Carbs at high altitude

[DemonShee]

I talked with Packard racing today about the lectron carbs. I have been thinking on the Lectrons for thier ease in jetting for altitude. Like I have said, I can go from 5000 ft to 11,000 feet in the same ride within an hours time here in Wyoming. This is a major pain in the a$$ on the stock carbs so I have been looking for alternatives.

 

He suggested going with the 36mm Lectrons. I was shocked that he would suggest such a big carb. I will have a 4-mil stroker with Redline racing dune porting, FMF fatty pipes, cool head, +4-7(he also recomended the +7) timing advance, and lightend flywheel. I got thinking, would the larger carbs help flow more of this thin air? Maybe making the quad less finicky to altitude?

 

I also considerd having Jeff at FAST bore my stock carbs and then run the dial-a-jets in them. How do you think would work Jeff (reminder, I am the guy from Wyoming that goes to St. A's)?

 

The biggy is DAMN those lectrons are spendy, $540 is alot of dough!!

[locogato11283]

sounds like you need EFI...

[ellison445]

Word, Might be time to find a new bike

 

 

sounds like you need EFI...

438701[/snapback]

[DemonShee]

Word, Might be time to find a new bike    

438705[/snapback]

 

 

Not gunna happen, dont have the $$ to sink into a 4 stroke so I have to make this quad work.

[Ducman]

I have my shee jetted for sea level. One local place I ride trails goes from 1000' to 5000' and when I ride at Sand mountain it goes from about 3000' to 4000'. I rode both locations with my stock carbs/ stock port/ FMF pipes setup and also with my 4mm stroker/ 34mm Mikuni Flat Slides/ rocket pipes. The stock carbs/port/ and FMF pipe setup did seam to run much more noticeably richer when going up a large difference in elevation VS the 34mm carbs/ 4mm stroker/ dune port/ rocket pipe/ v-force setup. I changed a bunch of things going to the new set-up so I couldn't say if it is just the larger carbs. For whatever reason, it does seem to be less effected by large changes in elevation now. Before it would be noticeably down on power and run a lot hotter due to being righ. Now it seems to run fine, not much power loss, and stays cool, but does start to spit oil out of the silencers when it gets rich from going to high elevations. The plugs stay clean, no fouling problems, but darken up quite a bit.

[DemonShee]

Thanks Ducman, I can tell, this carb thing is gunna drive me insane. The more I think about it the more the larger carbs seem to make since to use. They can flow more air than the smaller carbs can. Gunna be a bit more tricky to get jetted as it will be using smaller jets than what most people would use. They should deffinatly help maintain HP at the high elevations.

 

I like the sounds that I have read alot on here that the single carb setup produces a much better bottom end. Thats what I am after. I am thinking about finding a Trinity setup without the carb and then getting a large Lectron, like maybe 44mm. The 44 is very common in the DS650 world so I know I can find one for a decent price. Then mod the intake to fit the 44mm.

 

OR

 

I could find some bigger than stock carbs like the 34's or whatever and still do the dial-a-jet. The way it would work is I would basically jet the carb to run at highest alt.. Then I would use the D.A.J. to add additional fuel as I drop in Alt.. D.A.J. also claims that they add more fuel instantly for a stronger holeshot in racing. It actually kinda works the same way as the Boondocker Nitrous does. They also claim to eliminate dead spots throughout the powerband that you will see from moving from one circut to the next. Makes since to me.

 

I dunno but I will get it figured out one way or another.

[locogato11283]

yea if u need adjustability go with big lectron single with power jet or dial a jet like u said. id prolly go for the lectron.