Hi all

It was raining tonight so i took my bike down the woods - as i knew there wouldnt be many kids/dogs about. I started it up- put it in gear and let out the clutch. The bike went backwards. I put it back into neutral and tried again and it went backwards again. i thought great a TY175 WITH REVERSE! 2 more shots and the bike went forward. I was out for over an hour and the gearbox and everything else seems fine now.

Has this happened to anyone else before. Is my gearbox about to crash

Thanks William

The timings out! you'll need to get it set up correctly!

Thanks Scotty. sounds good. Whys that make it go backwards?

its because the bike is ignting the fuel too early so its pushing the piston back down in the way it should really be coming up.

I see. Ill need to get the manual out. but thinking back -

Is this the bit where the points should be fully open as the piston is at the top of the barrel.

If bike runs ok normally then could be that with the engine being cold the engine has missed but rather than stoping the piston has started going back and the engine was running in reverse. Should have sounded like a diesel when it was going backwards.

Had a 250 Bultaco do this to me many years ago, very amusing at the time!!!!

Its great fun alright, particularly for those in the section queue behind you, as you hit them and you all fall over.

I had the first model of the 325cc Sherpa in 1973. The Wollongong trial here in Oz was held on a steamy sub-tropical mountainside.

Basically, an un-vented magneto case use to allow the points to oxidize excessively and close up the points gap -result, timing out, and bike went backwards when started after a section inspection and rammed those behind when kicked into gear when my turn came up. The noise of other bikes around usually meant the rider could not hear it running rough as it ran backwards.

Solution-vent magneto case and set the points a smidgeon wider before going to that venue. Probably did not help that the Bulty was a little oversquare

The bike was cold at the time so could have just been that it missed as suggested. Its running ok now so ill leave it and see if it hapens again. W

My dad's old golf cart they used at the farm had forward and reverse, only selected by which way the electric starter turned the engine when it fired up the two cycle engine!

The Bult and Monts of the 70's prone to that, stall part way up a hill, roll back, and restart going in the opposite direction. I have never heard of how it happens when kickstarting though, as the engine should only be going one directioin.

In theory, the TY250/350mono with electronic ignition was a big improvement over the old spanish stuff. Can't go reverse....NOT! I've had it happen twice, same summer a couple weeks apart, about 3 years back. First time, almost stalled going up a climib, pull clutch, rev a bit, let out clutch, and it shot down the hill 5 ft under power in reverse. It had truly stalled, bumped into reverse, I declutched and reved it up and it went backwards. Thrilling. The second time was more traditional, stalled, rolled back, restarted and just chugged a few times backward before I stopped it. So it can happen, although never before or since. I have no idea why. Timing was fine, actually a bit retarded.

kcj

Any two stroke can run in either direction. A diode can be placed in line to the coil wich would only allow voltage in one direction. Honda used them on MR's.

the TY with electronic ignition was supposed to have that, but apparently not always workihng. If diode fails closed, will pass both ways.

175 with points/magneto though ??? is your timing too far close to TDC?

Hi all

It was raining tonight so i took my bike down the woods - as i knew there wouldnt be many kids/dogs about. I started it up- put it in gear and let out the clutch. The bike went backwards. I put it back into neutral and tried again and it went backwards again. i thought great a TY175 WITH REVERSE! 2 more shots and the bike went forward. I was out for over an hour and the gearbox and everything else seems fine now.

Has this happened to anyone else before. Is my gearbox about to crash

Thanks William

Like every one else said, quite common on Bultaco's, basically if the timing isnt spot on, and you give it a half harted kick, the piston doesnt go over TDC and fires in the wrong direction. Moral of the story - ease the clutch out.

The timing does not have to be wrong for the motor to run backwards. With the timing set perfectly for running in the normal direction, a TY175 will also run backwards. It will be less responsive and less powerful than when running forwards because the timing will be retarded compared with ideal.

Although it is possible to get one with good timing running backwards by half-hearted kicking, if it happens frequently, the timing is probably too far advanced.

Any two stroke can run in either direction. A diode can be placed in line to the coil wich would only allow voltage in one direction. Honda used them on MR's.

My TY250 1976 had such a diode, mounted next to the headlight.

It was an official part of the bike.

This is a picture of my (former) bike.

My (1976 Oceania) TY250 has an ignition diode, but it is a solid black object about 5mm square and 20mm long, in the ignition wire between the points and the HT coil and is located near the carby.

The object on that European TY250 in the photo looks to me like a power resistor used to reduce the current to the battery when the lights are not being used, or in the case of the bike not having a battery, to reduce the voltage to the lights.