Workin on a Harley

comnoz

comnoz

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Dec 10, 2008
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I had some Ducati guys come by my shop and accuse me of working on a Sportster head. I guess the technology is similar. It's not a Commando but a 36 Norton. Other than the open valve gear it is a pretty decent design. I can see why they could be made fast.

Workin on a Harley


Workin on a Harley


Workin on a Harley


Workin on a Harley
 
swooshdave said:
comnoz said:
swooshdave said:
Not putting that on the flow bench?
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The thought did cross my mind. :D
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It would interesting to see how similar the single port and combustion chamber design was to the twin.
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The port design is very similar. The chamber is a little deeper and the valves have a bit more angle. The valves are quite a bit larger than the twins to go with the larger displacement and the intake and exhaust valve were the same part originally.
I installed hardened seats and used a DLC coated intake valve and a hard chrome exhaust valve. [sourced from a Cummins turbo diesel !] We are also looking into a better way of getting oil to the stems. They had a bad habit of running too dry.
 
Workin on a Harley


Oil pipes up to the valve stem, low pressure, of course, crimped so they barely drip.

How do they do it on a stock Model 18?
 
The model 18 has a couple small tubes that exit the bottom of the rocker boxes and go into a drilled hole in the side of the guide. The rocker boxes are supposed to get enough oil vapor up the pushrod tubes to collect a bit of oil to feed the guides. When Steve sent this head the exhaust guide was worn nearly all the way through to the head. 3/16 clearance? I guess that was a pretty common problem. I drilled the head and made up some little fittings with banjo adapters on them. I think he is planning on a drip feed oiler. Jim
 
Seems the hemi head has been around for a long time in motorcycle design. Was Ricardo the first to use it (triumph)?

Had a 1930triumph 500 single, twin exhaust ports, hemi head.

Glen
 
worntorn said:
Seems the hemi head has been around for a long time in motorcycle design. Was Ricardo the first to use it (triumph)?

Had a 1930triumph 500 single, twin exhaust ports, hemi head.

Glen
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It has been around longer than I have been. I don't know who used it first. Jim
 
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