Cynic

So they both start off closed and then open, just in different directions? Or are you saying MaD's is closing up? Its just looking at the video they both move to the same point during the clean cycle. So if mad reverses the cables it will be wrong even though its right, er? The pv pulley box has 1 and 2 on yours OG, is it the same on MaDs?

So whats confusing? One goes clockwise the other counterclockwise. The question is are the valves the same?

Sorry mate don't know WHERE that came from.

Very nice. If you want honesty, spoked wheels would have been my choice.

I'm not blaming the new kids phill, i'm just saying its a shame they will never know them, the greenies will have then removed from memory if they have their way, deliberately burning oil! shock horror. Even the GP riders like Rossi say the 4 strokes just don't light up like the smokers did. One of stoners biggest regrets is that he will never get to ride one of the strokers in anger like rossi did. I know some of the gp stokers were bloody lethal but lets be honest when a tidy 2stroke, even a 50cc comes into the pipe there is a little bit of magic a 4stroke will just never have. They are fikle, difficult to ride effectively and not very economical i'll admit. But when they come good its worth ALL the hassle.

An important point, i can't help with making the diesels go any better but get your e-mail out of open forum or you will have spam from now till christmas. So true Mad so true. I was on to OG the other night and we recon most of the kids in 5 years time wont even know what a 2 stroke is.

I'm thinking the later headlight assy like the one in the clicky link would fit pretty much straight in. It does seem to be uses in a lot of Yam bikes through the seventies.

Well its been a long time since i took any driving test so all i can say s good luck.

Ahhh, the modern view of the world, somethings a little difficult so i'll quit. Buck yourself up man, the amount of sadly's and self defeating trollop in that last post is pathetic.

The last dodgy lever i had, long time ago now though. I drilled and tapped a hole for a set screw that would tighten down onto the shaft, i filed a flat onto the shaft (with the electric file ), drop of loctite to finish. Lasted till i sold the bike.

Plugs can just die, i had one fail just as i was pulling in front of a truck i was overtaking, 2 strokes are dirty engines no matter how you look at it and as a result have bits of burnt oil and bits of carbon floating around. This leads to something called whiskering where a bit of rubbish has briged the gap at the plug. Stops the engine cold as it causes a misfire then the plug wets and thats it. Never run again till the plugs cleaned. You need a plug spanner to have the plug out and check the spark. No point checking it with another plug due to the obvious fact that you don't know if your plug is the problem. As a rule on a 2stroke especially older ones you should have a plug spanner and a spare plug with you all the time, i do. As far as it goes 55mph isn't all that slow for a 100cc bike. Good ones will do more but its by no means an indicator of terminal engine issues.

One of the primary problems for spluttering to a stop with an easy fix . You have tried a new plug haven't you.

Can you not fit a later headlight from a 79, even if you have to fit the shell too surely thats better than these sealed beam units. You can buy the bulbs in packs of 5 i think and that way they aren't expensive. They are 35w too which should help keep the voltage in check. You are getting 8.5v with a 17w lamp so if 25 will bring it in on spec which we expect you should still be safe with 35w. Maybe it will take an extra half of one volt. But you will have a better headlight into the bargain. And spares will fit in your pocket. Have a look, surely that will be a straight sap with the sealed beam? Clicky

The lighting spec for a DT175A is 8.2v at 8000rpm. So maxing out at 8.5V sounds pretty good to me. It gives 6.9V +/-0.5 at 3000rpm too, how does that compare.

And from the connector in the headlamp assy it will run to the ig sw. Sounds like its in there to work with the ig circuit then, maybe prevent sparking at the switch when it connects the coil feed to ground. There is a voltage regulator listed on the drawing, its a sealed metal unit 'that should be' under the tank mounted securely to the frame with a single yellow/white wire. You have proved the battery and the rectifier which will give a high voltage in the lighting circuit (by causing a low charging circuit voltage). The yellow white wire should come from the birds nest behind the headlight. The bit thats intreging me is when my regulator failed my lights STOPPED working unless i disconnected it, then it blew the bulbs out. Like chineese crackers pop,pop,pop

Depends on the model, there are a couple of names for it. Its location is also a little hit and miss. The really early ones are in the loom under the tank. The engine number is always the best way to identify the age and model.

That is more than likely the issue. These bikes use a resistance in the ground/earth return line in the charging,lighting circuit. The resistance caps the voltage at a safe(ish) max of around 8 volts. If you check back that should lead back to the lighting circuit ac connections at the headlight. Thing is it can fail, that will allow un capped voltage into the AC lighting circuit and when the lights are off depending on model and markets the same 13 odd volts into your battery. Destroying it in the process by boiling out the fluid. If you post the first half of the frame/engine number we can narrow it down a bit.

Made me chuckle anyway. Have you got power at the connections?

back to the plot, the pv controllers on RD350's (chances are the dt's do as well) are all worked the same way, Yamaha have been their usual basic selves. The pv sevo and servo controller are fed from the taco feed from the cdi. Or what could be used as a taco feed on the early bikes with the mechanical taco. So, that means that any pv kit with the respective servo will power up the valve so you could use the newer stuff too, so long as the pv motor and the controller match up. Bit of basic wiring to connect the 2 together and your away. Common sence (steady) sayes the 350 kit , or TDR/TZR 250 stuff will be better as it will have been designed from the begining to give full power so no built in meddling to spoil the fun. They all go ape shit at around 6 grand so the valve must opperate at pretty much the same time and with the 250 being 2 125's (litterally it appears) it should open about right as well. I'm not going to say absolutely it will work, but i don't see why it can't.

From previous posts in the past, there will be a cursory regulator. Basically a resistor in the loom somewhere that controls the peak voltage. Its basic and generally works after a fasion. Trouble being its in the earth/ground circuit which is not normally shown (especially on early drawings for clarity ) just to confuse things. I would advise against using a 12v bulb. In the short term it may work but generating double the voltage and the associated increace in power will stress the other electrics. I'm willing to bet they will be a lot rarer than the bulbs. Not to mention it may be damaging the battery as that could also be coping for double figure voltage. Personally i would be looking at sneaking a more modern proper 6v regulator in somewhere out of the way, although it needs some cooling as it can get warm it should be possible to sneak it in. As to wiring, the lighting circuit/charging circuit feed (i'll double check that later) will need to be connected to it, this then allows excess voltage to bleed off and supposedly keep the headlight at a constant level.

Hey don't knock it MaD, when i was fiddling with these they were new, and there was no ebay etc. These bikes went like F seriously seriously fast when you compare it to the stuff trundling around in the early mid eighties. Yamaha and co wanted megga bucks for any kind of servo stuff. I know people nicked bits off 350's. The powervalve controler/ servo motor and stuff. One smart arse made his own programmable PV controller. The more financially challenged like myself and my mates who put 90% of our earnings in the tank needed to use imagination. For me and my mates pretty was far too expensive. Our bikes were fast pure and simple, no tat, trinkets or otherwise added. If it didn't make it faster it went in the bin simple. Indicators gone,mirrors,chrome swapped for plastic. Friday and Saturday nights on the 'new' bypass called the mad mile. A roundabout at each end and 2 miles of dual carriageway inbetween in open country, now surrounded by houses and has 40 limit with 3-4 extra roundabouts in it . Speed was king. I'll stop now.

Nothing wrong with that mate, rode one myself for a couple of weeks after my bike was nicked years ago, well one of the early RD's with the ALL NEW powervalve motor. Dead as a dodo till just under 7 grand then bang, lean foreward and hello captain Kirk, "warp speed Mr Sulu". The later powervalve servo stuff will retro fit if you swap the loom in from a later bike, probably not all that cheap, but you will need the later cdi and servo controller and the PV motor to go with it. You can see the mountings for the black box, or should under the pillion seat. I recall that 350 ypvs stuff can work quite well, i believe its the same stuff (Yam are pretty lazy like that). Trouble with that is finding good kit to begin with. A couple of TZR's were converted using old fasioned car choke cables and a 350pv cable box (the bit that fits on the barrel)Back in the day. When you want low grunt pull one cable, when you want fast pull the other. With gradients in between. Not all that sophisticated but its not all that dear either. And can be opperated going down the road if you fix the top of the cables on the top yolk.

£18 and hour, your vehicle, your tax, your insurance, your fuel more than likely. Who's paying who.

You've bought it new and had it for 4 years but its been nothing but hassle, grow up. With a first post like that you may want to stay with the Suzuki's.

Don't know whats going on at the front there, but essentially the big big bits in the picture are Yamaha RXS100 circa late eighties/early nineties. Probably later with the blue colour i don't recall it being all that popular the burgandy seemed the colour of coice.