DT125R ARCHIVE

NorDt · Guru

RE: 34mm manifold for the dt.

the only way is YAMAHA DTR · Guru

ye i will make a difference with your 34mm biggrin , have you got any pictures?

NorDt · Guru

No, but can get some tomorrow

miguelNS · DTR Respected Member

the only way is YAMAHA DTR wrote:

that's a bad ass project from a guy from lisbon.. he has some insane bikes!

NorDt · Guru

We didnt have workshop day at school today, so i made my stock manifold 34mm all the way trough, And fittet the powerfilter, And not changing the jet, its a 250 jet, I dont know if it made any change on it running any cleaner or not. its snowy and really slippery so all i noticed is that when it revs up, it almost cuts when it gets on the high rpms. Ill proboably just have to adjust the carb abit. ill fix it later, I forgot to check the spark plug, Im gonna do that tomorrow, to see if its still black.

Here are some pics of it all.

Heres the bike, Had the tank and all of it off while having the carb and manifold off.

The manifold before modding it.

The powerfilter fitted on the carb.

The manifold also before modding

The manifold after cutting of the "Restriction " on the top, btw, this doesent restrict anything on the stock reed valve housing, Bechause the stock reed valve housing has a metal inner frame, the frame goes about 2mm further in than the rubber "Restrictions" do, So even without the restrictions the valve housing is restricting itself, To derestrict the manifold and get any effect out of it you need another reed valve house

The manifold after modding it, its now 34mm all the way trough.

the only way is YAMAHA DTR · Guru

good job, with it 34mm you will get the full power of that carburettor, why do you want that air filter? it will get muddy and wet?

NorDt · Guru

Hoping to get better air flow, it used to get too much fuel and too little air.

NorDt · Guru

Heres some pics of the bike.

285103_10150275089792793_544197792_8165257_2112674_n.jpg

NorDt · Guru

Btw this helped alot. it made the bike run clean and therfore made it much faster. The powerfilter definetly helped.

birdys3 · DTR Respected Member

Yeah was lookin at them carbs on ebay for 60 quid but one i seen was 32mm wats the carb like m8???

NorDt · Guru

My carb is pretty much the same as the stock one, Just bigger.

I never tried the 170cc with the stock carb, so cant say anything about the difference.

But its a mikuni tm 34mm flatside. And is pretty much the same as the stock one, but the shock, Or what you call it in english, (The part of the carb you pull to make the bike start when its cold, The part wich gives the engine a bit more fuel untill you push it down again ). is a bit different, The stock one has a lever you press down ( if i remember correctly) and it automaticly goes up again after a while, But this one has more of a button wich you lift up, but it doesent go down by itself.

its a good carb. And changing the jet on it is a piece of cake, Just unscrew a bolt at the bottom of it. And then you can just change the jet without taking off all of the floatation chamber.

(When it comes to naming engine parts in english im having a hard time, cause in norwegian they have mostly english words for them, but with a norwegian pronounce, And therefore i cant just translate it into english cause its already an english word, so im not shure if its called the shock, Or flotation chamber.. )

NORFE · DTR Trusted Engine Builder

NorDt wrote:
My carb is pretty much the same as the stock one, Just bigger.

I never tried the 170cc with the stock carb, so cant say anything about the difference.

But its a mikuni tm 34mm flatside. And is pretty much the same as the stock one, but the shock, Or what you call it in english, (The part of the carb you pull to make the bike start when its cold, The part wich gives the engine a bit more fuel untill you push it down again ). is a bit different, The stock one has a lever you press down ( if i remember correctly) and it automaticly goes up again after a while, But this one has more of a button wich you lift up, but it doesent go down by itself.

its a good carb. And changing the jet on it is a piece of cake, Just unscrew a bolt at the bottom of it. And then you can just change the jet without taking off all of the floatation chamber.

(When it comes to naming engine parts in english im having a hard time, cause in norwegian they have mostly english words for them, but with a norwegian pronounce, And therefore i cant just translate it into english cause its already an english word, so im not shure if its called the shock, Or flotation chamber.. )

CHOKE

wink

NorDt · Guru

Ohh yeah thats the word, thats actually what its called in norwegian too but we pronounce it shock for some reason..

NORFE · DTR Trusted Engine Builder

there must be some reason / gain in performance by cutting flush the reed stuffers as ERIC GORR lists this as 1 of the mods to the 1989-1991 honda cr 250 and he does no his shizzle lol

most say not to bother on here so its just a difference in styles/thinkin on tuning

im gonna try it when mine needs re building see what difrence it makes

Calum122 · Guru

We used a 38mm carb on our DT. Just customed up the manifold to fit. Not difficult.