Motorcycle Forum banner
1 - 14 of 14 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter · #1 ·
I just purchased my first motorcycle, a 1984 Suzuki GS450. It idles and accelerates fine up to about 5k rpms. I think this happens in all gears, but I usually don't get more than 4k rpms in 1st, 2nd, or 3rd gear. I can feel the bike surging when around 50 - 55 mph and around 5k rpm. It does the same at higher speeds and rpms (when it lets me get this fast), but it's not as noticable. Sometimes I lose power all together and I have to pull off the road. Even after letting it sit it still does the same thing. I thought it might be a plug wire at first. It's not. Now I'm thinking it's a carb problem, but out of gear it revs great. Could it be a problem in the trans? Clutch? Carb? Fuel? Again, this is my first bike and I know little about motorcycle engines and transmissions. Any suggestions will be welcome.

Mike
 

·
I took the All Bran Challenge
Joined
·
7,753 Posts
The jets could be plugged with varnish from gas left sitting for a period of time without stabil being added.
You can try some carb. cleaner but pulling the carbs and having them cleaned may be required.
 

·
Registered
Joined
·
4,801 Posts
You could be running out of gas.due to a blocked fuel filter, or your float may be adjusted wrong in the carb.
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #5 ·
Just removed the carbs to clean. Lots of greyish black powery stuff in the bowls. One of the jets looked plugged and was cleaned out. Checked float level. Set them at 22.4mm. That's what I read it is supposed to be online. Let me know if this isn't right. Put carbs back on and now it won't fire. UG! Will take them off again tomorrow to find out the problem. Got to be something stupid.

It's been running up till today. And I've put 3 or 4 tanks of gas in. So, it's not bad gas. Fuel filter is clean. Could be float level is I was given the wrong info on float measurement. I'll re-clean the carb tomorrow since I'll have it back off.

Thanks for your replies!!! I appreciate it! I will post again if and when I figure out the problem.

Mike
 

·
Registered
Joined
·
4,801 Posts
Sounds like a fuel delivery problem. If you have a drain plug on the bottom of the float bowl, you can shut off the fuel petcock, than remove the drain plug. If there is little, or no gas in the float bowl, than you can be pretty sure your float is set to high.
Pull the plug, and squirt a small amount of gas in the top of the cylinder, if it starts for a second or two, it's most likely a fuel delivery problem. Well you have the plug out, make sure there isn't something in the gap.
 

·
Still crazy after all these years
Joined
·
14,185 Posts
92Notch said:
could be old gas. old gas does not work as well as new gas.
Isn't it all like millions of years old?
 

·
Premium Member
Joined
·
20,860 Posts
LOL.

Surging to me means revving higher than input calls for. Is it surging or bogging? Does it sound and feel like it's missing or just losing power?
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #10 · (Edited)
AH HA! Foound the problem. I guess surging wasn't the best choice of words. It's just the first one that came to mind. Bogging for very a short period of time is more accurate.

Here's the problem, then the fix:

0 - 45mph no problems, runs great! 45 and up there were problems. The bike would lose power. Here's a kicker... It would intermittantly bog down every few seconds while cruising along. It would act up even more as soon as a large vehicle (i.e tractor trailer) began to pass (yes, I ride slow). Once the vehicle passes, and I get into that air space where there's no wind, the bike runs perfect. Once the wind starts beating on me again the bogging starts up again.

Problem: The filament inside the fuse was broke. You couldn't see it from looking through the glass and just wiggleing it with your hand didn't make it act up. It required shaking it real hard. Put another fuse in and it works perfect. So, Wildwolf was the closest; although, not right on. It was a miracle I found it going 65 mph. Not real pleasing when it bogged down hard while holding the handlebars with one hand and the wire in the other! Don't try that at home. I'm a trained idiot! I'd rather have never found it than to know that was gonna happen!

Just my little 2 cent nugget of info.

Mike
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #11 ·
And the no fire problem after putting the carbs back on... I took them off again, checked everything and put them back on when I couldn't find anything wrong. The cylinders were flooded at first, then I guess it just took a while to draw the fuel up through the carb. Had to crank for about 15 seconds 5 or 6 times without giving it any gas. Starts right up now.

Mike
 

·
Registered
Joined
·
4,801 Posts
Glad you got her going. I never heard of a fuse blowing intermittently, the filament must have been lose inside the casing.
 

·
Registered
Joined
·
1 Posts
AH HA! Foound the problem. I guess surging wasn't the best choice of words. It's just the first one that came to mind. Bogging for very a short period of time is more accurate.

Here's the problem, then the fix:

0 - 45mph no problems, runs great! 45 and up there were problems. The bike would lose power. Here's a kicker... It would intermittantly bog down every few seconds while cruising along. It would act up even more as soon as a large vehicle (i.e tractor trailer) began to pass (yes, I ride slow). Once the vehicle passes, and I get into that air space where there's no wind, the bike runs perfect. Once the wind starts beating on me again the bogging starts up again.

Problem: The filament inside the fuse was broke. You couldn't see it from looking through the glass and just wiggleing it with your hand didn't make it act up. It required shaking it real hard. Put another fuse in and it works perfect. So, Wildwolf was the closest; although, not right on. It was a miracle I found it going 65 mph. Not real pleasing when it bogged down hard while holding the handlebars with one hand and the wire in the other! Don't try that at home. I'm a trained idiot! I'd rather have never found it than to know that was gonna happen!

Just my little 2 cent nugget of info.

Mike
Which Fuse is this? I have a similar problem.
 
1 - 14 of 14 Posts
Top