Author Topic: INDIAN 741 Supercharged...See you in 2011  (Read 740540 times)

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Offline octane

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Re: My INDIAN 741 Supercharged Low-tech LSR Racer
« Reply #15 on: April 09, 2009, 10:16:03 AM »
Oi !
Thank you ever so much guys for your kind words
and your encouragements.
Highly appreciated !!!
Thanks!


Very nice.
With your kind permission, a few questions & comments?
Absolutely!..Thanks for showing an interest in my little project.
I'm quite sure no-one knows more about supercharging old bikes than you Jeff.
Thanks for publishing your absolutely brilliant site: Supercharger Installation on Older Motorcycles
A fountain of info to be gathered there.


Quote
This is bored to the H-D 45 cylinder size, 70mm?
Yes
Quote
The SCTA class will be 500, not 650, since your actual displacement of 600cc is discounted by 1/3 for side-valve cylinders and heads. IIRC you must exceed 750cc to qualify for the 650 class (i.e., be illegal for 500).
Yep, but I'm running at the BUB Motorcycle Speed Trails, that does not go by the SCTA-rules
but goes by the A.M.A. rules (..and F.I.M. rules) that gives NO 'allowance' for side-valve engines.

(BTW AMA/FIM do NOT even consider the Indian engine to be a 'side-valve' at all (!!!)...
I checked that with the Tech. Inspector. Something to do with the very short lengths of Indian ...erh...non-pushrods.
I find that a little weird as the specific definition of "push-rod" in the rule-book reads:

"..with camshafts located below the cylinder head deck, push rods that open valves
with the use of individual lifters
...". No mention of length.

I would assume that the push-rod-class was set up to distinguish these engines from overhead valve engines,
but Hey!..it's their party and if I wonna join it, I'll go by their rules.
An idea would be to clearify by using the definition from 'Utah Salt Flats Racing Association"
which reads:

"...Pushrod: “must have pushrod operated valves with camshaft located
 at least one crankshaft (stroke) length below the OEM cylinder deck
or utilize OEM pushrod length at least twice the crankshaft stroke
....”)


....so anyway;  it has to run in the 'Vintage' class; that is; engine manufactured before prior to 1956,
must retain O.E.M. heads and cases.(Rule '12.J.').
Quote
Are you using the same drive ratio for the Aisin as used on the automobile engine? IIRC that's about 1.25:1 (25% overdrive).
IMHO this isn't fast enough, and won't develop boost until far up the RPM scale.
I'll start of with something around 1 : 1,5 and probably move up to somewhere close to 1 : 2.
I'm in contact with a guy in Australia that has just finished his blown Triumph 650
using the same blower as mine. He runs close to 1:2 and develops around 6psi. at around 10000 RPM's blower speed.
Works just fine.

Now, I've looked into several sources of calculation pressure, drive ratio etc. etc.
both using the calculations on your site and from the old book
by Maurice Brierly "Supercharging Cars and Motor Cycles" and other places.
I bumped into a few problems; I needed to know the comp.ratio and the valve-overlap.:

...apparently no-one had ever measured the compression ratio on the 741 engine
so I did a low-tech measurement; glued a transparent plastic to the 'under'side of
one of the heads (with a head-gasket attached).
Stuck in a syringe and measured the quantity of water I could pump in:



...then calculated the comp. ration (in case of being bored to 600cc) to 1 : 6.
Now that's low-comp.

Same thing with the valve overlap. No where could I find any info,
so did a real low-tech test. Sat up the cam'wheels' (cams are behind the wheels)
and held down the (non)-push-rods with rubber bands.



...turned the wheels and by holding each of two fingers
on top of the in- and out-let (non)-push-rods, respectively,
tried to feel the period where there was an actual overlap (both rods moved by cams)
Surprise: there was none...or it was negligible, to the point where my "test" couldn't detect it.

In all the literature on blowing (old) engines I've plowed through,
I'm told that 'low comp. ratio' and 'small overlap' is a good thing on a blown engine.
So this has got'a be good

.-)


Quote
I'd expect some fuel drop-out
 in the plenum because of the large cross-sectional area.
Yep. I'm aware of this potential problem, but in order to get a proper
volume of the intake/plenum that's what I ended up with. There
is no practical provision for making it narrower (and therefore longer).
We'll see how it works out.

Quote
BTW: a 1940 military engine is 740, since the last 2 digits are the year.
Naaaa! I could be wrong, but I'm quite sure
all these engine are designated 741 irrespectively of the year of manufacture. Never seen an engine designated, let's say: 740 0r 742.


Quote
Did Rivera equip the carburetor for methanol as to needle & seat size?
Nope. The carb was a gift from a friend. Unknown former application.
I'll set it up myself. The rule of thumb seams to be to enlarge the jet to around
double size (double area of cross-section, so to speak) compared to running gas,
when running methanol.
I have a couple of books on SU carbs and some calculations relating to the subject
including haw to size down needle-profile etc. I'll give it a go.
One other problem when using the Rivera SU (compared to the car-application SU carbs)
is this thing here



a bi-metal mechanism that moves the jet 'down' when cold (to make the mixture richer on cold-start)

...here you can see it inside the float-bowl:



I'll have to '"kill" that thingy so it doesn't interfere with the mixture, what with running
alcohol that will make things cool down there.

Quote
That's a huge carburetor, which means that spring tension and needle
 profile will be critical to get good atomization.
Yeah, I know, but that's the carburettor I had available,
and looking at it very un-scientifically, it kind'a looked "right" ;
almost the same cross-section on carb-outlet andblower intake



...and it being a CV-carb it will hopefully "self-adjust"(*) to the requirements
of the engine.

(*)..sort of
.-)

The carb/blower intake on the photos above (cut-off blower intake and cut-off carb. manifold...welded together)
will be replaced by this adaptor we made up a couple of days ago,
to go between carb and blower:




Quote
Is the cam timing doped out yet?
No. I do not plan to do anything in that department (..but I could be wrong is not doing so).
Remember; this is a low-tech attempt to spice up things...not to go for the ultimate power-gain
at the cost of loosing reliability.
On a side-note: I've installed a blower on my Honda GL1000
(60 cubic inch Magnacharger and double barrel Weber carb,)
with no other modification, including valve timing, and it goes like flipping stink.




Again; thank you guys
and thanks 'panic' for taking an interests and offering advise.
Please keep 'em coming.
« Last Edit: April 09, 2009, 11:09:43 AM by octane »
"A designer knows he has achieved perfection
not when there is nothing left to add
but when there is nothing left to take away"

Antoine de Saint-Exupery

Offline Rex Schimmer

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Re: My INDIAN 741 Supercharged Low-tech LSR Racer
« Reply #16 on: April 09, 2009, 11:52:22 AM »
Octane,
Your project is so cool! Very "grass roots" and I love the looks of your bike. I really hope it goes well and if nothing else you will have fun.

Regarding the SU carb, my son had SUs on his Datsun and he would take them apart and look at some parts and wonder what they did so he would remove them from the carb and every time he took something off it would run better!!! A throttle slide, a needle jet, main jet and a venturi and it will probably work. My bet is that most of the other stuff can be thrown in the "bin".

Your motor should really love that little supercharger, nothing makes a flathead come alive like a blower.

Love your project keep the post coming.

Rex
Rex

Not much matters and the rest doesn't matter at all.

Offline panic

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Re: My INDIAN 741 Supercharged Low-tech LSR Racer
« Reply #17 on: April 09, 2009, 12:26:36 PM »
..
« Last Edit: October 03, 2010, 10:31:16 AM by panic »

1194

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Re: My INDIAN 741 Supercharged Low-tech LSR Racer
« Reply #18 on: April 09, 2009, 12:34:19 PM »
GREAT bike, look forward to seeing it at the 2009 BUB........if you have problems with the SU carb. you might want to try a S&S carb.......I have always had good luck with them.....they make a
"Fuel Carb." complete with a large bowl............

Offline octane

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Re: My INDIAN 741 Supercharged Low-tech LSR Racer
« Reply #19 on: April 11, 2009, 01:16:01 PM »
Thank you Rex , thank you 1194 for your kind comments and advise !

Thanks Jeff too, for your advise.
One thing though that I don't quite get:
I'd go even larger than 2:1 for flow area if you can, but I'm not sure there's room in the top...
"...room at the top.." . Sorry; I don't understand that; What top would that be?

About the carb; mmmm: I tend to favour the SU
1. I have one
2. they are supposed to adapt quite well to supercharging.
See them all the time on the old blown cars and motorcycles,
at least this side of the pond.
Addressing the floatbowl-issue, I've attained a float-bowl-spacer-expansion-thingy:
dunno if it's enough though ?! Time will tell.



"A designer knows he has achieved perfection
not when there is nothing left to add
but when there is nothing left to take away"

Antoine de Saint-Exupery

Offline octane

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Re: My INDIAN 741 Supercharged Low-tech LSR Racer
« Reply #20 on: April 11, 2009, 01:26:21 PM »
Tonight I'm doing all kinds of small jobs in preparation
for putting the engine together next week (OOOOOOOOOOhhhh...can't wait to do that !!!)

Genneraly cleaning up the top ends and getting rid of sharp edges etc. to avoid potential hot-spots



...this is what they looked like before:



...and you don't want to run with a spark thread like this do you:



...so new plug inserts has been inserted and the area where the top bolts
press down has been cut back a bit to make even surfaces




Then little things like making sure the sidecover is absolutely 'flat'.
Write with a maker



..take it to the 'flat' (a sheet of thick glass with abrasive paper)



...and repeat and repeat till you won't find any 'raised' area like this



...and then a quick shower in my glass bead blasting cabinet,
and they are as good as new.
« Last Edit: April 11, 2009, 01:34:07 PM by octane »
"A designer knows he has achieved perfection
not when there is nothing left to add
but when there is nothing left to take away"

Antoine de Saint-Exupery

1194

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Re: My INDIAN 741 Supercharged Low-tech LSR Racer
« Reply #21 on: April 11, 2009, 03:24:56 PM »
I know this will get some replies.......but I put SU carbs. in the same class as Lucas components....
Have one on my 1953 Tri. bird....................................

Offline Nortonist 592

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Re: My INDIAN 741 Supercharged Low-tech LSR Racer
« Reply #22 on: April 11, 2009, 05:28:22 PM »
but I put SU carbs. in the same class as Lucas components....


What class is that Bob?   The non electrical class?  :-D

Lars,  The Indian is looking fantastic.  Saw a couple f photos of it at a show over there.  You sure you want to run something so nice on the salt?
Get off the stove Grandad.  You're too old to be riding the range.

Offline ironwigwam

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Re: My INDIAN 741 Supercharged Low-tech LSR Racer
« Reply #23 on: April 11, 2009, 07:49:22 PM »
Lars,
   Quite an eyeful of tenacious going on over there, can't wait until August.
   Rocky

Offline oz

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Re: My INDIAN 741 Supercharged Low-tech LSR Racer
« Reply #24 on: April 12, 2009, 12:06:42 PM »
Cool I just love to see Blowers on bikes. Especially an Indian Fantastic.
Newcastle born and bred a City built on Coal and Steel and a people built of stronger stuff

Offline octane

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Re: My INDIAN 741 Supercharged Low-tech LSR Racer
« Reply #25 on: April 12, 2009, 01:17:27 PM »

Lars,  The Indian is looking fantastic.  Saw a couple f photos of it at a show over there.  You sure you want to run something so nice on the salt?

Yes! Positively sure. Thanks

Lars,
   Quite an eyeful of tenacious going on over there, can't wait until August.
   Rocky
Ditto ! See ya' then.

Cool I just love to see Blowers on bikes. Especially an Indian Fantastic.
Thanks Oz. I checked your build.
What can I say, except it's fantastic. Makes my 'build' look like I'm doing a darn bicycle
.-)

Yeah: blowers. Wonderful contraptions. Wonder why more people aren't using them on bikes.
It ain't that complicated, as proven by the fact that I am doing it.
I have another blown bike; a 1976 Honda GL1000 (...that's a pre-Winnibago-sized-fairing Goldwing)
that I build a couple of years ago:



60" Magnacharger root-type blower. Double barrel Weber carb.

It's a LOT of fun.
"A designer knows he has achieved perfection
not when there is nothing left to add
but when there is nothing left to take away"

Antoine de Saint-Exupery

Offline octane

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Re: My INDIAN 741 Supercharged Low-tech LSR Racer
« Reply #26 on: April 12, 2009, 01:23:14 PM »
Signed up and paid my entry to BUB Motorcycle Speed Trails today.
It's official: I'm in !
Kind of ...erh...grand, feeling.  Ahhhhhh !

Guess all I have to do now is put the thing together,
and test is, and hopefully (ok call me an optimist) all goes well.

That leaves the small problem of finding some freight company
that won't charge me a billion dollars to fly it cross the big pond (and back again)...we'll see.
"A designer knows he has achieved perfection
not when there is nothing left to add
but when there is nothing left to take away"

Antoine de Saint-Exupery

Offline panic

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Re: My INDIAN 741 Supercharged Low-tech LSR Racer
« Reply #27 on: April 12, 2009, 06:55:29 PM »
..
« Last Edit: October 03, 2010, 10:32:10 AM by panic »

Offline oz

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Re: My INDIAN 741 Supercharged Low-tech LSR Racer
« Reply #28 on: April 13, 2009, 05:49:36 AM »
Thanks fella but I think mine is going to be a bit under powered until the Nitrous goes in but it is a fifteen year old engine.
If you are containering your Indian out why dont you ship the wing out too its a fine looking bike low centre of gravity should be good on the salt.
We strapped a shorocks onto a 1200 wing motor fifteen or so years ago that went very well..... For a while anyway, reckon we were pushing in a bit too much boost,Unfortunatley we lost alot our pictures a few years ago in a fire
You have got me thinking though I have a 1979 1100 without all the rubbish on it but has a blown head gasket I reckon when I fix that I may have to fix the fact it dosnt have a Blower
I Have had some crazy quotes for shipping some are coming in at around 3000 GBP and others are as high as 5400 GBP but that is Air freight out and sea freight back and you have a little further to go than myself,It is also getting more expensive to go with the exchange rates not being so good at the moment.
Anyway good luck I reckon you will be ready in plenty time and its a fantastic build way cool.
Oz
Newcastle born and bred a City built on Coal and Steel and a people built of stronger stuff

Offline DavidinDurango

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Re: My INDIAN 741 Supercharged Low-tech LSR Racer
« Reply #29 on: April 13, 2009, 10:51:37 AM »
you should market that "flippin' stink"  (as in "goes like flippin stink" here in amerika.  I know I could use some . . .

Ok, I could use a lot.

Here's to flippin' stink and your project!
DavidinDurango
Mostly Fords with "some stuff"
LSR, because it takes more than one ball to play.