backfire and oil leak

[Anonymous]

I just rode my 81 gs450 yesterday for the first time. Had to replace stator, regulater, clean carbs and fix a side cover leak. Well I let it warm up for about 2 min. wile I locked the shop. Started down the road and had little power and backfire on the left side. After about 3to 5 miles the poping stopped and I was happy with the power(my wife wont like it much).Been raining since so I havent started cold again.Forcast for sun tomarrow. But I do have a small oil leak around the base of the head gasket on the left side, thought it was stator cover at first(new gasket) Should I try retorqueing the head? And should I let it warm up a little more?
I am having the carbs sincro. some time next week or so,never done this so I am sending it to a bike shop. I am an auto mechanic and I have done multi carb setups on cars before using regular vacuum gauges, can I do the same here(that would save me about 45 bucks)
Thanks Kyle

[Anonymous]

450 woes

I too have a 450, and it is cold hearted! I let it idle choked for at least five minutes then another five to ten unchocked and it still acts up for the first couple miles. I have only synced one bike before, not my gs, and had to remove the boots between the carbs and air box to do it(duh). It worked but it was a task. The only thing I learned from it that stuck was to not blip the throttle while the boots are off, the lean mixture conditions will keep the idle up to high and you will have to shut it down and restart without throttle help to get back to it. But that was a 2 stroke, so....

[nabrams]

Kyle,

Seems like this is a VERY common question for the GS450.

For My 1980 GS450, I had mild back-firing during idle, warm-up, and higher revs. In my case, everything was running too lean (my plugs were VERY light gray). I had to do ALL of the following in order to totally get rid of the back-firing:

1. Adjust the mixture screw for max RPM at idle (I had to remove the tamper-proof caps). They should be between 2 and 6 turns out from bottom.
2. Clean idle and main jets with a copper wire (spraying tons of carb cleaner through them didn't quite get all the gunk out).
3. Install a proper foam air filter element (mine had disintegrated).
4. Seal ALL air leaks (no matter how tiny) at all boots and at air box lid.

Steps 3 and 4 above are just as important (perhaps more so) as steps 1 and 2.
Do all of the above and then move on to other areas if necessary (coils, timing, etc.).

In my case, the air filter element had disintegrated and there were tiny air leaks in various other places. I had cleaned the carbs (several times) and it would not run right. It was only after I resolved all the air flow and air leak issues that the bike ran decently. The CV carbs on our bikes are VERY sensitive to improper air flow.
You will drive yourself nuts cleaning the carb a million times (as I did) only to finally realize that the air flow (or leak) problems were critical as well.

Also, I agree with Frank about warming up. My GS450 sure does run smoother though after a long warm-up. If I just let it warm up for a couple of minutes, it is significantly less responsive.

[Anonymous]

no popping today....guess I will never know what it was...I hope

[Anonymous]

I mus have done something right. After the day it was backfireing I can start it and go without any choke at all. This scared me at first so I checked the plugs for rich condition, they looked great.

As far as the leak goes, it isnt the base of the head it is at the crankcase split. Not sure if I am going to fix it now or wait til winter