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re-use new rings? how long to build compression on new motor


volcrano

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Coolant leak possibly washed rings from seating. I bought the bike as a basket case. Rebuilt the bottom and top end, using stock 64mm jugs and head. Put new vito Superstock forged pistons in it. Ring gap at .012. Started the bike going through heat cycles. First few the plugs were like wet gray oily. It had about 3 10 minute heat cycles with no load from idling to revving and in between. Changed the head and gasket to a set up I knew worked. Not leaking any coolant, and honestly I'm not sure if it was during the beginning, but the wet metallic shit didn't seem right. Anyway, not trying to make a novel, but I took it for 2 heat cycles after that under a load and the bike doesn't run bad, it is a little sluggish at bottom but starts clearing up. Few backfires here and there not constant. I got it hot and checked compression. 70 in the left and right and it drips to 35 before it holds. The question is, is it possible it is still breaking in and will build compression, or should I take it as the rings are glazed and pull it? I had thought about pulling jugs and honing them and putting them back on with the same rings. The bike starts on the 4th kick at half choke. Left pipe smokes a little more than right. Jetting is 25 pilots 1/2 turn out to keep good response, and 210 mains. Stock pipes. I hope it just needs the shit beat out of it and will build compression. You think it has broke in enough? Thanks guys.

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Yes I stated I honed the jugs and checked ring gap after. I know the jetting is close to stock but it has stock pipes and the plugs are wet as hell. It has foam filter and airbox lid also. I am doubting it ran lean as it fogged the neighborhood when it was starting. Even with the simulated porting of the piston, no more air was given than stock.

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Also the mere fact that a fresh motor needs 4 kicks with choke in warmer weather months is a red flag to lean to me. Possible air leak. Right side smoke more? I get that it smoked, doesn't mean it wasn't lean. But if you're positive I'll just quit yappin and see if any one else has an idea.

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Ok well if it's "toast", can I hone the jugs and try again or will it need to be re-run also? And how should it be lean with stock air system? Not being a cock if it sounds like it, just trying to understand the need for more fuel with stock pipes and box. Also, when should the motor build it's compression limit while breaking in? I mean after a few heat cycles and load runs it will be fully seated or will it take like a tank of fuel? It might have a half a gallon of fuel run through it.

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Hey man you could be right. It might be washed out. That's why I'm trying to find answers. The reeds aren't in bad shape, but I flipped them as they weren't fully seated. I know that can deal with compression. They are dual stage Boyes end and there is like a very slight gap on the outer reeds, not the ones that seat on the cages. I have a new set coming.

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Should definitely be fully seated within a tank of fuel. Is it starting with those compression readings? I'm suspecting your compression gauge may be a little bit off.

I'd definitely pop the head and look at the condition of the cylinder walls. If there's still cross hatching I'd just throw new rings at it. If you are sure they are roasted.

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Well that's the thing man. When i switched heads, I didn't really see any cross hatching and a few vertical scores, which Is why it's bothering me. If I pull and hone the jugs and go, or should I swap rings? Or is it possible to run some 1000 grit on the rings quick with the hone? I'm irritated about the shitty head and trying not to spend another 60 in rings, but if it needs done it needs done. Then if that is the case, what jetting should be needed for the super stocks on oem set up?

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Oh, and yes its still starting with those readings. It's a Cornwell comp gauge so I hope it's not bad, it's only been used like 5 times and is a year old. Or should I get a full tank of fuel in it and then see where the comp is and tear it down then. I mean when it warms, it pulls pretty good and wants to lift wheels sometimes just cruising, that's why it doesn't seem like it's that trashed...

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No i did the hone not a machine shop. I gauge the bore and it looked good and not out of round. I didn't check piston to wall clearance though, just set the rings in there and measured gap. In all honesty, the .012 gap was tight, like they were slightly under that and might have been a tad too tight and that's what gave me the metallic oil on the plugs. Maybe I should have had it bored idk. The budget build isn't so budget now. I guess if I'm going to have to get back in there anyway, I'm going to finish a full tank and check compression then. If it's low, it will get redone. It's worth a try if I'm gonna spend the cash anyway. Thanks for the help!

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