80 GS550E with no power...

[HiSPL]

OK this one is starting to stump me. This is for a friends bike BTW, but I'm doing almost all the work on it. This bike was bought from a 'tard who didn't maintain anything for years, and what he did touch was broken, glued, or stripped when it was put back together. OK, this bike had decent (not great) power when we first aquired it. It was sucking down the gas though so I rebuilt the carbs (CV's) but managed to fubar two of the idle screws while doing it. New carbs from ebay fixed that problem. they are cleaned and jetted. We have newish coils from a bandit 600 with new wires in them, new plugs, valves adjusted, k&n pods, 4-2 exhaust (stock header with emgo Dunstall type mufflers), new clutch discs and springs, and replaced the o-rings in the carb boots (they were missing completely!). I think thats about it. Oh yeah, compression is like 150-145-128-150 They all go up considerably with oil.

The plugs show a nice color at idle and at WOT but are a little lean in the mid range. The problem I'm having is that no matter what you do, this bike won't break 55-60 mph in 5th or 6th gear. It seems like a timing or advance problem to me but there is no way to adjust the electronic ignition system on this bike. At least that's what clymer tells us. The cams are timed right, I double checked that also. This bike would cruise at 80+ before we replaced the mufflers, but now it won't get out of it's own way. I don't understand what happened and I'm getting frustrated with the thing. Please point me in a direction folks, I'm at one of those places where everything *looks* right but it's still not working right ....


Thanks...

[HiSPL]

Bump.....

[Hap Call]

It sounds like it is running too lean. Have you tried raising the needles? I'm sure you've already balanced the carbs...

Hap

[Pete's GS]

Did you check to see that the ignition wires are hooked up correctly, with the left coil serving the outer cylinders and the right one the inner ones? I believe the firing order is 1-4-2-3 on 550s.

[HiSPL]

Hap,
Yes the needles have been raised by a washer. It's still lean but I haven't had time to put another washer in it yet. The thing that bugs me most is that at WOT the plugs look great but it still won't go past 55 MPH.

Pete,
Yes the wires are routed correctly, but you just reminded me that I should double check the low voltage side to see if their getting enough juice.... Thanks

[HiSPL]

Anyone else want to suggest a place to look?

[focus frenzy]

the key is,
"it would cruse at 80+ before we changed mufflers"

are the new mufflers restricted?
is it bogging?
will it go past 55 in fourth?
if it does what happens when you up shift?

[HiSPL]

the key is,
"it would cruse at 80+ before we changed mufflers"

are the new mufflers restricted?

No, however the old mufflers were rusted out so bad they were candidates for a harley :twisted:

is it bogging?

Nope

will it go past 55 in fourth?

Yes.

if it does what happens when you up shift?

It slows down to 55-60 regardless of throttle position. It shows good plug color at WOT and a little lean at @ 5000 - 6000 RPM


Strange, Huh

[focus frenzy]

sounds like something is binding causing severe drag, put it on the center stand and lock it on the center stand!! and run it through gears and see if it will runn in the upper gears.
see if you can detect drag.

[HiSPL]

8-[ 'k...... Here's to hopin I don't turn into a rocket ship.....

[focus frenzy]

8-[ 'k...... Here's to hopin I don't turn into a rocket ship.....

1= dont sit back when doing this!!!!
2= use tie downs to compress fork to give more clearance
3= put front end against a unmovable object like a brick wall

[Pete's GS]

It actually could be a dragging rear rotor, which happened to me at 70 mph, locking up the rear wheel and pinning the tach at 12,000 rpm. I had to bleed some fluid to free the brake. You can't shorten the pedal throw on these bikes. You have to keep them at Suzuki's recommended clearance so you might want to check that.

[focus frenzy]

well???????? what did you find??

[HiSPL]

Well, a finicky "new" petcock for one thing. It's closing off at certain RPM's. I balanced the carbs again with my new twinmax guage and that cleared up some of the roll on hesitation. I had "bench synched" the carbs but hadn't done it with vacuum yet.

It's getting there.