Timing all lined up and checked , but although it runs it is still sluggish and now i think its a fuel problem with acceleration . Ticks over fine , & revs ok , bit hard to start & if you spray carb cleaner down the bore it will start straight away & idle but when ridden its is slow , popping & farting and running shite , i have sonic cleaned & rebuilt this carb checked for leaks , does anyone know of a compatible carb that will fit ( at least to try ) as XT carbs in the UK are rare & very expensive. Thanks

I've forgotten what I said on this post but did I mention I've replaced cdi boxes on a few at work as blow the advance thingy in the box. If that was the case the header pipe would glow red in the dark & it would barely drag itself along. Only other thing is S I think I said or showed a pic of my inlet cam almost totally round with no lift. Or a low flying duck up the exhaust. I guess the exhaust could collapse inside & block it when powering on, like blowing stuff against the inside stopping exhaust gas getting out. Had that on a go-kart but muffler on the end fell to bits blocking it. OK I'm clutching at straws but I don't realy suspect carb well not yet anyway. See what others say. One more, any chance the flywheel key has broken. We love videos. Helps a lot.

My first thought was that old saying "90% of carburetor problems are electrical"...  but just a gut feeling that CDI might be bad if you truly have gone through the carb well and checked everything out.

I think you’re on to something here, I fought and fought what I thought was carburetor issues on my 83 XT250, ended up switching out my CDI and all of a sudden everything was all good!

Another random thought wnhen we got the source coil rewound on one the guy rewound it back to front --or something. Man did that cause headaches lol.
But a phone call sorted it & said reverse the red & the brown.
That's probably something you'll never come across again.
But by memory the red & brown from the stator the colors fade bad & red & brown look similar.
If they go to a multi pug which i think they do--then cant realy go wrong.
Just keep any DC red battery power away from any cdi red or you'll know where the problem is--follow the smoke.

RT325 the stator was rewired & also a new loom all by Rexspeed shop so i dont think the problem is there but MarkT might be onto it so can i check if the CDI is bad as the manual states i need a Yamaha pocket tester !!!! to do it . Regards

Be real easy if you had a strobe light pointing at the flywheel to see if it's advancing. It moves through about 30 degrees so is a lot of movement to read on the outside of the flywheel. Strobe lights are cheap if you look on the right sites.

Hi , i have put a strobe on the flywheel & the F mark is spot on with the marking on the engine casing . I take it that is as it should be .

But what happens as you rev it?  On a four stroke it must advance smoothly.

Also look for erratic flashing

I will have another go tomorrow and give it a good rev up , should the timing mark (F) stay on the mark or should it move . Thanks