Kickstart moves in and out

Norton46 · May 24, 2011

what would cause the wear of the layshaft bush in the kickstart shaft?
This gearbox was serviced about 2 years ago and the left side mainshaft and layshaft bearings were replaced.
The layshaft with a roller to eliminate the dreaded Portuguese layshaft bearing. The rest of the box bushings and such was deemed serviceable.
Now the kickstart shaft is moving in and out almost a .1" and the gear box oil is full of bronze.
Wondering what cause the bush to wear so quickly? Only a about 2.5K miles have been ridden since the bearings installed.

Thanks

kraakevik · May 24, 2011

In my experience the layshaft bush outlasts any bush in the gearbox. There should be almost zero end-play in the kickstart stub. You may want to to shim the kickstart stub under the knuckle and take a look at the layshaft first gear bush. I'm surprised you haven't had problems with first gear jumping out of engagement with that much play--good luck

Tim Kraakevik
kraakevik@voyager.net

Hobot · May 24, 2011

If ya don't coast rather slowly in 1st matching throttle w/o any engine drag or power pressure then a worn 1st bush will not jump out of gear, but that state is constantly lurking and can snatch ya right down, when easing into a parking lot turn or slowing up w/o a thought of trouble for traffic ahead in a bit of leaning turning. I don't think thinned to broken up 1st bush allows length wise slack in lay shaft though as should be trapped by the up graded bearing tight fit on shaft end.

cash · May 24, 2011

and the gear box oil is full of bronze.

That's bad news, I reckon it's time to take the box apart.
Cash

Hobot · May 24, 2011

The bush kits do not fit shafts and cogs w/o reaming to size. IIRC you don't want to burnish the bush oil holding pores surface, so best to have em cut or maybe dowel and sand paper it ya can get embeded grit out.

I once pressed on using gearbox with worn bushes but found out that ain't such a good idea as it then lets cog wobble on shafts and wear the shifter dogs contact surfaces out for terrible to not shifting and then new dogs.

Don Tovey · May 30, 2011

Hi N,
I get the same thing with my Kickstart.
Somtimes if I give it a handful of throttle once ive put it into 1st from nuetrel it slips out of 1st.
If from a standing start I put it in 2nd then slip it into 1st it does not slip out of 1st gear.
I once had the lay shaft bearing collapse & rebuilt the gearbox myself but maybe not properly.
There is a Norton Gearbox DVD available from Mick Hemmings or The Norton Owners Club Merchandise online shop.
Its very helpful & well worth getting to do a proper rebuild.
I am leaving mine until it starts to give trouble or I may do it over the winter. I'm not spoiling good weather on a rebuild.
Cheers

swooshdave · May 30, 2011

Don Tovey said:
Hi N,
I get the same thing with my Kickstart.
Somtimes if I give it a handful of throttle once ive put it into 1st from nuetrel it slips out of 1st.
If from a standing start I put it in 2nd then slip it into 1st it does not slip out of 1st gear.
I once had the lay shaft bearing collapse & rebuilt the gearbox myself but maybe not properly.
There is a Norton Gearbox DVD available from Mick Hemmings or The Norton Owners Club Merchandise online shop.
Its very helpful & well worth getting to do a proper rebuild.
I am leaving mine until it starts to give trouble or I may do it over the winter. I'm not spoiling good weather on a rebuild.
Cheers

Did you shim it?

Don Tovey · May 31, 2011

Hi,
I can not tell a lie, I did not shim it.
I did not have any experience at stripping gearboxes & it was my 1st attempt at repairing the gearbox.
Having watched the NOC gearbox rebuild that Mick Hemmings did I now realise I made a poor job of it.
It has lasted 15 years since I repaired it though so it was not too bad a repair.
The NOC gearbox rebuild DVD is availabe for £21 + postage from NOC website or the Video tape is even cheaper.
Worth buying if your stripping your box down.
Ive also rebuilt the engine & probably not done that how it should be done but it goes well so i'm leaving that as it is & enjoying riding it.
Cheers Don

Kickstart moves in and out

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