I have an ESR exhaust ordered for my 86 250R, and was wonderin what size jets would be best for it. Where i live we're about 2600 feet above sea level i usually run mid, or high test gas and use Motul T2 oil (synthetic). It has a Kehein carb on it now, and i am not sure wether it is pre-jetted or not; because it was on it when i got it. Also i was wonderin if V-Force 3 reeds for it would help it out any. I have heard people talk about them but i don't know anyone that his them in their quads.
Thanks

 

Not sure about the jetting.

For reeds, G3 Power Curve Reeds here - You will also need to rejet and probably regear for these.

 

You are going to have to give me a little more info

- is it bored
- what size in the carb
- what jet does it have now
- what pipe is on it now
- what reeds does it have now

jetting isn't a standard setup that can be tossed out there, it is a setting that can only be obtained EXACTLY with a dyno. So without a dyno we carb tuners use MAGIC. Help me out on the mods and I'll help you on the jetting.

 

Not for sure if it is bored or not the guy i bought it from said as far as he knew it was stock. It has the stock exhaust on it as far as he knew too, but i am upgrading to the ESR TRX5 exhaust. Iwill check on the carb size do u know where it would tell u, or if it does tell u on the carb somewhere. The reeds in it now are stock i am assuming like i said i just bought it and don't know to awfully much about it.

Thanks

 

With new reads and a new reed cage and a new pipe and from the sounds of it, stock carb - I would say: Leave the jetting where it is for now if it runs good with the stock stuff. With a pipe I had to richen and with reeds I had to lean - so that x's them out. Leave the airbox lid off after you get the mods on and do a few plug checks and go from there to set your main jet - the rest of the carb settings are your preference.

 

My standard reply to something like this is, what ever jets you have stock,
and you upgrade exhust/air filter (you are doing this aren't you??), go up 3 main jet sizes to start checking. Adding new reeds will mostly "richen" your motor and you may have to step back down a size.
Start at least 3 jets larger, do some plug chops and determine from there what to do.
I tend to keep mine on the slightly "rich" side, my plug is black but dry, as long as it runs crisply throughout the power band. Running a little rich won't hurt your motor, running to lean will smoke it.

 

If you get the G3 power curve reeds, you will have to bump up your main quite a bit. Probably drop one on your needle and might have to adjust your pilot too. You may want to simply take your airbox lid off or use an outerwears airbox cover