850 with a drouin, Bruce Mcgregor

Hey Bruce,
Glad to run into you here.
Just posting to hear of your ongoing joys with the re-worked Drouin.
I need to hear lasting success as about all prior owners have either died
got divorced, blew up or plain gave up on Drouins, like its a bad ju ju trinket.

I sent a handful of era magazine articles to DynoDave.
Of special interest to me was that engine size did not inhibit
Drouin boost feeding up 2500 cc by Tom Drouin advertising.
Said it'd make about same boost, if you can load the engine and
not just smoke tire or wheelie.
Tom states 11CR ok but not to use Combat or any hot rod cam.
But I've got story of youthful success on 11.5 CR and 4S cam.
So hoping Drouin was misled by the standard wisdoms on
positive displacement blowers instead of turbine belt drive type.

I think you have converted to 520 chain and wondering how that's
working out. I gave up on those too thin fast wear fanning over sprocket
teeth on both my SV650 and Peel Combat, converted back to 530
and steel teeth.

hobot

In the late 70's thru early 80's i built and raced a supercharged Norton speedway sidecar unit, rigonally fitted with a 750 combat engine Sherock supercharger
running methanol through a 1.75" SU carb with twin float bowls, compression ratio was 7.3-1 and a 2s cam was chosen by my engineer as the timing was closest to the formula he had for supercharging using methanol. Later on we replaced the 750 with a mk3 850 motor but retained the same cam.
Al

Dang it Al, I'll a lot of catching up to do with motorcycle fun and games.
Alas your set up just don't apply to Centrifugal Commando blowers in public on
pump gas. But I do desire to explore rear boost aiming in turns. I really
studied up on sidecars of all types in hope that I can better survive
the deer strikes from the side and ride on. Otherwise I hunt dam
deer Down AGGRESSIVELY so serrated sharp bladed armored 3 wheeler
has been on my mind and old fractured spine and limbs.
Spoke with a fella 2 wks ago on a Russian early version of Ural side rig,
said all's he had to do was wash off the blood and bang out some
sheet metal after getting his first kill.
I go 80-85 if out after dark on hwys and speed
up into any deer I see that ain't leaped on me or out the way yet.

Bruce touches in now and then, I just want to hear he's still
fine and enjoying his Commando blow jobs as much as he likes.

hobot

Hi Steve,
It's been since 2003 that I rebuilt our Drouins, Mine has been running great and has not been apart since then. I ride it a couple of times a week back & forth to work and rode it to the meet in Auburn Ma. in the beginning of June (about 70 miles each way).
It runs way better with the 40 MM Lectron than with the Hardly CV carb. that I screwed around with for a few years.
It will really ,really pull in 2nd, 3rd.& 4th when the boost gets up to 12 psi.
The 850 engine seems well suited to the extra power as I have hand no problems as of yet.
I'm running total seal rings, stock pistons & cam.. The pipes tend to blue for about 20 ".
In an other post I wrote about going to a solid axle and 520 chain and an Old Britts sprocket carrier. Right now I,m running a rear sprocket that is giving me a ratio equal to about a 21.5 tooth counter sprocket. I can change sprockets in 15 min. So far the 520 chain is great.
At the meet in Auburn at least 3 people came up to me to say they still had Drouins but did not like the way gas used to leak all over the place, so they took them off. Maybe now they will consider reworking them.
I think you should put yours on PEEL after you get her sorted out .
Bruce

OK Bruce you are living the life I'm aiming for, taking no short cuts
or prisoners [me] to get there.

One I'm tickled to death no bad fate have ruined your bike life,
and do remember your sensing the Lake injector hanging on
just warming up first time and wisely delayed road risk till
a real carb that will close down and not leak out for fire hazard
was adapted. I've yet to mock up enough to know where
the 38mm QwickSilver carb will hang on your snorkel.

I've instructions and cable ferral intended to covert the
Lake 'Injector' for push/pull dual cable but decided Not too.
You may have sent that early on, forget at this point but
sent to DynoDave to put up for posterity .

Two I'm tickled to my teeth that your gear box is holding up.
Peel+me will not weigh hardly 2/3rd of your 850 I think.

Three, I'm pensive to go back to 520 - 0.24" thin teeth, but
pleased to hear almost 22T equivalent final ratio can
take advantage of the excess torque over the years, YEA!
implies Peel top speed can match what the elite sports
riders are willing to pull in public, are able to on short straights
of tighter technical tracks.

Still tingle from your mention of turbo whine in back ground
power and wind noise.
OH yeah, I know what happens now on over powered
wheelies on Commando's to Ninja and SV650. Busted up
no fun.
So will have active suspension squat to 1" below factory
at either end.

I'm going to try 10:5 CR plus drag only cam to help get
decent runner w/o boost - so yes blower will have to wait
till I get past some dialing in and learning curves.
Duh what octane are you limited too, or are you?

hobot -refinished Drouin to match engine color scheme,
All Swian Black-Body-Radiation coated with shiny highlights
fasteners, fittings, fins and covers,
but no photos so far. I see the diamond fin edge treatment
claims extra heat radiation, so considering a head job.
I guess about another year and $3000 to go, if gearbox up
to my antics.

Hey Bruce stumbled on this Triumph build and comments. My other Drouin helper and supplier is Rod Rayborn in NC, he also wants it for a lowered seat frame chopper... as they are harder to wheelie even with big fat tire...

While running SCM I bought a Drouin Supercharger from a guy who lived near Luton Airport, he had it fitted to his 850 Norton Commando, he had flipped the bike when pulling a wheelie and took it off, "to much power" he said, I thought "Just what I want"
http://www.chopperz.co.uk/choppers_in_s ... per_3.html

Bruce MacGregor said:

Hi Steve,
It's been since 2003 that I rebuilt our Drouins, Mine has been running great and has not been apart since then. I ride it a couple of times a week back & forth to work and rode it to the meet in Auburn Ma. in the beginning of June (about 70 miles each way).
It runs way better with the 40 MM Lectron than with the Hardly CV carb. that I screwed around with for a few years.
It will really ,really pull in 2nd, 3rd.& 4th when the boost gets up to 12 psi.
The 850 engine seems well suited to the extra power as I have hand no problems as of yet.
I'm running total seal rings, stock pistons & cam.. The pipes tend to blue for about 20 ".
In an other post I wrote about going to a solid axle and 520 chain and an Old Britts sprocket carrier. Right now I,m running a rear sprocket that is giving me a ratio equal to about a 21.5 tooth counter sprocket. I can change sprockets in 15 min. So far the 520 chain is great.
At the meet in Auburn at least 3 people came up to me to say they still had Drouins but did not like the way gas used to leak all over the place, so they took them off. Maybe now they will consider reworking them.
I think you should put yours on PEEL after you get her sorted out .
Bruce

Click to expand...

this must be fun to run

but there is one thing that i do not get ,and i do not want to be rude here , why do americans build all these superfast ROADGOING bikes ( so am not talking about circuit racing ) when you can only do 90km/h legally
am i missing something here or are you as anarchistic as me ? i blew my commando the other week when an exhoust fell off and i could not resist the nature of the beast . but that was after a run of 350km with revs to 5000 (~160km/h) not uncommon .as we are legally allowed to do 90/120kmh i wasn't really breaking the law ,officer
again , this is NO pisstaking

Silly Rabbit, its for the Rush of course.