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dt125 overfuelling(?) problem


veesix24
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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.

Huh loads of em, next to hens teeth and flying pigs. :D

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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.

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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.

Dont forget the circular gasket for under the valve seat ;)

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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!?!

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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!?!

What can i say...for that price its probably worth it for the needle valve and bowl gasket alone. I bought a kit once and a word of warning, take it easy with the air mixture screw...the one i bought seemed tight in the thread so i didnt force it,,,or fit it for that matter. paid a lot more than that too.

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What can i say...for that price its probably worth it for the needle valve and bowl gasket alone. I bought a kit once and a word of warning, take it easy with the air mixture screw...the one i bought seemed tight in the thread so i didnt force it,,,or fit it for that matter. paid a lot more than that too.

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

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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!

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  • 2 weeks later...

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.

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One vulnerable area is where the HT cap screws on to the lead, if you have some spare, unscrew it and cut off around 20mm of the lead for a 'fresh' connection.

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)?

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Dunno but you will presumably be going to a car spares shop to buy the replacements eh?

Back when i were a lad they used to sell it by the yard and it had real copper strands.

You may see something in your manual about the cap resistance so have a look there.

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Dunno but you will presumably be going to a car spares shop to buy the replacements eh?

Back when i were a lad they used to sell it by the yard and it had real copper strands.

You may see something in your manual about the cap resistance so have a look there.

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

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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?

so u have the manual is there anyway i can get a copy i to have that bike and im tying to get it running do you have to plugs coming from the top of the head

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so u have the manual is there anyway i can get a copy i to have that bike and im tying to get it running do you have to plugs coming from the top of the head

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

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