Cynic

As a chain wears it developes a tight spot, this gets tighter and tighter. The bikes only got 9000mile so it could be the original chain (23years young). I adjusted it before i left for the squires. If the chain has tightend up with the 300miles of motorway the tight spot will be felt every time it travels over the front sprocket. Thats what i'm hoping for anyway.

May have some good news, went all over the bike today running the motor listening for noises and such. Deffinite top end rattle, slap or little end not sure but the motor don't vibrate on the stand. Looked a bit more started to piss the neighbours off a bit with revving and such . Still no real vibes. I'm thinking it may be the chain, looks ok but there is a defo tight spot and the sprockets are worn. Could be the 400mile weekend killed it and i've got hung up on the oil thing. Going to order a c/s set and some cush rubbers, no loss if it don't help. Maybe Kev distracted fate's attention

Then you want to be looking at head bearings, rear wheel alignment and check your tyres carefully. A squared off rear tyre or a stepped/worn front, even missmatched/odd sized tyres will cause it. Riding style can also cause it, if you are holding the bars too tight not allowing the subtle moves that you need to keep the bike true, that will give the impression of tramlining too as you are not letting the bike correct its self.

Is there anything that happend at the same time, a new noise, pothole, you found a better way to corner faster so exposing an unknown issue (not as rare as you might think). What is the handling issue, weave on braking, tramlining, no confidence in corners, understeer, oversteer? That may help.

And you've checked tyre condition, pressure, examined fork oil/seals, greased the rear linkage recently?, adjusted the head bearings? checked the play on the swing arm bearings? that is by no means an exhaustive list.....

Kev you've done it now, fate is going to bend you over and make whoopie with yo arse for that statement.

Shit about 5 grand for 13 years service. Bastards.

vibrations got worse today, the vibes were getting worse this morning and were bad enough on the way home to make my feet go numb. Hey ho, i was going to do the wheels over the winter, looks like its the motor instead.

That proves the statement, "The camera never lies" is wrong eh

No, not any noise i can here but there is a definite vibe in the bars and some of the horses have fled the stable. She felt slower when i was out this afternoon. I'm hoping its a compression difference between the barrels.

I hope not, wont know till i take it down.

Oh well, got a high frequency vibe at around 7000rpm now and down around 10mph, definitely need more throttle for comparable amounts of go so looks like i'm rebuilding the TDR's top end over the winter...

As far as the inlet gasket goes its a lot easier to replace than the base gasket so you can save using gen gaskets, just use an old cereal box and cut out a new gasket using a very sharp knife. Using a smear of grease all over the gasket will help prevent it sticking and promote a good seal. Another tip, to make life easy, pop the gugeon pin in the fridge the night before you fit it as they can be a bit stiff, cooling it will make it shrink a tiny bit and it will slide in real easy. Also, put one of the circlips in the piston on the bench before you start. The rags all very well but this way you reduce the chance of dropping a circlip by half.

Dont worry on the gaskets the example photo is for a water cooled bike thats all, the big bore is just that a bigger bore. The dimentions of the base of the cylinder will be the same as the std unit. The head gasket will have a slightly smaller hole in it, whatever the std bore size is but the piston will never make it that far up the cylinder so it will be fine. If you really want to you could trim the copper slightly but i never botherd when i had a bigbored DT50. The only shame is that the pukka kits that used to be about are gone, big ports and high compression rings, the top ring on my old 50 was an L shape and reached up the side of the piston by around 4mm, the second ring was a keystone with expander. The kit i had was just as good to look at as use. Cost 70 odd quid back in the late eighties mind. God that old 50 of mine flew.

Mate of mine had one that was chopped and recond it vibrated like a whacker plate. When we got to rallies you could almost see the releif when he switched it off, he didn't keep it long

Before you start getting all wound up in restrictions, have you serviced it. New blug, checked the brakes don't drag, clean air filter good chain and engine and exhaust not choked with carbon, sprockets good etc. It can make a BIG difference.

I have one of the old aircooled jobbies, an ex enduro racer that has had a colourfull life. In my experience of 2 strokes you realisticly have 2 options. Leave it as is, tolerate 60mph and have a bike that will run to 20000 miles without any majour work. Which is superb for a 2 stroke. Or make it faster, do the earth thing. OG or VEZ can detail that for you and fit a sports exhaust, the tailpipe really does very little except noise. A freer air filter, but keep the original airbox and richen the carb a little. All that may get you to 75ish. But you will be compromising the reliability of the bike, by how much depends on the myriad of other owners. Something for you to think on, my TDR 250 has 4 times the power of your DT but realisticly tops out at around a ton. It weighs about the same and the aerodynamics are comparable to a DT125. A TZR 250, same engine, same power as my TDR. That can crack 140mph in perfect conditions. But, a TDR250 well ridden can lick a 90's 600 sports bike on a twisty road and totally ahnialate the TZR, its the same with the DT. Stay off the straight stuff, drag the racers onto the b roads and you will be king. Something i used to do regular when i was using the DT as main transport when people gave it some stick i had a simple bet for them. "Anywhere you like. You pick the way there, I pick the way back" Funnily enough never had any takers

I in no way ment they are shit bikes, i've got a DT myself, but fast no. As for reliability, parts supply, comfort, fuel, etc they are hard to beat. Its been in production largely unchanged since 1989 (i think, Vez?). The one thing they struggle with is fast.

No way it would be fast enough or able to last more than a few minutes tops before the relay failed.

Far as i can make out i think its reading around 130-140kms thats 75 odd MPH. Has cardboarddave's engine man gone global?

They are pretty much the same as the DT coil, the points should interupt the live feed to the coil by discharging it to earth. Or on a cdi switching it off electronically. Black wire for primary coil earthing to the frame and big wire the secondary high tension earth'd via the spark plug. I take it you need two of them then?

If you wanted to go fast why did you buy a DT?

Yes the later MX has 6. The twinshock DT would be a better bet if you are planning road use. Seats better, gearchange mech is stronger and they are easier and cheaper to get hold of. These are the people to talk to about TY's. If they don't know it then its not worth the bother. Their main business is finding,restoring and riding/competing TY's. TY Trials Good luck.......

Much as i'm going to suffer this, i nearly blew the motor in my TDR thanks to a dead bulb in the 2Tlight. Its very worth the check.