Hey whats up?
I have a 88 TRX250r with the following mods.
Coolhead, 21cc domes,highcompression gasket, FMF fatty pipes and Power Core II silencer, spacer plate, cylinder Ported by Eric Gorr, the cylinder is bored to 66mm. or .20 over I think.
The carb is stock, with 158 jet. I dont ride at high altitude.
I would like to know if the jetting is correct.
The bike has alot of power, but when I leave it idleling and then I rip-it, it kinda chokes up, and then it clears up.
The carb is clean, everything is it top shape. Does anybody know what can be causing this?
Thanx, peace

 

That jet sounds awfully small for your machine, I think that is stock. I have an 88 also and I am running a 160 main right know and am going to put in a 162 next time I ride cuz it has gotten colder here in the last couple of weeks. I think that you need to really get some help. My only mod currently is a FMF Fatty. I would think that you should be at least running a 162 or 165. Good luck.

 

my cylinder is done by Eric as well..I ran a 165 in it when I had the stock carb.

 

Alright, thanx dudes.
I'll get me new jets. Also how many turns out should the air screw have?
I got two on mine.
Also if I get an AirStriker carb for my quad do you think I will overcarb my quad with the mods I have?
Thanx, peace

 

I have yet to do any more engine mods to my R because FMF will be making a powervalved big bore for it next year. I have been told that the stock bore will pull a 38 mm carb. I think you should be getting more help from whoever is selling you parts. The further you go from stock, the more important and difficult jetting becomes.

 

When you are idling and open the throtle quickly. It has noting to do with the main jet. Only the airscrew and the clip on the needle. Try putting the clip at the top of the needle or next to the top and see if this helps. But, still take a plug reading. You don't want to lean it out to much and put a hole in the peston.

 

Well I was gonna buy a bigger jet for this weekend but all of the stores are closed for the holidays until next year.
I dont know mind cuz its too cold up here to ride anyways. I am gonna get a 165 jet and see how that works out.
Peace.

 

try changing the piolt jet as this controls the idle circut to about 1/3 throttle. above 1/3 throttle you are only using the main jet and the .158 does not sound out of the ordinary depending on the altitude you are running at.
i run a .158 with a 270cc motor with a paul turner type 6 pipe and a 34mm carb and i usually run at about 600ft above sea level. i hope this helps

 

I took my carburator apart yesterday, and the pilot has the size of 45. I gonna buy a 50 for it and I will get a 165 for the main jet.
Also whats the resonator for, that little bottle on the intake boot. I would like to get rid of it cuz the chances of an air leak is higher with it. But I dont just wanna get rid of the airbox, because I might go through water. Any suggestions?
Peace