Author Topic: Twin Engine Panther from England  (Read 108073 times)

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Offline SUMO

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Re: Twin Engine Panther from England
« Reply #180 on: February 13, 2012, 04:17:42 AM »
got the crank back together and all lined up. needs balancing now but that's the difference between the now and then :)




dropped into case to show clearance on old oil weir [used to be about 1/16"]. will be machinging bottom of the cases around the flywheel so oil drains through and doesnt need to be flung over the weir. the flywheels will no longer run in oil so that should help matters



Offline wobblywalrus

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Re: Twin Engine Panther from England
« Reply #181 on: February 23, 2012, 08:22:41 PM »
Sumo, today I was looking in the Fastenal catalog page 10-203 under Power Transmission.  www.fastenal.com  There are commercially available power transmission couplings with rubber spider inserts.  That might help on the double engine bike.  This is an American company but something similar might be available in England.  It is off-the-shelf and one less part you will need to design and fabricate.   

Offline SUMO

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Re: Twin Engine Panther from England
« Reply #182 on: February 24, 2012, 02:11:25 AM »
cheers mate. my coupling system is actually built. but if it looks like it might fail I'll def look into that as an option. thanks for the heads up

Offline SUMO

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Re: Twin Engine Panther from England
« Reply #183 on: March 09, 2012, 04:52:04 AM »
the cases are up at my dads getting some work by my team of retired old men. i have my dad retired engineer, melvin retired welder, and rod, semi-retired bike shop owner / tuner. between them they have pretty much all the bases covered for anything dumb i can dream up that i cant handle myself [along with a lot of why? what the hell? but its a panther, they arent meant to go fast etc type comments]

dad nearly sorted out my re-routing oil system [theres a good bit more to it that just draining different too...] bit of welding to be done on them and some more machining and we will be ready for a bottom end assembling pretty soon - hope to have it running in a solo bike in the next few weeks to see how it responds to the tuning





if you dont know panthers then this looks normal - but pushrod tube normally has 2 guide holes in it - machined out to run solid rods


Offline Old Scrambler

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Re: Twin Engine Panther from England
« Reply #184 on: March 10, 2012, 08:06:10 PM »
Two Panthers is a probable cat fight!............take a look at the coupling plates being installed on the double Vincent build thread for potential applicaiton to your cats.  I'm staying out of the fray with my single Tiger Cub.
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 SUMO

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Re: Twin Engine Panther from England
« Reply #185 on: March 13, 2012, 05:22:32 AM »
i have done a lot of reading and talking to people that have built and raced twin engine bikes. all seem pretty confident that my coupling system is overkill and should hold up fine but theres only one way to find out really - have a go, so thats what im doing. its built and ready for the 2 motors [see a few pages back] now im concentrating on making 1 motor go fast then making a matching pair

things are moving at pace on the test engine - hope to have it installed into the testbed bike the first week of april fingers crossed if all keeps going to plan

the hot cam i got made an age ago arrived yesterday for the test motor, just in time for bottom end assembly. not we've got to sort out the new pushrod arrangement [more like the solid 30's panther setup than stock later one with the adjusters in the middle]





Offline SUMO

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Re: Twin Engine Panther from England
« Reply #186 on: March 27, 2012, 05:51:39 AM »
things are marching on still

modified pushrod tube so it doesnt fall into the modified cases, i welded up adjuster cups onto the cam followers to accommodate the single piece pushrods, new single piece pushrods made, access hatch into rocker cover welded up and cover machined.

steady away, still plenty to do but on course to having this motor into the black bike at the weekend with a little luck and a fair breeze.








Offline panic

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Re: Twin Engine Panther from England
« Reply #187 on: March 27, 2012, 08:25:58 AM »
I'm puzzled by the cam followers?
Just a guess: somehow they didn't want/couldn't fit 2 conventional tappets in there, so a lever reduces the footprint?
Big question: what does the follower's contact surface look like: flat or radiused?
Not sure how fast you're going to turn these, or how much spring pressure, but those pushrods look a bit wiggly. Is there any room to increase the diameter at least mid-way?

Offline SUMO

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Re: Twin Engine Panther from England
« Reply #188 on: March 27, 2012, 08:45:41 AM »
panic - its essentially their 1920s design they just carried on using. i never really considered the cam followers to be anything but normal haha guess its what you are used to

the cam follower surface is curved, although a tuning mod i havent done on this set is to put a flat surface on them

as for the pushrods - they are pretty thick - they are just long so look thin with nothing to scale them against. they are as thick as they will go to go through my hole in the casings which makes them thicker than stock, from memory a good 1/2" thick

spring pressure still needs a little working on - im going to try the stock springs and see how they are for a start and go from there

Offline Tman

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Re: Twin Engine Panther from England
« Reply #189 on: March 27, 2012, 10:49:44 AM »
Looking good, it had been a while since I looked.  :cheers:

Offline wobblywalrus

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Re: Twin Engine Panther from England
« Reply #190 on: March 28, 2012, 01:37:02 AM »
The flat lifters and a high lift cam will accelerate and decelerate the valves really quick off of and on to the seat.  Those are big valves and the spring quality will be critical.  There have been a lot of advances in spring wire metallurgy and manufacturing since the Phelon and Moore days.  Dave Flintoft of Dave Flintoft Engineering recently wrote an article for Classic Bike Guide about valve springs.  Some of the valve spring technology he described might be a help.     

Offline SUMO

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Re: Twin Engine Panther from England
« Reply #191 on: March 28, 2012, 02:13:42 AM »
sounds like good useful read. is that our British mag as in www.classicbikeguide.com ? or is there an American magazine of the same name? don't suppose you happen to know the issue? I'll get a copy for sure

Offline Briz

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Re: Twin Engine Panther from England
« Reply #192 on: March 28, 2012, 08:01:49 AM »
If you're flattening off the followers Sumo, make sure the edge of the follower doesn't dig into the lobe... You might want to leave a bit of a radius on the leading edge.
With that welding so close to the followers surface, might the hardening not be affected? A soft follower will flatten itself off pretty quick!

Offline SUMO

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Re: Twin Engine Panther from England
« Reply #193 on: March 28, 2012, 08:12:40 AM »
it may be affected briz, was a concern but it passes the highly technical "it wont take a mark from a file" test.

each one welded in 4 goes and allowed to cool between welds to keep heat down as best as possible. will be inspected regular for wear at first - if they appear to be wearing i will kasenit harden them [thats why didnt braze them on so could reheat later on if need be to harden] thats the plan anyway...

not flatting the followers just yet, but tis a thought for next phase

Offline Koncretekid

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Re: Twin Engine Panther from England
« Reply #194 on: March 28, 2012, 08:33:02 AM »
I only see one rocker arm where I think I should see two; maybe just hidden behind the outside one.  But they look like they would benefit from going on a diet.  Heavy cast steel?  I realize you don't expect high RPM's, but that's reciprocating weight and without a lot of spring pressure, I can visualize them being lofted off the cam at higher RPM.  Are the pushrods aluminum?  Wall thickness, even solid, won't make them much stiffer.  Have you considered thin walled tubular steel instead?  I think they can make them any length you want and might be a good investment.  As usual, we all like to make as many changes we can think of on the first pass out, which sometimes causes problems we can't solve.  Walk slowly, carry a big Panther!
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