Ty 250 Autobule

[mjmotorfactors]

Hi All,

I have recently bought a Yamaha TY250 Mono Shock which I have been slowly bringing back to life. I dont know much about the year of the bike and that would be a help so first off, if anyone can point me in the right direction of finding out the year of the bike I would be very grateful. It has a plastic tank and a mono shock rear, with Gold wheel rims.

The reason for this post is that I cannot find the autolube oil resevoir. There just isnt one and from a pdf manual i bought (not very good) I cannot get any info about the engine setup of this.

When I bought the bike I was told to mix the fuel 70:1, but ive since been told it should be autolubed.

I think the bilke has been heaviliy stripped for trails riding and it may have been disabled in favour of direct mix.

Is this approach going to ruin the engine?

Thanks in advance of any responses.

Scot

TY250 (no idea of the year and all the gear no idea :-)

[kevin j]

never had one!

premix a good synthetic oil, use some race gas blended with 92 octane. Not sure of 250, but 350 needs about 95 octane to get rid of the hot pinging, even with head gasket removed.

I run about 60:1 or so.

Eventually youmight want to trim the flywheel to reduce the overun when slowing down the engine, and add cutch extender to soften the lever.

enjoy it.

k

[kevin j]

never had autolube!

Twinshocks did, but more serious off road engines never did. More weight of pump and tank, more complexity to fail, less directly related to fuel flow, and added to throttle cable pull.

premix a good synthetic oil, use some race gas blended with 92 octane. Not sure of 250, but 350 needs about 95 octane to get rid of the hot pinging, even with head gasket removed.

I run about 60:1 or so.

Eventually you might want to trim the flywheel to reduce the overun when slowing down the engine, and add cutch extender to soften the lever.

enjoy it.

k

[dougalthedog]

I have a Japanese Import TY250 Mono (1984) is has a complete autolube system fitted (or will have once the bike is back in one piece again). The main difference between this and the twinshock versions appears to be that the speed of the oil pump is not controlled by a split throttle cable, but only by the speed of the crank.

There is a feed pipe from the oil tank to the oil pump and a return pipe to tha carb, thats it - no cable attachment at all.

I have spoken to several people about this and no-one is sure how the correct amount of oil is sent to the carb as obviously the amount of oil being pumped will be a fraction delayed behind the engine speed and will also be affected by which gear you are in rather than the throttle opening.

Anyone got an answer to this one??

[feetupfun]

Regarding the lack of throttle position input to the oil pump on your Jap import TY mono, the amount of oil sent the carby does not have to match the quantity of oil required on such a short time scale as you are imagining. The intention is to match demand and supply over a timescale of a few seconds rather than a few milliseconds. For this reason it is not essential that throttle position is a control input on an off-road motor. Yes it is a compromise and would probably put the motor at risk if you used the bike for a application where the speed and load did not vary for long periods ie road riding.Yes it is not as technically sophisticated as the system on the TY twinshock bikes but there is also less to go wrong.

I have lost count of the number of friend's bikes that have had the engine ruined when the autolube system stopped autolubing without warning.

If you want oil metering with the highest reliability and the rate well matched to the demand, I recommend using pre-mix fuel.