83 GS750ES ?'s Carb, Brake, Chain and oil use

[Guest]

Carb:

I've always thought my GS750ES was kind of gutless when rolling on in 5th gear on the highway (70mph or so) but I never really thought TOO much about it since I don't really feel any flat spots or hesitation. I can ride all day and have no problems...it just doesn't feel very strong in top gear.

I didn't think too much about this until I put in a few miles on a friends '82 GS750L back to back with my bike and it had WAY more grunt in the same conditions. I'm running a stock airbox setup with a K&N filter and 'busa cans grafted onto a stock GS750ES header and I think my main jets are the stock 117.5 pieces, could be 120's but I'm not sure which ones I installed anymore....

Does this sound like float height, mains or some other problem? Other than this I'm VERY happy with the way the bike runs.

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Brake:
After a run up to WV recently I started hearing a faint ratcheting sound from the front end as I'm coming to a stop. It is very clearly related to the front brakes being applied but I haven't been able to find the source yet. Any ideas? The speedo sender was greased last year with few miles since. I don't hear anything if I coast down to a stop and modulating the front brake seems to modulate the noise.

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Chain:
What should the chain feel like with the rider on the bike? It seems I've been running the chain pretty loose (more like 1in of play with me on the bike) so I adjusted it today to what I think it about 7/8in of movement with the bike on the centerstand. With me ON the bike it now has much less slack above the swingarm and I can move it up and down about 1/4in but it doesn't feel loose at all.

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Oil use:

The engine in this bike sat for about 8 years before I got hold of it and finally got it running. Compression is good and I've had no mechanical issues with it but I do burn some oil. I mostly see this when I come to a light on a highway offramp.... at times I get an embarrassing wreath of smoke curling around me that I can see very well in headlights from cars.... I've had several people follow me and they say they only see smoke when I'm opening it up (redline runs) and when I've been coasting down in gear and then give it throttle again.
I guess my question is this: Is it more likely to be worn valve guides or tired, dry seals from sitting so long and could being lean at WOT promote burning more oil?

It isn't too bad, that cases are dry and the plugs look fine (not fouled) but I'd rather not have to bring 2 quarts on an all day ride.

Thanks, as always, for the advise TGSRer's!
-/\/\ac

[t3rmin]

Blowing smoke is definitely embarrassing! My 750 did it just like you said -- only when really gettin' on it. I didn't worry about it since it ran strong but had over 40k miles and I figured by that time clearances had to be loosening up...

Do you burn enough to have to top it off frequently?

[t3rmin]

And I think that with a K&N filter and aftermarket exhaust cans, you're definitely going to need to bump the main jet and/or needle (?).

[Macmatic]

t3rmin,

Thanks for the input. The amount of oil I go through seems to be variable...sometimes its a quart every tank, sometimes a quart every three or four. Load, speed and riding style seem to have almost no effect that I can find. Nothing direct anyway.

Someone else suggested that the rings might need to be worn in again since the engine sat for so long but I've put thousands of miles on the bike now... should be good and worn in I think! I don't really want to pull the head for this but I guess I'll try changing out the valve stems seals this Fall and see if that helps. If not then I'll just ride it as is until the (next) project bike is done and then rebuild the engine, which I've always intended to do at some point anyway... as a winter project in NY or once I have a backup bike now that I'm down South.

-/\/\ac

[Griffin]

A quart of oil every tank or two is WAY too much. My GS700ES has about 50,000 miles on it and uses maybe 1/2 quart every 1,000 miles or so. I change oil about every 2,500 miles, and generally go through most of a quart in topping off between changes.

Check compression, a piston ring (or two or three) may be stuck and not sealing well. It's a very common problem after a bike sits for years.

[Macmatic]

A quart of oil every tank or two is WAY too much. My GS700ES has about 50,000 miles on it and uses maybe 1/2 quart every 1,000 miles or so. I change oil about every 2,500 miles, and generally go through most of a quart in topping off between changes.

Check compression, a piston ring (or two or three) may be stuck and not sealing well. It's a very common problem after a bike sits for years.

Maybe I overstated things a little when I said a quart a tank but I have had trips where its a quart a day easy. Then again sometimes I don't have to add any for several days of riding. I know its burning too much but it isn't leaking and its not bad enough to take it off the road yet...it can wait for the back up/project bike to be rolling.

Compression is good. I don't have the numbers anymore and I have to get an adapter so that the gauge I have now will fit the plug hole but when I checked all the numbers were well within spec and pretty close together. This was right after I got the engine running and rings aren't going to get stuck once its running, right? I mean its not going to sit for years, be fine and then get stuck rings...I think.

It smokes more when I coast down in gear (high vacuum) and then open it up so I'm pretty sure its mostly the guides or hopefully just the seals. I don't know if it makes sense or not but I've got a gut feeling that being lean on the high end might be having an effect. I think I'm going to try 120 or 122.5 mains and see if that helps my top end power issue as well as the oil issue.

-/\/\ac

[t3rmin]

I've heard people say to pour a bit of ATF or MMO or SeaFoam in the spark plug holes and let it sit for a while to free stuck rings. Wouldn't hurt to try...

[chef1366]

If the oil was getting through the rings it would smoke under load. The conditions like deaccel would suggest bad oil stem seals. I bet it smokes alot at startup with full choke. With the throttle closed the pull from the cylinders can suck oil through the valve stem seals like a straw.