Yamaha DT 125 Problem (I'm Clueless) Please Help BCF's!

[RalphCh97]

I have a Yamaha DTR 125 2003 Model, A RPM problem occurred a few weeks ago now, I have tried everything that I can think of, Before i start ill explain what the bike is doing.
The bike wont rev past 5000 RPM, In fact depending on gear lets say 5000-6000-7000 RPM, It splutters when you get there but it doesn't feel like its electronically restricted, The bike revved smoothly and high before the other week, I went to ride it one day and this occurred, It hasn't been sat for a long time or anything!
Its been fully de-restricted, if this helps to anyone, Has Power-valve servo, Reed switch done, Dep pipe, Athena 170 Top end, The CDI is 3RM 30, But it revved before nicely so surely it can't just suddenly be the CDI.
Since the issue, I have cleaned carb, checked powervalve, Changed plug, Drained fuel, changed spark plug cap, Cut coil and rethreaded to make sure the connection is solid, Has plenty of compression, Should I replace my coil?
I'm stuck for ideas now.
Please help if you can, Cheers- Ralph.

[Taught2BCauti...]

If you still have the old ECU, try putting it back on to eliminate the new one.
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Honda Varadero XL125(V8)
www.TheFutureIsHere.eu

[monkeybiker]

Was tank low on fuel when problem happened? When you say you drained the fuel did you drain the fuel tank? Could it be possible that water got into the fuel tank?

[DMCpro]

Coils always going on these sounds like it's starting to pack up. I would replace coil and plug after putting the coil on a coil tester
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Honda CB-1, TS125X
VW Golf Estate

[robertw95]

Whats the mileage? Has the green/black wire been earthed
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07 Dt125r, sv650s k8, zx6rr 04

[RalphCh97]

Thanks for the replys! Green and black wire is earthed, done 1000 miles since full engine rebuild! I was doing research yesterday and like you said, I have heard the coils are always going! So I have ordered one on eBay, Only 12 pounds so not the end of the world if it's not the coil!
I will let you know in the next few days if it makes a difference!

[RalphCh97]

Wasn't the ignition coil, next up shall I remove exhaust and check if it's blocked?

[Boxing]

Mine wouldn't rev past 7,000 RPM's. It turned out to be the exhaust padding in the silencer not lining up with the hole. Cleaned the expanny with petrol and a rod as well. Often get bits stuck in the little bit of the exhaust going past the battery tray to connect to the silencer.

You haven't installed any alarms or anything under the seat where the airbox is? If you have make sure you aren't blocking the hole if you've removed the snorkel.

[RalphCh97]

Cheers for last reply! My exhaust looks very clogged at the silencer, can't take the deps apart though as far as I can see so I'll do what you did, just pure petrol and some skins of rod!? No additives in fuel? Anything else I can clean it with? thanks!

[RalphCh97]

So I cleaned out the exhaust and no difference! I then took the snorkel off the top of my airbox and now it's revs fine and smooth but I'm worried it's running to lean, running a 260 main jet!

[RalphCh97]

What I'm unsure about is how it could all of a sudden work without the snorkel, but worked fine with the snorkel the other week?

[Boxing]

[RalphCh97]

Seat isn't, it's now running lean, I am going to try a 270 main jet instead of 260, but I might try the snorkel back in and then try a 250 jet as its running way to rich with the snorkel because of this!
im just curious on how it can suddenly run rubbish with the snorkel in and good without when it was set up with the snorkel in!