Author Topic: New Vintage Project, 250cc M-VG, Reconstruction of a 1933 French Jonghi 350  (Read 27673 times)

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Offline wobblywalrus

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Re: New Vintage Project, 250cc M-VG, Reconstruction of a 1933 French Jonghi 350
« Reply #135 on: January 12, 2019, 06:59:59 PM »
Patrick, will you be running this bike on the salt?

Offline thefrenchowl

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Re: New Vintage Project, 250cc M-VG, Reconstruction of a 1933 French Jonghi 350
« Reply #136 on: January 13, 2019, 03:53:01 AM »
Yes Wobblywalrus,

The plan is entering Speed Week this August 2019...

1st proper run will be where the original racer did the 24 hour world record, the Montlhery oval concrete track near Paris in early May (built in 1924 and still standing!!!), big vintage meet there called the Vintage Revival...



https://en.wikipedia.org/wiki/Autodrome_de_Linas-Montlh%C3%A9ry



See you there maybe?

Patrick
« Last Edit: January 13, 2019, 03:56:25 AM by thefrenchowl »
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Offline thefrenchowl

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Re: New Vintage Project, 250cc M-VG, Reconstruction of a 1933 French Jonghi 350
« Reply #137 on: January 13, 2019, 10:59:04 AM »
Good evening,

 Tap finished after a few problems...  :-D





Patrick
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Offline thefrenchowl

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Re: New Vintage Project, 250cc M-VG, Reconstruction of a 1933 French Jonghi 350
« Reply #138 on: January 25, 2019, 01:07:05 PM »
Hi...

Never sewed in me life, so a 1st...

Started the tank leather pad.





After a few trys, this is the outcome:



But I used all the strong thread I had, so waiting for some more so I can start on the 4 straps....

Found a Ferodo lining box:



Miracle: nearly the same diameter...



Glue...



I'll rivet and trim them later once super dry......



So long, Patrick
« Last Edit: January 25, 2019, 01:10:03 PM by thefrenchowl »
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Offline ProjectROTM

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Re: New Vintage Project, 250cc M-VG, Reconstruction of a 1933 French Jonghi 350
« Reply #139 on: January 27, 2019, 12:48:55 PM »
Hi Patrick,

Where did you get the aluminium number boards from?

Cheers,

ROTM

Offline thefrenchowl

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Re: New Vintage Project, 250cc M-VG, Reconstruction of a 1933 French Jonghi 350
« Reply #140 on: January 28, 2019, 03:21:06 PM »
Hi, Velocette Man,

From this GB ebay seller:

https://www.ebay.co.uk/itm/Oval-Racing-Motorcycle-Number-Plate/392101615385?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

There are others around...

Any news on the MAC?

Cheers from Patrick
« Last Edit: January 28, 2019, 03:22:53 PM by thefrenchowl »
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Offline ProjectROTM

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Re: New Vintage Project, 250cc M-VG, Reconstruction of a 1933 French Jonghi 350
« Reply #141 on: January 29, 2019, 01:21:21 PM »
Hi Patrick,

Thanks for the link.

Slow progress on the MAC, but I am hoping to upload another video soon. I don’t want to hijack your thread, but if you are on Facebook I have created a page for more regular updates. @ProjectROTM

Cheers,

Christian

Offline thefrenchowl

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Re: New Vintage Project, 250cc M-VG, Reconstruction of a 1933 French Jonghi 350
« Reply #142 on: February 08, 2019, 10:30:10 AM »
Hi,

Good day today, collected all my machined bits from B&E.

Keith, the workshop manager:



Levers for the petrol tank caps:





My friend Frederic in France dis these special nuts for me:



Cylinder deck milled and square to crank:



I did the manifold, B&E did the thread and castlenated nut:



Inlet track bored to 28mm, plus new M33 x 1.00 thread:







General view...





So long...

Patrick
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Offline wobblywalrus

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Re: New Vintage Project, 250cc M-VG, Reconstruction of a 1933 French Jonghi 350
« Reply #143 on: February 08, 2019, 11:00:12 AM »
Patrick, will the carb have any additional support?

Offline Harold Bettes

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Re: New Vintage Project, 250cc M-VG, Reconstruction of a 1933 French Jonghi 350
« Reply #144 on: February 08, 2019, 05:25:13 PM »
Patrick, :-D

WW has brought up a good point about supporting the overhung load of the carb and float bowls. Thinking about the resonant frequencies of the one cylinder engine made me think of the one good thing the GP bowls help and that is surface area and volume available in a straight line acceleration mode. If you take a jar of water approximately equal to the diameter of the bowl and take a look at what happens as you introduce various frequencies to it you will see at some point(s) the surface of the water will begin to grow vertical columns that resemble stalactites and stalagmites. Any vibration isolation while supporting the weight/mass of the carb and bowls with fuel you can provide will help decrease those problems. Even a simple flexible coupling and a vertical support (also damped) will help. 8-)

As I recall, isn't the oil pump driven via a nylon looking gear? IF so, you should probably go to another material. :? Please forgive my questionable memory.

I thoroughly enjoy following your thread on the old flat motor and congratulate you on your dedication and workmanship. :cheers:

Regards,
HB2 :-)

 
If it was easy, everybody would be doing it.

As iron sharpens iron, one man sharpens another.

Offline thefrenchowl

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Re: New Vintage Project, 250cc M-VG, Reconstruction of a 1933 French Jonghi 350
« Reply #145 on: February 09, 2019, 03:54:18 AM »
Hi,

It's in the plan to seek a support for the carb!!! But I will not cut the manifold to insert a flexible pipe damper!!!  There is actually an alloy sleeve at the end of the manifold that locates inside the carb spigot, might make a soft plastic one to replace the alloy one...



All the gears in the timing cover are treated steel, so no worries there...

B&E also did a few alloy weld in there.

One of the TJ 4 problems is the sliding 2nd gear in the crash gear box. Not only it slams into his brother everytime one changes gear, but it also is not helped by the wet clutch which makes it difficult to obtain a clean separation of the driving and driven plates. So I decided to use ATF in the gear box and primary spaces, a solution most used in 70's wet clutch Sportsters,

The engine oil in the Jonghi is circulated via windows and they have been welded shut.





B&E also repaired the broken clutch cable anchor:





Patrick
« Last Edit: February 09, 2019, 03:58:01 AM by thefrenchowl »
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Offline thefrenchowl

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Re: New Vintage Project, 250cc M-VG, Reconstruction of a 1933 French Jonghi 350
« Reply #146 on: February 09, 2019, 02:17:33 PM »
Hi,

I wasn't too pleased with my 1st tank pad, see above......

So I made another one these last few days...







Patrick
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Offline thefrenchowl

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Re: New Vintage Project, 250cc M-VG, Reconstruction of a 1933 French Jonghi 350
« Reply #147 on: February 11, 2019, 11:13:55 AM »
Hi,

Other stuff done this weekend: mods to the oiling system.

There's a hole in the primary cavity that transfer lubricant back to the sump:



Blocked it with a screw.

I transfered that level to the primary cover for a new level plug::



No breathers left for gearbox and clutch cavities after all the welding, so install a new fitting on top of the box for a breather pipe:



Since the bottom of the box is much higher than the botton of the clutch, design of a transfer system between them, using centrifugal and gravity forces: little dam  with hole behind to collect ATF from clutch cavity and to transfer it to the box:









Also drilled big breather hole in between both cavities:



So the box will fill with ATF from the clutch, so new hole down to limit level in box and diminish ATF volume:



In the timing cover, there were just 2 little holes to drain it into the sump, same, increased hole size to speed up drainage.



So long...

Patrick
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Offline Duck-Stew

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Re: New Vintage Project, 250cc M-VG, Reconstruction of a 1933 French Jonghi 350
« Reply #148 on: February 13, 2019, 09:08:43 AM »
Absolutely enjoying this build.  I'm in the process of building a much more modern single cylinder but a lot of the thought processes are similar.

Wish you the best with this project.
--Stuart
Team UnorthoDUX

Offline thefrenchowl

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Re: New Vintage Project, 250cc M-VG, Reconstruction of a 1933 French Jonghi 350
« Reply #149 on: February 15, 2019, 12:01:59 PM »
Hi...

Thanks, Duck Stew...

Considering the race cams and the rpm, 6000, I thought I'd better find stronger valve springs!!!

These are internal Sportster ones, with their cups moded to suit.

With valve lift, it leaves 2mm before coil bind and before the lower cup hit the valve guide, so all good and a lot more pressure..

On the right the mod, on the left the std set up:





Patrick
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