DT125R FORUM

It should rev to the redline.

Depends on where you get your Zeel from, I paid £200 for mine, but that was like 12+ years ago.

Did you try the powervalve trick I just told you about?

I know that the restrictions on the UK models differ from overseas models, so I am not familiar with what restrictions there are on other regions.

Either way, grabbing yourself a Zeeltronic ignition system will make all of these problems disappear and you'll gain a noticeable midrange boost.

Clutch could be stiff for many reasons. I run uprated clutch springs on my DTR so it is stiffer.

The clutch cable comes off very simply, just slacken the adjuster nuts on the clutch arm on the engine, then remove the cable from the engine. Route it through the frame and disconnect from the clutch perch.

You can then run some lubricant through the cable. I suspect though it'll be the clutch springs.

If the bike is falling flat on its face at 8k, then I'd initially say Powervalve.

Easy way to tell. Take the exhaust off, switch the ignition on and off (you'll hear the servo do the cleaning cycle). Once the powervalve turns flush with the exhaust port, switch the ignition off. Disconnect the powervalve servo from the main loom and ride the bike.

The bike should lose all bottom end, so basically gutless below 6k, but should rev to the limiter.

If this is the case, you've identified it's the powervalve. If this is not the case, then you know the problem lies elsewhere.

I don't support image hosting sadly as it's very costly.

That's a tidy looking DT you got there though.

Best thing you can do for derestriction is to get yourself a nice Zeeltronic ignition system for it. That was the best bang for buck I can think of.

Hey All!

Due to personal circumstances I will be needing to suspend the DT125R Forum for an indeterminate amount of time.

This is an advance notice to say that at some point, in the not to distant future, I will be switching off this forum.

My intention is to relocate the forum/database hosting as the current situation is no longer economically viable.

It is unclear at the moment as to what the future will be for this forum, but rest assured it will be back online in the fullness of time.

I appreciate each and every one of you that contributes to this forum so there is a BIG thank you from me.

Take care & keep smoking!

Calum

Aww that's awesome.

Glad you're getting out there on this motor and it's giving you some success

Such an iconic livery set on there as well. Looks great

Oh wow, what a lovely lovely DTR you have there. Please please please keep that original and no silly mods. That is a little time capsule there.

Sounds good listening to it on my phone.

If it pulls well and starts easy then in all likelihood it's a good motor congratulations

Hello,

Oh okay that sounds good.

There isn't exactly common problems with these bikes, if it's well maintained then they really do go on forever.

At that sort of mileage, and if it truly has never been opened, I'd expect the little end bearing to have worn excessively and rings need replacing. This will be tellable through a rattly top end from the small bearing and piston slap.

But again it's all down to how it's been treated.

The clutch baskets wear out over time so you can expect noise coming from the clutch area.

Other things can be like the bushes on the powervalves can be known go wear out. Again this will be proceeded by rattling noise from the top end. If the bushes are left to wear out so much they can have quite dire consequences.

All of these are minor really and shouldn't take any time all to address.

Look forward to hearing more about your endeavours, they're brilliant little machines when maintained properly.

Have you got access to a compression gauge? Can you measure the health of the engine?

I mean it could literally be anything.

You shouldn't be fouling plugs, ever...

So something isn't right there

Is it smoking excessively?

Are you losing coolant?

Are you losing gearbox oil?

I've had something similar when I fitted a cheap chinese knock off 'racing' coil, so make sure you have a genuine 3RM coil fitted.

Make sure the exhaust is cleaned through.

Make sure the airbox and inlet tract is cleared through.

Measure the HT lead resistance make sure it's within spec.

It sounds to me like the relay. So the starter motor button isn't wired directly to the starter motor as the starter motor requires a lot of current.

Instead the wire is connected to the relay and the relay activates the starter.

So I'd look in that general vicinity, sounds like it's starting to go faulty, which isn't bad considering it's age and the high amperage that it is subjected to.

These bikes are getting to an age where the clutch cush drive rubbers will start to wear out.

It's possible that this is where the rattling is coming from.

Whip the clutch cover off and try and rotate the clutch basket by hand. There should be no discernible play in it.

These rubbers sit behind the clutch basket

Sandwiched between the primary gear.

There were chaps on here that used to do something very similar but to the UK. Go down with a van and collect 5 or 6 bikes at a time.

Definitely worth while if it means you get the right bike.

My Dad imported a Lambretta GP from Brussells a few years ago, was no hassle.

Fair play that's mint.

Hello

Welcome to the forum

Yes, photo uploading is disabled as I host all of this myself and imagine hosting is expensive.

Imgur was the preference, but is now blocked in the UK and therefore cannot be viewed here

But yes a build thread would be awesome.

Very sick! That exhaust looks PHAT!

I am in the process of designing an airbox blanking kit which would plug the gap up nicely and then also house the battery/fuses. Although I've only designed it to replace the DTRE/X airbox.

Hi there,

Pretty sure the RPMs as far as the CDI are concerned are determined by the pick-up/magneto.

So when you switch the ignition on and off, the powervalve does a cleaning cycle. Once this cycle is complete and the engine is running the valve should return into its closed state.

If it is not, then it's possible that the powervalve wires have been inverted and the powervalve hasn't been adjusted properly. I feintly recall this being a common problem back in the day.

Interesting, what inlet manifold are you running.

Presumably the cylinder you have is a 3BN model on there. I wasn't aware they ran a 24mm carb, I thought the earlier models ran a 26mm round slide.

If you keep having problems then it might be worth sending the barrel off to someone lile PJME to have the O-Ring conversion...