My seal and gasket kits will be here next week. The engine's all apart. Done a few dry fits. A little nervous. I like making old shit look new again, not mechanicals. It'll be s few months till I start it. Got to go through the carbs, port the piston skirts and finish some wiring and stuff. One question. I've read I need to check ring to cylinder wall wall clearance. I got new rings and pistons and had the dealer bore it. Can't I just trust their work?
This depends on how much you trust them to be in the know as far as finishing touches. Me I have trust issues, so I'd probably double check. It never hurts these days to make sure, but if you know them well enough to feel good about it, then what the Hey. then there's the question, do you have the tools for that job?
Guess I'll have to dig up the manual and see how it's done. Weird thing is, I think the pistons aren't round.
a round and a round we go. Sometimes that's the case. Things are never what they seem, so yea double checking is a good thing.
It's not really difficult, you push the ring down into the bore with the top of the piston, that way it's square in the bore. Now measure the distance between the ends of the ring, and go from there. It's always best to double check someone else's work, in fact it's not a bad idea to double check your own AFATG. :courage: The bore and piston should be round. Not round, unless it's a Honda NR 500, is not good.
That measurement would be the ring END- GAP, not the cylinder wall- to- ring distance, which would be normally be zero that Rob asked about. Typical build #s would be about .004-006 " ring end-gap (minimum) and up to .002" piston -to- wall if i remember. :unsure: Best to overload the oil in the fuel mixture at first start-up if possible. Wash the muffler baffles out in solvent as they tend to soot and oil- up often on 2-strokes. How many miles on the little gem ?
Yeah, since ring to cylinder wall is zero, as you said, I was assuming he was talking about making sure there was enough ring gap so it doesn't bind up. Perhaps he was thinking of cylinder wall to piston clearance.
I had two of the RD350, and one RD400. Took some getting used to when coming from a four stroke though. And the gas mileage was for shit, but you didn't really care because they were so much fun.
Yea baby, nothing like the smell of a two smoke, and the wing dinging is fun to hear. https://www.youtube.com/watch?v=GpKSllqzr1w
I have the same autolube on my first bike, the "TwinJet" Yamaha YL-1 from 1966. Before you start it, you'll need to bleed air from autolube line by kicking the engine over a few times until oil comes out of the end, b4 bolting it up. In addition to the automatic oil injection, it's OK to add a small portion of additional lube in the form of 2-stroke oil to the fuel, just for initial break-in, what i was trying to suggest above.
Not much to report. Seals came. Cleaned everything again. I was dealing with a shop that sold me some Threebond gasket maker- 1207b. Service manual says to use Yamabond 4. I'd feel more comfortable using the Yamaha product so I ordered some.
Just for comparison.... my 390 Duke weighs right at 300 pounds. Makes aprox 42 hp. A little bike is a nice change of pace, once in a while.
