82 GS550 Cafe

[Guest]

Well I am starting to build my gs550l into a cafe racer. but first I have to get it running good. currently it starts fine cold, it acts lean when running low on power the revs hang when i crack the throttle etc.

Lets start with a little background. I picked the bike up last july with all the intensions to just keep it stock and ride it the last leg of summer. But I could never get the thing to run good or longer then 30 minutes at that.

So I went and tore the carbs down, rebuilt them all new orings made sure every nook and cranny was clean. soaked the jets over night then used a fine wire to clean them.

I also installed new factory orings behind the intake boots.

There was a oil leak at both the head gasket and base gasket so i replaced those.

What gets me is why is it stalling. carbs are full of gas when it stalls. battery voltage is up around 13v.

now it would be one thing if it would start back up but it doesn't. i have to wait 30-40minutes to start it back up.

Could it be cam timing? would that cause hanging revs and stalling? Could it be valve clearance? Im running out of ideas here.

I know valve clearance can cause stalling but can it cause hanging revs?

I just picked up a new 2015 Yamaha FZ-09 so I have time to mess with the gs now

[78550GS]

You did all the work on the carbs, and didn't adjust the valves?

Get those done and re-sync the carbs with a vac gauge. You may find the issue is gone. Or maybe your petcock is faulty.

Also, how is air getting into the carbs? Stock box? Pods?

[curtie94]

I did adjust the valves but I wasn't too confident in it since when I pulled the head off all the shims fell on the floor so I had no starting point.

But I'll go ahead right now and check the clearances.

What should they be .05mm

And to answer your question stock air box.

[shinzon1]

Valve clearance should be .03 mm-.08 mm or .001 in. to .003 inches.

[curtie94]

i checked the clearenced and I had 2 that where too tight. All I could find was a .05mm feeler gauge.

But the shim in one that was tight was a 2.80mm and I swapped it with a 2.70mm I had and the .05mm had slight drag so I guess that one was too tight.

So ill finish my valve adjustment and check to make sure timing is good. Then ill see if it runs better

[JTGS850GL]

Don't forget to sync the carbs after the valve adjustment as well.

[curtie94]

Alright so I just Finished my valve adjustment after I got my new shims. I had the intake valve on cyl 1 that was too tight I ended up dropping from a 2.70mm to a 2.60mm and it was right around .07mm tolerance afterward.

The exhaust on cyl 4 was also tight it had a 2.80mm shim and I had to drop it to a 2.70mm and after the adjustment it was around .05mm afterward.

[JTGS850GL]

Great. That should make a difference. Now it's time to vacuum sync the carbs.

[curtie94]

I went ahead and started to vacuum sync my carbs when the bike stalled just like it has been.

I went to restart it and nothing. It just cranks. I'm getting spark when I put the spark plugs on the cylinder.

This is really getting frustrating.

It does have fuel I was using the gas tank and a vacuum pump to open the petcock.

It cranks strong when it cranks over just won't catch

The previous owner installed points in place of the electronic ignition.

[curtie94]

I let it cool down with a fan on it for 30 minutes and it started right back up.

I got it synced took it for a spin and it ran good. Got home let it idle for a minute and again it stalled. This time it will start back up but will only run if I'm on the throttle.

I say it starts back up but it starts hard.

I noticed when its about to stall it will pop out the exhaust and intake.

All of the valve clearences are above .05mm so its not valves.

Points are brand new. Condensers are new. Coils tested fine. Hot and cold.

A couple days ago I put 42.5 pilot jets in it in place of 40s. Will that make a difference. Remember I have had this issue since I bought the bike in July.

If I'm riding the bike it runs fine as long as I don't let it idle.

[curtie94]

New update.

After it stalled I restarted it and tried to rev it out. It reved to about 6k but it was working hard then it started to backfire out of the right exhaust pipe. I even saw a couple flames.

[curtie94]

I tested the ignition coils hot and the 1-4 coil was barely giving me a spark, the 2-3 coil was giving a decent spark.

I then let the bike cool down and the 1-4 coil was giving a better spark it was sparking across a 1/4" gap but didn't always spark

So I guess I'll see about getting new coils

[78550GS]

Get the original ignition.

Also, how many link pins are between the cams? I may be wrong, but I think it should be 20 or 22?

[shinzon1]

should be 20 pins between arrows on camshafts with no. 1 cyl. at tdc. If you have the manual from bikecliffs website it is page 64. can't seem to get the image to come up on here.

[curtie94]

Yeah I checked my timing and it is perfect.

I ended up getting a new to me set of coils and its night and day.

It starts great hot and cold. It did stall on me after about 45 minutes of idling but only because my mixture screws where set too rich a. I fouled out a couple plugs.

It started right back up and I reved it till it cleaned up and then I reset my mixture screws.