One exhaust pipe hot, other cold...

[ericp501]

1977 gs400x..Carbs were cleaned, bike usually starts first kick. I had it idle yesterday for about 2 mins. The pipe on the right side got hot, the pipe on the left was cold. The exhaust air felt the same way. I'm getting a spark on the left cylinder and have good compression. I've heard of some twins running hotter on one side, but we're talking really hot and cold. Any thoughts? Or is this normal and I should take her for a spin around the block to see if the pipe gets hot?

[tkent02]

One side not sparking?

[dr_fosg8]

You mention spark and compression, but did you verify you are getting fuel to the carb? To the cylinder? Check the float bowl on the carb and make sure fuel is getting in there. If it is, check the spark plug and see if it is wet with fuel. If your getting fuel in the carb but not to the engine its time to tear the carbs down again and find out why.

Have the valve clearances been checked?

[chuck hahn]

He says theres sprak on the left...the cold cylinder. Whats going on is the carb isnt set right. Check the float height again and double check the jets to be sure they arent reclogged from junk flowing down from the tank.

[tkent02]

Coffee not kicked in yet.
So both sides sparking, did you clean the choke feed passage in the float bowl itself when you did the carbs? It is usually the first to clog. How about the tiny holes in the choke feed pipe sticking down from the carb body?

[sedelen]

Pull the plugs and compare them, same heat range? and is the carbon build up different? Could swap them around for starters and see if it makes any difference.

Is it just cold on start up, or does it continue after it's been running awhile?

[chuck hahn]

Cheap as new ones are, I would just get new plugs and then be able to see some clean uncompromised porcelean.

[ericp501]

This was the second time I pulled the carb to be sure it was clean. I used b12 Chem tool. Let it soak for hours and blew it out with the air compressor.. I guess I'll pull it again.. Should I try raising the jet pin to richin it up a bit?

[tkent02]

Did you somehow ensure all of the passages are clear? Even the ones in the float bowl?

[chuck hahn]

How long is "hours"? And did you fully disassemble them? Poke out all the holes in the needle jets and pilot jets...and the little hole on the very end of the pilot jets? If the answer is no to any of these questions..you have not cleaned the carbs right.

[chuck hahn]

Dont raise anyhting on the jet needle..use the middle groove. Just reclean everything again, do a full 24 hr soaking of the carb bodies, recheck and verify your float heights and she will probably be ok.


I dont know all about that B12 stuff but a full 24 hrs in Berrymans will have them clean for sure.

[tkent02]

I dont know all about that B12 stuff but a full 24 hrs in Berrymans will have them clean for sure.

Not necessarily. A gain of sand will withstand the dip forever. That's why you must ensure the passages are clear.

[barnbiketom]

one pipe cold?

90% carb plugged ..

9% ignition

1% gremlin like creatures hating you

[5150/gs]

Why do people never think Fuel?My 1100 did this,i sync'd carbs and all was fine.With spark and good comp,only thing left is propper fuel.After cleaning and all that,you can only get close bench syncing,Must fine tune things.

[lake_harley]

I found the answer to my question below right after I posted. What I was looking for is the float height and found it on a manual linked in another thread. It's .84"- .92" for my 450.

In doing a search for the answer to my question, I came across this thread. I have a similar problem...one "hot" pipe and one "warm" pipe. In my case the bike is a '81 GS450T. I have the carbs off again now and really gave them the business, cleaning everything I could find to clean and tried to clean things that didn't end up having holes in them. Wanting to double check the float height....and that's what brings me here. I haven't found a float height for my bike in the searching I've done. Anyone have a manual handy?

Thanks...In advance.

Lynn