question, carb cleaning tech tip

[scalded dog]

In all the times I've cleaned my carbs, I have never seen the rubber washers, on the Idle mixture screws, now I have problems with high speed missing, still runs great when cruising? Ive checked every tip I could find to try to diagnose the high speed miss, any help would be appreciated. Thanks 'Dog

[psycoreefer]

what year carbs do you have? The 78's and 79's don't have a rubber o-ring and washer.

[bikerphil]

miss

Those little o-rings on the idle mixture screws (80-81) aren't that critical. I've put these carbs back together missing a couple and no noticeable difference in performance. They are probably there mostly to keep crap from getting down the threads. As for high speed miss mabye check for..

1. dirty air, fuel filters
2. kinked fuel lines
3. clogged gas cap vent
4. incorrect float height (lean)
5. Try running with petcocks in the prime position

Problem could be electrical too

[scalded dog]

Thanks for the reply guys, I have checked all the normal things, double checked the pick ups, but have always soaked each carb for around 30 mins in carb cleaner, and have never taken the butterfys out, I will need to check the seals there. There may be some extra air getting in there, but I went and practiced on two parts carbs this am, and only got one of the little screws out, rounded the other three out with a screwdriver, going to try to figure out how to get them out. any suggetions would be appreciated. Later 'Dog

[EGRon]

Scalded Dog your problem with the screws might be a good time to remind us metric bike owners that all phillips screw drivers were not created equal. These bikes use a screw driver refered to as "Japanese Industrial Standard" (JIS) , and they are actually shorter and more blunt than the Americam conterpart. No need to go out and buy a set of theses however, by using a bench grinder you can file the point of your screw driver off making for a tighter fit. Hope I did not rain on a previous post for this.

EGRON

[scalded dog]

Thanks Ron, I will keep that in mind. Later 'Dog

[ridinghard]

Thanks for the tip on the screw driver, I stripped a few of the carb screws before I read this one though. I found a screw same size and thread, but a regular (american) end. I will be grinding off a phillips before I touch them again though.

[Broz97]

Viola!

Outstanding tip... I have been cussing & rounding off these phillips for 40 years..... thought it was just my bad luck....
Heading to the grinder now.... uh...
keep the good tips coming! LOL Broz



82 XJ1100 Max -Currently resurrecting
82 XJ750 Ol' Blue (bad starter gear)
81 XJ650 In a Box
81 XJ750 Seca (organ donor)

[mitch]

Cleaner

DO NOT SOAK YOUR CARBS, it will swell the o-rings in the butterflyshafts could be your high speed miss right there sucking air at higher revs. Some others might know more on this i just remember i think it was TC stating this.
Doug

[tarzan]

Scalded-Are you talking about the screws holding the butterflies in?If so ,you know the threaded side of the screw is staked after installation so they dont vibrate out over time and get sucked in the carb.So to get them out you can grind the end of the screw with a dremel or if your careful you can drill the screws out.But it is difficult to get them out without removing the deformed part first.