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I'm not familiar with the market, but a cylinder piston combo with all the work ready to go has got to be £300+. Any more than that then I wouldn't understand why someone wouldn't go for a brand new Athena 125 kit, or a little extra for the 170 kit.
The Zeeltronic, new they're around £240, so with the programmer I'd say £160ish is what I'd pay, otherwise I'd just go new.
Hope that helps.
Oh how annoying! I've seen this before when people have incorrectly set up the YPVS servo and stripped the teeth on the gears.
It's probably easier to just buy another YPVS servo sadly than trying to find the individual cog.
https://www.ebay.co.uk/itm/307114030022?_skw=Yamaha+DT+125+R+YPVS+servo&itmmeta=01M0T0CTAKVKYBVERW4KK9HKJQ&hash=item47816c33c6:g:QqIAAeSwkVdqdvO2&itmprp=enc%3AAQALAAABAGfYFPkwiKCW4ZNSs2u11xDV5F88zNLFmQlOj5cc4%2FxlPVfMrS0CX9zdgmCMx0exrIiMBYEnl2C70gEhZcvwr3BYq%2BewLJHyMjxf%2BATBLTUnAq5B4Os%2FAuVyeOUNpVSRYxblUNuwL%2BjqWn0F95mbpkEWkXEDU%2F4blrRDuajNXDPVd8py1aTbWsSecsyFqwFQqqWjrgMG65s52PTjh2LPZ%2FOmWbQsy4dMVcVkq6VX2lCX6cdUUBN6SMPZHm3xNkDwYsJXuOa1TCyyOEaSwcuLKfJrQwb9YP1PtVMNdQS0UqCxAXfBI4hQNMZjPJwu4V6qdKAjffzCnESPO3DSoS0%2FsfE%3D|tkp%3ABk9SR9als8CGaA
If you have access to the a 3D printer, or are capable on CAD, you might be able to 3D print a new set of teeth, setting the TPU to 100% fill should be strong enough to cope with the demand. My 3D printer is pretty darn accurate so it would probably do a fair go at it to be fair.
@elan-n Too much to list.
I've done basically most things to it, the thing that's impressed me the most is specifically the Zeeltronic ignition system. I have like 5 of those CDI units now as they're excellent! I fit them to all of my bikes. Single biggest bang for buck.
I've done everything to it: https://www.youtube.com/watch?v=jZ1C_xCmqWg&pp=ygUbVGhlIGxldmlhdGhhbiBQcmplY3QgZHQgMTI1 (build video).
I've ran TZR R 4DL Belgarda setup, to ported Athena 170 kit. I'd say, if you dampen your expectations, then the Athena kit is next inline (after exhaust setup). This is because, whilst it's not rip roaring tear your arms off performance, it gives you more low-end grunt and that suits my setup better.
I have my RS for all out smoker power.
I have had my Romeu for 13 years, it's been absolutely solid for me.
My DTR is wildly tuned though, so it's hard to say precisely what the pipe was responsible for.
I got mine originally from a local Yamaha dealer.
But nowadays either TheTuningWorks or just go to PJME
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 
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.
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.
