gearing/jetting suggestions

[chris p.]

looking for a little direction.08 drr raced mx with a malossi big bore,over-range and a mach1 pipe.first,pipe is new to us and looking for jetting suggestion.carb is a koso 28mm and currently we run a 132 main and a 40 pilot but that was with the old pipe which was a kx65 pipe made to fit.second,we had a 19/31 gear combo but we switched it to a 19/28 for some top end.rear tires are 18-8-8 itp quad cross mx.any pointers would be appreciated.thanks guys. :D :D :D

[jerkyboy]

That topend and pipe combo wants to screem and with a 19/28
your holding it back. Go back with what you had or maybee a 19/33.

[edwardsp&b]

Raven is spot on with the gearing. Where do you live? Those Malossi big bores like the fuel, I would probably go a little richer on jetting too.
Bryan

[chris p.]

were in ct but we race in mass.,ny,jersey.at the end of the season at a practice we felt the gearing was topped out but the engine wasn't so thats when we switched the gears to 19/28 and picked up top end but lost nothing on the holeshot.FORGOT TO MENTION IT'S A 90CC.thanks.

[jerkyboy]

The 19/28 makes the cvt work harder creating alot of heat. Some also has to do with your spring/roller combo also. You might think it does'nt hurt the bottom end but its got to somewhat.

[Logan #34's Dad]

I'm gonna have to disagree with you Dale and Bryan. I think a 19/33 is entirely to high in the rear. The Big-bore is a torque engine and can pull a lower gear.
I'd say go to a 30 rear and you'd be good. Gearing will affect clutching somewhat also. Lower gear = more lug....

[jerkyboy]

Rocky you always where a little different on setup than most out there and you made it work. But looking back You broke alot of parts in the drive train that might have to do with the low gearing you where running. That low gear puts alot more strain on those parts that we are already over worked. I could be wrong but thats my opinion.

Remember hes running the mock 1 pipe and i have found thats not really a torque pipe and likes to turn some good RPM.

[Logan #34's Dad]

I suppose you could be right on the added stress. But no be clear, I've never had a clutch set up failure. Any DNF's we've ever had was because of those junk slipper sprockets (for high HP engines anyhow) or Logan crashing. I can out clutch and gear 95% of them out there. Once we got our hands on the slipper clutch set up - no mechanical failures.
A 33 is too high unless your doing indoors. It'd launch good but run out of gear by turn one - at least on National tracks. There is only two dad's (not shops) that are better than me at the holeshot. Bassani and Wotring. And my engine (70 n 90) were bolt on - no porting or case work.

[jerkyboy]

Well they are 2 of the best and Dale has grown up raceing against both of them. Im not going to talk about what they run but Its not that low of a gear.

[Logan #34's Dad]

One question we have not asked him is what internal transmission gears he is running. That obviously will affect gearing....

[chris p.]

with the 19/31 our drr was a holeshot machine but would run out of gear on a long straight.you could definitely hear it.on 60 foot times on asphalt it would spin then launch but after switching to 19/28 it won't spin but will carry the front wheels for about 25 feet then settle down nice.the mach1 is a new pipe for us so i'm just not sure what to expect so i figured why not ask the seasoned guys.i definitely don't want to run into reliability issues as we had no breakage last year(knock on wood !!).just the usual thrown chain or dirt in the jets.one more thing.do certain pipes like more fuel than others beside the fact that we have the malossi big bore ????????

[Logan #34's Dad]

Best thing you could do is get to a dyno to have the carb dialed in.