Carb talk

[BSR6]

Before you go any further, clean them again. This time use carb cleaner and compressed air like Paul mentioned. Be as thorough as you can be and don't miss anything. Remove the jets, spray both the jets themselves (even if they look clean) and spray the openings they bolt into with carb cleaner, then hit them with compressed air. This includes the passages the jets screw into along with the air passage for the pilot air screw. Put it back together and make sure its all at stock settings.

Trust me, I went through this with my sled last fall. It ran like total shit, I pulled the carbs, which were spotless, cleaned them by removing all the jets (which all looked spotless and brand new) and squirted them with carb cleaner. They looked perfect, to the naked eye you could not see a spec of anything in any of the jets. It still ran like shit. My buddy starts spitting out all these theories about bad compression (it was dropping a cylinder) etc. We were all convinced it was something else but I decided to pull the carbs one more time, and used compressed air to blow the parts off after spraying them with carb cleaner. The thing never ran so good after that second cleaning.

In all the years I have dealt with carb issues between sleds, bikes, and jet skis, I have given up trying to diagnose exactly what the problem is by observing how it runs. I piece of something stuck in the wrong place in your carbs can make an engine run all kinds of crazy ways, convincing you it's something that its not. Then you end up spending money and time on problems that don't exist. Make sure you were thorough with your cleaning, and used compressed air before you go off on any other channels and waste more time or money.

[SSearchVT]

Given the age of the bike there's another thing to look out for - ethanol breaking down the O-rings and gas lines. Little tiny bits will break off and crap up a carb in a matter of days.

[xrocket21]

Given the age of the bike there's another thing to look out for - ethanol breaking down the O-rings and gas lines. Little tiny bits will break off and crap up a carb in a matter of days.

heh, got stranded last week and had to put a new gas line in...

[xrocket21]

Well, that's a bit more drastic than I originally thought. It does imply an air leak somewhere. Start looking for a mikuni flatslide on ebay?

I dont think it is THAT drastic, this is the first response:

PC,
Your symptoms are classic idle mis-adjust.

With idle mixture screwed all the way in, turn it about
1 1/2 turn out and start the bike. (Of course after you have verified the valves have 4-5 thou clearance when piston at TDC) Raise the slide with the Idle speed screw for a fast idle. Then, screw the idle mixture screw in till engine speed falters than back out till it falters. Split the difference and then re-adjust the idle speed screw for a comfortable idle. If the idle mixture screw doesn't have enough range to find the lean and rich faltering points, you need a different idle jet. I think stock is a 60. By the way, the idle speed screw is the big one with a spring around it along the centerline of the slide and the mixture screw is forward just behind the neoprene sleeve clamped to the carb. Screw out for richer, in for leaner.
The possible air leaks are around the neoprene manifold clamped to the carb or the joint between head and manifold flange sealed with an "O" ring.
:thumbsup:

[SSearchVT]

heh, got stranded last week and had to put a new gas line in...

All those little pieces of the old fuel line had to go somewhere. I bet I know where a bunch of them still are...

[xrocket21]

I tried a cold start tonight, and my adjustments definitely didn't help.

Actually, I bought 2 bikes, cleaned both carbs.

When I told the kid I bought them from , he said, "Oh man, you only had to clean the XT carb, I had the ATK carb professionally cleaned before i sold it to you." So I actually felt bad about cleaned an already cleaned carb.

Its gotta be the wrong jet or some shit

[xrocket21]

[Kurlon]

I think I hear the start of a wrench party...

[xrocket21]

cold blooded slutbag

[xrocket21]

carb tuning party? Giant garage with cable tv and free beer? in july?

[Kurlon]

I like the way this man thinks.

Carb tuning party!!!

[xrocket21]

windham maine..... we have a guest room you can sleep in!