New Pistons are here.

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Oct 9, 2004
The Big Brown Truck stopped by with presents today.

Custom 10.25:1 JE Pistons
New Pistons are here.

They've got a dry-film lubricant coating on the skirts and I'm sending them out for ceramic thermal barrier coating for the domes. I had them made to use gapless Total Seal rings that're made for Acura race engines (on the advice of Total Seal and JE).

They go nicely with my Carrillo connecting rods
New Pistons are here.

Now I can *finally* weigh everything and finish getting the crank balanced. Bottom end of the motor may be together by next weekend.

Got a call from Johnson Cams yesterday saying the cylinder head will be ready in 2 weeks.

Woo hoo, progress!
lots of toys

Hi David,

With all the go fast goodies, what's your plan for the crankcases and gearbox to keep everything in one piece? Nice stuff!

The motor's just barely hotter than Combat spec and not as radical as the custom parts list makes it look. However, modern materials and a dose of technology should allow us to produce substantially more power.

We're only shooting for 68hp at the the crank, so the stress isn't as bad as you might think. The lightened crank and reciprocating assembly will help reduce that further.

As for the crankcases, I'm using the beefier 1973 cases. I've removed all of the casting-flash and potential stress risers with a die-grinder. Following that I had them shot-peened to improve the surface hardness of the aluminum.

I'm also using a different type of roller-bearing (suggestion courtesy of Kelly Cork via Greg Fauth - aka Norbsa) that's better at accommodating crankshaft flex, without transmitting that flex to the cases, than superblends. They're SKF 21306 EC's and they cost about 40% more than superblends - but the peace of mind is worth it.

I've also had the breather relocation and sump mod done to prevent oil pressure loss at high rpm's.

FWIW, none of my plans involve spending much time north of 6500 rpm's - so the 1973 case halves should be more than sufficient. But if they're not, there's always Maney cases and his lightened crank. (Pretty but pricey!)
Oh, and the gearbox has a Steve Maney outrigger bearing and all the other recommended upgrades.
new pistons are here

David, are the '73 cases 850 or 750? Does use of the out rigger bearing require the installation of a belt primary drive?

They're 750 cases, and its easy to see where they were beefed up by the foundry. Norton then went and spoiled it by relocating the breather someplace stoopid. :roll: Had that fixed though.

As for the outrigger, it definitely requires machining or grinding off the chain guard that's cast into the inner primary cover. (That may not be the correct name for it, but that's what *I'm* calling it.)

I don't know if it also requires running a belt primary, but I'm running a Maney 30mm belt nonetheless.
I just checked out Steve Maney's web site, mighty fine stuff there.
I haven't seen an outrigger installed. I assume it mounts outboard of the countershaft sprocket before the inner primary. Is this correct?
There are three types that I have seen. One is a plate that replaces the sliding dust seal in the inter primay cover. One made by RGM at one time comes with a belt drive kit and is an a alum basket that supports the clutch out side. The last is an adjustable hollow bar that ties the main shaft to the crank with ball bearings. norbsa

Yep, the Maney outrigger uses the gearbox mounting bolts, extending out from the cradle to the other side of the drive-gear. The bearing sits between the drive-chain and the inner primary. Am I making any sense?

I'll take pics when its in. Much easier to see than to explain. May be two or three weeks before I've got the gearbox finished and the drive-gear modified for the 520 x-ring chain though.


Those SKF Explorer 21306 bearings you recommended are *sweet*! Less friction, higher rpm ceiling, greater load carrying capacity, more tolerant of shaft deflection - what more could a man ask for?

Anyway, its almost May and the Rogue's Rally is sneaking up on us awful fast.... hope I'm finished in time.
Commando go fast stuff

Hi David,

Since you've already gotten pretty far into upgrading this and have a good grasp on cost, what's you take on cost the way you're going or just buying a Dreer Commando?

Yes, it’s an expensive project. However, this is the first time in my life that I've been in a financial position go all out on something.

Cheap? No. Fun? You betcha!

The motor's a little less than $4k. The rest should bring the whole project in slightly under $16k. I have $12k in it so far, so I'm over the hump.

You're right to point out that I could buy a new bike with the money I'm spending. Alternatively, I could put a hefty deposit on a Norton 952 (which, according to some of the companies Kenny owes money, may never see the light of day).

However, I'm not concerned about the cost. Further, I doubt there are many on this board who ride Nortons because they are a cheap option. Finally, where's the challenge in buying a "ready to run" bike?

In the end, I will have put every nut, bolt and washer on this bike. I will have researched every sound and stupid modification that could be made, and plan to do everything that survived the vetting process. Moreover, I'm doing it in 7 months - and will complete the bike in time for my one-year Norton anniversary. Not bad, eh?

Therefore, yes, I could buy a cool bike with my budget. However, it’s the intangibles that I'm after: knowledge, experience, pride, etc. Does that make sense, or do you all think I’m crazy?

You are certainly going to have an awesome norton & we all know the feeling you will have riding a bike you have rebuilt yourself.

Good on you, I say., I would think you are loving it :D
You cannot put a price on happiness.
go fast Norton

Hi David,

You answered my question about cost to build your's versus a ready built Dreer. I didn't mean you should have gone that way, just wanted to know for my own interest which way I might go. Eight years ago I build my '72 combat the way I wanted it and agree there's a lot of satisfaction in doing that. Already having done that, I've been interested in a really fast and reliable Commando. Dreer has pretty much answered all the issues surrounding the unreliability of the original Commandos and the 952 puts out nice hp numbers. Time will tell if they can really be the pheonix of Norton. I'll be convinced when they finally start shipping the first 100 signature editions at the end of this year.
By comparison, a disposable plastic crotch rocket would run about $10K plus another $2k or so per year for insurance. So $16K for a custom handbuilt bike doesn't sound so bad. Definitely for gearheads only however!

As for the Dreer bikes (if they ever make it into production) - well, I guess you either love them or hate them.

"Hate" maybe is a little strong. I just don't like the way they look. Their marketing is too sexist for my taste as well, although you guys probably like that!

For the money, I'd get a CNW rebuild (I've seen some of their work - VERY nice) or one of those new Ducati Sport Classics (now taking deposits for delivery who knows when).

go fast stuff

Sexist? Have you seen the late sixties and early seventies Norton ads that were inside the front cover of Cycle magazine? Austin Powers!
I am still salivating over the Steve Maney web site. One thing I could actually afford is the outrigger bearing support. Apparently this is a sealed bearing. Does anyone know the life expectancy on this?
And why is this outrigger bearing thing desirable? My bike seems to shift just fine without one!

It's only needed when working it so hard that the main shaft is flexed. If it is pushed hard enough the gears between the main and lay shafts pull apart. This causes the presure angle of the gear teeth to push the shafts even further apart cracking the alum. casting that holds the whole thing together. Hard down shifting is to be avoided. Unit BSA's are known to do this more often than Norton's. If you could get the main shaft and the crank linked by bearings you could solve both problems caused by power in the 80-90 hp range. A fuss idem Debby. norbsa
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