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Droopy kickstart

Submitted by keith_smith2 on Tue, 08/08/2023
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Commando

My 1972 commando works on the kickstart, but when I was out on it on Saturday I noticed that the kickstart had dropped down below the exhaust, the bike was still running fine and I can still kick it over once I have moved by hand the leaver back to its proper place.  Now when I start it and engage 1st gear to pull away as soon as I start rolling the leaver drops to its position below the exhaust.

Any suggestions as to what I am likely to find if I open up the gearbox cover.

Submitted by ian_soady on Tue, 08/08/2023

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This can often indicate that the layshaft bearing in the left hand side of the gearbox is failing. This can result in the gearbox seizing which is not a nice thing to happen.

 

My first Commando was an ex-police model converted to a roadster which had had this happen - consequently I got it very cheap.

Submitted by peter_shand on Tue, 08/08/2023

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As the layshaft bearing, at the lefthand side in the g/box case gradually collapses, the layshaft falls out of alignment with the mainshaft and binds in the bush that lives in the kickstart shaft, so moving the lever round and down. With the engine stopped does the lever return upright?

If the above is the case do not run/ride the bike until sorted. At the minimum an internal inspection of the g/box is needed asap 

 

Submitted by neill_watkins on Wed, 09/08/2023

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If it's the layshaft bearing rather than the spring, best to replace along with the kickstart bushes if they're worn. Here's a current Access Norton post relating to this.      https://www.accessnorton.com/NortonCommando/portugese-layshaft-bearing.37690/page-2

Some good info on the 6203-TB-P63-FAG bearing which Mick Hemmings recommended and also supplied with his Quaife 5 speeds. Peace of mind for around £35 from 123Bearing.                        

As Ian suggests, some eye watering possibilities if you're unlucky and it seizes at open road speeds.

 

 

Submitted by keith_smith2 on Wed, 09/08/2023

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Thanks for the info, I have ordered the bearing from 123Brearing, what convinced me was the comment someone had posted on the Access site which said "tapping of the kickstarter lever on the back of the leg will be the warning" which is exactly what happened on Saturday.

Can this be changed with the gear box in situ, or any other advice more than welcome about how to fix this issue.

Im fairly competent with the spanners just that ive never delved into a gear box before, but I do have all the manuals.

Submitted by ian_soady on Wed, 09/08/2023

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.. as well as the gearbox internals so I'd remove the box which is only a little more work. You can then check that the case hasn't cracket between the mainshaft and layshaft bearings and it'll make it easier to fit the bearing.

I changed my layshaft bearing in situ, heated the case with a hot air gun and pulled the bearing out with the layshaft. Fitted the new bearing to the shaft and tapped it back home.

Submitted by keith_smith2 on Sun, 10/09/2023

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I have now started striping down using the Mick Hemming video as I go, I was trying to do it in situ as the last poster but have come a little unstuck where you seem to have to dismantle the primary side to take out the clutch, so I have removed the stator and have come to a stop as I don't have a clutch compressor tool, (but have just ordered one).

Can someone verify the next process. I'm up to section D5 where it tells you to go to C13 & C14 items 1 to 9. I'm up to C14 section 6.

What I'm unsure of is I use the clutch tool I've ordered does that release the main shaft and I can continue stripping the box or what is the full process from this point.

Im still unsure if I should take out the gearbox from the rest of the bike, I thinking I should as I have also ordered from Andover the overall kit and it look to me that some of the items to install will be easier to do with the gearbox out.

Any advice much appreciated.

Submitted by david_cooper on Sun, 10/09/2023

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It's not clear from your post, but have you removed the kick-start and layshaft and identified the problem?

Submitted by keith_smith2 on Mon, 11/09/2023

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I have removed the kick shaft and seeing that the kick shaft return spring was not broken I’m going to assume it’s the lay shaft bearing that needs replacing. 

Dear keith,

To remove mainshaft, you have to first remove clutch diaphragm spring to gain access to nut holding cluch centre to mainshaft. Thats why you need compressor tool.

Regards Martin

Nb when you use compressor it's a good time to clock space between spring and plates, fitting one thicker plate in place of existing ones on reassembly works wonders for lightness of clutch.

 


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