First gear problem

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windsorsmith

windsorsmith

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May 22, 2015
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G'day all.
My bike slips out of first gear regularly just after take off, has anyone else had this problem & fixed it? Also I would like to get a reverse gearshift cam plate, does anyone sell these in Australia, or will I have to order one from England? My bike is a 1971 750 fastback. Thanks in advance if anyone can help me.
Grant.
 
Grant,
Well the first thing you need to do is get into the gearbox and have a look.
Whitworth wrenches and sockets are needed so that would be your first thing on the list if you don't have them.
The layshaft first gear, has a bushing that likes to crumble or fail. (my guess)... You need to open it up to see what is happening. Pictures would help in a diagnostic.
Cheers,
Tom
 
For the reverse pattern shifting, there is one available (was it AN?). Also recall reading it was possible to remove the pivot bushing and replace on other side of plate, allowing it fit "upside down" , giving the "one down, three up" shift pattern.
 
Thanks Tom.
I knew I would have to open the gearbox, I thought I might change the camplate at the same time. I have all the tools I need, but I can't get to my workshop, heaps of rain and the creek crossing is flooded. Some sun would be good.
regards,
Grant.
 
Tornado said:
For the reverse pattern shifting, there is one available (was it AN?). Also recall reading it was possible to remove the pivot bushing and replace on other side of plate, allowing it fit "upside down" , giving the "one down, three up" shift pattern.
Click to expand...
Thanks Tornado.
I'll look on their website & see what they have. I have never got used to the upside down gears. I also have a 1957 Triumph Thunderbird that I ride as well.
Grant.
 
andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Genuine Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk

andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Genuine Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk
out of stock but you could email and ask.
Cheers,
Tom
 
windsorsmith said:
Thanks Tornado.
I'll look on their website & see what they have. I have never got used to the upside down gears. I also have a 1957 Triumph Thunderbird that I ride as well.
Grant.
Click to expand...
I hear ya. I seem to mange OK switching between a modern Bonneville with left foot/1down4up shifting to the Commando. Somehow my feet know what bike they are on.
 
windsorsmith said:
My bike slips out of first gear regularly just after take off, has anyone else had this problem & fixed it?
Click to expand...

Yes, and that was due to a worn layshaft first gear bush as CanukNortonNut mentioned although the layshaft 2nd gear dogs and engagement holes in 1st gear need to be checked for wear.
First gear problem


Also, a good time to change/upgrade the layshaft drive-side bearing if it hasn't been done.
 
CanukNortonNut said:
andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Genuine Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk

andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Genuine Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk
out of stock but you could email and ask.
Cheers,
Tom
Click to expand...
The reversible camplates are being machined.
 
The checks L.A.B advice you to do can be done with gearbox still in the bike. To remove the camplate it might be easier to take out the gearbox.
It might also be worth checking the index plunger spring.
As I have have two bikes LH shift first up, one bike LH shift first down, three bikes RH shift first down and five bikes RH shift first up, I can't really understand why you want to have a reversed camplate.
 
Last edited:
windsorsmith said:
Thanks Tom.
I knew I would have to open the gearbox, I thought I might change the camplate at the same time. I have all the tools I need, but I can't get to my workshop, heaps of rain and the creek crossing is flooded. Some sun would be good.
regards,
Grant.
Click to expand...
NSW is getting hammered.

I'm sorry, but Dondingalong is just about the funniest place name ever.
 
Hello Grant, I had the problem with jumping 1st gear as well. In my case it was too much endplay of the layshaft. Check the endplay before you open up the box so that you have the endplay how it is now. when you have already the layshaft roller bearing upgrade with the FAG NJ203 (C3) then you should go in anyway for 0.005" to 0.010" endplay. I`ll do it also with ball bearing....but that is a another threat. when you shim the layshaft on the kickstarter shaft (I only do it in this way) be careful with the shims: they should have enough ID so they don`t clamp on the tiny radius on the shaft facing to the timing side. Put the shims on.....and hold the kickstartshaft firmly in the inner cover when you put it back on the shell (so that the shims stay in the right place and don`t move down....so that they don`t get clamped with the small radius). hope my 2 cents help!
 
Does it always do it?
Sometimes it's actually not engaging properly rather than jumping out
I had this problem with my gearbox
It was the hairpin spring I believe
But as stated above it may need shimming
 
Last edited:
NO need to freeze but a bath in oil the night before would help
use a vise or drill press to push the old one out and new one in.
IMHO.
 
CanukNortonNut said:
NO need to freeze but a bath in oil the night before would help
use a vise or drill press to push the old one out and new one in.
IMHO.
Click to expand...
I did the layshaft replacement can't remember if it was with rolers or balls I had never seen the inside of a gearbox before so I downloaded the Old Brits instructions and had complete success. It needed no further adjustment and has since done thousands of worry free up and downs using the RGM rearsets . If asked I would advise any amateur fiddler like me to do likewise . Cheers Ian
 
Ian James said:
I did the layshaft replacement can't remember if it was with rolers or balls I had never seen the inside of a gearbox before so I downloaded the Old Brits instructions and had complete success. It needed no further adjustment and has since done thousands of worry free up and downs using the RGM rearsets . If asked I would advise any amateur fiddler like me to do likewise . Cheers Ian
Click to expand...
I followed the Mick Hemmings Dvd guide and bought all the new parts from him directly, including his recommended phenolic cage ball bearing for layshaft. Bike still had the Portuguese Piece of S### (PPOS) and looked to be in good condition at around 12k on the clock.
 
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