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Author Topic: New Vintage Project, 250cc M-VG, Reconstruction of a 1933 French Jonghi 350  (Read 38303 times)

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Offline fordboy628

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YES!   It is the tapered fit which "holds", the key is just for initial alignment.

If ANYTHING prevents the taper from "fully seating" (key fit, inside edge hub interference, etc)  GAME OVER!

Just like a BMC Mini tailshaft, fitted length, precision lapping and proper torque are essential for success.

 :cheers:
M
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Offline ggl205

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Patrick, that flywheel nut is looking pretty gnarley. Any chance of getting a new one? Not sure what SCTA will think of an unshielded flywheel but you may want to check if you have not already done so.

An additional thought; now that you have renewed the flywheel nut mating surface, is there room for an AN style flat washer between nut and flywheel? This may assist in securing a reliable torque value.

John
« Last Edit: April 27, 2019, 07:03:32 AM by ggl205 »

Offline thefrenchowl

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Hi,

Thanks for the headers...

All the lapping work above was done with the tranny cover off to better access the tapers...

When I came to re-assemble it all yesterday, I discovered AT LAST the reason for the key breakage and the following flywheel taking liberties...

There'a a ball bearing in the cover that sits between flywheel and transmission gear.

The end of the female taper was ever so slightly touching that bearing inner ring and that prevented full blooded contact of the 2 tapers...

Flywheel was soon back in the lathe to slim that end a touch and it's all back to normal now. I lockpress-ed the assembly yesterday and torqued the nut to about 100lbs/ft, I daren't go higher.

Will dismantle it again today to see how tight the tapers are together when I apply the flywheel extractor...

If conclusive, after that, just tank and a few pipes to fit AGAIN and it's ready to fire again...

Patrick
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Offline Peter Jack

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It will fire a lot easier with the flywheel tight on the shaft. The key probably broke with your first kick!

Good luck. What a nice build.

Pete

Offline wobblywalrus

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It would be a good idea to check the suctioning body rules and get an opinion from the technical inspectors.  Sometimes with problem flywheels I will heat them in an oven before pressing them on.  They cool and contract around the shaft taper.  One problem is they can be a bugger to remove and sometimes they need to be reheated with a torch so they will come off.

Offline Bookfla

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The diameter of the flywheel bore area does not leave much parent metal above the keyway.  When I first saw this my mind went to the hundreds of damaged Harley Davidson clutch baskets that were designed with the keyway cut too close to the outside diameter. Put a little too much torque on it and the keyway will crack. Not sure if you have room but we used to put a "ring" around the outside diameter to give it more support. The flywheel looks very touchy.

Regards

Tom 

Offline thefrenchowl

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Hi,

Some unforeseen delay due to a quick trip in France last week...

Back on Monday, finished the bike... Alan came this afternoon to help me start it.

Two starts without problems, flywheel well and truly attached!!!  :-D

So loaded it all in a rental van, I'm off to France again, direction Montlhery for the Vintage Revival meeting this weekend...







So long, Patrick
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...What exactly are we trying to do here?...

Offline Peter Jack

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Hi,

Some unforeseen delay due to a quick trip in France last week...

Back on Monday, finished the bike... Alan came this afternoon to help me start it.

Two starts without problems, flywheel well and truly attached!!!  :-D

So loaded it all in a rental van, I'm off to France again, direction Montlhery for the Vintage Revival meeting this weekend...

So long, Patrick

Good luck and have fun Patrick.  :cheers: :cheers: :cheers:

Pete

Offline wobblywalrus

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That is great, Patrick.  Will you be riding it on the speed bowl?

Offline comet

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Good luck Patrick. Enjoy it.

Offline thefrenchowl

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Thanks, lads!!!

Yes, I should be on the bowl if the bike behaves!!!

Show is only Sat and Sund, but I'll be helping a friend on Friday with the Terrot Competition display, it will be the biggest ever gathering of OEM racing TerroT motorcycles , about 50 anticipated... Will be busy with the camera, that's for sure!!!

Here's one of them, not quite finished, but with a full blooded history, a consistant winner of all sorts of events between 1935 and 1960, including the 24 hour Bol d'Or race and the 1950 French 350cc Championchip, ex Leroy and Belkechout, a semi-works machine...



Talk to you soon in a few days!!!

Patrick
« Last Edit: May 09, 2019, 02:07:08 AM by thefrenchowl »
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Offline Old Scrambler

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We get to know of the numerous French motorcycles.............good to know about the survivors :-) :-) :-)
2011 AMA Record - 250cc M-PG TRIUMPH Tiger Cub - 82.5 mph
2013 AMA Record - 250cc MPS-PG TRIUMPH Tiger Cub - 88.7 mph
2018 AMA Record - 750cc M-CG HONDA CB750 sohc - 136.6 mph
2018 AMA Record - 750cc MPS-CG HONDA CB750 sohc - 143.005 mph
2018 AMA Record - 750cc M-CF HONDA CB750 sohc - 139.85 mph
2018 AMA Record - 750cc MPS-CF HONDA CB750 sohc - 144.2025 mph

Chassis Builder / Tuner: Dave Murre

Offline thefrenchowl

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Montlhery...

The bike starts now on the kicker 1st time all the time, BUT, broke again the centre stand and the magneto is weak in the revs, so did nor ride it on the track at all... But worked all Saturday to sort out the jetting, so no wasted time.

My friend Claude Caucal who gave the TT 2 race parts to build my reconstruction was there with 12 Terrot or Magnat-Debon ( a trade name for TerroT) race bikes and he lent me the unique Jean Nougier made 1937 DOHC 500 Magnat Debon officially raced by Jacques Onda in them days...

What an honour!!!

En pre-grille, waiting for the previous session to finish, warming up the engines, Claude on right, meself on left:



On the track, ready to pounce on the oval:



What a weekend!!!!!!!!!!!!  :-D

Started retuning and repairs in anger, more news soon!!!

Patrick
« Last Edit: May 17, 2019, 09:19:25 AM by thefrenchowl »
Flat Head Forever

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Online Seldom Seen Slim

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How cool is that -- someone letting you ride a precious bike for your fun.  Great stuff!!
Jon E. Wennerberg
 a/k/a Seldom Seen Slim
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 (that's way up north)
2 Club member x2
Owner of landracing.com

Offline thefrenchowl

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Repairs...

I bought some Dowty Seals to replace the red fibre washers...





All the carb parts, beautiful bronze stuff!!!...

.

In 2006, I found a local guy to help me adapt a tractor Wico magneto on my KHK... Not seen him since, no name, no address, no telephone...

Found him again yesterday after trawling his street... He's now 80 and retired but has kept all his gear... So I visited him today with the Bosch magneto

Gauss counter that measure magnetisation amplitude... nearly zero on my magneto...:



The machine made by his dad to remagnetize magnets::



The Gauss counter is now off the scale, good and the spark is blue with a nice crackle...



The old man has a lot of equipment, including a bobbin's rewinder and a growler for dynamos:





He did not charge me a penny for wasting 1/2 hour of his life on a young'un, good on him!

So long, Patrick
« Last Edit: May 18, 2019, 10:48:57 AM by thefrenchowl »
Flat Head Forever

...What exactly are we trying to do here?...