Thanks calum,as u can see its a way off yet,we've got 2 other dtr's and a derbi atm so lots of bits to sort out but thats all part of the fun ay

Hi guys just a quick hello ,I'm new here but not new to bikes,the forum looks great already and I hope to contribute to that and some good banter of course.
So hi guys

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

The engineering side of it is right up my street however the funding side of things escapes me right now haha oh well one day maybe

Check this version out yuck
https://m.youtube.com/watch?v=kuq7KZJl6vk

Cheers rogering

Thanks guys,I'm currently learning to upload pics as we speak,hopefully I've got it sorted,so will upload some pics asap,I've got a busted leg atm from coming off a couple weeks ago so can't get down to the garage very easily but I'll get some done

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

Ah I see,get a long screwdriver and put it through one bearing so it touches the inside of other bearing and slowly tap it out,make sure to move the screwdriver so the bearing comes out strait

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

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