Help! Yam SR 125 gear-jumping, and start-up problems

[jen99]

I've been learning to ride on SR125s. I've had the same problem with two school bikes, and now with a 2001 SR which I've just bought.

This is: if I'm waiting any length of time at a junction / lights, I often find that even though I've put the bike in 1st gear, when I go to take off, it's in neutral. It seems to 'jump' back into neutral. It happens about one time in four. Even if I keep the clutch and throttle at biting point, it happens. Is it me, or the bike??

Also, changing down - often I stamp down pretty hard, but sometimes in the lower gears (2nd and 1st) the 'message' doesn't get through. This can be really dangerous when I stop, and have to take off quickly due to traffic conditons and don't get time to check whether I'm REALLY in first. I stalled while entering a big roundabout yesterday, side on to the traffic.

My second main problem - this is specific to the bike I've just bought - is difficulty starting and warming up. I pull the choke out, and use the electric starter - the engine quickly revs really hard . But as soon as I put the choke back in, the engine dies, even if I open the throttle a bit first. Then it's hard to start again. It can take 5 or 6 attempts.

I bought the bike from a girl who'd left it standing (with petrol in) for over a year. I had it serviced and mot'd, and the mechanic says he cleaned out the carburettor. I'm using the bike for my practical test on Tuesday, and am afraid I'll stuff up.

Thanks for any help you can give.

Jen99

[Frost]

starting problems are common on old small capacity bikes. i normally start mine, and leave it running for a good 2 mins before i try and ride.

try starting it without any choke, or on half choke. try starting it with choke, leaving it running for a minute and gradually easing the choke off.

if nothing works then check the mixture to make sure its not running too lean.

as for the bouncing in and out of gear issue, alot of bikes do it, some more so than others.
if a bike wont go into gear, try putting it into neutral, letting the clutch out all the way, then have another go at changing into the gear.
some bikes bounce out of gear because the gears don't mesh together properly, roll the bike backwards or forwards and it should go in next time.

I've found my best solution to this problem is not to block change, when stopping at traffic lights, rather than stopping in top gear, then changing down to first, change down using the engine breaking, together witht he brakes so that you roll up to the lights in first gear and are ready to go at any time.

[jen99]

I do warm up but it doesn't make any diff. As soon as I put the choke in, even half-way, it tends to cut out. Also, even when the bike is really warm - i.e. after riding for an hour - if I stall, I can't get the bike to start up without putting the bike in neutral and pulling the choke out. This just happened to me now, in the middle of a roundabout. I was there for 3 minutes trying to get the bike started and safely into 1st gear again. (It wouldn't start when I first tried in 1st gear).

But a worse problem is the gear jumping. I do roll up to junctions in 1st - or I try to (sometimes the 'message' doesn't get through - I can stamp two or three times or four times, but when I come to pull off I'm still in second gear, so of course I stall.). Even if I've managed to arrive in 1st, while I'm waiting the bloody gear moves into neutral - and sometimes without the light coming on.

I haven't had these problems with a Honda CG, so I do think it's the bike. I don't know what to do - I've got a training day tomorrow and my test on Tuesday, so won't have time to take it back to the garage where it was supposed to be serviced.