Problem with gearbox selection

LotusSevenMan · Post by **LotusSevenMan** » Fri Oct 19, 2007 8:10 pm

I'm having a strange problem with my KR1 'box.

First, neutral and second can be selected fine. The other four 'up' gears are much less so. What you need to do is apply a little bit of downward pressure on the change lever BEFORE lifting the foot and selecting the next higher (than second) gears. Comes down the 'box all OK. I've had the g.box all to pieces and there is nothing obviously wrong. The little spring is in place for the ident wheel etc. Any ideas guys?

Thanks in advance!!!!!

nate · Post by **nate** » Fri Oct 19, 2007 8:40 pm

Don't know and I am sure someone will be along to give you a definitive answer... But... I found I couldn't select neutral very easily and stripped my clutch...

It turned out someone had put the thrust washer in back to front... Off the top of my head... I can't remember which way it goes...

Cheers

Nate

mr_bungholeo · Post by **mr_bungholeo** » Fri Oct 19, 2007 10:29 pm

could be the star on the end of the selector drum....?
or.....more likely its the arm that goes onto the star...its the bit with two hooks at the end that operates the star though ive never heard of a kr with that problem...its usually the thrust washer in the basket but it would do all gears...hmmm
...unless you've done all the dogs on those gears

check that the gear changer going through the casing is not wobbling about cos that could also b it...er...um....think it must b one of those....anybody???

rc46 · Post by **rc46** » Fri Oct 19, 2007 10:47 pm

Where are you?
I have a spare box you can have! Worth a try, MJ came round and said its the selector dogs that cause the main problems, I found another SLIM washer on the thrust washer helped selection but changing has always been okay... the star may be worn......

LotusSevenMan · Post by **LotusSevenMan** » Fri Oct 19, 2007 11:10 pm

I'm in Kent so not too close for Peterborough I'm afaid. Thanks for the offer though.
Well the star bit on the end would have been my favourite excpt it all looks fine. Almost as if the thing was machined with the location pin in slightly the wrong place. Impossible I'm sure. Very strange this one.

mr_bungholeo · Post by **mr_bungholeo** » Fri Oct 19, 2007 11:17 pm

where in kent?..if you can get to the north side of dartford i could get a gearbox to u.....complete...but u would owe me a pint....

can also bring cases n bits to match up...can do this weekend if its good for u...will b down that way...if not next weekend....

rc46 · Post by **rc46** » Fri Oct 19, 2007 11:17 pm

Well if you get stuck give me a shout, ill send you a spare for the price of postage!

mr_bungholeo · Post by **mr_bungholeo** » Fri Oct 19, 2007 11:25 pm

stop sellin them bits..you'll have nothing left....(give me a shout if u need anything..lol)

LotusSevenMan · Post by **LotusSevenMan** » Fri Oct 19, 2007 11:46 pm

You have PM.

Thanks!!!! =D>

the-elf · Post by **the-elf** » Sat Oct 20, 2007 10:25 am

Gearbox problems are often caused by bent gear selector forks or wear within the selector mechs. Trouble is the amount of wear that can cause problems is often too little to been seen just by eye.

BTW If you are swapping gearboxes then be warned that there are some very slight differences between KR1 and KR1S selector mech. Which means you can't pick and mix between the two very easily. IIRC from experience the bearing in one of the cases is a different width which will require swapping and a few other fits vary in the odd dimension which makes it a PITA although it can be done (in the end I swapped the entire lot rather than swapping odd parts).

LotusSevenMan · Post by **LotusSevenMan** » Sun Nov 18, 2007 4:46 pm

Well thanks to the RC45 man who supplied me with the 'new' gearbox and some other parts.
I started by just changing the selector pawl as I had a choice of two (you know the one that looks a bit like the crank handle in that 'Mouse Trap' game). It worked!!!!

I can get all the gears now no problem. Neutral is a bit of a bu**ger to find, but I was advised that these boxes are set-up for production racing and that the neutral is a bit like that as they don't want racers finding that neutral on the circuit by accident!

Nice to get all six easily though!!!!!

mgtkr1 · Post by **mgtkr1** » Sun Nov 18, 2007 8:51 pm

when they work they work pretty slick but when there worn there a nightmare and selecting 2nd from 1st is a no no at anything like peak power, actually 6000rpm plus more like! if the one the james has supplied allows you to get all gears then the chances are its a good un. i found the knackered input shaft(output shaft? cant remember

)bearing had been a cause as i replaced it and this made a huge diffrence to gear selection. the old bearing was a bugger to turn when spinning it in my hand so theres little wonder! when splitting cases i always replace this bearing as a rule on engines of unkown history since i came across that. its worth the 15 quid or whatever it cost.