I started my bike today, it revs quick, no misses, idles fine, sounds like it does not miss, doesnt back fire, doesnt smoke and exhaust doesnt smell like unburned fuel. So, just for the hell of it it check the header temps coming from the head, if sitting on the bike the far left pipe temp is 100 to 150 degrees, the other three are 250 to 300. What the hell, any ideas? Is that cylinder rich, is it lean, is that carb not working. But like I said, it revs quick with no misses etc. Also I recently cleaned my carbs spotless, you could eat off of them and installed a 1.7 racing jet kit and went up to 40s on the pilot jet. Any ideas would be appreciated.

 

Could be running richer than the rest. Did you sync the carbs after cleaning? Check spark there too. 100-150 is a pretty cool EGT, even if its running rich.

 

Dont have a sync tool. Had one years ago and loaned it to a friend. Havent seen him or the tool in years. When you say "check spark" do you mean like it says in the manual. Probably wouldnt hurt to change the plugs anyway. Why would that cylinder be richer than the other ones if all the carbs have the same size jets, needle clip position, etc. Like I said it doesnt miss and revs clear and quick.

 

Well, I still got the colder header down pipe. I've been through the carbs twice since the cleaning and dont see anything wrong. Slides are working, floats not sticking, "D" shape adjustment are all the same etc. I seen spark, when you pull the plug the stick it in the wire and hold it against the block. I've swapped the coils from one side to the other, thinking if the coil was bad a different cylinder would be colder instead of the usual one. Even though I know 1 coil fires two cylinders but I only have 1 cold cylinder. Had to try something. And brand new plugs. I also took it for a very short ride, high rpm in first gear, it sounds like a EX500 Ninja. Also check the compression on the cold cylinder, close to 200 psi. And the new plug is kind of black, probly from only firing sometimes with a build up of fuel in that cylinder. I'm friggin stumped. Major kick in the *****. I should have left it alone last year. It ran just fine. Now it dont. WTF!

 

Hey Frank,
What color are the other plugs ?
The main and/or pilot jet may be loose in the #1 carb, or the float may be too high.

 

3 good tan colored plugs 1 black plug. All four plug were new then I took if to a 4 mile ride. I know the floats are not adjustable, but something might have got tweak some how. I believe for some reason the number 1 carb is getting too much fuel. I'm going to check the carbs one more time and if I cant figure it out I'm going to order a refurbished set with all brand new internals.

 

Same thing was happening to me. Syncing fixed it. You can make a gauge yourself, it's an easy job.

 

I just order some carb tools, motion pro sync and float level height measure tool. Hopefully I'll get this figured out before the next track day. Havent been to a track day yet this year. Been doing 7 to 10 track days a year for the last 3 years. I'm going nuts, I need track. I need track bad. hahahah.

 

Well I figured it out hahahahaha. I swapped the float and float needle from carb 1 with float and float needle from carb 2. Now number 1 cylinder is 250ish degrees and number 2 cylinder is 110ish degrees. So I need to replace the float and/or float needle. I have two sets of cheap ebay carbs that should have a good float and float needle in them out of the 8 available. To bad the track day weather report for this weekend at Summit Point is calling for 60% chance of thunder storms.

 

Well I thought I figured it out. Wrong. After it idled for about 30 to 40 seconds #1 was cold again wtf. I havent messed with it for a while til this past Sunday, been working lots of overtime down in the hole. I checked valve clearances on #1, all 4 are within spec. Next step I think will be to install the cleaned carbs off of the 91 along with checking the rest of the valves.