feetupfun

1 Yes just cut the wire and leave it there 2 I just run a short wire to the condenser from the LT side of the HT coil and have a bullet connector at about carby position that is easy to get to to disconnect the points from everything else and easy to connect the light bulb wire to for static timing setting (don't have to take the tank off) 3 Any condenser from a car that has points/coil ignition is fine. They are getting harder to find nowadays.

That plate also allows the ignition to be removed and replaced to inspect or replace the crank seal, without having to reset the points when reassembling.

That plate allows different ignition systems to be fitted to a generic inner case casting ie a trailbike or MX bike that shares the same LH motor casting with the TY250A may have a points ignition with mechanical advance, or it might have an internal rotor elctronic ignition.

Taking out the lighting coil will not affect the ignition system. If you are talking about the stator backing plate, then it just a slight issue with the english translation from Japanese. What do you reckon it should be called?

Alan yes it is fine to do that on a TY. The condenser can't tell what brand bike it is on. Regards David

What makes you think you will get unconflicting answers about premix ratios on this forum?

Yes you did miss something. They were sold in Europe and are something of a cult bike - as are TY50s. We didn't get any TY125s here either.

Its good they eventually ditched the tubes. Thanks Tim I wasn't sure which models had them.

Yes probably piston slap but may also be the primary drive gears if the crank end is running out. If the noise is from the primary gears the noise will be the same under most conditions while piston slap will sound worst while on closed throttle overrun from highish RPM. Spring loaded tensioners seem to be more popular than the chain guides. Theres a neat one available that mounts on the gearbox case. Have a look at what other riders use. Museum standard bikes will have the tube guides while many ride bikes have a tensioner.

Sorry no photo, but a riding buddy of mine used the same system for transporting his trials bike from Rockhampton (Queeensland) to Brisbane (Queensland) (650km each way) for trials competitions through the late 1990s. He used a Yamaha Super Tenere XTZ660 and had it set up well with communications (CB radio, phone and stereo).

I sometimes suggest to young people that they should get a job and earn squillions of dollars using their knowledge while they still know everything (before they get older and forget it all)

Replicas of the standard mounts but made in stainless steel are available from Fred and Debs KT Parts in New Zealand (and lots of other good stuff for KTs)

The reason why the condenser may be the problem is that you are checking the ignition timing by measuring when the points open, while the timing of the spark at the plug can be quite different to when the points open if the condenser is not working. Reasons for why the motor may not be sucking enough air are most commonly the rubber tube between the carby and barrel gets a split, crankshaft seals leaking or blown cylinder base gasket.

Is the fuel in the float bowl getting mixed with the incoming air? You haven't said if the plug is getting wet or not. If the plug isn't getting wet by you trying to start it, then the fuel is not getting mixed with the incoming air. You also didn't mention checking the pilot air passage for a blockage (old filter foam maybe).

Here is a brochure gallery that may help you ID your 349 http://www.southwestmontesa.com/gallery.html

I agree with mattylad about the monoshock OSSA and I would also allow Mick Andrew's 1973 works cantilever monoshock trials bike in Twinshock class, on the same basis. The Yamaha cantilever rear end was obviously found wanting because the frame was later modified to a twinshock rear end. Like the Yamaha works bike, the OSSA cantilever suspension was a design dead end. Both would be quite inferior to most of the twinshock bikes commonly seen in competition nowadays - and should be warmly welcomed into twinshock competition.

I see the bike you are talking about now. We didn't get that model here but it looks just like the XT350 we did get till about 1984. Yes the XT400 motor is way too tall to fit in the TY250 frame.

There is no XT400. The bloke in France modified an XT500 to look like a trials bike. An XT500 motor will not come anywhere near fitting in the space of the TY250 motor. Run a tape measure over a few 4 stroke motors (mainly the height of the motor but also the length) and compare them to the TY250 motor you will see what I'm on about. A TTR125 motor would come close to fitting (with reduced ground clearance) but I suspect you are after something bigger.

The "air" is meant to be nitrogen and I have found that 70-80 psi works fine. 25 psi is probably a little low for the seals to work properly.

Using the (64mm stroke) Alpina crankshaft and top end is a common mod for people who want more grunt than a 325 Sherpa T provides. The Alpina port timing and compression ratio is fine for trials. My Alpina 138 is an overbored (360cc) 64mm stroke motor and the performance is quite refreshing on big hills - even with the standard 27mm carby and exhaust.

Yes there are different model 349s The first model was 1979 and has a red tank with fuel level sight guage in the side of the tank, and has a longer wheelbase than the later models. The white tank one in the photo is the second model 349 and is sometimes called the "white wonder" Third and later models also had red tanks.

Dave you aren't the only one I confess to assembling my M138 Alpina motor (my first Bultaco engine rebuild) three times in 2003 before I got it right Attempt 1 - crankshaft wrong way round (I managed to do this by holding a conversation while I worked) Attempt 2 - one shift fork installed backwards (it looked OK and fitted together nicely, but would only allow 1st and 2nd gear to be used) Attempt 3 - hooray, it all worked and has ever since!

The crankshaft bearing issue can be tricky if you look at repair manuals because some 5 speed motors have two bearings on one side and one on the other while others have only one bearing on each side. A point to note is that some people use a roller bearing one side to better allow for differential expansion between crank shaft and casings. This also makes assembly even easier. The ball bearing in the other side holds the crank in the middle. Another point is that the 5 speed Bultaco motor has a tendency for the main bearings to spin in the casings. It's usually no big deal, but it is a good idea to have a good look at the bearing seats in the cases to see of yours has had this happen. If the old bearing outers have been rotating, it is a good idea to have the bearing seats sleeved back to the correct size, using either steel or aluminium sleeves, to reduce the risk of it happening again. Providing enough bearing (balls to grooves) clearance is important because unless there is enough clearance within the bearing, differential expansion (crank to casings) will eventually work the bearing seat fit loose either in the cases or on the crank (as well as putting a lot of side loading on the bearings).

AVGAS is fine if the sparkplug heat range is right. I don't know what pump gas to recommend otherwise because your pump gas is likely to be quite different to our car fuel. We can buy 98 Octane unleaded car fuel from the bowser, has no ethanol in it and it works fine in all my air-cooled trials bikes. Standard car fuel here is 92 octane with no ethanol and it does not go quite as well in the bikes as the 98 octane. We also have 95 octane with ethanol which I only use in my car. I suspect all your unleaded pump gas varieties will contain ethanol and that the ethanol may damage your fibreglass fuel tank. My recommendadtion for your OSSA is to use an NGK B6ES plug and AVGAS premix, and if it fouls another plug, work out what is causing the fouling by inspecting it closely.