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Old 05-20-2008, 09:51 PM   #1
pommie john OP
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Airhead racer rebuild

Well it's been on the track for more than a few years and it's time for a rebuild and upgrade.
It used to look like this
Photobucket

Now it's all over the garage floor.
I've braced the frame at the rear to stiffen up the rear loops in the hope it will help that hinged in the middle feeling when powering out of corners.
Photobucket



Photobucket

The side braces have been there all along, but the triangle at the rear is the new bit.
As soon as it's back on the track, I'l report back on the handling.

The engine is braced to the top tube.
Photobucket

And is raised about an inch.
Photobucket
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Old 05-20-2008, 10:29 PM   #2
Bigger Al
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Jeebus, that's pretty!!


Crap, now I miss racing even more than I did yesterday............
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Old 05-21-2008, 07:30 AM   #3
Nick Makwell
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That looks fantastic John - what sort of horsepower is your bike putting out?

I doubt an R65 would need that sort of bracing (40rwhp?) Can you explain how you did it?

Also, what class are you racing in? Post Classic after 1973?

Pictures are good!
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Old 05-21-2008, 09:34 AM   #4
P B G
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Who manufactured that fairing.

I have an S on my bike now, and would love to go to a non-bar mounted, similar to that.
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Old 05-21-2008, 10:21 AM   #5
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QuickQuestions:

If you raised it an inch, how does that affect the driveline matchup? (trans/shaft/swingarm) and also how does it affect getting to your oil filter?

it looks like the front cover had a little surgery as well-- like to see details of that.
its a fine bad ass looking bike, thats for sure
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Old 05-21-2008, 10:38 AM   #6
Uncle Ernie
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I was wondering that, too. I'm also wonding WHY he raised the engine? How would that affect the handling and feel?

Maybe there's no need for an oil filter for racing if he changes the oil at the end of each day?
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Old 05-21-2008, 11:11 AM   #7
kixtand
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Quote:
Originally Posted by Stagehand
QuickQuestions:

If you raised it an inch, how does that affect the driveline matchup? (trans/shaft/swingarm) and also how does it affect getting to your oil filter?
I can't speak in this case, but all of the other folks I've talked to either have to drop the front of engine of they make that part of the frame removable.
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Old 05-21-2008, 11:13 AM   #8
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Quote:
Originally Posted by Uncle Ernie
...I'm also wonding WHY he raised the engine? ...
Raising the engine gives you more cornering clearance. A lot of folks will also move the engine forward a bit in addition to raising it to give you more weight on the front end (although it does not look like that was done in this case.)
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Old 05-21-2008, 05:25 PM   #9
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Morning all. Thanks for your kind comments.
Time to answer a few questions

Quote:
Originally Posted by Nick Makwell
That looks fantastic John - what sort of horsepower is your bike putting out?

I doubt an R65 would need that sort of bracing (40rwhp?) Can you explain how you did it?

Also, what class are you racing in? Post Classic after 1973?

Pictures are good!
In race trim it puts out 88bhp at the rear wheel. the most we saw on the dyno was 92, but that needed velocity stacks that were so long I couldn't get my feet on the footrests.
Many people don't believe the figures, but I can dig out the dyno charts if necessary.
I race it in Post Classic pre1972. It started life as an R75/5 so that makes it eligible even though it has been bored to 1000cc.
I do have to use an early crankcase which had problems with crankcase breathing when two 500cc pistons were flying up and down at 8500rpm, but some mods fixed that.
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Old 05-21-2008, 05:33 PM   #10
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Quote:
Originally Posted by Stagehand
QuickQuestions:

If you raised it an inch, how does that affect the driveline matchup? (trans/shaft/swingarm) and also how does it affect getting to your oil filter?

it looks like the front cover had a little surgery as well-- like to see details of that.
its a fine bad ass looking bike, thats for sure
The place that raised the engine have a jig that rotates about the swing arm pivot to ensure the transmission lines up still. So when i say the engine was raised an inch, I really meant the front was raised an inch and the back a bit less.
As for the oil filter, I have to take out the engine mounting bolts, remove the exhausts and drop the engine a bit to get at the filter. I just put a jack under the sump. No one said race prep had to be easy!

I have a custom made slimline oil cooler take-off plate .
Photobucket

I've machined a load of stuff from the front timing cover. The more observant amongst you will have noticed it's a late model timing cover, the fins on the side give it away. If anyone complains that it's not in the correct period, I'll fill between the fins with devcon. The later cover is necessary so I can use a Boyer ignition.
Photobucket
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Old 05-21-2008, 05:38 PM   #11
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Kixstand is correct about the reason for raising the engine. Cornering clearance. I did try it with the engine in the normal position and it definately turned into corners better, but I kept hitting the rocker covers on the ground so we had to raise it.
I later got hold of some Mahle race pistons which are 16mm shorter than standard ones. You then machine 16mm of the cylinders and end up with an engine that is 32mm narrower. I never have clearance problems now, and could probably go back to the original engine position if I could be bothered.

Mahle piston
Photobucket
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Old 05-21-2008, 05:43 PM   #12
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Quote:
Originally Posted by P B G
Who manufactured that fairing.

I have an S on my bike now, and would love to go to a non-bar mounted, similar to that.
It's a Ducati 900SS replica fairing. I can't remember where I got it but plenty of places make them.
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Old 05-21-2008, 06:10 PM   #13
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Hi.

I like what you're doing

But what about the rear frame? You still use the bolt-on rear?

I've seen a plenty of old-skool racers fitting an X-shaped re-inforcement between the main frame and the top of the shock mounts.

Paul.
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Old 05-21-2008, 06:14 PM   #14
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Quote:
Originally Posted by PaulRS
Hi.

I like what you're doing

But what about the rear frame? You still use the bolt-on rear?

I've seen a plenty of old-skool racers fitting an X-shaped re-inforcement between the main frame and the top of the shock mounts.

Paul.

It is a bolt on subframe, but it's been modified to take a P&M seat which is a bit narrower. It's also been lowered to take into account my ,err, Pedrosa sized legs.
I'd be very interested to see what others have done to beef up the subframe.
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Old 05-22-2008, 05:59 AM   #15
Nick Makwell
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Thanks for the replies - I can understand the bracing now, 88rwhp!! Holy hell.

My R1100S probably didnt put that out!

Friend of mine when I was a postie raced Nortons in PCRA (pre-72).
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