Hi guys,

My DT 125 MX has been running well with very few problems apart from it dying when accelerating quickly. 

The bike runs well but when you pin the accelerator open fast, the bike feels like it doesn't want to go any faster, and the revs drop 'bogs down'. 

I took the carb off and cleaned all the jets, put it back on and still have the same problem. The clean helped slightly but not much. 

 At the moment, the air filter is a stocking which isn't ideal, when I remove the air filter the bike dyes much more, even at slower speeds. I tried putting some thicker foam over the intake to in theory 'increase pressure' thinking this might solve the problem as seen as I already cleaned the carb. This made the bike way underpowered and it wouldn't pull off. 

I've seen you can buy cheap replacement carbs of the Internet for the DT but wasn't sure if they'd be any good. 

 

Since cleaning the carb, the bike started as usual for around half a week.  Forthe the past few days, the bike didn't want to start, it did nothing when being kicked. Then all of a sudden of the 10th or so kick it would start, when the bike had been used for a little while and sat again for an hour or so it would start first or second kick. Just when it had sat overnight and throughout the day it wouldn't start. This sounded like a faulty kill switch but I don't think it can be. Since it doesn't want to start, the bike starts second kick rather than like it did previously on the first kick  

 

There re is a tiny minute hole on the front end of the exhaust that does let out some air, could this cause such a big decrease in power?

 

Any advise you have is much appreciated. Should I buy a carb? Should I buy new jets? Should I buy a proper foam filter or will this have the same affect as before? Is there something else I'm missing?

ps. I can't find any leaks in gaskets that might cause loss of pressure. 

 

Thanks for all

 

Dan

Edited October 15, 20159 yr by DJYAM

Fit a proper air filter...stocking indeed!..,

Do you think that'd solve the power issue? If so I'll order one now! Hahah. 

Have you any experience of these carbs that are sold on the web? 

I'd stick with the original carb unless for some reason it's not useable. Have you got all the original airbox and filter arrangement?

The airbox is all original, Just the stocking which obviously isn't haha!

I have ordered a new filter and see if I get any results. 

 

Thanks 

Gut feeling for me is float height. It is something that dt mx's seem sensitive to.

What colour is the plug?

Hi Cynic, 

Plug is a tan/black dusty colour. 

I'll open the carb again and try a new pilot jet as the one I have is knackered. 

I'll also give the floats a good look at.