the truth is out there!............

[dave higgins]

Prompted by one of rob t`s comments in the new member thread about his works griffon, i have always been keen to find out the factory mods that were used to improve the griffon 380 from a stock bike.
I can appreciate different works riders using different mods to which ever suited them best, but were there outline engine & chassis mods that were used on all the works griffons? has anybody ever stripped one to see what they got up to.......

[Rob]

I've tried hard to find any factory reference to my bike or even who might have ridden it. I have had the engine in bits for years so I could check the head and barrel for any differences. I did have a 380 engine in the dead leaves in the field (ooh the shame!) but I kept tripping over the clutch cable and put it somewhere else. If I could find that, I could do a comparison. My one had Motoplat so I would think it is not the original engine.

Come on Druid - what were the secrets and when was GPWM 2 about? What was GPWM anyway, Greeves Payment Without Money??!!

[druid]

works bikes

Rob.
All the Challenger and Griffon engines were designated GP, I'm not certain what it stood for, the suffix WM means "Works Motor". Your engine GPWM 2 was Brownings 380. That's the good news.
The bad news is that there was nothing special about these bikes other the factory tried various mods which, if they worked, were incorporated into production and in the bin if they didn't.
There were occasions where the works bikes had something a bit special like Browning's Challenger with the Silverstone barrel or Bicker's Coupe d'Europe bike with the magnesium engine or Dave Harper's full 500.
Almost without exception the performances of the works bikes was down to the rider's talent.
In fact the comp shop ( not the Dev shop) survived on bits from the production line which were considered outside production spec.
In fact most of the fast bikes in Dave's championship nowadays exceed the performance of the old works bikes.

Of course I could be wrong.

Druid

[Kim275]

Fascinating thread

Druid - that is a really interesting insight........and maybe behind a lot of the Greeves success - i.e when you bought one it was quick out of the box - and as a works bike !!...and as you said earlier they got most things pretty right!....

I did have the great fortune to spend a weekend with Kenny Sykes (Bearingman) in California this summer - a joy in itself - but we also had a chance to look over many Griffon Barrels (and I mean many !) the Nicholson motors stock.......and we spent many happy hours comparing and tracing Barrels - and suffice to say clearly some of the US desert racers have done a lot of mods ......The most overly modified and interesting ones were a 380 twin port and 250 bridged port .........and of course we don't know whether the mods worked or not - but if there is interest I could share on the GRA members page ?

[Andy Z]

Druid - that is a really interesting insight........and maybe behind a lot of the Greeves success - i.e when you bought one it was quick out of the box - and as a works bike !!...and as you said earlier they got most things pretty right!....

I did have the great fortune to spend a weekend with Kenny Sykes (Bearingman) in California this summer - a joy in itself - but we also had a chance to look over many Griffon Barrels (and I mean many !) the Nicholson motors stock.......and we spent many happy hours comparing and tracing Barrels - and suffice to say clearly some of the US desert racers have done a lot of mods ......The most overly modified and interesting ones were a 380 twin port and 250 bridged port .........and of course we don't know whether the mods worked or not - but if there is interest I could share on the GRA members page ?

Always interested in any porting or tweeking info!

[dave higgins]

Thanks for the input fella`s, great bit of in house know how from druid, but development shop?......well!....thats another thread on its own......
What really went on in there?...Did greeves have there own Q.... was the drop head invacar, with front heatseeking missiles really a myth.....
We can only guess......

[Rob]

Don't worry, Brian will come up with a picture of that weapon if I don't moderate him first

Thanks Druid and also Kim! Could say he needs to get out more but there again, he did go to California to peer into 380 barrels. That's got me thinking.

I once ventured almost as far as Druidsville to buy a Griffon gear lever (they must have been hard to come by then). "Found a few more bits" said the seller and I came away with most of a 380 engine and gearbox and a 250 frame, all at a bargain price so I had to take it. I think the barrel had a manifold attached with stud spacing to take a GP carb. The rod and big-end was a glorious shade of blue so I think it had been subjected to some hard use. It laid around in the dead leaves for quite a while. Will have a look around the junk yard in daylight and peer into the barrel if I can find it!

[Brian Thompson]

Blue Chickens - The Truth Is 'Out There'!

Don't worry, Brian will come up with a picture of that weapon if I don't moderate him first The rod and big-end was a glorious shade of blue.....

Same thing happened to me Rob......only the 'bluing' extended right up to the little hen as well.....

Pike.

[MikeV]

Mods'

Just picked up on the discussions about "works" engines.
When I looked after Daves Challenger, GP1, the engine was standard but carefully prepared. As an example, after returning from races, the head and barrel were removed and inspected. Regardless of any pick-up from the piston, the barrel was vey lightly honed to remove the glaze and then rebuilt using new rings. This, of course, lent the engine to get close to oversize! So a barrel would be selected from production samples and be fitted to DPC's 3 wheeler,who better to get a barrel normalised, and after some time would be carefully honed and tried, sometimes wth success sometimes not. So the proccess was repeated until a good barrel was found.
We did try a mod' suggested by Frits Selling, but returned to a standard set up as Dave did not feel it made any difference for him.
Basically the engine was "blue printed" on all occasions on each rebuild.
As to the devolpment shop, the last time I saw that it was just a lot of parts lying around with the dyno' not in a working condition!
Another thing that came to mind after reading this through was that the expansion chamber was modified using a small bore tube in the end cone.
Mike.

[Kim275]

Mike Great Greeves factory insights - Thanks for sharing

Mike,
Much appreciate you taking the time to share your experience of the works bike prep with us
The discussion carried on in the members area on this thread - on mods and blueprinting engines.
Cheers Kim

http://www.greeves-riders.org.uk/forums/showthread.php?t=4793

[Colin Sparrow]

Just picked up on the discussions about "works" engines.
When I looked after Daves Challenger, GP1, the engine was standard but carefully prepared. As an example, after returning from races, the head and barrel were removed and inspected. Regardless of any pick-up from the piston, the barrel was vey lightly honed to remove the glaze and then rebuilt using new rings. This, of course, lent the engine to get close to oversize! So a barrel would be selected from production samples and be fitted to DPC's 3 wheeler,who better to get a barrel normalised, and after some time would be carefully honed and tried, sometimes wth success sometimes not. So the proccess was repeated until a good barrel was found.
We did try a mod' suggested by Frits Selling, but returned to a standard set up as Dave did not feel it made any difference for him.
Basically the engine was "blue printed" on all occasions on each rebuild.
As to the devolpment shop, the last time I saw that it was just a lot of parts lying around with the dyno' not in a working condition!
Another thing that came to mind after reading this through was that the expansion chamber was modified using a small bore tube in the end cone.
Mike.

What a wonderful insight that is about using Derry's EHJ 19 to develop Dave's works barrels. I wish I'd known about that before I finished the book. Maybe they'll let me add it when the second edition comes along...

[MikeV]

Edit

Thanks Colin for the spelling check, brain and fingers don't seem to co-ordinate that well at that time of the day!

Mike.