need help taming abrupt power delivery on airfooler

[mikey's250sx]

i have a 300 kit ,38mm carb,dg pipe and fmf silencer,aftermarket reeds.

this thing is like a light switch. as soon as it hits the pipe it is screaming!! it's fun across a field but i do a lot of woods and trails riding. i figured that when i was building it it would be a torque monster with the big cc so i used a big carb to get a high rpm hit but this thing is too much in the tight stuff. before i have a chance to figure out wether i can make it through some mud or around a tree i am in 3rd or 4th flying through the woods. i have had some close calls already and have only about 1.5 hrs on the engine. it sure is fun on the mile long street back to my house though.

is there anything i can do to get a more manageable power delivery or should i just use the new big red for the tight stuff and mud? is it common of big 2 strokes to be so on or off?

[twoodward15]

You could always change the sprockets so that you have a really super low first gear. it'll still hit hard but when you need to go slower you'll be able to and have all the power you could ever need.

[TtownJoeShow]

Sweeet, i'm in the prosess of doing damn near the same upgrade, just don't have the 300cc kit, oh and i have the full DG. Oh do you have the air striker or just a PWK?
Some say that a reed spacer (mounted between the reed and cylender) gives you more low end.
i wonder if a smaller carb would do the trick?

[Billy Golightly]

What is your sprocket setup right now? I'd also go with gearing it down some more if you ride mostly in woods. It wont help the "light switchness" of the power curve but you wont have to slip the clutch as much when your doing tight stuff, you can just kind of go around at a low rpm and roll onto the throttle.

[mikey's250sx]

gearing is 13/47 - give or take a tooth. hard to count the rear with a chain on. carb is a mikuni from a cr250. i really don't want to go back to a smaller carb if i can avoid it. i may just have to become a better rider with it. i'll tell you what though, i have a lot more respect for the guys who race big 2 strokes through the woods now. i can't wait for some better weather so i can go up to the coal hills and see what she can really do!!

[BLAZERONE22]

I would just pull the motor and box it up and send it to Oregon to be used at the dunes, where it can scream and run free.lol

I'd just change the carb though. the 85 R carb is perfect. and go back to stock gearing.

[mikey's250sx]

what is the stock gearing?

[Billy Golightly]

Man thats already a pretty big rear sprocket. I'd try for maybe a 12 on the front. I'm not positive on the stock gearing probably in the 13/40 or 13/42 area.

[mikey's250sx]

as far as the rear goes i may be off a few teeth. i really didn't feel like getting dirty pulling the chain.

won't a rear with more teeth give me more low end and less speed?

[BLAZERONE22]

I think its 13/44 I've played with gearing and 13/44 was perfect on my R running 22 inch tires 12/44 is not bad, but on open stretches you were wishing for a 6th gear bad.

[mikey's250sx]

i am running 20x11x8 holeshots.

it sounds like everything i am doing is conspiring to get me to 60 in 1.5 seconds and 62 in half an hour.

correct me if i am wrong but here it goes.
to get better acceleration but slower top end;
smaller tires
smaller front sproket
bigger rear sproket


i've got two out of three there. i'm keeping the tires so mabye i will get a new rear sprocket. how about 42 teeth?

[BLAZERONE22]

Yeah, the way your setup you more of a torque monster. if your going to be woods riding I'd go to a 22inch tire and a 44 rear sprocket, I used to run a set of wooly boogers on my old aircooled and that thing would rail on the trails. On my daughters R she runs a 13/38 sprocket with 20 inch tires that combo seems to run great thru the gears with the 20's.

[Louis Mielke]

Mikey welcome to the world of 2-strokes, other than some porting i don't think you'll really get completely rid of the hit your talking about, its just the way a two stroke is. The tire and carb changes will help but you will still have the hit, you won't get rid of it, only change were/when it comes in. Told you it was a whole different world. My advice, ride the trails more and get used to it, it is tameable, I ride my R in tight woods, yeah I've had the close calls but it comes with the territory. Just ride it and you'll learn to adjust your riding style. Its just not the nice tame trail cruiser that the SX and the Big Red are.

You'll get some practice this saturday cause thats mainly what we'll be riding, tight woods.

[mikey's250sx]

i'm hoping for warmer weather. right now they are forecasting 34 degrees

[BigGreenMachine]

I have the same problem with my Tecate, almost no bottom end grunt and keeping it from stringing me up in a tree is hard when she gets on the pipe. Sprockets and a smaller flatslide carb would be the only way to go. The reed spacer makes no noticable difference. I have mine geared low and the top speed suffered, like blazer said 6th would be nice on a long stretch of trail.