DT125R FORUM

Been on the RD sites and they are full of info on these bushes ????
Shocked as I've done a lot of Dt's over the years and never had this problem.
A firm called tss make billet power valves and bushes and there is talk of boring out old bushes and having a sleeve pressed in.

Hello bud,probably a bad earth on the rear light or indicators

https://www.cmsnl.com/yamaha-dt125r-1997-3rm9-england-273rm-300e1_model38365/holder-3_31k1131u00/#.WVJpeqfTXMI

Their not failing,they wear out and allow too much movement as in the vid,I've been building 2strokes for over 20 years and have only just come across this problem and thought it might help others out

Yh all new o-rings and oil seals in the PV but the bushes wear and let the PV move causing it to rub on the piston,it's not about shaving down your PV for rebore as even if it had lots of clearance when in correct position it is still able to move sideways and the rounded part of PV is then not inline with centre of piston and will catch the piston,not in the middle like when PV isn't shaved down after large rebore size but more like the side of exhaust port, also standard bore size is still susceptible.
Anyone had this ?

+1 on the braided hose plus jubilee clips
I go to the breakers and cut a big piece of any old car rad hoses and it will do about 5 bikes.
Works every time

Elo guys, has anyone had to replace their PV and bushes/holders ?
It says on a lot of parts websites that this is a high wear item and should be replaced as a matter of course when rebuilding a fresh engine or if it has worn.
I've just done a full rebuild on my nephews engine and the piston seems to be hitting the PV,it isn't because of the rebore or size of new piston etc as it's only on 0.5 OS.
The valve has sideways play (can move valve in and out) and a little up n down play too.
Just thought I would bring this to other people's attention
Hope this stops someone ruining a new engine or helps keep an old engine running.

https://youtu.be/REPjGEhrZKQ

What year bike is it mate as the early dtr ran a bigger piston as standard 56.40
The newer ones use 56.00 ,had this problem myself some years ago,the piston slapped around causing it to eventually shatter and scrape the valve on its way outta the exhaust port (I was young then tho haha)
Definitely get the bore measured by a local engine shop,they won't charge u to tell u the size if ur nice to em
Then u can buy a piston that fits £35-40 or have them bore it to the next size and supply a piston £75 WILL BE LIKE A NEW BARREL HAHA

One of my dt carbs were like that,the best thing to remove it from all the delicate passage ways was acetone,soak it in a container with a lid because it's very flammable and the fumes creep until they find an ignition sorce

Just remove ur clutch first to see if it's a clutch issue,it could be a collapsed clutch BB etc

Check they balanced the clutch properly as this also causes vibration if not built correctly,good luck bud

I thought that too but the piston is fine so not 100%convinced,I thought the piston would suffer first as it's hot and the crank splashes thru a little puddle of oil in the crank cases.
That's why I'm asking tho guys,any input welcomed

No was brand new crank,I know the previous owner and where he had it done
He didn't buy cheap either,everything was mitaka,genuine gaskets and seals,oil pump checked and adjusted £££££ 400 miles bang,big end bearing failure but not 100% sure why

Just taken this outta my nephews dtr all that sharp metal is the rollers themselves all smeared into each other.
I think it was grit sucked in from a badly sealed air filter as the piston has little scratches on the intake skirt but I do know the bike wasn't run in by the previous owner and only had 400 miles on a fresh full rebuild
Any thoughts?

Nice one guys,you learn something new every day as they say,I've always known it as a daytime mot haha turns out there's no such thing

It's my girls bike (offroad)50cc atm but there are loads of bore kits for am6 70,80,90 etc even a 110cc kit
I know they used to use a minarelli am6 in the Derbi too but this one says e50b or something like that haha
Was just wondering if underneath they are petty much the same
Thanks bud

Does anybody know about am6 engines ? and are they the same as a derbi senda engine ?
Thanks guys

Yeah daytime mot, but then u gotta be home by dark