rh-dt100

Hi I am still looking to cure my DT 100 fault. It wil not pull at anywhere near full revs under load on the road. It will rev up on the stand but will just not pull. I have re built the carb, cleaned the exhaust out etc etc. I have put it at the back of the garage since September (in frustration!!!!), but I really want to get it running properly if I can Could I be loosing crankcase pressure? If so is the cure an engine strip down to replace the gasket (s)? Many thanks

Hi The air filter had turned to mush, so I tracked down a genuine part from the Netherlands The reed valve looked ok (removed it a few weeks ago) but I will look again, maybe I will post a picture. My propblem was initially overflowing (the bike started then stopped), then no fuel at all getting into the bowl depending upon my setting of the float. The best information I have been able to find is a setting of 20mm float height, Mr Haynes does not give a measurement. Following your advice I have measured it and it seems to be set at 22mm, so I guess that might be the problem. I am off to the Beaulieu National Autojumble in Hampshire at the weekend, I will be looking for a geunuine workshop manual, they turn up from time to time Thanks again.

Hello Thanks for this, to be clear it did run but it was pumping fuel out of the overflow. After I tried to adjust it no fuel at all, then back to overflowing, a bit of a see saw, all or nothing! I will try again this weekend......... instead of smashing it with a club hammer.......I was very tempted!

Hi It seems my problem is the float height, I am getting either too much fuel or none at all. Spent all day tying to set the height but I can not find a middle setting, any suggestions on how to set it correctly please

Hi Can I have some pointers to help me with my latest problem in getting my DT100 on the road? Having got it up and running (well enough to get its MOT and able to be used at low revs) it refused to pull from mid range, 30 mph max. I have now looked at the possible reasons I have stripped out the exhaust and decoked it, lots of carbon, but no difference on the road. I sent off the carb to be ultrasonically cleaned and it has been returned re set, with new jets etc I also cleaned out the tank and fuel filter at the same time Now having re fitted the carb it will not start, noithing, no sign of life. I have a healthy spark but a wet plug. I also noticed fuel coming from the overflow. So could the needle jet be stuck open? Where should I set the mixture and air screw (assuming they are wrong) and what else should I check? Fuel is getting to the carb no problem. Any advice much appreciated!

Hi. So far i have replaced both tyres and battery. The air cleaner element had turned to dust, i tracked down a genuine part in Holland. The carb had 20 year old petrol in it and has taken some cleaning to make it run. The front fork seals needed changing along with the kick start oil seal. It now runs and now has a mot. I took it out on the road for the first time in over 30 years last weekend. It has a couple of issues. One it will not pick up and run at high revs under load.I have removed and cleaned the exhaust by burning out the carbon. result, no change. I have now sent the carb for a re build. The other problem is not charging the battery. This results in the turn indicators not flashing. no idea where to start with this one.

Yes, too good to let it go. Only 12k on the clock. A few problems to sort (carb & charge fault) but it got its MOT last week.

Hi Yes,not everyone likes it, but it is very 1970's .

Here is my 1977 DT 100. I have owned it since it was 6 months old, stored for last 31 years.

Hi Can anyone tell me how to set the air screw on my carb please? not sure how many turns out it should be. Diagram of my carb at http://www.cmsnl.com/yamaha-dt100d-1977_model8610/partslist/B-02.html Thanks.

Yes I can see the logic. I have also been told to look again at the carb, could a jet be blocked even though it runs evenly, but only shows as a problem under load? thanks

Hi no it is a sealed unit, it splits as a whole unit. More heat might do it.........

Hello not sure where to start really,here goes. I have just put my 1977 DT 100 back on the road after 31 years. This has been a great project for me and my 20 year old son. We have replaced a few oil seals,battery tyres, air filter (original foam type).Cleaned the carb half a dozen times and it now runs fine on idle and revs. My problem is that it will not pull up the rev range,it is flat out at 30 mph (ish) and you can feel it holding back. I have tried to clean out the exhaust (by heating with propane gas torch) as I thought that might be the cause. Not sure if it could still have a carbon build up. Also the fuel tap will only work on reserve, could it be running out of fuel under load? Any advice would be great.Thanks Richard & Matt.

Hi Thought I would join the forum to mark the return to the road of my 1977 dt100. It has spent the last 31 years in a shed I.last rode it in 1980! It looks pretty good,I took the time to grease all the chrome,oil in the tank etc to preserve it. Have a few issues to sort out,will be asking for some advice no doubt. Anyway I rode it today and it made me feel 30 years younger if nothing else.