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let them soak as long as you can the longer the better.
diesel fuel will get to places wd 40 and other miracle chemicals are afraid to go.just the end of the carb where the screws are stuck is all you need to soak.

My advice: Make absolutely certain your screwdrive fits the screw perfectly. Not "good enough" but perfectly, so it has the largest amount of contact area possible. You've already been soaking it in PB Blaster and now are trying diesel, so it should be penetrated ok.

I would put the carbs on a bench and press down as hard as you can and firmly try to back them off. They should free themselves eventually.

If this fails, I second the setting them on fire route, but I get frustrated easily.

Thanks for the help all! With any luck I'll save me the trouble of new carbs.

Peter

how did it go? is it an xs or xj?

why do u wanna take em out anyway?

i think on these bikes u were not supposed to mess with them

like they are factory pre set or something!

and that hole is ussually plugged w/lead or something.

do u really have to take them out?

or just wanted to take them out?

sidecarguy wrote:how did it go? is it an xs or xj?

why do u wanna take em out anyway?

i think on these bikes u were not supposed to mess with them

like they are factory pre set or something!

and that hole is ussually plugged w/lead or something.

do u really have to take them out?

or just wanted to take them out?

This is an xs400k, and I don't really want to take them out. And I am not positive they need to be taken out. I did a lot of the work to get the bike running but when it came time to sync the carbs and get it dialed in I took it to a shop. The shop called and said that they can sync the carbs but without being able to adjust those screws they can't get it dialed in. I assumed they were correct because it runs rich. It may be important to note that this isn't a Yamaha dealership just a local place that specializes in Triumph sales.

If these are preset and it is running rich does that mean I need to change my jets?

you know, now that I think about it, I doubt they are supposed to come out. The reason I think this is because you can't buy that screw for replacement. If I go to Yamaha and pull up the parts pages for my bike you can get almost every screw you need for this carb except those two. They also have alternate jet sizes which leads me to believe you adjust the jets not a pilot screw.

Is this thinking bass ackwards?

the screws have been discontinued by yamaha.
they control the idle circuit up to about 1200 rpm.
if it has the original jets there is no reason to change them.
90% of the time the reason these old yamahas run rich is because there is an o ring on the float valve seat that gas leaks by and overfills the float bowls even though the float valve needle stops the gas from entering through the seat.if the plugs were removed from the adjusting screws somebody may have turned them out too far.these screws have no affect on carburetor synchronizing.you do the synchronizing then set them.

9000white wrote:the screws have been discontinued by yamaha.
they control the idle circuit up to about 1200 rpm.
if it has the original jets there is no reason to change them.
90% of the time the reason these old yamahas run rich is because there is an o ring on the float valve seat that gas leaks by and overfills the float bowls even though the float valve needle stops the gas from entering through the seat.if the plugs were removed from the adjusting screws somebody may have turned them out too far.these screws have no affect on carburetor synchronizing.you do the synchronizing then set them.

It does look like the plugs were removed but I don't think they have been changed from the factory. I plan on leaving them alone. I also have no reason to believe that the jets have been changed. So it sounds like (and check me if I'm wrong here) I should get the carbs synchronized then look to replace an o-ring. And as long as the jets haven't been changed and the floats aren't too high I should be ok, right

how does it idle now.
you need to replace the o rings now before synchronizing the carburetors.
and check the float settings.
you can synchronize them close enough with a feeler gauge.
have you set the valves yet??

9000white wrote:how does it idle now.
you need to replace the o rings now before synchronizing the carburetors.
and check the float settings.
you can synchronize them close enough with a feeler gauge.
have you set the valves yet??

When I've had it going it seems to idle pretty good. The only indication that it is rich is smoke from the exauhst and black plugs.

I haven't set the valves yet, I wouldn't even know where to begin with that.

As far as the o-rings go I see that I can get a needle valve assembly kit for both carbs for $80. If I can find just the o-rings I'll do those and worry then get it synced. I may need to adjust the floats as well but I don't know what I am looking for there.

Thanks for all the great advice, you have already saved me money I didn't need to spend.

Peter