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Re: M20 sprinter...

Ian, That all looks stunning - and expensive !
I recall reading many years ago an article about a 100mph M20, possibly in Australia. The work was described in detail. It might have been in the VMCC mag or similar. I believe it was actually timed at 100mph.
I assume you know of it already.
Look forward to updates and results. Hope you've got someone young and fearless in mind to ride it.

Best Wishes
Peter Smith

email (option): 73pgsmith@gmail.com

Re: M20 sprinter...

The Aussie bike was owned by a chap called Bill Gough and is now restored and in a museum in Tasmania...He did 104mph at a beach race event in the 60's I recall....Two carbs on one cylinder!...

Here in the UK Pat Jeal managed 112mph on his M20 'Claudius' and I think that is the fastest normally aspirated M20 recorded to date...If anyone hears of another though....

I have a keen volunteer when the time comes...He has the desired 'dual modes', standing still and flat out...Personally I'm not very competitive and don't have any interest in speed and/or riding it to its limit...My interest is purely the engineering challenge involved and exploring what I can achieve in that regard...Ian

email (option): ian@wright52.plus.com

Re: M20 sprinter...

That is stunning Ian and just what i have come to expect from you.
I have been planning a trip To Yorkshire for years to watch you razz up that runway.

Cant wait to see how this develops. Well done that man
Darren

email (option): d.wrudd At sky . com

Re: M20 sprinter...

Ian,

I only see three main bearings in the picture? Not using four as factory? Most of the parts, especially the crankshaft, look to be too nice to hide inside the motor. I am assuming the crank is a special build as a Gold Star crank won't fit inside a M20 and the timing side shaft would have to be different???? Also did not think there is enough metal to bore the cylinder to 94mm.


What is you guesstimate as to the power it will produce?

Regards,
Bruce

Re: M20 sprinter...

Is it the earlier 1937/8 narrower engine. I noticed Ian advertised for an 8 stud barrel a while back. Ron

email (option): ronpier@talk21.com

Re: M20 sprinter...

It's the drive side crank case half from a 1948 M20 and the timing side half from a 1947 B31..The standard 8 stud engine has an arrangement where the cam spindles etc. fit directly into the back of the timing cover and no outrigger plate is fitted.
That makes it impossible to check the cam shaft and idler pinion clearances once the cover is fitted and currently would be limited by both the rarity of early engine components and their incompatibility with later parts.....This arrangement uses the outrigger plate set up, along with the later timing cover, cams, spindles etc. etc...

The narrower crank case allows the use of the 8 stud barrel but the timing side half has to be extensively modified to make the fit possible, along with other mods for cam clearance etc. and the barrel also has to be modified......The cylinder head is a 'one off' in aluminium...
I've no idea how much power the engine will produce, as just about every aspect of its specification has been modified to increase its power output and nothing to this spec. has been built previously on which an estimate can be based...It's going to end up on a dyno at some point to determine that...

The basic spec. I have settled on is therefore a 'best guess' based on previous experimentation, my own ideas and a lot of research into the tuning of various side valve engine types with possible applications to the M20 in mind...

The engine has a bore of 90mm and the same stroke as an M20 (94mm) to give a nominal capacity of 600cc (598cc)...

The flywheels are completely non standard, being a mixture of side valve and OHV dimensionally and not the same diameter, width or weight as either..Late Gold Star big end oil feed arrangements are used...Ian

email (option): ian@wright52.plus.com

Re: M20 sprinter...

Ian,

Why only 600cc? I would think you would use the M21 stroke to get the motor up to 700cc?

Bruce

Re: M20 sprinter...

With the (112mm) M21 stroke and the rev limit I have in mind the piston speed would be a bit high...Ian

email (option): ian@wright52.plus.com

Re: M20 sprinter...

Hi Ian
That looks superb.

I assume you've already machined the crankcase to allow the cams to turn without jamming the tappets. I found out the hard way!

You are doing what I decided not to do when I retired Claudius. I'd had a lot of fun for not much money and decided enough was enough but you are making me wish I'd carried on.

I used cut-down D1 Bantam forks with a Honda 90 front hub so your bike is pure class in comparison.

I was told that the Gough M20 only actually used the lower, updraft carb with the upper one there just to confuse the opposition. Don't know if that is true.

Dick O'Brien warned me to note that the H-D sidevalve racing cam timing was nothing like the OHV equivalent.

Good luck, I want to see (and hear) it run,

Pat Jeal

Re: M20 sprinter...

Those sorts of tricks were common in the day
I think it was on one of the Walsh Bantams there was a 4 stroke tacho fitted which of course made it look like he was getting 16,000 rpm out of the engine .

email (option): bsansw1@tpg.com.au

Re: M20 sprinter...

Hi Ian,

Have tried to email you regarding doing a deal for you M21 fly wheels. You can get me on email or telephone on 07855433835. I would be really keen to do a deal with you if you would still be prepared to part with them.

Rob

email (option): arbtraining@hotmail.com

Re: M20 sprinter...

Hi Pat...Yes, I came across the clearance problem as soon as I fitted the cam I'd had made!...
I have the article written about Claudius at the time and a few other snippets and have to admit I'm an admirer of your efforts and the great results you ultimately achieved with the bike...To my knowledge you have achieved the best results so far with an M20... So you are, unfortunately, one of the 'windmills' I'm tilting at...perhaps 'Don Quixote' as a potential name for the bike?:laughing: ...Did you campaign the twin cylinder version in the end?...

Apart from the 'Claudius' articles I've amassed a large amount of information on the work HD carried out on the factory K Models. Pretty extensive information on these models from Patrick Delli in Dijon was a further source...
I also acquired the full set of (excellent) articles by Peter Crespin on side valve tuning and read much on tuning side valve cars (primarily Austin and Ford)....In fact I've read as much as I can on the subject from any source, even accessing the patent museum archives for relevant information that might be useful...An article of particular interest was one written about Nigel Foxes Norton 16H with which he also achieved brilliant results...

Information from multiple sources and the results of a lot of experimentation over the years, along with my own ideas on the subject, has lead over time to the specifications of this particular engine....Hopefully it will be successful..Ian

email (option): ian@wright52.plus.com

Re: M20 sprinter...

How is this project going Ian?
I was looking for your posts on adjustable magneto timing gears when I found this.
Prompted by another post, I thought of you.
I remember the project stalled for some reason.

Mark

email (option): pes.sales@btconnect.com

Re: M20 sprinter...

Yes, if there was ever a long project this is it...Like many I guess I had too many projects and kept taking on more...As I couldn't use this one on the road it kept slipping onto the 'back burner' as I rebuilt other bikes..However, I have completed a lot of the work on it so it's not all bad...
It will be at the top of the pile when I finish my current project, a 'special' that will be the last road bike I build...Ian

email (option): ian@wright52.plus.com

Re: M20 sprinter...

this is really exciting and am looking forward to follow up information and photos. i remember many years ago seeing a young chap at Russell motors - near where i lived - with a stripped down M20 which he said could do 100 mph. I don't know if it could, but it looked the part. would be great to see this terrific project come to fulfilment. all very best with it. and thanks for keeping us posted.

Re: M20 sprinter...

Ian Wright
Yes, if there was ever a long project this is it...Like many I guess I had too many projects and kept taking on more...As I couldn't use this one on the road it kept slipping onto the 'back burner' as I rebuilt other bikes..However, I have completed a lot of the work on it so it's not all bad...
It will be at the top of the pile when I finish my current project, a 'special' that will be the last road bike I build...Ian
Good luck with that 'last road bike' Ian. :laughing:
At 84 I am on about my fifth 'last bike' at the moment, a 1961 T21.
Already thinking about the next 'last one'
Baz

email (option): binnawan@iinet.net.au

Re: M20 sprinter...

Ha Ha Baz! Good on you mate. I said "LAST ONE" about 3 bikes ago. But I'm still a way off 84. I'm just finishing off my nod to the "Bar None motorcycle club"..... Never say never!! Ron

DSCF6051

email (option): ronpier@talk21.com

Re: M20 sprinter...

Very nice Ian, did you make the flywheel assembly yourself or have it made by someone else? Cheers JT

Re: M20 sprinter...

The crank was made by Phil Pearson to my specifications...The conrod is a 'one off' from Carillo...The piston a 'one off' from CP Pistons...Valves are specials from Manley Valves in America..Cams are Gold Star Scrambles (Ex) and a 'one off' inlet to my specs....Ian

email (option): ian@wright52.plus.com

Re: M20 sprinter...

Ian, outstanding work. best of luck you are an outstanding craftsman. please keep us informed. Charlie

email (option): millcrocfarm@gmail.com

Re: M20 sprinter...

Hi Ian, wow that's very impressive. Harry

email (option): gerbil1066@hotmail.com

Re: M20 sprinter...

And we are all curious how fast it will be...!

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