Drouin Supercharger Belts

bwolfie · Jan 29, 2014

I have just purchased a Drouin with the single flat belt.

It is missing the belt, and I have found a source for them.

Anyone out there in need of belts? The more I buy the cheaper they are.

Right now they are around $20 each.

Hobot · Jan 29, 2014

Brent I've not shopped for belts myself yet as have the original that looks in good condition at least to get started on. I would love to alter the adjuster to turn Doruin on/off with the belt tensioner but don't know if the belt would stay on or the spin of crank pulley would burn it up. Would need longer belt to accomdate the mod. Its a bit touchy to climb loose graded Gravel steeps with just normal Combat 'wimpy' low rpm torque so my concern a bump could spin us off slope. I just want to be a pilot not an inovator-inventor so put your mind on it please.

Belts from Belt corp. #400 panther 29 x 3/4" about $6.00 ea., one will last all season, Assuming you have a late model Drouin and the pulleys are aligned properly. McMaster Carr belts will not work! I frequently see 15 psi of boost on my stock 850, especially in 3 & 4 gear. Also expect your pipes to blue for about 20 inches. Bruce McGregor

http://www.beltcorp.com/index.html

https://www.google.com/#q=drouin%20supercharger

Dkt26 · Jan 29, 2014

Awesome!!
Any photos would be appreciated I'm sure!!

Hobot · Jan 29, 2014

Belts aren't that awesome to see by themselves.

Dkt26 · Jan 30, 2014

Steve you Larakin!!
They are internet photos
Would be keen to see Brett's purchase

bwolfie · Jan 30, 2014

It showed up yesterday while I was at work. I haven't had any time to really look at it. Just un boxed it and did a quick inspection.

Need to get some belts, and possibly replace the bearings. I have the part numbers, just need to see if there are cheaper sources.

The bearings I found were $250 each. It is missing the sliding plate and metering needle, which is fine with me. I'm planning on running a 40mm carb with it.

I don't know if i'll ultimately keep it, I will probably cleanup and service the whole thing, set it up and run it a little bit, then sell it.

I have always wanted to mess around with one, and for once I had the money when one came up for sale.

Bruce MacGregor · Jan 30, 2014

Looks complete, Get the belts from Belt corp, #400 Panther 29" by 3/4 works fine!
Forget the built in injector , get the 40 mm Lectron. There is not much room to put a carb in there! mine is in tight to the compressor inlet.

Bruce MacGregor

Bruce MacGregor · Jan 30, 2014

P.S.
that's me & my Norton in the Drouin Start U tube video shot @ the Auburn Meet a couple of years ago!

Bruce MacGregor

bwolfie · Jan 30, 2014

Thanks Bruce. I have printed out all of your notes. I'm going to use a carb on it.

I need to find some bearings for it. It was missing one and the one I have is bad.

Dkt26 · Jan 30, 2014

Brett when you are ready to sell it I would like to take it off your hands.
DKT

Hobot · Jan 31, 2014

Bruce, did it ever scare you and what was happening when seeing boost spikes to 15 PSI ?

bwolfie · Jan 31, 2014

Bruce, do you know what size the LH rotor nut is. Mine is missing.

Bruce MacGregor · Jan 31, 2014

Do you mean the nut that holds the impeller on the shaft?

Answer for Steve, In 1st & second gear there is hardly any boost. The engine gets to 6500 RPM before the boost has a chance to build.
The boost builds up under load over time, like a few seconds.
3rd & 4th will show the boost increasing.
The boost will go to 15 # passing a car or truck at Highway speeds in 3rd & 4th and the acceleration of the bike will increase with the increase in boost.
It seems to accelerate faster in 4th due to the boost than in second.
Strange Feeling!
Acts kind of like Turbocharger lag which is caused by something completely different.
I would expect a centrifugal compressor output (Boost pressure) to be dictated by RPM.
But it is definitely load that influences the boost pressure more, at least on my bike.

I'm not sure if it's the cam (Stock 850) has too much overlap and the charge gets blown in & out of the cylinder before the intake manifold pressure can build.
Or maybe it needs the exhaust back pressure to increase to generate pressure in the intake manifold where the boost is sensed.
Any way , Load = Boost = More power

Hobot · Jan 31, 2014

The nut that holds big pulley on is same as magnetic rotor nut threads but extended length to pass thru pulley and reach crank threads. Basically a top hat nut-end tube threaded inside.

Very interesting power band description Bruce and pretty much what I've planned Ms Peel for, nil boost down low that builds up as head flow clogs up. Peel's new TTI has 4 wide spaced ratio's to attempt to allow Drouin loading across more speed ranges. Very glad detonation was not an issue in your case.

bwolfie · Jan 31, 2014

Do you mean the nut that holds the impeller on the shaft?

yes

Bruce MacGregor · Feb 1, 2014

I'll look in my spare parts for a nut!
It seems to me that I bought new and may have the originals some where. I'm pretty sure its a standard U.S. thread like 7/16' 20
The impeller fit to the shaft is a poor arrangement with the pin + sloppy fit. Makes it hard to balance.
Bruce

Bruce MacGregor · Feb 2, 2014

I have one, PM me an address and I'll put it in an envelope ASAP

Hobot · Jun 14, 2014

DKt mentioned interest in tuning the simplest of 'carbs' Lake Injector nail in a tube so hope it leaves him as satisfied as me on the delicate tedious process. Its a true low head, nil pressure injector as does not depend on venture suction like a carb just pure air mass flow, so self corrects for great altitude manifold pressure changes.

http://www.greatplainsas.com/iposa.html

http://www.aircooled-rd.com
/default.asp?txtPage=lectrons.htm

phil yates · Jun 17, 2014

bwolfie said:
It showed up yesterday while I was at work. I haven't had any time to really look at it. Just un boxed it and did a quick inspection.

Need to get some belts, and possibly replace the bearings. I have the part numbers, just need to see if there are cheaper sources.

The bearings I found were $250 each. It is missing the sliding plate and metering needle, which is fine with me. I'm planning on running a 40mm carb with it.

I don't know if i'll ultimately keep it, I will probably cleanup and service the whole thing, set it up and run it a little bit, then sell it.

I have always wanted to mess around with one, and for once I had the money when one came up for sale.

Any idea what sort of money you would be wanting for it, if you decide to sell it? I think it would be a great project to blow a Commando.

Phil

phil yates · Jun 17, 2014

Bruce MacGregor said:
Do you mean the nut that holds the impeller on the shaft?

Answer for Steve, In 1st & second gear there is hardly any boost. The engine gets to 6500 RPM before the boost has a chance to build.
The boost builds up under load over time, like a few seconds.
3rd & 4th will show the boost increasing.
The boost will go to 15 # passing a car or truck at Highway speeds in 3rd & 4th and the acceleration of the bike will increase with the increase in boost.
It seems to accelerate faster in 4th due to the boost than in second.
Strange Feeling!
Acts kind of like Turbocharger lag which is caused by something completely different.
I would expect a centrifugal compressor output (Boost pressure) to be dictated by RPM.
But it is definitely load that influences the boost pressure more, at least on my bike.

I'm not sure if it's the cam (Stock 850) has too much overlap and the charge gets blown in & out of the cylinder before the intake manifold pressure can build.
Or maybe it needs the exhaust back pressure to increase to generate pressure in the intake manifold where the boost is sensed.
Any way , Load = Boost = More power

Just trying to get my head around this Bruce.
Taking off in third gear (if you could with lots of revs), are you saying you would accelerate faster to 7000rpm than if you took off in 1st or 2nd? I certainly would have thought boost was purely a function of rpm. It would be disappointing indeed to have a blower that won't function until you get into your top two gears.

Phil

Drouin Supercharger Belts

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