1985 gs700 lack of revs????

[Guest]

IMG_4746.jpg maybe someone can help. problem is: bike runs poorly, if at all past 6000rpm and looking at the plugs all 4 are black and "sooty" . bike was bought as a non runner with pipe and w/o airbox. so far what I can see as "good"-- gas flows freely from tank, petcock is new and works , rubber intake boots are new, uni foam filters, new plugs, does it regardless of jetting ( stock, dynojet stage 1 and 3). because all cylinders are a problem do I rule out ignition? coils? ( 1 bad , 2 cylinders , 1/4, 2/3 but all 4?). bike starts fine with choke and after warming up idle fine w/o choke, pilot and air jets are clean/new. there again cause all 4 do it makes be rule out a problem with 1 or 2 carbs/jets,. bad rings/ oil blow bye? all 4 cylinders? mileage 20K. thanks in advance and stranded at the track, tom

[TxGSrider]

First off, I like that bike.
Ok, does it blow black smoke when you try to rev it?

[tomp]

First off, I like that bike.
Ok, does it blow black smoke when you try to rev it?

no...........

[dorkburger]

Not sure, but are the filters oiled? I read here a while ago that someone had overoiled theirs and it caused problems similar to yours. Maybe pop them off and see if anything changes. You will probably need to stay with the stage 3 jetting due to the exhaust.

And welcome to the GSR. Where in CNJ are you?

[TxGSrider]

no...........

It sounds like it may be electrical.

[TxGSrider]

I'd start with fresh plugs and be sure they're gapped correctly. Then replace the caps.

[tomp]

Not sure, but are the filters oiled? I read here a while ago that someone had overoiled theirs and it caused problems similar to yours. Maybe pop them off and see if anything changes. You will probably need to stay with the stage 3 jetting due to the exhaust.

And welcome to the GSR. Where in CNJ are you?

ill try it, been a member for years, for some reason (lack of activity ?)I had to re up membership. hunterdon cty

[tomp]

I'd start with fresh plugs and be sure they're gapped correctly. Then replace the caps.

had -did , done, did, no luck

[TxGSrider]

had -did , done, did, no luck

Usually if it were running rich enough to foul all spark plugs and make the engine cut out, I'd expect you to see black smoke. Since it seems to start and run ok at low speeds it sounds like your compression is probably ok. So I'd keep checking for a weak spark or spark timing issue.

[dorkburger]

Agreed with the ignition checkouts. Also verify full 12 volt power to the coils and test the coils if you have a meter. Coils can also act up when heat soaked - if it was running long enough.

Hunterdon is nice. Good riding up there. If inactive for 6 months (I think) members get deleted.