Will.wood

I've just finished the assessment (

I've left it for tonight but I'm going to check it out tomorrow morning. Was thinking of doing a compression test but I dont have a tester. Think I'll probably just open up the top end tomorrow and see what's going on, if I've holed it or it's stuck that means most likely damage to the barrel right?

Well it seems I've encountered another problem with the dt. I was riding home from work and as I turned down my lane the throttle suddenly didn't feel as responsive. My cable is a bit sticky atm so I thought it could be snapping but then the bike cut out completely and refused to start by kicking or bumping. As I was riding home I noticed that the bike wasn't idling and I had to keep revving when i stopped to keep it running. I walked it home and after about half hour I tried kicking it over again to no avail, and after about 6-7 kicks it made a fairly loud bang and started to smell like a firework! But I don't know where the bang came from. I should also mention that all the gears are fine, plenty of fuel, needed to top up on 2t oil but the light only came on 5 minutes before it cut out. The kick start also seems very easy to kick and I can easily push it all the way down with my hand. My guess is that something major has gone wrong inside the engine, but id need to take apart to see the real damage. Just wanted to hear other opinions before I do anything lol. Thanks!

Sorry it's a bit late but I did manage fix it eventually. I did originally use a cheap metal gasket which I expect is why it blew again but I replaced it with a genuine yamaha one and and now it works perfectly and still is.

Well I checked the head again how you said and it all looks okay. However the gasket seems to have blown again! Lots of brown around the middle of it? Anyway I thought for now I'd try and reseat it and see if it worked. I set off 90 seconds up the road and pulled over to check everything was okay. The coolant tank had filled up a fair bit and was bubbling a little bit even though the tank felt sort of luke warm.

Ok thanks, will try this out later on this evening. Shall I check the top of the cylinder like this as well?

Hi everyone, just thought i'd introduce myself. Recently bought a 2001 dt 125 which isn't in the best nick after doing nearly 29000 miles(!) Expect a lot of problem solving threads!

Hi, thanks for the reply. Sorry I forgot to say I did check if it had warped with a flat edge on both the barrel and cylinder head and it was all good.

Hi everyone, I'm new to the site. Hopefully someone can reply and give me an idea of what's going on, any help is appreciated. So I'll start from the start. I bought the 2001 dt 125 and rode it home (about 50 miles) on dual carriage ways and a roads and everything was fine, really pleased with my new purchase. About a month later I noticed water dripping from the coolant expansion overflow pipe from the frame. I rode it the next day to work and it seemed to get really hot. When I finished work I thought I'd top up the radiator only to find that it took nearly 500ml of water! Soon after that the water in the expansion tank started boiling and in the end managed to pop the cap of the tank! I searched around on the internet to see what the problem could be and after scouring forums of a lot of people with similar problems, I thought that the answer is the head gasket. Even though I couldn't see any leakage from the cylinder head I thought I'd give it a go anyway. So I changed the head gasket and got some brand new coolant. I couldn't find a cap/plug anywhere however so I had to get a different one which doesn't really fit well. It sort of just sits on top but fits the rim so I wrapped the cap on with some tape and put some zip ties on. For a few days it ran perfectly, not getting hot, but still leaked a little bit of coolant which I thought was down to me overfilling the radiator. I tried to ride it to college one morning and by the time I got about 8 minutes into my journey the temp gauge was going all over the place. So I stop and see that I've left a big trail of coolant behind me and it's all dripping over the floor (the coolant tank was also steaming but I guess this was because I had hardly any in there?) So if anyone has actually read that essay and has ideas I would be so grateful! I was thinking it could be the water pump maybe(?) but I'm not too sure. Thanks! Will