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Author Topic: New Vintage Project, 250cc M-VG, Reconstruction of a 1933 French Jonghi 350  (Read 10773 times)
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thefrenchowl
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« Reply #105 on: August 09, 2018, 12:31:02 PM »

 grin



 grin



Patrick
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Harold Bettes
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« Reply #106 on: August 09, 2018, 02:28:30 PM »

Patrick,

What diameters are the valves? What is the overall length of the valves? And of course, what is the stem diameter?

What is the CR of the thing? Approx 6:1 or so?

Regards,
HB2
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thefrenchowl
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« Reply #107 on: August 09, 2018, 04:24:07 PM »

Hi Harold,

Valves are both the same dimms, but the inlet is more tuliped than the exhaust.

They used the same valves on the OHV version...

Head diameter 44.5mm, 1"751, length 121mm, 4"763, stem diameter 9mm, 354 thou.

Not too restricted then for a 70mm bore and 90mm stroke

The head has no "Ricardo" squish, I doubt there more than 4.5 CR... I'll measure it soon.

Thanks for theyour interest,

Patrick
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thefrenchowl
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« Reply #108 on: August 11, 2018, 10:33:46 AM »

Exhaust pipe...



Curve retouched and small extension to get it to 38" from valve to end like my KHK...



Recycled stainless brackets:





Welded back to back:



Frame bracket:









So long,

Patrick

« Last Edit: August 11, 2018, 10:37:13 AM by thefrenchowl » Logged

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wobblywalrus
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« Reply #109 on: August 11, 2018, 01:33:31 PM »

That might be a good place to put a rubber mount between the header and the bracket on the frame so the pipe can grow and contract due to thermal expansion and not overstress the bracket.
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thefrenchowl
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« Reply #110 on: August 23, 2018, 05:30:13 PM »

Hi Everybody,

Not too much enthusiasm these last weeks, two funerals, old friends of my wife Susan... Plus a few difficulties to visualise the braketry needed for the saddle...

The vertical supports are easy enough to do...







After that, quite challenging, space geometry with the saddle suspended precariously above the tyre!!!



It stayed like this for about a week, time and rest needed to decide where to start the rest.

Started with the front, A Frame, don't quite see where the word stemed from!!!





Above these was a bit Gaudiesque, branches in every direction towards the saddle frame. I started with the lateral ones.





Just enough support to allow spot brasing...



I'll continue with the front branches tomorrow.

Patrick

« Last Edit: August 23, 2018, 05:35:07 PM by thefrenchowl » Logged

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thefrenchowl
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« Reply #111 on: August 25, 2018, 12:19:39 PM »

Hi...

Finished saddle frame, just needs a good seance of filing...





Then rear fender, there were none on the original bike, but SCTIA/BNI who run Bonneville Speed Week insists it's mandatory...





So long, Patrick
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thefrenchowl
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« Reply #112 on: August 28, 2018, 03:47:08 PM »

Hi,

Needed sommat to relax this weekend... Nothing like monotonous stuff to do that!!!

Swiss cheese endeavour for the rear sproket!!!!

I started with this boring part:



Central portion thinned out:











Cheers,

Patrick
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Koncretekid
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« Reply #113 on: August 28, 2018, 06:41:57 PM »

Nice work, Patrick!  Do you plan to bring the bike to Bonneville?

The valve sizes sound huge for the 70mm bore.  44mm intake valve is the same as for the 84mm bore BSA B50.
How did they ever fit the same valve sizes in the overhead valve version?

Tom 
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« Reply #114 on: August 29, 2018, 01:40:29 AM »

 grin With great difficulty, Tom!!!



And yes, the plan is to bring this bike to Speed Week next year if all goes well...

Patrick
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« Reply #115 on: September 05, 2018, 04:07:17 AM »

Hi,

Finished the saddle frame...







And did a 18/14 reducer for the spark plug:



Choice of modern super cold NGK:



Of NOS Harley KR Champion plug:



Patrick
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