Boxerworks.com

My 1981 ST is blowing smoke, not a lot but sufficient for me to want to rememdy the situation .

I'm going to pull the barrels and pistons and take them to my local and very good automotive maching workshop. I'm quite confident the owner will do a good job but I'm less than confident about the removal and replacement.

My Clymer manual is uninspiring so can someone recommend a Youtube video to me ? I dare not choose one myself as I've heard a few of them give very poor advice.

Grant did his for the first time recently, and found it easy enough. He was doing the push rod rubbers.
I think he watched the 3 Chris Harris videos on the subject.

https://www.youtube.com/watch?v=A47LiKSYD9o

Thanks Steve. I really don't know where the smoke is coming from, the bike pulls well, starts well but blows smoke and especially after a run when it's hot .

What are the symptoms of worn push rod rubbers ? Just weeping around the base ?

I'm assuming I need rings .

How many miles are on the bike? Did you do a compression or leak down test?

80,000 miles . No tests , she starts , runs and goes well but smokes .

Back tomorrow , bed time here.

Drips come from Push rod seals, or any other external seam or seal on an airhead. Usually all of them.

Smokes on start up, comes from valve guide seals or sitting on the side stand.

Smokes on deceleration, comes from rings.

I am a "B" grade mechanic and I have done the job on my R90/6 without much guidance and it was pretty straight forward.

Don't open it up until you perform the proper tests. Think of it as an autopsy.

Duane Ausherman wrote:Don't open it up until you perform the proper tests.

Park it for a week. If there is a puddle under it, its a drip.

Have someone follow you and either decelerate from high speed in gear or role down a hill at speed with the throttle closed. If it smokes its rings.

If it smokes only on start up, its valve guides. Or possibly an electrical fire if Ken has rebuilt your starter.

bbelk wrote:

Duane Ausherman wrote:Don't open it up until you perform the proper tests.

Park it for a week. If there is a puddle under it, its a drip.

Have someone follow you and either decelerate from high speed in gear or role down a hill at speed with the throttle closed. If it smokes its rings.

If it smokes only on start up, its valve guides. Or possibly an electrical fire if Ken has rebuilt your starter.

It's rings in that case. Thanks .

Do this test at night, as then the smoke shows up much better. Run it up to a high speed and close the throttle, as suggested.