Hi, I'm new to this forum. Just got my Yamaha DT125 R 1999.

I have a little problem with it, it runs fine at low revs but as soon as it gets to around 6000 revs it bogs out, also as soon as the throttle is opened fully it does exactly the same. It's not a restriction as the amount of revs it bogs at changes every time. Thought it was a dirty carb but its not that as had it all cleaned up and didn't stop the bogginess. Been told it could be my coil so I've brought a new coil.

Any other ideas on what it could be?

Carb balance, timing, idle, clogged fuel line, dirty air filter... Need more info.

An Intro wouldn't go amiss, either

Sorry, it ticks over fine, all of my fuel line has been cleared, have a brand new air filter in there and brand new spark plug.

And what sort of intro would you like sorry? Haha

Here's an example of a good one:

This is a community, so folk here not so keen on replying to one-post wonders whose first post is a demand for help and doesn't even have 'please'. It's considered kinda rude, y'see

I apologise, I'm just young and rush in to wanting to know things quickly. Well I'm 17 and from Essex, my DT is my second bike, hardly got to ride it yet but I bloody love it. I've always loved bikes growing up, main reason being I have a dad who's a biker and also a motorcycle instructor.

Hi and welcome to the forum.

As Ttaskie say's, this section is for new members to say a hello and, if they want to. tell us a little about them. Please have a look at the following link.

We are a friendly bunch but many of us don't bother to respond to first post questions, especially when they are posted in the wrong section. This type of post should be posted in the workshop area or the duel bike/off road section which can be found at the bottom of the first page.

Telling us a little about you helps to answer the questions better.

Thank you for the advice, wasn't too sure what to do or where to post anything. As I said about, just young and eager to get closer to finding the problem with my bike

Hi, assuming your bike is 2 stroke not too sure if this will help,if you are having to get this done by others,but here goes. First make sure you have a good flow of fuel from your tank,just remove the pipe from the carb,have a container ready,then open your petrol tap,should be a steady stream,(same "thickness" as the bore of the pipe)

If this is ok,then you are going to be looking at the carb again, if you are able to, 1/remove carb,2/check float height(if this is set too low it will starve the engine at high throttle openings. 2/ check the main jet size against makers spec,it will have a number stamped on it,generally it's the biggest jet.

Take your time dismantling the carb and do it somewhere clean,noting everything you do carefully,use tools that fit and you should be ok.

Your float height and jet size should be available on the web or manual if you have one,along with instructions how to do it.

Finally if this all seems ok,I would check your oil pump settings,as too much oil will make your bike run too lean,this will probably show up on your spark plug colour,

Hope this helps

Pete

A new thread has been started for technical help on this. It is in the duel sport area.

Please feel free to welcome the new member using this thread but can you please post any technical suggestions in the new thread.

Thanks.

Cosgrove thank you very much for that advice. The carb was cleaned up by a trained mechanic and the float level was all fine. One thing we did find was that the main needle was bent but we manages to straighten that out for the time being but I have ordered another. After it was cleaned out the bike run a lot better but bogged out at around 8-9k revs which is making us think its an electrical problem.

Sorry DirtyDT, will go onto there now

Welcome geordy " thats a great reply from cosgrove, covered every angle. bent needle sounds suspect, or too big Main jet,

and just because it says 190 [ or whatever] on the jet, dosnt mean some flash Harry hasn"t drilled it bigger, at some point,

Thanks a lot for all the help, appreciate it a lot. I have ordered a new standard jet too but do you know believe it could be electrics at all then?

Is the air filter standard or has is a k&n fitted.

TTB