Author Topic: Tuning the Electra-X ?  (Read 7841 times)

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Adrian

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on: December 18, 2007, 08:59:33 pm
Hi All,

prompted by the 80 MPH topic, I thought you might like to see what can be done with the 500 Lean Burn head.  My apologies to those of you including Ric and Tiny Tim who have already seen this elsewhere.

My Electra already had one of the UK importer's PHF 32 Dell'orto carb from new, but having played with unit single BSA's in my past biking life I was keen to get in and er... mess with my head! I bought a new spare head from the UK importers, have a look at these:



Nice modern combustion chamber design, room for a 2nd spark plug too...



That exhaust port is unbelievable! Surely something can be done?



What's happening with the inlet? That's quite a large hole already, 1 1/4" (32mm) at the narrowest part. Are you thinking what I'm thinking? ??? Anyhow, that exhaust port cleans up nicely:





You're ahead of me on this one, but here's the picture anyway. With VERY little work you can get a nice shiny 36mm inlet port, allowing you to fit the Dell'orto/Mikuni/Keihin of your choice. There's just enough metal to take it out to 38mm if you have a spare Amal 1 1/2" GP carburettor lying around  ;D

With the head finally fitted I experimented with the 32mm Dell'orto before parting with my money for THIS,



a TM36-31 Mikuni flat slide pumper carb. It just about fits under the gas tank, though I had to lop a spare bracket off the carb first!  :o The ally sleeve is the same one used for the Dell'orto kit as it lines up with the airbox, though if I put the bike back in Woodsman trim I'll use a pod air filter



Performance has improved noticeably in the mid range, though it is now crying out for a smaller countershaft sprocket to get max revs in top gear. Down one to 17T should do it. Porting the head and fitting the 36mm Mikuni hasn't spoilt the low-speed riding in town or guzzled lots of extra gas, I'm pleased to say.

I would be very interested to know what else is going on in Electra-land. The CMW big bore conversion looks promising, is there any more news? What are our Indian friends doing with their 500 Machismo Lean Burn engines?

Hope this is of interest to somebody...

Regards,

Adrian
« Last Edit: December 19, 2007, 08:03:56 am by Adrian »


scoTTy

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Reply #1 on: December 19, 2007, 12:43:30 am
thanks for that,  very interesting..  .. great pictures..



scoTTy

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Reply #2 on: December 19, 2007, 03:44:51 am
and a gOOd loOkN biKe   ;D


rochitsen

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Reply #3 on: December 19, 2007, 06:05:02 am
Great Job and some amazing info... would surely like to try something like this on my bike.


HRAB

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Reply #4 on: December 19, 2007, 10:07:38 pm
CMW is snow and ice bound right now. Not much riding going on. So there sits the AVL 560 unpampered but not forgotton .
jim
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luoma

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Reply #5 on: December 20, 2007, 02:38:39 pm
Adrian, you say that you need to drop your geering after your modifications. Are you saying that you lost power on the top end?


LJRead

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Reply #6 on: December 22, 2007, 09:52:32 pm

Actually, Adrian, isn't the increase in wind resistance helping, since you have to rev more to get the same speed?  The increase in mid-range performance conflicts a little with what I have read about larger carburetors only being effective in the higher rev ranges, or have I got that correct?


faltnerc

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Reply #7 on: December 26, 2007, 08:02:02 pm
Hello Adrian!
Reading about your efforts tuning the Electra cylinder head proves that you need more to tune it than to make the intake and exhaust ways wider and use a bigger carburator.
I think that the guys of AVL know their job very well.
They are specialists in shaping these items and any modification will bring negativ effects. I am convinced that bigger carburators and cross-sections af intake and exhausts will bring only good effects at high revving. But high revs are very bad for our "old" british long stroke single cylinder bikes because of high piston speeds and vibrations who will destroy our crankshafts and bearings! The Suzuki of my wife has two 34mm Mikunis at 450 ccm and has its best performance at 8000 revs.
Of course this bike is faster but - who cares? She has to wait for me!
Best regards
Chris


Adrian

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Reply #8 on: February 10, 2008, 11:04:22 pm
Hi All,

I finally got my countershaft sprocket swapped to 17T in place of the stock 18T and the bike is much happier, both footling around town AND getting better revs in 5th gear on the open road.

The quest will continue, with more developments planned for later this year, but I'm happy with things as they are for now...

Regards,

Adrian


Kevin Mahoney

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Reply #9 on: February 14, 2008, 11:15:34 pm
We horsed around with the Electra head quite a bit and finally gave up. We couldn't improve it. Pity that we can't make something to sell for it, but it is a good flowing head right from the factory
Best Regards,
Kevin Mahoney
www.cyclesidecar.com


LJRead

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Reply #10 on: February 16, 2008, 06:53:57 pm

Adrian,

I'm wondering what sort of fork top yolk you are using as well as instruments and their bracket.  Looks nice and simple, Also the fork top tubes and headlight bracket - are they stock?

Thanks,

Larry