First time working on multiple carbs on the Trashboat

[sparkfly88]

http://static.photobucket.com/player...505_181553.mp4

[bikerphil]

Well it runs, try with the air box attached and a filter in there. They don't run too well with the backs of the carbs open like that. I'd check the sync also.

[sparkfly88]

Okay. Will do.

I'll also finish tuning it when I get the baffle and packing installed in the muffler

[sparkfly88]

I don't think my bike likes the carbtune at all.

It came today and I hooked it up.

My carbs are a little off, pretty good for eyeballing it.... But it hated it.


So, I think I'm gonna remove the carbs, get the OE type floats so I know without a doubt those will be right...


It was purring away yesterday... Today, it's backfiring and blowing out the carbs at times.
When it finally decides to idle... It'll be fine for a bit, then it'll skyrocket to 4k rpm and sit there till I turn the idle down...

Ugh.

Frustrating.

[sparkfly88]

Ya know.... It sounds timing related.... Backfires and carb burps....


I think I'll run out and get a timing light and check that out before fartin around with the carbs more...

Ya think ?

[bikerphil]

You don't need a light, just put a mark where the plate meets the engine case, loosen the 2 screws and rotate the plate CCW a little to advance. That way you can put it back to where it was if it doesn't help.

[sparkfly88]

https://www.youtube.com/watch?v=ZUJ_...e_gdata_player

[natemoen]

What are your idle mix screws set at right now?

[sparkfly88]

https://www.youtube.com/watch?v=pxmM...e_gdata_player


In a nutshell.... If you don't wanna watch... It floors itself now if I touch the accelerator.

[natemoen]

Put your idle mix screws at 3 turns out and start over. 1.5 is too lean.

[sparkfly88]

So that'll be a cause of the hovering?

[natemoen]

So that'll be a cause of the hovering?

Could be...

[Rasputin]

When you throttle up and the idle hangs at higher RPM you are to lean.
I agree with Nate that you should try the pilot screws out a bit. I have carbs that are turned out as much as 5 turns and they work well. It is a matter of what the bike wants and not what the opening settings are.
If you read up a bit there is a recent thread about synching and then setting the pilots with the carbtune and then doing the synch all over again.
You synch the carbs and then set the idle by vacuum to the highest reading on each carb. Note you do not set them equal but to the highest on each cylinder. Then do a synch to balance the carbs. Well at least that is my understanding of the procedure. I have not yet tried this but it sounds good.
Rooster is trying that very method tonight with his carbs so maybe he will chime in as to how well it works. I use the colortune and then set it with plug color but this may well be a better method. YMMV

[sparkfly88]

That makes sense. Better the burn the more oxygen that's pulled in. Thus the reading would be higher.

I'll experiment with that tomorrow.

I was unaware that the pilot screws could move to that much to adjust, I'll fidget more for sure.

Thanks guys!

[sparkfly88]

I tried adjusting the needles, and no change happened that was noticeable. It still revs high, and still hovers at RPM ranges...

I have the feeling the carbs are just running insane lean due to those aftermarket floats....which would explain the giant jets that had installed in it...


tomorrow I get paid, I'll order tires and the floats.