Hello, my Dt 100 is making a noise that I’m not sure what it means. The bike runs well and starts well. The noise is not affected by engine speed, it started after I changed the crank seals. I did have a bit of bother getting the clutch side off. Please don’t laugh but it sounds like blub blub blub blub with a rise in tone that repeats. What might this be? best wishes Tunnie.

 

Try uploading a video to YouTube and then post a link to the video. That way we can hear what you are hearing.

If it started after you changed the crank seals, there is where to suspect first.  If the clutch side is blowing, the noise could conceivably be coming from the transmission breather pipe?

Thanks for replies will try to get the video 

Don’t want to sound too stupid but should you be able to blow or suck through the breather pipe or does it have some sort of valve on a Dt 100

No valve in the transmission breather hose.  I have come across plugged hoses.