Yamaha DT 125 DERESTRICTING

[Minia]

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

There is a guide on this forum already. Literally in the "derestricting" sub-forum.

[markus.w]

@Lukas55 it is hard to see the picture but it looks to me that just under the Speedo cable connector is the place where the reed switch was, maybe it's there but the wires are not. Try tracing the wires back it may be tucked away somewhere if it's already been done or you may just find the wires had been cut with no reed switch on the end of them (it looks like a glass fuse or bulb) now I understand they shouldn't be cut off because it could cause you problems with the way it runs so maybe that is your problem.

[Lukas55]

@Minia I know that but there is nothing similar like in my case...

[Lukas55]

@markus-w Thats what I thought, but there is no slot or anything where reed switch could be...
This is how it looks:

[url=https://postimg.cc/7J0LL548][img]https://i.postimg.cc/7J0LL548/IMG-20200922-181715.jpg[/img][/url]

[url=https://postimg.cc/pmpL9cRJ][img]https://i.postimg.cc/pmpL9cRJ/IMG-20200922-181721.jpg[/img][/url]

[url=https://postimg.cc/FkZ2Gvgk][img]https://i.postimg.cc/FkZ2Gvgk/IMG-20200922-181728.jpg[/img][/url]

[url=https://postimg.cc/vDsTPvtG][img]https://i.postimg.cc/vDsTPvtG/IMG-20200922-181733.jpg[/img][/url]

That means there must be some cable but obviously its not black/green because someone changed wires and made mess...
Like there is no white block where wires are supposed to go...It looks like this:

[url=https://postimg.cc/pmtsr4Dg][img]https://i.postimg.cc/pmtsr4Dg/IMG-20200922-193040.jpg[/img][/url]

[url=https://postimg.cc/RJHTVLqS][img]https://i.postimg.cc/RJHTVLqS/IMG-20200922-193042.jpg[/img][/url]

[url=https://postimg.cc/CBtNgQhr][img]https://i.postimg.cc/CBtNgQhr/IMG-20200922-193103.jpg[/img][/url]

[DTR+NSR]

@Lukas55 you first need to work out what model of dtr you have, it looks like it could be a bitsa'. Be worth looking to see what markings are on the cdi and wether it has a 3 or 5 wire power valve servo.

[Lukas55]

@DTR-NSR I am not sure but I think that 3 wires are coming out of servo...Markings on CDI are a little bit erased so it is not clear what does it say...
https://i.postimg.cc/vDXz2TwH/cc.jpg
https://i.postimg.cc/NK2k0x95/ccccc.jpg
https://i.postimg.cc/ns8Y9QBT/cdi.jpg
https://i.postimg.cc/RNDT9Y0k/cdii.jpg

Btw what is bitsa'?

[DTR+NSR]

@Lukas55 bitsa = bike made up from parts from several different bikes.
It sounds like your bike might have early wiring and cdi. I'd be checking the powervalve is in the open position and the exhaust has had the restrictions removed if it's a original yamaha one. Hard to make out much out from your pics.

[Lukas55]

@DTR-NSR Yea I know pictures are not great but I can not even see better with my eyes xD. It has some different exhaust I would say that it have yz 125 silincer... Okay so if the black/green wire is going into the speedo it must come from somewhere...

[Lukas55]

Btw that is 3MB cdi.

[DTR+NSR]

@Lukas55 the black green wire comes from the cdi, but your bike will not have the black green wire. It's only found on later bikes 2004/5 onwards. I've got a feeling yours is running about 1998 wiring and cdi. The restrictions in the exhaust are in the front expansion chamber part.

[Lukas55]

@DTR-NSR So it has only exhaust restriction?

[Lukas55]

Here is video of power valve, maybe its something wrong with it... If video quality is bad I will make better one tomorrow...
https://youtu.be/naA3Zt0piGs

[DTR+NSR]

@Lukas55 the powervalve seems to operate as expected. It'd be worth taking the exhaust off to see if the valve is in the open position when it's supposed to be. It can be fitted 180° out. And to check there's no restrict ions in the exhuast it self.

[Lukas55]

@DTR-NSR I will check that tomorrow. One more question, so is there any chance of putting different CDI with higher rev limiter?

[DTR+NSR]

@Lukas55 yours looks to have a earlier cdi which are considered the best.

[Lukas55]

@DTR-NSR Hmmm okay, that's great. It tops at 5500 rpms in 6 gear so it must be because of exhaust...

[SpookDog]

In my opinion, If it’s only doing 50mph, it’s not because of restrictions, it’s cause there is something wrong with it...
How long have you had the bike? Has it always been so slow? It might just be rebuilding time...

[Lukas55]

I have it for about 3 months and it was like that when I bought it. It had 13-57 gearing so I thought it's because of that but when I bought 16t front sprocket then I noticed it's something wrong... The piston and bearings in the crankshaft are changed 400km ago...

[Lukas55]

I removed the exhaust and the piston looks like this...
https://i.postimg.cc/Bj4tBnD6/adw.jpg
https://i.postimg.cc/xcrXqR1L/daw.jpg
https://i.postimg.cc/ykFkRZDt/daws.jpg

Btw is YVPS set good? Is it supposed to look like that in the cylinder?

[declan]

@Lukas55 looks like the ypvs can be set better did you have proof that the piston was changed