What's missing here?

[Pablo13]

Cool. Thanks for the replies, I'll keep on scratching me head

[NINJA]

@Pablo13 I would be very surprised if the carb was restricting RPM's, I would look elsewhere for more obvious restrictions if I were you. Such as CDI, exhaust, Post some pics and tell us the specs of your bike, Ie. Which mods it has etc and I'm sure someone on here will have some answers for ya!!!

[NINJA]

@Pablo13 Also see here for info and tips on derestricting;

https://dt125r.co.uk/topic/578/derestricting-guide

[Pablo13]

It does rev higher than 9k, just very slowly, lol. It's a 93 French import, and I didn't think that year bike has any CDI restriction?

The bike came with an aftermarket exhaust made by Rino Racing, And I've tried a 220 main jet, now on a 240. Might be placebo effect, but might get to 9.5 a touch quicker that it did. Any help would be appreciated

[Calum]

@Pablo13 Sounds like powervalve to me.

[NINJA]

@Calum Didn't you post a tutorial on 'How to set-up the powervalve correctly dude? As I can't seem to find it. :pouting_face:

[Pablo13]

It goes through the cleaning cycle ok when I turn the ignition on, but does sound lethargic doing it. so that would be a new servo/motor thats needed? To be fair I've not tested the battery either, so not sure what kind of condition thats in. That could affect it too couldn't it?

[NINJA]

@Pablo13 Yes a battery not pumping out the required volts would surely affect a lot of things.

[Pablo13]

PV cables are all adjusted, holes line up etc.

[Calum]

@Pablo13 Yeah but on some CDI's it will retard the valve at certain RPM.

That engine should rev out hard all the way to the red line.

The best way to eliminate it not being the powervalve is to align the valve up through the exhaust port, then disconnect the servo. And take it for a test ride. Bottom end should be lost, but past 6K it should pull hard to 12k

[Pablo13]

So, check the green black wire is grounded and stick a finger in my exhaust is the next port of call?

Cheers for the help btw guys

[NINJA]

@Pablo13 LOLLZZZZZ Yep that's the top notch technical diagnosing we all love on this forum dude - very simple but highly effective!!!

Let us know how you get on??? :grinning_face_with_smiling_eyes:

[Calum]

@Pablo13 That's for RE's the green and black wire.

Just align the valve flush in the exhaust port and disconnect the servo.

That will eliminate it being the valve.

[Pablo13]

Cool. Its a bit dark out there now, but I'll let you al know how I got on soon

[Pablo13]

Its not the valve. I took the exhaust off and aligned the valve, unplugged the servo and it was still the same at the top. What should I look at next?

[Calum]

@Pablo13 Cool, you're getting the same issue then?

Have you done a plug chop? What's the fueling saying? You running snorkel in or out? How old is the spark plug. Is it the correct plug?

How old is the ignition system?

Is the air filter clogged up?

[Pablo13]

Yeah still going flat in the higher rpms. Maybe the coil is weak. No plug chops yet, but I stuck a new one in a few weeks back ngk 8 i believe. Also along with a new air filter as it just ticked over 24km.....about 15k miles. Snorkel is in. Problem has been there before the service too. Would be nice to get to the bottom of it

[Calum]

@Pablo13 Cool, fueling bone stock. Bike isn't modified?

It might be just a tired engine. Low compression and piston blowby.

[Pablo13]

Just an aftermarket exhaust and a 240 main jet I stuck in, that's it. So compression test next?

[Calum]

@Pablo13 What exhaust you running?

Most manufactures stipulate sticking with 210 main jet, despite the uprated exhaust.

I don't know the figures that constitute acceptable levels for the compression test.

I would look at the electrics first.

If the engine sounds sweet, then chances are it is.