GS750E acting 'sluggish'

[Jeepin_Jeff]

Hi all! First, I would like to say how happy I am to have found this web site...I've been checking it out for a couple of hours and it's great!

Anyway, here's my problem --

I recently purchased a 1979 GS750E. Got it home and rebuilt the carbs, lubed the chain, tightened all the loose bolts, changed the oil and filter, changed the plugs, installed a new battery, changed the brake fluid and pads and reassembled. I should mention that this is my FIRST motorcycle so you could call me a newb in the arena of motorcycle repair. So, I took her to work and back with no problems (about 15 miles each way, never going over 40 mph) Saturday, I set out on the highway for a trip to Nebraska (about 150 miles on the highway from Denver, CO) I get her into 5th gear and accelerate, but she suddenly loses power, feels really sluggish and won't go over about 4500 rpm. This continues for a few miles and I decide to head back home when it suddenly regains power. So, I continue. During the trip, it happens a few more times but is remedied by clutching and revving the engine and continuing on. On my way home today, the same thing happened, but the revving 'trick' wouldn't work anymore. So I started fiddling with the spark plug wires. When I moved the wire for the 2nd (I believe) cylinder, (right hand side, closest to the engine) the problem went away, but the idle speed went way up. I adjusted the idle screw and continued home with no more problems.

My question is -- What is wrong? I don't know if this is related, but I'm only getting like 25 mpg as well.

I'm sorry this is so long, but I read the sticky indicating that more info = more replies.

Thanks in advance for all your help!

Jeff

[Nessism]

Did you clean/replace/gap the points? Also, the spark plug caps go bad so you might want to check their resistance to make sure they are okay.

Another thing it could be is a petcock problem; either leaking down the vacuum port line and into the engine or not filling the carbs properly. You might want to check to see how well it works.

Good luck and welcome.

[ryonker]

I was thinking the same thing Nessism did. My 79 GS750 did pretty much the same thing yours is doing. I could barely get it up to 60 mph at times. I replaced the points and condensors (about $20 from z1) and set the timing correctly. Wow...it was like I had a different bike. Putting new points and condensors is just part of a basic tune up anyway so go ahead and try it...it's pretty cheap and a good skill to learn.

Rick

[doctorgonzo]

Good advice on ignition part (points, plug caps, etc). I've also had mine bog and perform poorly at higher speeds because of fuel starvation (kink in fuel line), but could also be float or petcock problem as nessism said.

[tkent02]

Where in Denver are you?