Best Methanol Carb for KTM250 or CR250

hunter123

Member
Looking for recommendations for the best carb to run for a two stroke 250 not sure which engine I’ll be going with either a KTM250 or CR250 it will be on a open kart on dirt with jackshaft very little uas racing will be done
 

Ted Hamilton

Helmet Painter / Racer
Balancing act -- smaller carb throat equals quicker flow rate = better throttle response...but .wider bore helps more top end... Decide what you want based on tracks you race at.
 

Don K

Member
You know, I wouldn't have a problem running gas/oil with a 250cc 2-s motor. Easy to jet and strong horsepower. The maybe three percent horsepower bump is only a horsepower or two. I understand alcohol is somewhat safer and helps to cool air cooled 2-s motors; but it is more of a hassle with purging and all. With a water cooled 2-s heat isn't a problem.

DK
 

hunter123

Member
You know, I wouldn't have a problem running gas/oil with a 250cc 2-s motor. Easy to jet and strong horsepower. The maybe three percent horsepower bump is only a horsepower or two. I understand alcohol is somewhat safer and helps to cool air cooled 2-s motors; but it is more of a hassle with purging and all. With a water cooled 2-s heat isn't a problem.

DK
We run 4 karts and this is the only 2 stroke the other karts run methanol so we buy it by the drum it just makes it cheaper on us in the long run
 
Balancing act -- smaller carb throat equals quicker flow rate = better throttle response...but .wider bore helps more top end... Decide what you want based on tracks you race at.
You aint puttin a 34mm on my 250. They make a SBN38 which I have 2 one I run on my 200cc. I'm right now considering putting one on my 250 cause my PWK39 is so inconsistent I'm at my wits end trying to get it right. Does anyone have contact info for Steven Gleason?
 

Don K

Member
I have an sbn39 on my KTM200 dirt bike. I couldn't get it right until I changed the slide to a leaner off idle piece. I can't remember the number of the piece but I will look back in my notes (if I can find them) and post it.

DK

ps, once I found the right slide jetting got easy. The stock slide was way off base.
 

Ted Hamilton

Helmet Painter / Racer
Has anyone had any experience with a Lectron Carburetor
I was talking with the microsprint 270 ppl about the Lectron and they said that "it worked..." but that it had sluggish throttle response. I don't know if this was due to improper tuning, sizing, or just a characteristic of the carb. The dirtbike reviews I've read all LOVE it...
 

Phiddy

Member
I was gonna say Lectron or convert a Kehin or Mikuni slide carb. Im guessing poor throttle response on a 250 2 stroke with a 40mm carb is in the tuning, not the size. The info is out there, pick your poison and decide how good of a carb tuner you are to decide your route. If you are not 100% confident in your tuning skills, I would buy someone else's carb that they have done the research on. Good Luck!
 

rainman

Site Supporter
I am not sure you are more safe on methanol. in theory lower temps should make them more reliable, but I have messed more engines on methanol even if I flush them right after race is over while I have rarely messed any 2 stroke engine on gas after my 1st season long long ago. I find it much easier to get the right carburation on gas.
 

Bradley71

Member
Put a 38mm gas lectron on it run it 32:1 forget alky and junk tillotsons.stock slide carbs have won championships before go karts where invented.🤣
 

Bradley71

Member
I thought long and hard about these carburetors.slide carb is way to go.on gas.5 hp isn’t worth the mess,the hassle of dealing w a tillotson.and I’d give a trophy to tillotson for the numbers of blown engines bc alky and a tillotson.i looked back I rode dirt bikes for yrs and never stuck a motor from a slide carb.watch bubba Stewart ride a 250cc.he never lifts off throttle and he’s prob running it 50:1,you never see him reaching for a needle either.braaaap
 
Odd I never stuck an engine with a tilly except one time when I put a little something in my fuel. If I'm a little off on carb going out or temp changes I can reach over and make an adjustment.JMO
 

welder60

Member
We bored our 38mm mikuni to 41mm for our micro sprint (250 kawasaki and a honda) also built a manifold to put twin tillys on the honda.
 
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