I've been having loads of problems with my Bill Blue 351 with a TM33. I bought it used; 250 miles ago i broke a jet needle (where the e-clip is) and chocked it up to bad luck. Was on a tour this weekend and broke another needle. Something is seriously wrong with the carb. I worried that I may have reassembled it incorrectly, forgotten a part or something, but I took a close look at the parts diagram and think I'm OK.

After reading up, I'm pretty sure the problem is a worn slide -- it's definitely tarnishing (I think on the airbox side? I'd have to go look...) and there is definitely play in the slide in the direction of airflow (but not side to side). I'm guessing it rattles to hell and the vibration wears down the needle clip groove....

My question: I don't want to spend the money on a replacement slide if its actually the carb body that's worn. Is there a way I can check before buying the slide? Anyone run into this problem before?

 

 

If the slide has a lot of play, if it was mine I would attempt to add some material to the track to tighten it up. You could use a digital caliper to measure the opening and the slide.
Maybe gorrilla tape is just the right thickness to tighten it up?
I have about 5K miles on my T33 and no problems.

 

The fit of the slide in the body of the fueling device has to be very, very accurate else air will get drawn in and you will get weak mixture. Also, and this is very nerdy, you will get fluctuating pressures that could confuse the ECU.

Not sure you will actually notice anything at all on a small 4 stroke engine but if you are a bit of a "engine freak" like me you will do the job properly or suffer "nagging doubts" (like on the TV advert).

Good luck my friend.

 

durielk, if I'm understanding you correctly, you're suggesting putting tape in the slide track? If so, wouldn't the tape react with fuel vapors to an extent where it would dissolve the adhesive and even the fabric itself? Maybe I'm misunderstanding the concept here.

 

I think it could work..... put it on the atmospheric side of the carb body, not the slide... with it up stream of the needle it shouldn't get too much fuel. If it does just use epoxy. Cheaper than a new carb. YOMV.
It must be really loose if it is shaking the needle.

 

Yeah i think the only way to do it is measure the raceway on my carb against a new carb... Or just buy a new slide. It's a hard measurement to make well with normal calipers

And I sincerely appreciate the input and suggestion, but for anyone reading this thread and trying things: putting tape in the carb is a terrible idea. it WILL eventually dislodge and it will get sucked into the engine. and it would probably make the slide stick to all hell... but the concept isnt a bad idea. if i were stuck with a bad carb, i would try to add material (to either the carb body or slide) with JB weld, properly sanded down and finished

 

I would imagine that it would be virtually impossible to add material to the carb body and sand it down. I'm thinking now best to focus on the slide, filter side and see how it looks.
To check the tolerances, use a feeler gauge, probably no way to get a digital caliper down in the middle of the slide slot. I don't think measuring the slide slot up top where the slide really doesn't have any load on it.