Whats a good carburetor for my DT125 with a 170cc athena cylinder kit?

[claws]

So what carburetors do you recommend to buy for my DT? I am currently running the stock carb but I'm planning on buying a bigger carburetor. I bought the bike with the 170cc cylinder kit and stock carb and it works fine but I think it needs a bigger carb though. Oh yea it's an 04 DT125RE

[Calum]

I reckon a VHSA would be a good car for that application

[claws]

@Calum buying a 36mm keihin pwk. yes its a bit overkill but i got it for cheap. and im also buying a pro circuit 304 silencer as well

[Calum]

36 is HUGE!

that will be horrendous on fuel!

[claws]

@Calum it is already because my ypvs is locked to the up right position and the carburetor isnt in perfect tune

[Calum]

@claws Well you've definitely got more money than me.

Once upon a time my brother ran a kehien 38 on his 170 Athena. The fueling was mental and the performance did not match.

That's just my advice, you don't have to take it. Bigger is not always better. You'd do well to lower it to get more performance and fuel economy.

My brother is currently running a 34mm on a 170cc two stroke, and he's looking at a 28mm for more performance and better economy.

[claws]

@Calum i cant really tune my current carb and i dont have that much money haha

[Calum]

@claws You're throwing good money after bad, a few jets is considerably cheaper than a 36mm carb. Besides, do you really think slapping on a carb will make your bike run right?

Fueling is no something you scrimp on, run it lean, and you'll run into detonation destroying both the bottom and top end. So don't scrimp on fueling.

[claws]

@Calum getting the keihin for 60 euros isnt a bad deal besides the screws for the carburetor are seized so i cant mess with the float or jets. also i can just sell the carb if i need to. im not an expert at tuning carbs but i can make it run ok

[Calum]

@claws It needs to run spot on, is my point. Even the new carb will need jetting.

[oldman]

@Calum said in Whats a good carburetor for my DT125 with a 170cc athena cylinder kit?:

@claws It needs to run spot on, is my point. Even the new carb will need jetting.

I second that

[claws]

@Calum gonna get it running great. better than with the original carb

[Calum]

@claws That's great to hear! I know from experience going too big is detrimental. But maybe I didn't spend enough time tweaking it!

[claws]

@Calum wouldnt be making any sense to not get it running great. gonna send a video of it running later

[Darty]

@claws

Not to sound boring, but, Keihin PWK 36mm of a KDX220

Been there done that, mental, makes no sense. Actually slower overall..

A 32mm can be spot on, if you like to 'hoon' constantly, but these engines are fussy to jet on a bigger carb, I don't recommend it.

[Calum]

@Darty Long time no post

[claws]

@Darty cant be slower than now though

[Calum]

@claws You'd be surprised.

I'm not going into the specifics.

But Pressure=force/area

The force is generated via the vacuum of the engine, the area is the size of the carb.

If the carb increases sizes, but the vacuum remains the same then you will see a drop in pressure. Aka, the pressure to actuate the carb will lower and it may not be as effective, sine the carb works off the venturi effect, getting this balance right is important. Going too big can have adverse affects. Is 36mm too big? I'm not saying that, I'm just saying bigger is not always better.

[claws]

@Calum of course a bigger carburetor isnt always better but i dont think that i can go slower with the keihin and if i cant get it to run great with the bike i will trade it for a smaller one. but a guy that i know put a 38mm carb in his 1998 dt125r and said that it runs great. still i believe that the new carburetor will out perform the one i have now but if it doesnt i will be a bit disappointed but anyways i wont lose anything with this new carb

[Calum]

Oh yeah! Report back to us your findings