Author Topic: Spares wanted for SW5  (Read 2713 times)

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Offline Kaz

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Spares wanted for SW5
« on: 16 May 2011 at 09:47 »
I'm looking for following SW5 spares.

1) Piston complete +040 or +060
2) Bigend assy
3) Valve springs
4) Valve guides

Anyone help me?


Offline Doug

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Re: Spares wanted for SW5
« Reply #1 on: 17 May 2011 at 02:22 »
Kaz,

(1)  No direct replacement pistons are available, unless you are luck enough to stumble across some old stock. Most alternate pistons give a lower compression ratio.

(2) An good entire big end assembly will set you back a several thousand, if you can locate one.

(3) Valve springs are available from the London Douglas Motor Cycle Club. You have to be a member to use the club spares service.

(4) Some folk have used Norton Atlas/Commando cast iron valve guides (in conjunction with Triumph or BSA valves), with a new groove added for a snap ring to replace the flange on the original Douglas valve guides. These would need to be reamed out to use with the original Douglas valves since they used a larger stem diameter.

(5) You did not ask, but original style valves are available new. See:
http://www.douglasmotorcycles.net/index.php?topic=2141.0

-Doug

Offline Kaz

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Re: Spares wanted for SW5
« Reply #2 on: 17 May 2011 at 03:53 »
Hello Doug,

Many thanks for your advice.

Kaz

Offline eddie

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Re: Spares wanted for SW5
« Reply #3 on: 17 May 2011 at 10:25 »
Kaz,
       I have a 500 DT motor running with pistons from a Kawasaki Z400 twin. Being 64mm, they take the capacity out to about 530cc, and do raise the compression a little. They need to be slightly modified to clear the valves, and new small end bushes are needed as the gudgeon pins are only 15mm diameter. Obviously, they should only be fitted in pairs.
      Regarding the big ends - the only replaceable parts are the actual rollers and cages. Because of the method of assembly, the crankpins can only be reground by a small amount (about .005" on diameter) otherwise it is impossible to insert the rollers. Then, of course, oversize rollers will be needed. As Doug says, you can use modified Norton Commando valve guides - but go for the earlier type as they have a larger head that will get over the problem of having to fit a snap ring.
                         Regards,
                                Eddie.

 

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