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Rob Harknett · Post by **Rob Harknett** » Tue Jan 10, 2012 11:18 am

Dating officer can tell where the bike went went sold

dogwheel · Post by **dogwheel** » Fri Jan 13, 2012 12:03 pm

I don't wish to "dis" anyone or anything AMC, and I don't have a Velo, but Velo bottom ends are really very wonderful and that's probably why they can stand the power output, and the thrashings they get.
I shall now put on my old Tin Hat and hide in a corner.

GOLDSTAR · Post by **GOLDSTAR** » Fri Jan 13, 2012 2:49 pm

I do'nt know much about the differing engine years but I have read somewhere that my G80cs short stroke engine has the same diameter crankpin etc as the 7R, someone will know I'm sure, if all the later engines had the same, kind regards

dogwheel · Post by **dogwheel** » Fri Jan 13, 2012 4:09 pm

Here I am again! The other thing about Velo bottom ends is the narrowness which results in such a stiff crankshaft assembly. Mind you as you suggest, there ain't a lot wrong with 7R/G50 bottom ends.
On reflection there's a long list of pushrod engines that are awfully quick, vintage AJS, Ariel, Rudge, Triumph, JAP and so on and on, then there's that NZ or Aussie ES2 that mixes with, and beats the cammies. Go for it!

zwarts · Post by **zwarts** » Sat Jan 14, 2012 5:42 pm

You need to have a chat with Ken de Groome (I think he still advertises in Jampot). He will be able to point you in the right direction re. what is available re. lightweight tappets and cam profiles etc. Over the years quite a few people involved in Vintage/Classic racing have been able to get these engines going well. With the head and barrel bolted right through to the crankcase and the excellent Norton oil pump, reliability should not be a problem.
Bob.

Merlin · Post by **Merlin** » Sun Jan 15, 2012 12:13 pm

Why not just buy a Velo

PGGuse · Post by **PGGuse** » Sun Jan 15, 2012 12:19 pm

Les, let me make another proposal to take into your considerations:
Keep the engine as a spare one as it is and get in touch with http://www.absaf.nl/
Then you have exactly what you are looking for

Paul in FrankfurtEdited by - PGGuse on 15 Jan 2012 12:26:41 PM

holland · Post by **holland** » Sun Jan 15, 2012 1:50 pm

quote:
Hi Everyone. I was wondering if a member here had uprated the performance of the 1964-on short stroke engine, but still remaining flexible and quiet enough for ordinary road use. I notice that G85 SH cams are available and it is also possible to get an 8.5:1 CR piston. I would imagine that it would possible to increase power output to somewhere near 32-34 BHP which would put it roughly in the same league as a Velo Venom. To achieve the power increase the cams and valve gear would probably have to allow the revs to increase to around 6200 RPM as per Venom and maybe the carb diameter would need to be increased in size too, but all the same it looks an easy "upgrade" to make, albeit quite an expensive one. I would be very interested to hear from anyone who has tried this...Many thanks.Edited by - Les P H on 13 Jan 2012 10:27:10 AMEdited by - Les P H on 13 Jan 2012 11:22:12 AM

The changes you are proposing are good changes which can be made with out any adverse effect to the motor, you will have to make some small changes to the carburation, but this is not major.
But can i advise you have the head gas flowed while it is removed and have the valves either replaced or refaced if in good order and the seats recut to match and install a coil valve spring kit to aid combustion seal thus increase performance.

Hope this helps.
james

holland · Post by **holland** » Sun Jan 15, 2012 4:26 pm

Peaky motor is not what you will have, it will be smooth with more go. I would'nt bother with the higher comp piston though, leave the stock one in there.
james

Les Howard · Post by **Les Howard** » Fri Jan 27, 2012 1:54 pm

deletedEdited by - Les P H on 28 Feb 2012 08:33:55 AM