Anyone know a close main jet starting point with these mods.

cobra exhaust, uni filter, no lid, 10.25:1 wisco.

Thanks in advance....


Mike

 

What altitude? Stock carb?

 

i ran 125 main and 25 piolet when i was using a stock carb

 

Im at 200ft. above sea level, stock carb.

 

<div class="FTQUOTE"><begin quote>Originally posted by: 270quadsportguy

i ran 125 main and 25 piolet when i was using a stock carb</end quote></div>

Wow I was hopeing it was a little more then that, I just bought a 130, 140, are you close to 200ft. elev.

what if i went with a web cam stg.1 same mods as above? anybody....

thanks for all the help

 

112.5 is the stock jet. What would make you think you would need a 140? I'm at 700ft and I had to lean mine out with a 60 over wiseco, KN filter and no air box lid, stock exhaust. I had the needle clip on the top notch so the needle was all the way in the hole. Then I scrapped the carb and went with a 28mm flatslide which came with a 180 jet. I had to drill that jet out about 8 times before I got it big enough. A guy at 7000 ft bolted the same carb on the same bike and didn't have to do anything to it.

With my setup I've noticed less exhaust backpressure = blacker spark plugs. Less intake restriction = leaner and won't run.

I dont know what the stage 1 will do. To require a large main jet you will need to have very low vacuum at WOT (wide open trottle). The more restrictive your air filter, the more vacuum you will have and the more gas will be sucked from the jet. Take the filter off and suddenly not much vacuum, so you need a larger jet.

I don't know much about UNI or Cobra, but I'm guessing you will need a bit larger jet than stock. The 125 that 270 said might be a decent place to start. I usually start small and drill my way bigger. To me, drilling is easier than trying to figure out what to buy.

 

Hey shockwave63. I used to ride one of those. Why even invest any money. They are great EZ going quads. Why not just get at an LT250R. They are wider,sit lower and go faster. I still have my 86 LT250R with full FMF exhaust. Still running strong. Good luck...

 

i like my 230 i can bout idle up hills a 450 would stall. i am running the 265 cc and web stage 1 cam with d.g exhaust and when i was running stock carb i used the combo of jets i said and plug was beer bottle color to a lil lighter tan . cant get much better than that

 

This is my oldest sons quad, when i installed the hrc kit on my quad it jumped from 119-180 mj thats why i thought 130-140 would be a good starting point. I ran the 140 today and did a couple good plug chops 800ft. 5th gear pinned chopped throdle and still no color on the plug..........
I think ill drop to 125 like suggested.

Anybody know what numbers these bikes pull on the dyno????

Thanks again for all the help

 

I'd say 20-25hp at around 7000 rpm from my dyno software. Although, I've had it in the 30-40 range with all the right options selected. I don't know if that's actually possible without forced induction, but the software says it is.

I wouldn't mind having a 250r, but I figure if I'm going to monkey around with 2-strokes it might as well be a 500r. My 230 runs like a 2-stroke anyway,,,, with the added bonus of the lowend grunt. As fast as I punch the throttle it revs out.... in the first 3 gears anyway, lol.

Seems like the number 26hp is sticking in my head for the atc 250r 2-stroke. 20-25hp for the same size 4-stroke would be very respectable.