DT125R FORUM

@Calum said in Restrictions:

@tunertom Yeah that inlet manifold is a load of tosh, but don't discount Scrim, he knows his shit.

@CYBER-NINJA haha yeah I did chop my exhaust up and removed the cat, but oh my seriously those pipes have some serious weight, so if not for the performance the weight alone is worth swapping out lmao!

Hi I have his destruction manual and seems mostly since 🙂

@markus-w
You told me to cut the wires and keep them apart lad. That didn't work, what i did was i cut the wires and connect them at the right time to somehow bypass the restriction.

@Hark_Ptooie

It’s a bit of a headfux isn’t it? The read switch might not be a simple magnetic on/off by the looks of it. It might set to a default mode if it the CDI doesn’t detect a continuity in the curcuit?

@Blasterguy
It would be helpful to know if it only restricts the revs in top gear, or every gear? I would try joining the wires at least once to see if there’s a change at all…

It might be easier to get an earlier CDI than a read switch…

@SpookDog I'll inspect the power valve from the exhaust port and try to post pictures later, just to be sure
The bike feels fast and has good acceleration so there's a possibility that it's just my speedometer that's screwed up LoL

1997:
Screenshot from 2023-09-04 00-57-29.jpg

Hilarious thing, but it developed a plenitude of electrical problems that I was to inept to manage, so I sold it cheap. Regrets.

@SpookDog Me on my 170 🤣 No maybe not quite that low, but that's what I've come to appreciate with the Yamaha now.

You look back 15 years ago when I first used the Athena kit and you'll see a completely different opinion from me.

But now I have my other screaming two strokes, I am happy to have a DT which doesn't need to be revved to the moon to enjoy. But oh boy I've had some good rips home from work this year on the DT 🙂

I'm sorry for my inactivity... Thanks, everyone for helping me out! I opened the power valve and removed the rubber tube that is on top of the airbox. Now the bike gets much more air and breathes as it should, it goes like a beast. THANKS, EVERYONE!!

Yeah, go through the derestriction guide.

Only when you know it’s properly deristricted can you address why you’re only getting 55-60 mph from your bike. Cause that’s not right restricted or not...

@Calum ok mate. Il speak to him about it

@Coreyp90 There's a full derestricting guide pinned to the top of this section. It covers all years and is most informative. 😉

@declan You can take them off.

Inner rotor kits. But they are not practical for the road. Kill engines and no good uphill.

But for a flat track they're fine.

@NINJA thanks

@calum ok cheers

@calum said in Derestricting 97 DT125r:

@sloanparkes Sounds like the powervalve isn't set up to me.

Ya well I've moved it back the other way... but it doesn't reg above 65000 in 5th and still sat at 60mph ish I'm so sure it's restricted...

And ya @NINJA it was right at the bottom and my toolbar on my phone was covering it saying 97 to 99 😧 cheers dude

@giorgio95 Must be first DTR with cdi on the back of the oiltank ? Wire in speedo you messed with white/black from the reed switch ? Thats linked to the cdi then ypvs servo. Sounds like it could just be a bad connection in the circuit somewhere if its kicking in when you move it.

Easiest and proper way to set the ypvs cables on the pully wheel under the cover is like this.

On the pully wheel in between the cables is a notch in the wheel, when you switch your ignition on and the ypvs spins over its cycle when it comes to a rest the notch should line up with the dot directly behind it. If it does thats it set properly just make sure the cables are tensioned up ok. Same applies if you have to adjust them to get it to line up and then your good to go.

@smudge1995 The complete guide for derestricting;

https://www.slideshare.net/kerryprinceuk/derestricting-the-yamaha-dt125-r-1988-through-to-2007-scrimsmustangs-classic-yamaha-restorations

@MIGHTYMAN That was a restriction on the RE models. To be honest the RE's always seemed simpler to derestrict.

The obvious ones were the exhaust pipe, YAIS (not convinced that's performance lol), Green Black Wire powervalve.

Older Models were reed switch, some had restrictive pipes,

Yeah no worries that what the forums here for.

Firstly carbs don't just fail so don't panic.

In order for the carb to be professionally setup they would be running your bike on a dyno. Failing that they would be doing runs up and down the street until it 'felt' right.

The best thing you could do is set the carb back up as standard as Yamaha spent many hours researching jetting so you don't have to. Unless of course there is a reason why you should be runnning it.differently.

If the plugs are fouled then it is more likely to be over oiling via the pump. Either the pump isn't setup properly or its broken. Despite this is should still run

If it's not the oil pump then it may very well be the crank shaft seals. Or rather seal located inside the clutch cover.

I would always replace the pair and its a crank case split job to fit. At which points it is always worth doing the main bearings and gearbox bearings.

Obviously if this seal is gone iit will draw in oil from the gearbox.

Easy way to check is to see how much oil is inside the gearbox. Although this would be very worse case scenario. Should just rule that out until we've investigated further first.