke from the right hand side is GONE!

Now I just have the much thinner, whitish smoke that appears evenly between both cylinders, and it's been doing that since I first got it.
Changed the oil again, carried some more crap away.

Even though it's not perfect, it's now very much improved since this problem started. I'm going to keep on the whitish smoke (check my mixture, etc.), I'm much happier now. Thanks for all of the advice everyone! I'll be sure to keep it handy for the inevitable day I get the engine apart.