900 big bores/twins and choke tubes

[rdr99]

Which big bore? What kind of pipes are you running? What size choke tubes have you tried and at what elevation? What differences did you see? What jetting? Race fuel?

 

[stock suks]

I have a speedwerx 1000 big bore with slp twins, airbox, bored carbs with dial-a-jets... And a d&d 1010 sleeper kit with the d&d twins and bored carbs. Both have shock tower dumps. The improvement was noticeable, im real happy with the d&d really no tinkering pull rope and go just like the 900 was.I run 91 pump gas, and occasionally throw in some octane booster. Only time i use race gas is if im using the nos on the 1010.

 

[spring snow hero]

not exactly what you are looking for but stock bore, slp's at 35mm per curt @ fastrax. mine has bored carbs and needs 20% fuel at 4-6k I am running 450-480.

cant comment on the diff, but curt said it helped out the mileage and woke em' up a bit.

 

[SLEDIOT]

900 BB for which sled? I run the D&D 900 on my m7 and its just ****in' nutz!!!!!!!!

 

[Pack Mule]

I have an 1160 engine tech, running at 6000 to 8000 ft, 13.3:1 comp (165lb at 1500ft elev) Have Jaws D pipes with 35mm chokes, Tried 38 and 36's 35 works best for my elevation. I have stock bored carbs 42.5mm running 470's with a high volume fuel pump, with a lower volume fuel pump the jetting was different.

I run 2.5 gal of C12 with 94oct premium pump. Don't need it at elevation but we start riding at about 2500ft so its for safety only. I premix 40:1 as well.

If on the button I run much more C12 - Usually bring a 3 gal can premixed up the trail and add it at elevation to save $$. running a 30 shot (haven't used the nos yet this year)

 

[rdr99]

Great info, keep it coming. Which works better, tuning bolts or choke tubes? What are you using for choke tubing?

 

[Pack Mule]

Welded in Steel pipe with the right inside diameter, You can cut the tubing lenghtwise with a zip disk to get a smaller size and then weld er up. I met a guy that had bolts and a small guage that he could hook uo to his pipes just before the choke "bolt". He targeted 3 psi if i remember... That way he could dial in the pipes at elavtion..

Never done it but it makes sence..

 

[rdr99]

That guage idea sounds interesting, might have to try it.