Author Topic: Golden Flash Side Car Gearing  (Read 1932 times)

Offline Stu55Flash

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Golden Flash Side Car Gearing
« on: 14.03. 2010 23:27 »
My Plunger Flash has sidecar gearing. Can anyone tell what difference this makes in practice. If I strip the gearbox what do I have to replace? Is it just one gear or several? Any advice gratefully received.

Stu
"Keep a distance from lady "L" drivers in cars. Some are not mechanically minded, are slow to acquire road sense, an are apt to panic..." The Pitman Book of the BSA Twins.
Golden Flash Plunger 1955, Francis Barnett Falcon 67 1954, Ferguson TEA Tractor 1951. Looking for another project!

Offline wilko

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Re: Golden Flash Side Car Gearing
« Reply #1 on: 14.03. 2010 23:43 »
Just up your gearbox or engine sprocket tooth count. Rarely did manufacturers change the g/box internals for sidecars.

Online Brian

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Re: Golden Flash Side Car Gearing
« Reply #2 on: 14.03. 2010 23:58 »
I run 19t gearbox sprockets on my plungers and find this the ideal gearing. Should have a 42t rear.

Offline Josh Cox

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Re: Golden Flash Side Car Gearing
« Reply #3 on: 15.03. 2010 04:24 »
Hi Stu,

I have just recently fixed the same issue, as far as I am aware the internals of the gear box are the same.

The chain gearing is different.

Side car: 18 front, 47/49 rear.

Normal: 18 front, 42 rear.

With the side car gearing, very quick off the lights and not alot top end.

Normal: a little clutch drag off the lights, but great top end.

For the speed nuts, go bigger on the front sprocket.

Oh, suprise suprise, Brian suggested exactly that  *smile*...........

I went out for a ride on the weekend up got upto 90 MPH on the normal gearing, next weekend I'm gunna have a crack at 100, armed with not much sense and a full sack of brown Adrenalin.
Black 1953 Golden Flash Plunger

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Re: Golden Flash Side Car Gearing
« Reply #4 on: 15.03. 2010 06:58 »
Go for it Josh, I see you use the refreshing brown adrenalin to get the speed. The other brown adrenalin comes out the other end when a car pulls out in front of you !!!
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
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Offline Josh Cox

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Re: Golden Flash Side Car Gearing
« Reply #5 on: 15.03. 2010 07:31 »
I was more referring to the later version of your brown adrenalin. *smile*
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Re: Golden Flash Side Car Gearing
« Reply #6 on: 15.03. 2010 08:55 »
What primary gearing have you got Josh ? Just took the cafe up over the ton. 23/43, 19/42 at 5400 rpm, if yours is 19/43, 19/42 she'll be doing 6500 rpm, pretty much max for a std motor.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline Josh Cox

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Re: Golden Flash Side Car Gearing
« Reply #7 on: 15.03. 2010 09:29 »
18/42, OK, I will not go there.
Black 1953 Golden Flash Plunger

Offline Stu55Flash

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Re: Golden Flash Side Car Gearing
« Reply #8 on: 15.03. 2010 19:54 »
Thanks for the info.

I have counted the sprockets and have 19 front and 49 on the rear.  Problem is the rear sprocket is cast with the break drum. How do I fit a 42 rear. By my calcs to keep the current rear drum and get the 2.3333 ratio I need 21 tooth front sprocket. Do these exist for the plunger? Does anyone know if front sprockets from later models fit?

Thanks

Stu 
"Keep a distance from lady "L" drivers in cars. Some are not mechanically minded, are slow to acquire road sense, an are apt to panic..." The Pitman Book of the BSA Twins.
Golden Flash Plunger 1955, Francis Barnett Falcon 67 1954, Ferguson TEA Tractor 1951. Looking for another project!

Offline trevinoz

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Re: Golden Flash Side Car Gearing
« Reply #9 on: 15.03. 2010 20:56 »
Stu,
         You will have to either replace your rear drum or have a new sprocket fitted.
New drums don't seem to be too expensive. I think they are Indian made generally and quality may be an issue.
Trev.

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Re: Golden Flash Side Car Gearing
« Reply #10 on: 16.03. 2010 19:52 »
G'day Stu,
              you could get the sprocket turned off the drum and bore out a blank sprocket to weld onto drum.
I have done this to a later type and used bolts as scotch keys. That way your not discarding a good drum.
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7