Yamaha TT400 - what is a hot start and other questions

[paddy]

Hey, I'm pretty new around here (I just finished introducing myself in the New members form). I'm not sure if this is better here or in the MX section; however, here goes.

I just bought a 1988 Yamaha TT400. I know next to nothing about bikes and have a few questions:

1) The clutch on the bike is really, very stiff (I suspect this is mainly due to a very old looking clutch cable). It definitely works as you can sit the bike stationary in first with the clutch disengaged (you can also stall the bike in first the same way). Because of all of this, I happened to notice that the bike will change gear quite happily (both up and down) with no clutch use whatsoever. It doesn't seem to need the revs to be equalised with the final drive speed to facilitate this. The changes seem as smooth as those performed with the clutch. I guess my question is this: is this really bad for the gearbox?

2) Is 91 octane an appropriate fuel for this age of bike? Do I need to be adding a lead substitute?

3) The bike is quite hard to start when it is hot. I have read a little about "hot starts" but have been unable to determine what they (mechanically) do. I notice the engine has a small lever on the left hand side of the carburettor. It has a two pronged slide that pulls a (spring loaded?) brass pin from the side of the carb. The lever looks like it is designed to have a cable attached. Could this be a hot start? What exactly does it do/how do you use it? Could it be anything else? Are there any other tips for starting a hot engine?

Thanks!

[motorbyclist]

disconnect the cable at the clutch end and see how well it moves - add some WD40 and work it down the cable and it should get easier - BUT the wire may be fraying/rusting in which case you need a new cable. If the shop quotes silly numbers take it to "Robinson Instruments" in the city and they'll make a new one for about $30 bucks ;)

Due to the squential nature of bike gearboxes, and the way a synchro acts as a clutch anyway when it encages a gear, yes bikes change happily clutchless, BUT this is still bad practice - it isn't good for the gearbox in general (ie everything suffers, in theory). Also, even with the clutch in do not 'force' a gear change, sometimes the dogs are hitting each other so let out the clutch slightly to move everthing around - this saves you from bent gear selector forks which basically means you'll be finding neutral instead of, say, 5th gear ;)


nah that's fine - my family used to run an '88 tt250 and it was fine on 91. if you're worried use 98. do keep an eye on the oil though


think of the hot start as an anti-choke; it leans out the mix to help start the hot engine, whereas the choke enrichens the mix to start it cold. attaching a cable is optional but in old bikes you tend to just hold the lever while you kick the bike over.



hope this helps :)