SP: Spring Boxes (Rear) Thornton coil over spring rate.

davidd

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Thanks, David

The next step up in the Works Performance springs is 300 lbs. It is 7.2" free length, 0.341" wire diameter, 9.3 coils and the ID is 1.75". I was hoping there might be a 280 lbs, but there is not. I found a spring on line, but it is 6" free length, which is probably not of help.

David
 

Dave Hulstone

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Now I know I’m running the same as most twins out there I feel I can make it work. I have plenty of preload left to play with. I have my friction dampers completely wound off? David, on a completely different topic, which cams have you ended up running in your Grey Flash, Megacycle?
 

davidd

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I ran a large lift cam that Megacycle makes for me. On David Tompkins racer I had clearance problems after I built the engine. The big lift cam caused the rocker to kiss the valve guide under power.

David's first engine (not the one I built) started with the 105 cam which lowered his BHP to about 26. He went back to the MK2 and got the power back to about 30. I told him to build a Gold Star exhaust system with a megaphone and it went to 34 BHP. When he put my engine into the bike it went to 37 BHP. Recently, he tried a different primary pipe (1-3/4" instead of 1-5/8") on the bike and got 38 BHP. Using the megaphone pushed the red line to 6700 RPM, which was nice.

I have been very impressed with the Megacycle Mk2 as a result. It is difficult to get all of this power on the street, but it showed me that the Mk2 is still an excellent cam.

David
 

Comet Rider

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David D and Dave H
1.75" ID is quite a common size used by many manufacturers including Ohlins etc for twin shock setups.
There maybe someone in Aus who can help you with alternative springs.

On my AVO as I'm a big fat bloke I ended up with a 300lb/in spring for my Rapide, which is heavier than the normal spec'd by Timetraveller/Hadron who did much of the development work

A point to note is that the AVO uses a 2" ID spring

All the best
Neil
 

Comet Rider

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Hi Bill,
I'm no expert, but the way I understand it is that soft spring high damping will not do you any favours as it makes the shock too rigid.
You need the right spring rate for your weight + plus luggage and moderate damping so the spring takes the hit and the damper smooths it out, also restricting rebound
 

bmetcalf

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This is the letter that Dave Molloy sent me with my coilover shock:

Malloy Instructions a.jpg
 
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