The Unapproachable Norton Commando

grandpaul · Posted: Fri Aug 01, 2008 9:10 am Post subject: Norton 880 long-term project

Okay, this begins my first bare-bones start to finish long-term race bike project - a Commando with Kenny Dreer jugs & pistons,
and a set of modified 850 cases.

So far, I've received the jugs & pistons, cases are on the way-

I've got a brand new belt drive kit sitting on the shelf, and I'm considering having a welded up 90 degree crank versus a billet crank,
then the top end using a properly ported RH10 with flat slide carbs and a trick exhaust.

This project is likely to take a couple of years, so don't hold your breath for progress photos as quick as they typically
appear on client's bikes...

frankdamp · Joined: 07 Oct 2005 Posts: 143 Location: Anacortes, WA, USA

Good luck with this one. It may tax your Norton knowledge to the max. I'm sure an 880 would have mind-blowing performance.

For me the original 750 Commando prototypes were hairy enough, but that was with previous experience of a 150 Vespa, an Ariel Leader 250 and an elderly BSA A7.

Out of the frying pan into the fire!

worntorn · Joined: 22 Dec 2006 Posts: 168 Location: Langley, B.C.

What are the advantages of the Dreer 880 over the RGM 920 kit?

The RGM pistons are forged pistons, (probably Cosworth) compression ratio can be set as desired up to about 10.5 to one. I plan to find an 850 basket case bike to use the 920 kit on.
The 920 uses sleeves which are pressed into the bored out 850 barrels.

grandpaul · Posted: Tue Aug 05, 2008 6:08 am Post subject:

I don't know that there are any advantages, I didn't do any research, I just wanted to try something different and I knew Kenny had some leftover stuff. He gave me a deal that beat the poop out of anything I could have done as far as RGM parts, for sure!

grandpaul · Posted: Thu Aug 07, 2008 3:18 pm Post subject:

Talked to Kenny at length and decided to take a VR880 head he had returned for a minor oil leak. He's going to sleeve the stud hole and ship it with professionally ported and polished 33mm intakes and matched exhausts, 17mm intake valves with titanium collets, and all polished up to go.

Kenny uses Megacycle 560-00 cams, I have yet to price one; also I'm sure the billet crank will be a spendy bit. Other than those two items, there's not much left to consider, engine-wise.

So, this is beginning to sound a lot more like a "VR" than a "BAB", the biggest difference will be in the builder and not so much the parts. I might just have to hunt down somebody with an 880 and have a go to see how well I did.

worntorn · Joined: 22 Dec 2006 Posts: 168 Location: Langley, B.C.

Is the VR880 head a totally different design or is it a reshaped Commando Head ti fit the larger bore?
BTW, the RGM 920 conversion kit is pretty cheap, just $320 but you must add to that the cost of boring out the cylinders then fitting the spun cast liners, which is about $200. And you must have some 850 cylinders to start with.

grandpaul · Posted: Fri Aug 08, 2008 7:49 am Post subject:

The VR880 head is basically either an RH4 or an RH10 that is ported and flowed, with intake ports sized to match whatever iteration they were on at the time. The head I'm getting is 33mm for the FCRs on custom machined intakes. Not that I have FCRs, but I'll work out something that will be properly matched.

The deal I got on the jugs & slugs was very similar, still cheaper.

grandpaul · Posted: Fri Aug 08, 2008 11:16 am Post subject:

Case halves arrived today. The stock Right half will need to be machined to match the mods that were done on the Left half,
but there's not a lot besides upsizing the main top end stud hole threads.

I'm going to fight the urge to use the Superblend bearing that's in the Right side, unless Kenny verifies that it's good.
There's also a nify upgraded roller style cam bearing instead of a plain bushing.

grandpaul · Posted: Sat Aug 09, 2008 2:26 pm Post subject:

I went to have a look at a set of modern forks with dual front discs and it turns out it's a complete rolling chassis;
so I thought "what the heck" and rounded up enough bits to check feasibility:

Not too bad of a fit...

A little too snug to get to the exhaust valve adjusters...

the pipes would clear with the head here, but the engine has to move higher and further back for the head to line up with the jugs...

The rear isolastic would be an easy fit to the existing mounts, but there are no front mounts...

Too many issues with this chassis, but i might still buy the forks and re-paint the wheel. I wonder if I could shoehorn the matching rear wheel
into Kenny's custom swingarm? hmmm....

grandpaul · Posted: Thu Aug 28, 2008 1:51 pm Post subject:

I just traded e-mails with Kenny and it looks like he's got the monoshock rear end and the blue bodywork that were on the original prototype 952, he say's he'll sell them to me as soon as he reverse-engineers the monoshock setup as he no longer has the drawings and patterns.

I went ahead and bought that rolling Kawasaki 636 chassis and found out I can slip that front end right onto my stock '74 Norton frame with a set of custom bearings and a bit of machining on the yoke stem. Piece o' cake! (I'll sell the frame arnd rear end on e-bay to help finance the Dreer parts)

This sucker is shaping up to be one heck of a special!

grandpaul · Posted: Thu Aug 28, 2008 2:36 pm Post subject:

By the way, here's my goal; this latest news gets me a LOT closer!

bill · Posted: Thu Aug 28, 2008 5:12 pm Post subject:

Gp I did an 880 motor last winter for a guy with a ported head and a 56-000 cam. a few notes, it CCed out at 10.25/1 with a base gasket and 10.5/1 without. the piston kit was from TC Christenson and was heavy so check what you have. The 56-000 cam is close to a combat as for timing events with more lift. My think is bigger bore =more lift so that came was a good choice and it does work VERY good. We also used 1 1/2 exhaust with peashooters. as of now it has a set of stock amals but looks like a set of 35 FCR's will happen this winter Very Happy

. it is already a hoss but the carbs should really help it. I don't like the 920 kit as it takes a lot of integrity from the jug. the one's I have looked at you can see the sleeves where the boring bar breaks through the casting.

windy

littlefield · Joined: 20 Jul 2008 Posts: 7 Location: Clute, TX

Grandpaul,
Are you using the 636 top clamp? I'm fitting some R6 forks onto my 71 using the stock 25mm bore bearings. 30mm on the Yamaha. The top clamp normally locates on a 1inch + fit on the stem. The easiest way I can see to do it is use a 3/4 or 7/8 hardware store nut to load the bearings and then make a locknut with the right size and height to locate the top clamp. What did you have in mind? I'm thinking about using Convertibars. They're kind of clunky looking but the Yamaha top clamp looks too thin to attach bars on top.

grandpaul · Posted: Fri Aug 29, 2008 5:25 am Post subject:

I hadn't thought about the bars on the 952 being standard style, and the 636 being clip-ons.

I'll have to give it a think.

grandpaul · Posted: Fri Sep 19, 2008 12:45 pm Post subject:

Back from a long race trip including the Bonneville Salt Flats, Miller Motorsports Park in salt Lake City, and the Sandia Classic at Albuquerque; fared quite well at all venues.

Meanwhile, I had a guy meet me at the track in Albuquerque and bring me an 850 Mark III es engine and rear wheel with all the brake parts & footpegs. I'll be able to use the primary cases, transmission, rear brake gear and rear hub on the project. Not so sure about the electric starter yet, have to check out the possibilities with the belt drive that I already have.

Talked to Kenny for nearly an hour about issues surrounding use of the monoshock rear end, rear tire & carburation possibilities, and various other stuff.

The head, bodywork & swingarm should be arriving soon!

The Unapproachable Norton Commando

At the end of 1967 the Norton Commando was announced.