Liam-WRX

I don't know what the reading was in PSI but the mechanic assured me that the bike has good compression and that the problem lies with the carburettor. That's exactly what happens with my bike, 15-20 kicks to start then as soon as I touched the throttle it would stall. The mechanic took the old carb away with him to try and fix it himself so I haven't been able to swap the float bowl yet. When I bought the bike, the previous owner described the carb as being knackered (gushing fuel, dodgy jets, missing hoses, and a broken choke) so I decided to just buy another. However, even though the old carb was in bad condition, it still worked better than the current one so when I get the old one back I'll try swapping the float bowl over first. If that doesn't work, I'll buy a carb repair kit for the old carb that was on the bike before.

Did a compression test and the bike has very high compression so that's good. Because of the weather, I stripped it down and cleaned it all, etc, and the spark, the magneto, and all the electrics seem fine. My uncle's mechanic came over to have a look at it and he said that the problem is with the carb. There's a few hoses missing and the choke's not working properly. I bought the carb in september and it was from a TZR. The same carb more or less but with different jets. Even though it has different jets, it still should have at least kicked into life. The carb on it before was absolutely knackered.

Awrite guys, Do youse think that a dirty carburettor could be the problem for my bike not starting? Cheers

Lol, sorry Vez. I'll try changing the float bowl and tell you how I get on.

I've not been working on the bike for quite a while due to school work and being too busy but on thursday I had some time to have a look at it. I replaced the spark plug with a brand new one (NGK BR9ES). Also, about a month ago, I bought a second hand carburettor off Ebay from a Yamaha TZR125 (Mikuni VM26SS). It's the same carburettor as the one fitted to the DT but has different jets. Since I've fitted the new spark plug, It hasn't solved the problem. It's still got good compression but it's not igniting the fuel. The only other thing I can think of is to thoroughly clean the TZR carburettor and fit the jets from the DT carburettor to it. Hopefully this will stop any chances of the cylinder flooding. But when I try to kick start the bike, I can smell the fuel strongly when I pull back on the throttle. This means that the fuel is definitely getting to the cylinder but there is no obvious reason why it's not igniting. I've fitted a new spark plug with a stronger spark than the previous plug so that should've made a difference when I try to kick start it, but it hasn't. Me and my mate have tried bump starting it and kick starting it loads of times but it still won't start properly. The last time it has started was when we fitted the new carburettor to it which was about 2 months ago. It started for about 2 seconds before cutting out. I waited until the next day before trying to kick start it again. It started on the first kick so I left it for a few seconds then gave it a rev. As I revved it more, it died down and cut out. It hasn't started since and me and Derik are out of ideas as to what could be wrong with it. The last thing we can try is to thoroughly clean the new carburettor and fit the DT jets to it. When I bought the bike, which was in august, it had a few problems. It has a broken kick start return spring so the previous owner personally found it easier to bump start but whenever I tried it, it didn't work so I just stuck to kick starting it. The old carburettor used to leak quite badly hence why I bought a replacement. I could only manage to get it started if the engine was warm and the cylinder had dried out. Everytime I started it, the engine eventually flooded and I wound have to wait a while until it had dried out to start it again. Since I've bought the bike, I've resprayed the frame black and resprayed the panels blue. It's a possibility that the wiring could be messed up. If I swap the jets and it doesn't make a difference then I'll have a look at the wiring.

Hi folks, I fitted the new spark plug three days ago and it still hasn't made any difference at all. It still has good compression but it isn't igniting the fuel so now I can only assume that the cylinder is flooding. Next, I'll thoroughly clean the carburettor and fit the jets from my spare DT carburettor to it to stop any chance of the cylinder flooding again. Apart from that, do you guys have any other ideas why my bike won't start properly? Thanks

The previous carburettor had a broken choke, a broken float valve and it kept pouring with petrol whenever I turned the fuel tap on. It needed to be replaced. I still have the old carburettor for spares. If I replace the spark plug and it still doesn't kick start properly then I'll take the carburettor from the TZR; strip it down, clean it thoroughly, and replace the jets with the ones from the DT carburettor. Surely this should have the same effect as fitting a new DT carburettor. After fitting the refurbished carburettor, the cylinder should have no reason for flooding and, with the new spark plug fitted, it should ignite properly aswell..... theoretically.

Hi guys, I've recently replaced the carburettor on my bike. The replacement carburettor I fitted was from a Yamaha TZR125 which, in essence, has the same overall engine layout and design as the DT125R. The carburettor I fitted was a Mikuni VM26SS which is what was already fitted to the DT125R before. The problem now is that when I try to kick start it, it starts for about three seconds before cutting out. When I kick start it, I can smell the fuel strongly so that means that the fuel is getting to the cylinder but isn't igniting properly. The spark plug hasn't been changed in at least a year so I was wondering if this could be the solution. If I replace the spark plug with a brand new one, will it start, and run, consistently? Thanks

My bike is only used as a field bike and I bought it last month quite cheap but it needed a bit of work. All I want to do now is get a replacement carburettor that will work on the bike and then take it down into the woods for a spin lol

Yeah I've already got one. It's the one with 2002 DT125R on the front.

I see you've got the Haynes manual lol

Yes the ID number is 3MB00.

It turns out that this carburettor repair kit won't be able to fix my VM26SS because it's only meant for a VM26-606 which looks the same but has different gaskets and pilot jets. So now I have a dilemma. If I bought a Mikuni VM24, and bought the correct jets, would it work? If any of you guys have a DT125R, which carburettor is it running on? Thanks

Thanks mate See if I bought a Mikuni VM22 and purchased the correct jets for the bike, would it be suitable for my bike? Cheers

I've just bought the carburettor repair kit on Ebay. I'll let yous know how I get on. Cheers