fuel issues

[jcwineman]

i still have problems with this sled at times you can start it and it runs good other times it wont pull its own weight. if anybody has any ideas i would be grateful.

[Bob Vehring]

I'll probably piss off the purests again, and I get it it that if your restoring a sled to orginal condition, you would want the OEM set up. On the other hand, I just want a good running sled, without tunning problems. Most sleds made, pre EFI simply use one pump, 1/4 in line and non PJ carb. I have several sets of V MaX Carbs and have battled with them and all the other stuff.This year with a fresh enging, started over with the same set up used on all my other sleds. One 1/4 line, one pump,no shutoffs, and a set of standard 38's off a Polaris. so far no issues at all, dials in like anyother sled, no fuel shortage, no flooding. Started jetting close to whats in my SRV and Eltigre, both lpw-mid 80 HP sleds, went richer for now on tubes and main and will fine tune from there, well when it gets back to normal, been - 20 here the last two nights.

I give Yami engineers creadit for trying somethings different, but clearly none of the fuel system things they tried on these transfered over to other models and no other OEM's followed with this setup

[Vmax540]

i still have problems with this sled at times you can start it and it runs good other times it wont pull its own weight. if anybody has any ideas i would be grateful.

Are you saying it will start but, not run correctly if so, does it run and shift out smoothly on a jack stand ? I do tend to agree with Bob's asessment that removing the PJ's, one fuel pump andd one fuel shut off can certainly simpily troubleshooting. I do believe a manual shut off is always a plus.

[Bob Vehring]

One of the things I did not like with the shutoffs was they make the flow make a 90 deg turn, that coupled with Yami's small 6mm fuel lines made me wonder about fuel flow. I learned many years a go on drag cars that even with big pumps and 1/2 line, a 90 deg fitting knocked the hell out of fuel flow.
I would say that theirs enough history to say it works ok with stock engines, mine is now 618 and while it has 38's on it now, thats not to say they might not get bigger if we take it racing someday.
I used the big black Micuni pump which we also use on the kids race sleds so I know its capable of supplying more fuel then what this one will need.

What I didn't feel good about on the PJ carbs, even if the PJ circuit is eliminated is, the main jet still points up. On normal carbs, I always use the deep well brass plug on the bottom of the bowl. That way, even with wheelies or big corner forces, there's always a "well" of fuel trapped around the main jet intake. With the main pointing up, I'm not so sure it couldn't suck alittle air if the gas gets to really sloshing around