DT125R ARCHIVE

Rebuilt the top end today and got it running, still revs way high on choke but I can get it to idle with minimal choke but still doesn't do want to idle off choke.

Turning out the mixture screw means I have to put more choke on to get it to idle

Turning it in means less choke, at the moment it's all the way in and it needs the smallest amount of choke to idle

Turning the throttle just makes it bog, although if I open it slightly it revs but then hangs

Definitely runs better than before but still have this problem just lesser

mr karnage wrote:

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so cleaned the tank and put another inlet manifold on and it runs better but the revs hang now

it was an air leak at the inlet manifold, I must have overtightened them too much and warped it. putting a flat piece of metal onb the surface and you can see its bowed

I torqued this second manifold up to spec and it ran fine for a while, but I'm still getting a slight air leak

it just doesn't want to sit flush

should I put some threebond on it

just to clarify it's between the manifolds and reed cage, where there's no gasket

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 Another 3-4 page thread where the answer was in the 2nd, 4th and then reiterated in the 6/7 posts.

I often use a silocone instant gasket on this to ensure a good seal. The mating surface of the reedblock has its own kind of "permanant gasket" which is a raised lip of rubber that will compress as tightened against the reedblocks mating surface.  If the reed block surface is warped then take it off and skim it as per Callums head skimming tutorial or buy a replacement reed block.

Once you have completely iradicated the possibility of an air leak, it is then time to set the carb again. This does suck if you've stripped it plenty of times before but atleast you'll be getting quicker at it.

Without meaning to rub salt into the wound, regarding the carb settings again...if you trusted the initial diagnosis we'd have been there alot sooner. It is so easy to over tighten those. I know I have stripped one on my 350 inlets but it doesnt appear to be leaking since using instant gasket so "if it aint broke" i aint fixing it.

Look forward to hearing a video of your bike running and revving nicely in the not too distant future!

it's bent around the corners so im not going to able to get it skimmed as the other side will still be uneven a second hand one is probably the best route