DT125R ARCHIVE

NorDt · Guru

34mm manifold for the dt.

the only way is YAMAHA DTR · Guru

like i said,use a "flapwheel" to make the manifold bigger, or make your own manifold?

NorDt · Guru

Well see, id rather buy one thats 34mm all the way trough.

the only way is YAMAHA DTR · Guru

have a look at honda nsr 125 manifolds, they are a similar size

NorDt · Guru

Okay, The only requirement for making it fit is that the holes to screw it onto the engine fits right ?

the only way is YAMAHA DTR · Guru

NorDt · Guru

Maybe ill make one like that too. Does the Angel on the bend matter ? Does it have to be exactly like the stock one ?

the only way is YAMAHA DTR · Guru

you will need to work out the angle to miss the shock absorber, this might help http://www.racingsm.org/evocrr.php

NorDt · Guru

Not to be rude, but why would it help ? xD, cant find anything there that sais anything about how he made the manifold ?

NORFE · DTR Trusted Engine Builder

looks like they just made it up out of alloy, then treated it so some fangle dangle coloured coating

another thing lookin at them heds on there with the o ring mod
http://www.racingsm.org/evocrr.php
what seals the outer edge of the water jacket?? cant see no outer groove in the hed or barrel??

confuse

NORFE · DTR Trusted Engine Builder

just reading about that crr bike and they have used a tzr gear box for the faster top end speed, im asuming the tzr gear box is better for the higher speeds ,and the dtr is geared high internaly is that right??

NorDt · Guru

Looks like he has a rubber tube around the manifold and the carb to make it air proof.

Is the trick then to make the manifold so big that the carb barely fits inside, and then wrap a rubber tube around it ?, or make it the same size with a tube around it ?

NorDt · Guru

Should i make it with or without the Vacuum box ?, The box on top of the manifold between the cyllinder and the carb ?. Seen someone that doesent use it. Does it have any real effect ?

the only way is YAMAHA DTR · Guru

i would personally, but you don't need it, its supposed to give a bit better low end torque, and make it more fuel efficient and i don't think the carb in the pictures "slots into" the manifold, just lines up and joined with a rubber tube

NorDt · Guru

I was reading on the de restriction part on the dt125r page, And i noticed that the manifold has a restriction i havent removed on my own bike.

So this is the plans for the near future, AKA tomorrow, Ill make a manifold wich wont have the restriction the stock one has, wich i am hoping will make a difference, it wil also be 34mm. Im hoping to get it done tomorrow.
Then i will get some carbon reeds.

I was really shocked to see that the really old dts came without a dyno engine for the power valve xD.

the only way is YAMAHA DTR · Guru

you might need to rejet after

NorDt · Guru

Yeah i know, im hoping that with the powerfilter and a new manifold i can use the 310 jet, That what i hear others are using. After taking out the reed valve and the manifold, i can clearly see how the manifold is restricted, alot. I cant wait to get a new manifold, And de-restricting my stock one and let my friend test it on hes dt.

NorDt · Guru

Have you de-restricted your manifold ?

the only way is YAMAHA DTR · Guru

my manifolds modded for my v-force reed block

NorDt · Guru

V-force reed block ?. How is it different from the stock ones ?

the only way is YAMAHA DTR · Guru

this is before i change the carb http://dt125r.activeboard.com/t43884306/have-now-fitted-my-v-force-delta-3/

NorDt · Guru

Nice, Im thinking ill just buy a uppgrade kit, And change the reed valves themselfes into carbon reeds. costs about 50 euro or something

NorDt · Guru

The reeds im considering buying is called carbon reeds, this is what the shop has to say about them .

Uppgrade kit for your reed valve,this kit comes with new reeds, wich you exhange the old ones with, You get better throttle response with this kit. Theres very small numbers and calculation involved here, but you will get throttle response :)

the only way is YAMAHA DTR · Guru

heres some of my pics of my manifold

NorDt · Guru

Is it the same at the two first pics as on the two last ?.

If it is, why havent you removed the restriction ?

NORFE · DTR Trusted Engine Builder

whats carb off your runnin...nice job on the manifold, smooooooooth as a baby ass ha

the only way is YAMAHA DTR · Guru

last 2 pics, btw it is not a restrictor unless its smaller than the bore of the carb, thanks mate

NorDt · Guru

Well its still a restriction, just read the de restriction part on the home page, makes sence,

the only way is YAMAHA DTR · Guru

i have read it and i did that "derestriction"and made no difference, also lots of people think its a "Guide" for the air flow, yz's cr's kx's all all have that part on there manifolds,

originally i thought i was a restriction, but i can now see it isn't

the only way is YAMAHA DTR · Guru

NORFE wrote:
whats carb off your runnin...nice job on the manifold, smooooooooth as a baby ass ha

TMX 30 with power jet