Hotting Up A MkIII

worntorn said:

Glen, Is this the bike you mentioned previously that had the unique cam grind in it, and if so how are you liking it?

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edward said:

Phil, there were nine of them (Vincents) 'beetling around Mittagong' yesterday and my lone Dreer commando. We had the annual Vincent/Velocette Rally at Moss Vale and surrounding areas.

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phil yates said:

... this idea of keeping bikes in your shed...

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Time Warp said:

phil yates said:

... this idea of keeping bikes in your shed...

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Only a scoundrel would keep Brit bikes in a shed.

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You are indeed a scoundrel Time. But an interesting one. Every avatar of yours I see a new machine. And very nice ones all of them. There is a limit to how many of them you can keep on full rego, just gets way too expensive. And I can see how an interest just developes and rolls on. The Commando is certainly very special to me as they have always been. But there are also some other very special machines out there worth having. They are all a bit like collecting and saving gold aren't they? Once you start hoarding, it is very hard to stop.

I have a nasty feeling I will be going the same way. MkIII No 1 was going to be it. Now MkIII No 2 is on its way.
What next? Maybe a Vincent and a Velocette!

Phil

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phil yates said:

worntorn said:

Glen, Is this the bike you mentioned previously that had the unique cam grind in it, and if so how are you liking it?

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No, that bike has not run yet, tho it is getting close. I just came in from the shop, the engine is now in the frame. It is an Egli Vincent of sorts, although quite different with modern wheels and suspension, stainless steel frame. It is about fifty pounds lighter than a conventional Egli.

The bike for the trip is a more or less standard Rapide, actually the 38 th one built after WW2, so very early production. It has the usual upgrades for doing high mileages, approximately Shadow tuned, oil seals on valves, low expansion 8 to one pistons, indicators, x ring chain, fully suspended seat, etc. It almost always gets to run two up plus luggage, 40,000 miles of that in the last ten years. Supposedly it has close to half a million miles on it now. I don't know how many rebuilds have been done.

Eddie, my friend John Mcdougall has found a way to make the standard Vincent gearbox shift quickly like a Norton. He recuts the camplate in exactly the same pattern as a Commando AMC , lo and behold it then shifts exactly like a Commando AMC box! So much for stock Vincent gears being too heavy to shift fast, which is a commonly held belief in the Vincent world.
Sorry for the Vincent sidetrack, but the quaife 5 speed vs 4 speed as seen on the road came to mind and I am pretty sure it would hold true for an 850 Commando.

Glen

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Matt Spencer said:

Ratios:::- 1st 2nd 3rd 4th 5th
1.986 1.654 1.351 1.106 1.000 Race
2.118 Race / Road
2.357 Road

http://quaife.co.uk/shop/search/results/taxonomy:808

Gear Ratios 1st 2nd 3rd 4th 5th 6th
2.250 1.737 1.429 1.227 1.109 1:1

QMCA2A5 - Quaife complete Norton 5-speed motorcycle gearbox
Prices from: £2,735.00

QMCA2A6 - Quaife complete Norton 6-speed motorcycle gearbox
Prices from: £2,915.00

:lol:

The Law of Deminishing Returns . ? :? We'll change 'A' therfore 'D' will need to be updated , which means 'C' & 'B' will need to be replaced . :|
At Some Point , its easier to START FROM SCRATCH . Though this requires a Dollar or two .

Cylinder barrels 750cc, 850cc & 920cc … £749.00

Pair of crankcases ... £995.00

Standard 89mm stroke crankshaft ... £1,295.00

http://www.stevemaney.com/products.html

Then theres the Rods , Cam , Lifters , Head ;

http://www.primemechanicaldesign.com.au ... 1-fullauto

fullauto-technologies-heads-t14842.html

Rockers , Valves Springs & Keepers .
A CLUTCH & Primary may be of some use too . . .

Commando 1969-74 -Includes two pulleys and a 32MM AT10 belt. The factory clutch center and plates from your clutch are retained to keep the cost down and ensure replacement parts are readily available. - #C3000 - $489.00

Commando MK3 - Similar to our #C3000 but modified to fit the MK3. If the electric start has been removed use - #C3030 - $559.00
For a MK3 with a working electric start use - #C3031 - $589.00
http://www.clubmanracing.com/beltdrivesnorton.php

At this stage , the Frame may be a bit inadequate , then theres the Brakes , and it might pay to look at the suspension . . . .

Or sleeves & Cortina Pistons & a Combat Spec. head , might haul ass . 8) :lol:

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Fast Eddie said:

phil yates said:

worntorn said:

Glen, Is this the bike you mentioned previously that had the unique cam grind in it, and if so how are you liking it?

Click to expand...

No, that bike has not run yet, tho it is getting close. I just came in from the shop, the engine is now in the frame. It is an Egli Vincent of sorts, although quite different with modern wheels and suspension, stainless steel frame. It is about fifty pounds lighter than a conventional Egli.

The bike for the trip is a more or less standard Rapide, actually the 38 th one built after WW2, so very early production. It has the usual upgrades for doing high mileages, approximately Shadow tuned, oil seals on valves, low expansion 8 to one pistons, indicators, x ring chain, fully suspended seat, etc. It almost always gets to run two up plus luggage, 40,000 miles of that in the last ten years. Supposedly it has close to half a million miles on it now. I don't know how many rebuilds have been done.

Eddie, my friend John Mcdougall has found a way to make the standard Vincent gearbox shift quickly like a Norton. He recuts the camplate in exactly the same pattern as a Commando AMC , lo and behold it then shifts exactly like a Commando AMC box! So much for stock Vincent gears being too heavy to shift fast, which is a commonly held belief in the Vincent world.
Sorry for the Vincent sidetrack, but the quaife 5 speed vs 4 speed as seen on the road came to mind and I am pretty sure it would hold true for an 850 Commando.

Glen

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Don't be sorry Glen
The Vincent comparison is very relevant, and fascinating. What a mighty machine it was/is. I'd like to see one beetling around Mittagong as does my Commando. I'm seriously thinking I'll dump the 5 speed box idea. Maybe dump the 10:1 compression. I'm now though interested to learn more about the 920 kit.

Phil

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worntorn said:

Jim Comstock has done a lot of dyno testing , race testing and road testing of various performance mods for Commandos. In a thread awhile back he described the results of reshaping the ports and doing a big valve conversion of a 1973 850 RH10 head. The RH10 head has the smaller stock ports at 30mm as opposed to 32 mm for MK111 RH4 heads.
He mentioned that the big valve conversion will net more bang for the performance buck than just about any other Commando performance mod. His target is extra power all along the band, not just on top at the expense of midrange.
So you might look for a good used rh10 as core, then send it to Jim for the big valve conversion. There was one in the For Sale section recently, but you are too late, I bought it!
The other option is a new Full auto head, something over 3 k.
As I recall, Jim's RH10 big valve conversion slightly out performed the unmodified Fullauto head for flow and velocity.

After that there is extra power all thru the range, better handling and braking all to be had by copying the weight reduction mods in Ludwig's 300 pound Commando thread. You likely won't get the bike down to 300 pounds unless you are prepared to do a tremendous amount of work and do away with the estart, however a fair bit of weight can come off.
7 lbs weight reduction = roughly 1 HP as far as acceleration at regular road speeds.

Glen

Glen

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hobot said:

What would your mommy and Commando sisters think of you doing this. One social event comnoz always attends has a HD camp site with a pastime past mid night doing burn outs of ever type and age of motorcycle known against a tree on a plank lubed by beer sweat and vomit with both genders helping to hold the rear on the plank yelling instructions and encouragement at the top of their tipsy lungs... I love our kissing cousins, except when time to shut down.

I think more to the point.
What would James Norton think?
He'd turn in his grave I reckon.

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hobot said:

Naw ole James and crew likely did the same thing on chipped rock paths and polished cobble stone roads before we were even a gleam in our daddies eyes. I'm feeling chipper surviving Graveling then non DOT tire heating front till its blunt cripple-ness juddered a bit out of grip so sense returned for some light rain riding that just felt good. Ran to the ton a few times but poor thing buzzes its strained brains out so miss Trixie Combat top end power on days like this. I do prefer the Commando torque control hits on Gravel for front tire relieving rear steering skips-slips rather than the slightly hesitant V-twin even in its rather lower gears. Oh it'll spin out just fine but just not quite as fast as needed then don't hook back up as sharply as the skinny tire Cdo. No great difference on Gravel regardless of what cycles on it but its so easy to loose it- every freaking little bit better is that less mess of skid-urine- blood marks. Still SuVee is set up to be supermotrad handy so allowed me to begin some Peel type handling by just holding a normal lean and fork angle then throttling up till its rolling out on tops of Gravel for the lazy-est non crossed up natural drift out the tangent till letting rear mildly hook up again to just finish the turn like ya been in that line all along. Only have to go like 35 mph in the right places so not exactly hair raising but helps sense of vulnerability sink in the easy way. I know the 850's could dice it up very similar, don't know if the steering stem angle reactions are fast enough to enjoy loose Gravel or pasture play.

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