Cynic

Dont worry we can arrange counciling to help you cope with riding a 4stroke........ Enjoy..:-)

Ha. Several times i have challenged folk taking one at my dt. Fine i say pick somewhere, sensible like 50 or 60 mile away. You pick the route out, i pick the route back. Legal highways at legal speeds and i'll win. Never had a power ranger dumb enough to take me on yet.

How did you get 1.8mm.

Seeing as you have a full gasket set get the bearings too and tear it down. You know it runs at present so a rebuild with seals and gaskets will solve a lot of the confusion. If you stretch to a carb overhaul kit you should be laughing. The only pieces of kit i would advise over a regular kit of sockets and spanners would be an impact driver, a heat gun and a flywheel puller. Good luck with it.

Just throwing something onto the fire here. I'll use my DT as an example. It spent its first 5 yesrs as a private enduro ride and was found as part of a house clearance.Its an 81 frame with 79 cdi a 125/175 hybrid engine with parts from at least 3 bikes. I have cut and modded the frame too. I know cos its all me i have had the bike from 16. Wifey moans about needing a bloddy big coffin come the day i drop off. Could this explain your bike. Mine in truth is just a 175mx as far as it goes but if you get into the numbers it makes your head hurt. Just a thought. 40 years is plenty for your bike to have been mauled.

At least it is not too complicated eh?

Could it be an import? A picture would be usefull.

Generally the fan and the gague use separate senders. One resistive for the gague genrally on the head somewhere,you may have one for the cdi too. The other a temp sensativeswitch. Prob on the rad somewhere. The very first thing to check here are the switches themselves. We all know just how boringly reliable the early blades are so thats where i would start. Then crack on with DDTs list.

You have the best of it. The early airbox is great if your up to the gearbox in mud but it is very restrictive. As can be seen from the jetting and carb size. You effectively have an upgraded inlet assembly. With a pipe she will be quite the rocket ship.(for a 35year old design). On that basis i would expect her to be happy at around 135 maybe a 140. Compared to the 175 you really do need to rev the nuts off the thing but aside from that the performance is pretty close.

Be very careful taking slack from cables if they are tight you may find the bike accelerates when you move the bars. Not good.

I would still have done it myself. What will you do if you return it to stock. Or is this a one way upgrade. Surely that could transfer on to your next bike......

Wow. Personally i think its terrible but a couple of weeks ago i stripped the engine down in wifeys car to replace the timing chain. A 7 to 8 hr dealer job (min 500 quid plus parts). Took me around 12hrs but including all the oil etc it cost me 70 quid. Was the spedo anything fancy.

Yep mk2

There fine.

The crank is a definite no go for the diy fix, simple as that. Unless of course your an engineer with the experience and kit to press up crankshafts leave well alone. Thats the dull bit done with, 'hand pressure' i thought that when i split one of these. I wouldn't want a slap from the fellow that dreamed that up. As to the bearings they are a doddle with a heat gun. A proper one though, the ones that strip paint not your sisters hair dryer. The cases being ally will expand quicker than the chromium steel bearings and they will come out, they should drift out though. When you put them back its the old heat the cases, freeze the bearings trick, it all fits easy then. Heating the cases makes the seals a doddle to fit too. You cool the crank too, then as you add the bearings to the case they warm and expand making the crank a dodle to fit. Really it will litterally drop in, if you have really got a good temp difference the bearings will rattle in the cases till they warm up. Best of luck getting them out then, LOL Be VERY carefull when you order the crank bearings, when they turn up they are easily mixed up be carefull. Also don't forget the O ring that fits on the crank under the primary drive gear spacer. Make sure you use a good quality liquid gasket on the centre mating face on the cases too. Be a bitch to have it leak later.

Amen to that, whats that saying? " More than 2 strokes is w@nk" or have i got that wrong.

The lil ol DT holds a soft spot in the forum, hell the squires meet could almost have been the DT appreciation society. We have everything from sweet restored rides like Blackhats and Airhead to my working classic. The best bit, nobody askes how to de restrict em, also you rarely get a 'how fast??' question either. We all know, don't care and just enjoy. She will run properly again, bear with it and us and you will be an expert in no time.

Gentle, hmmm, thats a new one. Welcome snuggykins, is that too much, may have had an extra cup of coffee.......wibble

When you put the throttle cable into the carb slide (or valve?) do you have the locking plate that fits in place to trap the clip and the cable in place with the carb spring. It is basically a posh washer but it has a tang that points down and fits into the grove in the throttle slide where the cable fits preventing it from coming out no matter what. Also without it the needle can lift and make things go right strange. just a thought....

Scottoiler would be a good move, i got 22k miles from my scottoiler equipped 600 on one chain and sprockets. I have a scottoiler on the tdr too.

Its biggest problem is its the slow colour, everybody knows the black ones are faster.... And its been steralised.....I mean 'restored'. The real mone goes for the original unfanny'd with stuff. Doubt it will cover the price of the parts.

The TZR's have always had a powervalve, the very first of them had no pully assembly at all but the valve was there and pinned at an ambiguous mid point to give all round performance. Together with knocking out a washer in the pipe, a 240 main (250 if you like flat out) and trimming some webbing in the inlet you got proper full power (albeit a big fkin wheel lifting kick up the arse at 7000rpm and cock all below it , felt great), full power was also available as an option at purchace if you produced a full uk bike licence. Then they fitted the ypvs controler near the tailight at the back of the bike and the pully system. Some people had conned full power bikes, some like an electronics student i knew built his own controller and used a 350 pully/motor combo, others pulled the cap from the rhs and removed the pin and turned it to their preference, be that wheelies or 90mph. Problem was that ment the valve was loose and would rotate back to the closed position, gravity is a bitch right. That sounds like part of the problem here. You need to take off the exhaust and see how the valve is positioned, no other way on these motors i'm afraid. They generally leak at the powervalve too if they have been done.

I can hear numan swearing from here. Pretty good place to start from for a resto......

Was my first suggestion but he said he has bypassed the switch and gone direct to the mag with the headlight. And still has issues.

This is the thing, yamaha's even right into the 90's generated all the power they needed for the ig with out affecting any other systems. The lighting as a result should have no connection whatsoever, the only places they come close are the ig switch, which you bypassed. Also the flywheel. Thing is there should be no connection to the headlight. Can i ask if you have 2 or 3 coils in the mag. Secondly which ones are you using for what? The lighting is deffinately affecting the ig but it should not be able to.