DT125R FORUM

Ok

Bike went to garage, and needed rebore skim new piston and genuine Yamaha head gasket. Power valve was shaved to stop wider piston hitting it.

Bottom end was OK

Rebuilt and filled with silkolene Comp 2 stroke oil and coolant.

Managed to find 3 wire servo, cables pulley etc, which the garaged fitted correctly for me.

Electrics were fixed and tidied up while they were at it - total cost was £360. Incl vat

Now I have full power!!

Not that I have fully tried it yet as the mechanic told me to run in at 200 miles under 6000rpm, 200 miles at under 7000rpm and 200 miles under 8000 rpm.

Does this seem a bit excessive - I want to get that power valve fully opened!

Thanks guys
A Yamaha Garage to do this?

Bad news.
Engine was always running a bit hot, but I topped up with coolant and decided to take advantage of the Sunny weather yeasterday.

Hit 60 on the main road and bam! Back wheel locked solid.
Managed to keep it upright.

Coolant all around back wheel.
Temp gauge off chart.

Wheel seems to be freed up now when in gear, but can't kick down gears into first.

Not tried to hard to do anything, but did kick it a couple of times after cooled - never sounded close to firing.

I'm a total novice in these things, but what's the worst case here!

Let me know, and we can make sure!

Thanks @Nottsbiker

If any one knows, finds or has one that fits please bear me in mind.

I can then start a build thread and you can all watch me mess it up!

@calum so I think I understand.

At the moment the power valve either works at low down or higher revs because it is fixed in position?
I choose that position by turning 180 degrees either way?
By fitting a servo, the power valve is rotated to give me full power depending on revs.
Is this correct?

My power valve doesn't look like most i see in pictures - no cables or slots for cables in the casing. Just a central bolt, flanked by 2 small outer bolts

Can a servo still be retro fitted to this?

@oldman soooo clean

Is it normal for the exhaust to heat up so much then, when the power valve is fully open?

Also died a bit when I kicked up into 6th, ran out of power (maybe wasn't high enough revs)

Another tool to purchase, but I do love having them.

Yeah, the head gasket is on my radar.
The oil looked ok when I changed it - so did the coolant, but I will check the consistency tomorrow.
How big a job is it to do the head gasket for a garage? Ball park cost? I think that may be a stage too far for me to do yet.

I actually put the power valve back to original position as the exhaust got very hot very quickly (smoking from end after I stopped after a 5 min blast)

Actually had a go at turning the power valve around today - 180 degrees so the top of it was flush with the manifold.

Took it out and I thought I had knackered it.... until I hit 7000 rpm OMG

Had a lot of owners, but I would guess garaged, yeah.
Was def kept in a garage from the bloke I brought it from for the last 5 years.

Still has some niggles that I will tackle one by one,
Got hot again today, so going to check coolant levels (only changed 2 weeks ago)
Back brake's pretty rubbish and spongy
Poor electrics mean that the headlights pretty much useless in dusk/night time
Badly resprayed tank means petrol lifting paint

I don't know anything about Engines/electrics but I'm practical enough to learn - Haynes manuals arrived to help me through

Rev counter wasn't working, so I brought a new cable.
Taped the end to the old cable and pulled it through - hey presto, working rev counter.

It's the little things!

Also changed the oil and flushed radiator and added new coolant as was running quiet hot (just before red).

Ordered a new seat cover, plastics and decals. Getting here next week.

About 14,000 miles, but who knows for sure!

Hello everyone,
Just brought myself a DT125R.
Always wanted one since I was knocking around at 15 on my CB125 - finally got the cash to treat myself.

Found on EBay
UK registered from new, engine and frame numbers match.

Bit scruffy, but perfect for me to fiddle around with at the weekends

Not sure if I loaded the photo properly!

Plenty of tidying to be done on the bike, electrics, decals, plastics, tank etc etc, but looking forward to it and coming here for advice!