Norton Commando
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Chip's '72 Combat project
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grandpaul



Joined: 15 Jan 2008
Posts: 436
Location: Laredo (south) Texas

PostPosted: Mon Jun 30, 2008 9:45 am    Post subject: Back to work! Reply with quote

Just back in after a 3-week road trip to 2 races and several tourist spots, so it's back to work on Chip's bike.

This phase should be interesting, we're getting down to basically the details and cosmetics, then some serious road testing.

Plenty of pix, and project wrap-up details including complete parts & modifications listings to come.
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grandpaul



Joined: 15 Jan 2008
Posts: 436
Location: Laredo (south) Texas

PostPosted: Tue Jul 01, 2008 2:19 pm    Post subject: Reply with quote

Back from a 3-week racing trip, time to get back to work. Got the decks cleared and hoisted the bike up on the stand-

Sure enough, the head gasket was damaged somehow. I thought I was being careful , but perhaps one of the new stainless headbolts grabbed the edge of the flame ring and damaged it to the point that it was a failure waiting to happen.

I'll have the machinist re-check the surfaces of the head & jugs to make sure they're okay, then re-install with a solid copper gasket and some copper seal. That's what I always used before this job, but decided on the flame ring on others' advice.

GOOD THING it happened here in my driveway, and not in Florida on some back road! (Thank God for small miracles)

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Ron L



Joined: 27 Feb 2004
Posts: 1018
Location: Ohio

PostPosted: Wed Jul 02, 2008 2:50 am    Post subject: Reply with quote

GrandPaul,

Unless it's an optical illusion, that gasket looks like it doesn't quite line up properly. I have seen this kind of problem on some (not all) 750 aftermarket flame-ring gaskets. The holes are slightly off and when you screw the bolts in the fibrous material puckers and keeps the head from being seated properly. Oddly, I have never seen this issue with an 850 gasket. I always use 750 gaskets from Andover Norton.

A good flame ring gasket is easier to get a seal than an annealed copper one in my experience. However, many prefer the copper.
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grandpaul



Joined: 15 Jan 2008
Posts: 436
Location: Laredo (south) Texas

PostPosted: Wed Jul 02, 2008 7:12 am    Post subject: Reply with quote

Actually, I had two to choose from, this one aligned MUCH better than the other one.

I may take a second look at the other one and dress the holes for proper alignment, but this incident has me shy...
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debby



Joined: 15 Apr 2004
Posts: 856
Location: Boulder, CO

PostPosted: Wed Jul 02, 2008 7:52 am    Post subject: Reply with quote

I use genuine Andover Norton gaskets and have never had a problem.

Debby
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cash



Joined: 10 Nov 2006
Posts: 359
Location: west cumbria

PostPosted: Wed Jul 02, 2008 8:12 am    Post subject: Reply with quote

grandpaul,
It looks to me those stainless steel bolts have given in to the combustion pressure and the gasket has blown out.

Weeeeee.... those soft stainless steel bolts and replace them with standard high tensile norton bolts. You can never be sure what grade of stainless has been used. High tensile stainless is a beggar to machine and polish, and is bloody expensive.

And fit a genuine Norton head gasket, a Reinz ( I think that's how you spell it) and you shouldn't have a problem.
Best of luck,
Cash
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Jason Curtiss



Joined: 14 Jun 2003
Posts: 642
Location: HOUSTON, TEXAS

PostPosted: Wed Jul 02, 2008 9:29 am    Post subject: Reply with quote

I've always been suspicious of stainless steel fasteners for use on engines. They don't seem near strong enough to me.

For instance, most 300 series stainless has a minimum yield strength of around 36,000 psi. In contrast, a grade 5 carbon steel bolt (typical hardware store variety) has a minimum yield of about 90,000 psi.
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grandpaul



Joined: 15 Jan 2008
Posts: 436
Location: Laredo (south) Texas

PostPosted: Wed Jul 02, 2008 9:57 am    Post subject: Reply with quote

Andover gasket ordered.

The stainless bolts are the high end parts from Old Britts, VERY highly reputed, and well suited to the task.
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grandpaul



Joined: 15 Jan 2008
Posts: 436
Location: Laredo (south) Texas

PostPosted: Mon Jul 07, 2008 12:02 pm    Post subject: Reply with quote

While the head gasket is winging it's way over, I got the bodywork fitment complete. Just need to CAREFULLY drill the windscreen and mount
it up. Good clearance from handlebars, but slightly limited steering at the far ends of the travel (as Chip said it was before).

It won't be much longer now...

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Ron L



Joined: 27 Feb 2004
Posts: 1018
Location: Ohio

PostPosted: Tue Jul 08, 2008 4:05 am    Post subject: Reply with quote

Grandpaul,
You probably already know this, but drilling windscreens requires a bit with a sharper angled point (90 or even 60 degree). These are available from Gustafson or Craftcs.com.

Here's a link worth reading http://www.bertram31.com/proj/tips/drill_acrylic.htm
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grandpaul



Joined: 15 Jan 2008
Posts: 436
Location: Laredo (south) Texas

PostPosted: Tue Jul 08, 2008 6:34 am    Post subject: Reply with quote

hee hee

Ron, I know ALL TOO WELL!!!

I just drilled the one on my Combat back in early May.

I had a spare windscreen with one small crack (guess when that happened?) that I was using, but it blew off while the bike was strapped to my open trailer, on the way home from a bike show; I had forgotten to tighten the screws and put a dab of silicone on the ends of the screws! It was a total drag, because the crack was very small and I intended to save the new screen for much later.

Drilling slowly and with next to zero pressure on the drill are the other two tips that pay off.
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grandpaul



Joined: 15 Jan 2008
Posts: 436
Location: Laredo (south) Texas

PostPosted: Mon Jul 14, 2008 6:01 pm    Post subject: Reply with quote

I went back and noted that the head gasket I pulled off during the tear-down was a solid copper one, the ones I ALWAYS use on my Triumphs.

Hmmmmmm.....

Worst case, I'll give the new flame ring gasket a careful try-out; anything suspect, I'm going back to my favorite tried-and-true method with the solid copper gasket that came in the Wassell Combat gasket set.

Went ahead and polished the oil pump plates JUST IN CASE. The pump shaft had a bit of end float, the book says that's the thing to check. I carefully reworked the plates and re-assembled it to the absolute minimum perceptible play in the shaft with a good snug rotational feel.

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cash



Joined: 10 Nov 2006
Posts: 359
Location: west cumbria

PostPosted: Tue Jul 15, 2008 7:51 am    Post subject: Reply with quote

I wish you the best of luck with the head gasket, but you really want to consider dumping those stainless steel head bolts.

I've just put my old girl back together using a Reins head gasket and HTS bolts. I've done a couple of hundred miles and found one nut needed a 1/4 turn the rest OK with no signs of leaking. I'll check again as usual.

The motor compression is tad under 9.5 : 1 with a 3s cam etc.

Cash
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grandpaul



Joined: 15 Jan 2008
Posts: 436
Location: Laredo (south) Texas

PostPosted: Thu Jul 17, 2008 9:27 am    Post subject: Reply with quote

This-



Is in here now-



I'm taking a lunch break, then I'll have it all nipped back up by this evening, maybe give it a test ride if it's not too late.
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grandpaul



Joined: 15 Jan 2008
Posts: 436
Location: Laredo (south) Texas

PostPosted: Fri Jul 18, 2008 8:25 am    Post subject: Reply with quote

ONE KICK!

(Well, that shouldn't suprise anyone, me least of all)

I'm going to stick a few more parts on it for a test ride, so as not to arouse the suspicion of the local constabulary.

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The Unapproachable Norton Commando

At the end of 1967 the Norton Commando was announced.

The Norton Commando was greeted with a certain amount of scepticism because on first sight the commando appeared to comprise of the old Norton Dominator twin cylinder engine mounted at an inclined angle in a set of new cylinder parts.

It was not realized that the new Norton Commando Isolastic method of engine suspension damped out all engine vibration and produced a machine which had uncanny smoothness for a vertical twin. In due course the critics were silenced and the Norton Commando had the distinction of being regarded as the first of todays so called superbikes. There can be little doubt that the original design concept of the Norton Commando has proved correct, since comparatively few modifications of any real consequence have been made since production commenced during 1968.

Now nearly 40 years later Norton Commando riders like us are a breed of our own, and as far as we are concerned its still more fun to go for a blat on the old Norton Commando, and fast. As a Norton Commando owner and enthusiast, my goal here is to promote and give credit to those who keep the Norton name going.

It is more deserving to give credit to the Commando itself, for after all these years it continues to be respected. The original Commando designers like John Favill are those who deserve the credit for developing this incredible motorcycle.

The Norton Commando Roadster and Interstate of the late seventies, never died. Although the Norton Villiers factory dispersed the tradition lived on. Today Kenny Dreer in the USA is developing the new 952 CC Norton. What a great looking bike this is, and its engineering is still based on the original layout. It will be interesting to see how the new 952CC Norton does in todays tough motorcycle market. One thing is for sure, I would own one if I could afford it.