na man you guys are wrong. the drz250 from 2002 to present (non california model)uses the tm28-1 carb. you guys are not gonna make big power running non accel pump carbs. these engines need a ton of fuel off idle. here is the 28-1 http://www.allensperformance.co.uk/tm28-1.html the 300ex carb with stock jetting is damn near right on, pilot is a tad lean. i am not sure how much room is in the lt230 since i have the engine in a dirtbike. you can pick up a 300ex carb on ebay for $40, best $40 you will spend. here is a video of my bike, remember it's a 190cc. does your quads sound like thIS.? http://www.youtube.com/watch?v=2QRJQoJXBXQ

 

from the looks of the picture your running a round slide vm carb, thats basicly a 2 stroke carb. i bet your running a super rich needle and a huge pilot so it does not stumble (bog)off idle. trust me i "been there done that" with these engines. just when i thought i had the tm28 dialed in and running good, i slaped on the tm28-1 and shi$ my pants when i almost flipped it over in 3rd gear. the difference was night and day.

 

AND IF YOUR REALLY LUCKY THERE WERE A FEW YEARS THE DRZ250 CAME WITH A TM28-1 THAT WEre BORE TO 31MM, I HAVE BOTH. I KNOW 2002 HAD THE 31MM VERSION. HERE IS A PICK OF BOTH TOGETHER, THE CARBS ARE IDENTICAL BUT THE BORE SIZE IS BIGGER ON ONE THAN THE OTHER.

 

<div class="FTQUOTE"><begin quote>Originally posted by: HACKMUNCH

from the looks of the picture your running a round slide vm carb, thats basicly a 2 stroke carb. i bet your running a super rich needle and a huge pilot so it does not stumble (bog)off idle. trust me i "been there done that" with these engines. just when i thought i had the tm28 dialed in and running good, </end quote></div>

In the pic is a 32mm roundslide. I took that off because I can't get it to take more than half throttle, like I said before. I have a tm28 flatslide on it now. You can't hit the throttle fast enough to make it stumble! No pump. Small engines like these don't need pumps. That's why you can't even buy a pump from mukuni for the little carbs.

You're right that I have to run a rich needle because I have no airfilter resistence. That's why I said you can't run a carb that big without huge filter resistence. An accelerator pump isn't going to help that. You'd need a fuel injector of some sort to constantly pump in fuel independant of the throttle.

Basically it boils down to: Is a 28mm carb with no airfilter better than a 32mm carb with a very restrictive filter. I've put the question to a few smart people and they all agree.... The 28 with no filter will make more power.

<div class="FTQUOTE"><begin quote>i slaped on the tm28-1 and shi$ my pants when i almost flipped it over in 3rd gear. the difference was night and day. </end quote></div>

My buddy's stock 250S with 26mm stock carb will do that. That's why he has no rear plastic. He flips all the time. [img]i/expressions/face-icon-small-happy.gif[/img]

 

<div class="FTQUOTE"><begin quote>Originally posted by: HACKMUNCH

na man you guys are wrong. the drz250 from 2002 to present (non california model)uses the tm28-1 carb. you guys are not gonna make big power running non accel pump carbs.</end quote></div>

Accel pump only works when you push the throttle.

<div class="FTQUOTE"><begin quote> these engines need a ton of fuel off idle.</end quote></div>

I don't think so. Small engines don't need pumps. If it was a 400cc then ya, but not a 230/250.

<div class="FTQUOTE"><begin quote> here is the 28-1 http://www.allensperformance.co.uk/tm28-1.html the 300ex carb with stock jetting is damn near right on, pilot is a tad lean. i am not sure how much room is in the lt230 since i have the engine in a dirtbike. you can pick up a 300ex carb on ebay for $40, best $40 you will spend. here is a video of my bike, remember it's a 190cc. does your quads sound like thIS.? http://www.youtube.com/watch?v=2QRJQoJXBXQ </end quote></div>

Hard to hear much online, but it doesn't sound like its revving out all the way.

 

<div class="FTQUOTE"><begin quote>Originally posted by: HACKMUNCH

AND IF YOUR REALLY LUCKY THERE WERE A FEW YEARS THE DRZ250 CAME WITH A TM28-1 THAT WEre BORE TO 31MM, I HAVE BOTH. I KNOW 2002 HAD THE 31MM VERSION. HERE IS A PICK OF BOTH TOGETHER, THE CARBS ARE IDENTICAL BUT THE BORE SIZE IS BIGGER ON ONE THAN THE OTHER.





</end quote></div>


Can you point out the accel pump? I still don't see it. [img]i/expressions/face-icon-small-blush.gif[/img]

 

you have to be kidding me? i guess i should have never posted any of this info here. never mind. if you knew any thing you would know the accel pump is on the other side of the carb. you are looking at the head side of the carb. there is a reason all 4 STROKE race bikes use accel pump carbs, even the small honda 150r. there is actually a 22mm pumper carb out know from mukini. good luck making any real hp with a 2 stroke carb. if you put your bike on a dyno you would see that the rich as$ needle you are running is killing the performace of your engine. we are making 21hp out of the 190cc.

 

<div class="FTQUOTE"><begin quote>Originally posted by: JustRandy

<div class="FTQUOTE"><begin quote>Originally posted by: HACKMUNCH



na man you guys are wrong. the drz250 from 2002 to present (non california model)uses the tm28-1 carb. you guys are not gonna make big power running non accel pump carbs.</end quote></div>



Accel pump only works when you push the throttle.



<div class="FTQUOTE"><begin quote> these engines need a ton of fuel off idle.</end quote></div>



I don't think so. Small engines don't need pumps. If it was a 400cc then ya, but not a 230/250.



<div class="FTQUOTE"><begin quote> here is the 28-1 http://www.allensperformance.co.uk/tm28-1.html the 300ex carb with stock jetting is damn near right on, pilot is a tad lean. i am not sure how much room is in the lt230 since i have the engine in a dirtbike. you can pick up a 300ex carb on ebay for $40, best $40 you will spend. here is a video of my bike, remember it's a 190cc. does your quads sound like thIS.? http://www.youtube.com/watch?v=2QRJQoJXBXQ </end quote></div>



Hard to hear much online, but it doesn't sound like its revving out all the way.</end quote></div>

 

<div class="FTQUOTE"><begin quote>Originally posted by: JustRandy

<div class="FTQUOTE"><begin quote>Originally posted by: HACKMUNCH



na man you guys are wrong. the drz250 from 2002 to present (non california model)uses the tm28-1 carb. you guys are not gonna make big power running non accel pump carbs.</end quote></div>



Accel pump only works when you push the throttle.



<div class="FTQUOTE"><begin quote> these engines need a ton of fuel off idle.</end quote></div>



I don't think so. Small engines don't need pumps. If it was a 400cc then ya, but not a 230/250.



<div class="FTQUOTE"><begin quote> here is the 28-1 http://www.allensperformance.co.uk/tm28-1.html the 300ex carb with stock jetting is damn near right on, pilot is a tad lean. i am not sure how much room is in the lt230 since i have the engine in a dirtbike. you can pick up a 300ex carb on ebay for $40, best $40 you will spend. here is a video of my bike, remember it's a 190cc. does your quads sound like thIS.? http://www.youtube.com/watch?v=2QRJQoJXBXQ </end quote></div>



Hard to hear much online, but it doesn't sound like its revving out all the way.</end quote></div>
the small engine comment has to be the dumbest thing i have heard on the net lately. you think 230cc is small. we have built and made 23hp with 177cc engines. it's not the cc, it's the hp. 11k rpms is not high enough for you? come on man do some research?

 

Nice VID. I have never ridden on an indorr track, none close to me, I have to wait for summer time and hope the track is not flooded!