proper jetting For 4,100 ft

[JrrMrrtt]

hey i could use some suggestions on jetting my carb. 2018 bms 250 crp or basically 2018 hawk 250. heres my situation does alright at lower speeds but cuts out alot at high rpms and at the end of the gears im pretty sure the jets are to big. i have a 32mm pwk amazon carb on it now i know thats a little to big of a carb for the bike but working with what i got. what would be the ball park on size of jets i should put in it im at 4,065ft to 4,330ft of elevation? or would i just be better of getting a 30mm carb and if so what would be the ball park jets to use on it. thanks in advance

[JerryHawk250]

A 32PWK is a bit on the large size for a stock motor. Even a 30 PKW can be a pain to tune. The best carb for your bike would be a Nibbi PE28fl. Easier to tune and work great with these engines. https://amzn.to/3R1vQg0

[bigdano711]

What is your current jetting? If it's cutting at full throttle but fine at all other ranges of throttle, I'd say try leaning your main jet, whatever it is.

[Megadan]

A 32mm isn't just a little too big. You will probably never get it to run right all the time and in all conditions.

[JrrMrrtt]

ok thanks jerry hawk you wouldnt happen to have a link to a correct length throttle cable to go with that 28mm carb and what jets would you recomend for me? And big dan its choppy at all throttle posistions but still rideable then bogs at higher rpm and speeds the jets that came with it i believe are 130 and a 30 ive tried leaning it but doesnt seem to change anything i went 3 turns.

[JrrMrrtt]

ok thanks megadan sounds like ill be ordering a new carb today

[ProDigit]

I would recommend a PZ28.
For reference, a lot of people closer to sea level start with a 35-40 pilot, and a 100-110 main.
If I were you, I'd start with a 30 pilot and 95 main due to your elevation, and work from there up or down.
No one can tell, you have to experiment yourself.

[Megadan]

Cheap PWK carbs are notoriously bad as well. Most never run right. Even Nibbi carbs get a bad one from time to time.

[XLsior]

There is also the PZ27B and PZ30B pumper carbs which may or may not fit in the frame with the pumper assembly however it can be removed to run as a stock non pumper carb if needs be.


With or without the splitter cables




https://www.aliexpress.com/item/1005...34231.html?spm

https://www.aliexpress.com/item/1005...66696.html?spm

[buzz]

What Megadan said is so true,i just rejeted my stock carb

[JerryHawk250]

Originally Posted by JrrMrrtt

ok thanks jerry hawk you wouldnt happen to have a link to a correct length throttle cable to go with that 28mm carb and what jets would you recomend for me? And big dan its choppy at all throttle posistions but still rideable then bogs at higher rpm and speeds the jets that came with it i believe are 130 and a 30 ive tried leaning it but doesnt seem to change anything i went 3 turns.

Your stock cable should work with the carb. I would start with a 105 main jet and 38 pilot jet.

[JrrMrrtt]

ok thanks for the help everyone i just ordered a pe28 should be here in a week. also ill try the stock cable when it gets here. i dont know if it makes a difference but i didnt mention that i got a aftermarket throttle handle would that work with stock cable?

[buzz]

You still should be good.