veesix24

I'm not quite sure what you mean by two plugs(?). But mine is a 1987 125 lc3, if there is any data etc you require I'll do my best to help. The haynes manual for this bike is easy to get hold of, but only covers the 125 Lc (liquid cooled) models

OK thanks. fortunately there i s a bike shop a few miles from me which still does things the old school way, so I should be able to get the correct lead

I tried that yesterday, I'm going to replace the lead and cap as the lead and cap on my bike at the moment are a one piecetype, and it looks like it came off of a car! Even if it's not part of the problem it'll be nice knowing its not going to cause me any problems in the near future. Would a car one work ok or is that likely to be causing problems (resistance issues)?

I've replaced the float bowl and valve and this has fixed the problem of my carb flooding. Unfortunately this has not solved the main issue and my bike still won't run properly (or not at all!). The sparkplug is still fouling very quickly but I believe this is due to a very weak spark. I have checked the sparkplug whilst kicking the engine over and the spark is very small and only just visible, this is leading me to believe that I must have a fault in the ignition system. I reckon the chances are that one or more of the different coils are screwed (I'm hoping it's not the CDI as they're a bit pricey). I've ordered a multimeter so that I can test the coils etc. hopefully that'll id the prob. If anyone has any other ideas please let me know.

I'm not going to get service kit from the site on ebay i phoned him to check it was the correct kit, he said it was but when i asked him the sizes he told me it was a 20 pilot jet and 140 main jet, mine uses a 25 pilot jet and a 200 main jet. His recommendation was to drill the 140 jet with a 2mm drill bit! knowing that tolerances for these parts are in microns I don't think i'll be doing that! I'll order the parts from motocarb this week as his price is nearly as good but the parts are mikuni not some cheap chinese rubbish!

ok thanks, I will order it and let you know if it's any good

I bought a new one today, yesterday I completely stripped the carb and bathed it to clear any debris/blockages, cleaned and blew through all jets and passageways, and ensured all were clear. I have spotted a full overhaul kit which seems very cheap, could you take a look and give me your opinion? http://cgi.ebay.co.uk/Yamaha-DT-100-125-175-250-YT175-Carb-Repair-kit_W0QQitemZ260566792992QQcmdZViewItemQQptZUK_Motorcycle_Parts?hash=item3caafdbb20 He also has a carb for 40 quid but the jet sizes seem wrong!?!

I believe i have discovered the cause of the issue, the for ridges which run down the length of the float needle are worn which is allowing sideways movement of the needle in the assembly.I will buy a new one this week and let you know if this solves it.

Thank you but I have one, I only use it for part codes and torque wrench settings as I prefer looking and learning for myself, it sticks better than just following instructions that way for me. Surprisingly all the codes and sizes are very clear on my carb parts.

So true. I will post when the problem is solved. Now to try and find some rocking horse dung (sidepanel which covers exhaust) in the for sale section.

Sorry I did mean the needle jet, i know what it all does when i'm looking at it but i dont have a clue what half the parts names are. thats the problem when teaching yourself i guess. Thanks for all the advice oldgitonabike and cynic you've been a great help. Hopefully you wont hear from me again on this subject. THANKS BOTH OF YOU!

I always make sure I shut the fuel off, I have to as a fuel leak where i keep my bike would be catastrophic! I have heard of other dts with the side stand issue so I only ever turn the fuel on once the bike is level. I will give motocarb a try thanks, i've struggled to find aftermarket parts so i've been going on yam main dealer prices. I have just noticed that the worn needle (main jet) i replaced was slightly bent could that damage the main jet and cause this problem? If so I might try and get a kit with all needles, jets, washers etc (is that possible?), at least i'll know i'll have a trouble-free carb for a bit then. Thanks again, it's good to know there are people willing to help someone less knowledgeable.

The problem is that the choke wont stay open the spring clip and rubber are not holding it open it springs shut immediately, if you hold it open it is impossible to start even from cold on a winters day!

Is there a way to test the valve without replacing it with a new one (they aint cheap!!) also I'm not sure how to check whether the choke plunger is seating well and whether it is closing off properly as was suggested in an post earlier, all I do know with the choke is that it wont stay open, it springs back in immediately.

UPDATE I have just double checked float height, book spec is 22mm +/- 1mm, and my reading is 24/25mm so fluel level is too low(?) I have also just noticed 1 float sits about 1mm lower at its base.Is that normal or something that needs correcting?

Thanks 4 the advice cynic & oldgitonabike, I have just tried controlling the flow of fuel using the tap and it does run better though not perfectly (maybe I need to adjust mixture etc once float level is adjusted), I am not sure how to check whether the choke plunger is seating well and whether it is closing off properly, all I do know with the choke is that it wont stay open, it springs back in immediately, I'm hoping I can sort it rather than buy a new one as they aint cheap. I bought this bike for 30 quid as basically a frame/suspension, engine, some electrics and wheels, I have spent 250 quid on all the rest of the parts (panels, tank, loom, lights, brakes etc). Unfortunately i've hit on hard times and can't afford to spend much more. I know i've probably spent out too much on it but I bought it for the fun of the project, not for a profit and to have something a bit different than a dtr. Thanks again for the help and my apologies for going off topic.

I have checked the float height, admittedly not with the best measuring equipment but it was correct to the specs in my manual, I have just looked at the float needle(?) and there is a slight line worn in to it at the point where it seats could this cause over fuelling?

I have a 1987 dt 125 which I am restoring, The engine fires easily and will run sweet for 30 seconds or so but then it very often bogs down, splutters, backfires lots and dies. The bike will not start or run using choke even from cold which leads me to beleive it is running rich, I have checked the (mikuni)carb settings and they are fine and I have replaced needle jet but still the problem persists. When it is ridden it lacks power and behaves as though the choke is on. I have noticed that the spark plug is fouling from the fuel and the bottom of the engine is collecting a lot of fuel. Although I have experience of car mechanics I am lacking in knowledge when it comes to 2 stroke engines, so if anybody has any ideas as to the cause of this problem I would greatly appreciate any input. If I have been to vague and anybody needs more info to help let me know and I will try to clarify the issue. Thanks