Rapide Project 2023

Here is the new thread as promised.
To recap, a local VOC club member found my phone number in the club directory and called me a couple of years ago asking for information about building his dismantled Vincent Rapide. He needed to install an electric start and was concerned about kickback during starting. I suggested the Tri-Spark ignition for its auto retard to facilitate starting. He is also fitting a sidecar to allow him to ride the machine safely. All things considered, I also suggested Mikuni carburetors. He said a friend was helping him build it.

A few months ago, he invited me to come look at his machine. No assembly had been done, and I soon realized he needed help getting this machine on the road again. I offered to help, so here we are today. He last rode it in the early 1960's; he put the crankcase together in the late '60's and painted the engine, heads, barrels and covers black. He had the heads done in the past few years including sealed valve guides; it looks like a good job. He installed new liners in the muffs and had them bored std. That's where I started.

I have been on it since October and am spending a day or two a week in his shop. Fortunately, he has a full set of Whitworth tools, taps, dies, precision measuring tools and machine tools including a Bridgeport mill. It is a joy to work in this shop!

I wrapped up the Grosset starter and gearchange yesterday and fitted the timing cover today.

Here is a photo of the engine. The oil quill is absent as is the plug in the K/S cover (left hand kickstart installed).




Russ

Keep ‘em coming Russ !

What size Mikunis ?

Good day Nigel,
Since I'm running 32mm VM's on my Shadow and have the jetting worked out, it was the easiest route to take. The availability of right and left hand throttle adjustment on the 32's was another factor.

Again, the concern is safety for the rider. Drooling Amals must be avoided in this case.

998cc said:

Good day Nigel,
Since I'm running 32mm VM's on my Shadow and have the jetting worked out, it was the easiest route to take. The availability of right and left hand throttle adjustment on the 32's was another factor.

Again, the concern is safety for the rider. Drooling Amals must be avoided in this case.

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My Black-Rap caught fire due to drooling Amals ! They got replaced by a pair of Miks.

Mikunis run great on Vins when dialled in, and start great too. And don’t tend to self combust !

Most likely doesn’t really need 32s, but won’t do any harm either. That said, I got 36s on the Egli.

I ran 30mm VM's on my Shadow for 35 years but wanted the opposite throttle adjustments. Originally, the 32's were on my '82 Meriden Bonneville; they were a PITA to set up on the 750cc engine and were never right. Putting the 30's on the Bonneville worked other than the non-left/right throttle adjustments. In any case, my thought is the smaller carbs are easier to setup since air velocity across the jets must be higher resulting in higher vacuum--more "breathing room" in jet selection so to speak. I have no data to support this--just my gut.

A two-valve speedway Jawa engine has the same size cylinder as a 1000cc Vincent and uses a similar rev range. I cannot remember the inlet port size, but in the 1950s it was reduced by 1mm, by the factory. My brother races Vincents and an 880 JAP on speedway in sidecars, Jawas had Dell-Orto carbs with no needles. My brother fits needles into them, and uses them on the 880 JAP. He also has a stroked Jawa engine in a sidecar, it is 630cc and is faster than the Vincents.

Not really very relevant to this Vincent build thread Al…

acotrel said:

A two-valve speedway Jawa engine has the same size cylinder as a 1000cc Vincent and uses a similar rev range. I cannot remember the inlet port size, but in the 1950s it was reduced by 1mm, by the factory. My brother races Vincents and an 880 JAP on speedway in sidecars, Jawas had Dell-Orto carbs with no needles. My brother fits needles into them, and uses them on the 880 JAP. He also has a stroked Jawa engine in a sidecar, it is 630cc and is faster than the Vincents.

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My Buell has fuel injection!

Well,
I suppose it is OK to post photos as the owner said I should be making a Youtube video of this build! When I responded it would likely take 6 months or more to script, layout and setup each segment then actually shoot it during construction, he decided it was more important finish the machine in a timely manner. In any case, the engine is done, and that was the most interesting part of the build. I plan to be there on Jan 4th-5th and will take a few shots and post them.

There was an unexpected setback which I found rather comical. Will go into details then...

Matchless said:

My Buell has fuel injection!

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My grandma has acute angina!

What I find with carburettors that are bigger than necessary, is that the carb is metering with the pilot jet and slide cutaway, at speeds and loads where the throttle should be further open, with the needle taper doing the metering.

If my Grandmother had wheels she would have been a bus!

-Once uttered by our Prime Minister Jean Chretien in response to an off kilter question.

Still building the Rapide. My wife came down with Covid, so I have not been back to work on the bike in a week.

Making progress; I rebuilt the two dampers and now have the UFM, gridraulics and RFM on.

A setback? When mounting the timing side rear footrest plate, one of the long engine bolt/studs was too short! I was thinking the owner had used the the wrong bolt when he put the cases together in '69. The completed primary drive had to come apart to check the bolt. Tapping the bolt out, I realized it was the correct bolt just not tapped home. It turned out to be a good thing because that bolt had not been sealed, nor had the others. They are now.

The Borrani Rims are laced/trued--just need to drill the valve stem and security bolt holes and put the tires (tyres) on. While shimming the rear wheel bearings, one of the bearing races fell out in my hand! Will check the fit next week and may refit it using Loctite 620. Relined brake shoes from the Spares Company are in the brake plates.

During my time away this week, I built a variable voltage power supply to do some electroplating. The plan is to experiment using fine beadblasting media on original fasteners to somewhat replicate the orignal cadmium plate using nickel. We'll see how it works.

More photos soon.

Russ

I love this forum.

Where else do people say that they couldn’t get any bike work done for a week cos their wife was ill… so instead they just built a new DIY plating bath !?!

Fast Eddie said:

I love this forum.

Where else do people say that they couldn’t get any bike work done for a week cos their wife was ill… so instead they just built a new DIY plating bath !?!

Click to expand...

Might as well do something positive. Miraculously, I avoided the Covid this time around, and we both tested negative today.

Here is a photo of the bath. It is a Frankenstein-looking device made from my "junque" box of electrical bits. It is capable of 12 volts DC at 35 Amperes based on the transformer specs and the bridge rectifier specs; 2 or 3 Amps would suffice.

The voltage is controlled by the 15 Amp variac on the upper left. The bath started out as white vinegar; the green tint is caused by the nickel ions from the sacrificial nickel sheets. The positive electrode is sacrificial while the negative is being plated with nickel. The goal here is to impart as much nickel into the solution as possible. Every hour or so, the poles are reversed so neither pole is completely consumed. It is nearly ready to begin plating.

The wheels: What an experience.
I won't complain about parts not fitting well because at least they are available. For this project, new brake drums were necessary.

The drums fit the hubs, and the bolts lined up well enough; however, the brake cam, H10 drags on the inner wall of the new drums. Apparently the brake drum casting is thicker than the original drums? Merely shimming the brake plates out caused the completed assembly to be too wide to fit between the lugs on the RFM. The fix was a compromise; 3/32" was skimmed off of each cam bush steady sleeve to regain clearance. Another issue was the new 56 tooth rear sprocket would not bed down on the new brake drum; it required a bit of creative machine work to slightly reduce the outer diameter of the drum flange.

For the upcoming Black Shadow project, we'll further investigate the brake drums and may skim the interior face if there is sufficient thickness.

Here are a few photos:

Part of the joy of this project is finding parts that have been in boxes since the 1960's.

This project is intended as a mechanical rebuild and certainly not a 100 point restoration. This will be a rider.

Fun stuff!
Regards,
Russ

This headlight is right out of a time capsule. It was removed in the early 1960's, and the bolts were wisely reinserted in the brackets. It was fitted with a sealed beam car type unit. What Mr. Lucas or Mr. Miller thought of pulling this ampere load can only be imagined!



Can't begin wiring without the headlamp shell in place, so it came home with me for painting. A few sunny days would help tremendously.

56 tooth is a big old scrambler sprocket on a Vincent. Is it really that big?

Glen

worntorn said:

56 tooth is a big old scrambler sprocket on a Vincent. Is it really that big?

Glen

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Hello Glen.
Yes, It is a big sprocket. The latter part of this Rapide build will be attaching a Steib sidecar, so the lower gearing is appropriate. The owner is in his 80's and is likely much more safe operating with a third wheel attached and at lesser speed. Conversely, in the late 1950's and early 1960's, he would wring every HP and MPH out of this bike.

Russ

Finally, the machine is rolling and resting on its side stand. The owner remarked it was the first time it has been on its own wheels in 60 years.

Painting bits this week.

Russ