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Discussion in 'Airheads' started by Plaka, Oct 30, 2018.
You'll be disappointed by the headlight bucket, there's nothing in there.
so it's full of nothingness? Most very zen gwasshoppah.
that will make it easy to switch buckets to keep the tip-o-lite controls.
This is Jim Gregory's pic of his mono RS bucket. Pathetic really, compared to my '81
Got out the pressure washer and some other tools. Time to get he grunge off. It's gonna snow tomorrow.
Then drained the oil. Not a magnetic plug. Bad. Also had truly big chunks in the oil film on it. Under the scope the chunks resolved into clumps of fine brown fiber. Looking at the oil filter should be interesting. The PO was running cheapo asian Emgo filters ( and was kind enough to include several in the sale).
The scope is a 70x B&L I got for cheap at an industrial auction along with a machinist stand. Priceless, if bulky.
Got into the left side. The mysteries deepen, a lot! I expected deposits on the exhaust side of a worn head from valve stem blow by. This head has them on the intake side also. The backside of the intake valve has as much carbon on it as the chamber side and that looks normal. Very light deposits in the intake tract of the head. No drippy oil in the carb tubes. Carbs show black streaking, they have been sucking piston blow by. Emissions removed. Supposedly a K&N air filter (did I say the guy was cheap?). The PO was running .004 intake clearance but I didn't check it befoe pulling the head. Piston skirts polished hiny with blow by streaking around the pins. Nickasil a bit worn---you can see the piston sweep area as more smooth. So what gives? Seems that intake valve is open during combustion, at which point the thing should barely run, yet it idled, fast and slow, fine. Spark plug looked fine.
Valve lips actually looked pretty good. Proud of the seats all the way around. Photoshop enhanced image.
Ex. lifter has a tiny pit dead center. I'll pick the best of he 8. I want to know at this point if the crank and cam are good. If so I'll run this bottom end.
Can we see pictures of the piston?
Asking for a friend.
couldn't get the piston pin circlip off. Will try again tomorrow maybe.
Did get the air filter out. Is indeed a K&N, vastly over oiled and weighs a ton. Doubt it's breathing. So the intake tuning is indeed srewed. My theory on the intake valve at this point is lack of scavenging during overlp due to intake tract obstruction with exhaust gasses blowing back onto the open intake valve.
If You get combustion residues in the intake tract then the valve is not sealing. Did you check how it seals?
Good point. no, I didn't. Given the wear I doubt the valve is concentric in the seat as it sits. They're junk. Good cores if someone has a damaged one but useless otherwise. But the bike came with a complete set of valve springs new in a sealed factory bag.
Well somebody wanted piston pics. Two things of interest, Best I can measure there is no measurable wear on them. The moire pattern in the photos shows that the machining marks go to the bottom of the shirts. However there are some light scratches going top to bottom on the thrust faces. Bad oil filtering.
But the rings are pretty gone. One big end bearing is cherry;. The other is scored deeply into the shell. But good to save on those cheap filters.
It was so cold in the shop today it took a heat gun to get the pan drain plug back in. But I got some things done anyway, narcotics be blessed. Went in to look at the oil filter, expecting it to be crushed. Nope. But what's wrong with these pictures? (hint, it isn't in the oil that came out either)
Compression on the white o-ring is minimal but existent. Canister depth is 3.26, 3.60, 3.80. No shims.
Unfiltered oil at worst, which could be worse than you expected.
You gonna pull the crank out? Do you know how hard it is to get someone to pull their crank 'round here?!
How's the check ball?
Is the little black o-ring on the filter missing?
Is this what Paul is seeing Too?
I don't see double.
But there should be an O-ring in the cover, middle ring, see where the wear mark is on the filter itself.
Not the small seal on the tube, that is not used in this case.
Further to the rocker shaft discussion, here are the two types. Earlier model with the drilled and plugged oilway.