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Author Topic: Twin Engine Panther from England  (Read 45481 times)
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wobblywalrus
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« Reply #240 on: October 02, 2012, 12:04:46 AM »

It looks like a stable layout.  Are you going to run it with carbs first, then blown later?
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SUMO
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« Reply #241 on: October 02, 2012, 02:09:18 AM »

 
It looks like a stable layout.  Are you going to run it with carbs first, then blown later?

in stages so yea. carbs first, then when that's sorted blower nitrous etc...

startup date... as soon as I can  grin
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wobblywalrus
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« Reply #242 on: October 03, 2012, 11:19:09 PM »

Sumo, connecting the two intake manifolds with a 1/4-inch or 5/16 inch diameter hose might smooth the engines out at low rpm and make them work better together.
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SUMO
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« Reply #243 on: October 05, 2012, 05:47:00 AM »

Sumo, connecting the two intake manifolds with a 1/4-inch or 5/16 inch diameter hose might smooth the engines out at low rpm and make them work better together.

thats not something ive read anything about...

whats the logic?
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Old Scrambler
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« Reply #244 on: October 19, 2012, 04:48:10 PM »

My twin-carb Triumph T100 has a balancer-tube between the intakes......If the tube is cracked or missing, the motor is hard to start and prone to running on one cylinder except when under load.  The distance between your motors and the separate cranks may not need that type of intake balance. I'm thinking that no matter how synchronized your motors are, one will tend to be the leader and the other the helper......just so they stay in step with each other.  Have you considered one or more slipper clutches?
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2013 AMA Record - 250cc MPS-PG TRIUMPH Tiger Cub - 88.7 mph
2016 AMA Record - 750cc M-CG HONDA CB750 sohc - 130.7 mph
2016 AMA Record - 750cc MPS-CG HONDA CB750 sohc - 137.7 mph
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wobblywalrus
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« Reply #245 on: October 19, 2012, 10:20:16 PM »

The logic of the balancer tube is beyond me.  Some guy showed it to me in the 1970's and I have used it ever since.  Most of the time it smooths out the engine at idle and at low rpm.   I have used it on in-line four bike engines by connecting cyls 1 to 4 and 2 to 3.  Sometimes the tube is no help whatsoever.  Most of the time it works.  It is a cheap trick and I always try it to see if it will work.
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Milwaukee Midget
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« Reply #246 on: October 19, 2012, 11:23:54 PM »

I agree with Old Scrambler on the two key issues.  The engines are physically too far apart, and it is likely that one will be nominally stronger than the other.
  
If the hose is a foot long, youíd wind up with better than a Ĺ ci column of air/fuel mixture, along with its associated momentum, affecting manifold volume by moving back and forth, possibly out of sync with what the engines are trying to draw.

If you're running vacuum advance and seperate ignitions, you would want to keep the two seperated.

In your case, I think you should maximize output of each engine individually, and give each what it wants as far as tune is concerned.

Iím sure that they will be close as far as output is concerned, but equal power is not necessarily the goal.  Maximum power from each engine is.  Seeing as there is no way to perfectly match power between the two without compromising the stronger engine, I wouldnít try.

Iím not saying donít try the tube Ė if thatís what the engines want, thatís what they should have.  I donít see it working, but I donít know for sure.  
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grumm441
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« Reply #247 on: October 20, 2012, 05:21:19 AM »

Sumo, connecting the two intake manifolds with a 1/4-inch or 5/16 inch diameter hose might smooth the engines out at low rpm and make them work better together.

thats not something ive read anything about...

whats the logic?

It's one of those things. if you balance all tne carbs at about 2500 - 3000 rpm you dont need the tube. however if you are running multiple carbs all on different length cables every time you turn the handlebars, the carb balance changes. In the grand scheme of things, it is mainly about making a bike streetable.
it's a race bike, it might make it easier to start but at wide open throttle it probably will not make huge difference.
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« Reply #248 on: November 26, 2012, 04:33:50 AM »

so i got my primary connection dealt with this weekend..[for a second time] its been kinda half done for ages now after the weekend of doom a month or 3 back when it all went tits up.

so i closed the motors together by few of mm. that way im not relying on my measurements and the belt not stretching - ill have an idler pulley now in the middle bottom run. plus a few fairly inconsequential tweaks that i will notice but dont really matter.

was a 1 hit job so ive been avoiding it. get it wrong, start primary plate again... but turned out not too bad after ive been making excuses not to do it. bit of turning, hammering, welding and grinding and im happy. essentially 2 of the bolts that hold the crank halfs of each engine together also clamp the primary connection to the motors through the dural plates - making everything stiffer.




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Old Scrambler
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« Reply #249 on: November 26, 2012, 12:57:15 PM »

I REALLY like this build..........and offer a suggestion for your consideration......

I see the carb is mounted with an all-metal (alloy) intake.  I was thinking this may crack from continuous vibration. I use a small section of 'rubber' hose to reduce harmonic vibration to the carb.

Also, numerous contenders show up at the salt-flats with restrictive fuel-flow to the carb-bowl, including me undecided undecided
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2011 AMA Record - 250cc M-PG TRIUMPH Tiger Cub - 82.5 mph
2013 AMA Record - 250cc MPS-PG TRIUMPH Tiger Cub - 88.7 mph
2016 AMA Record - 750cc M-CG HONDA CB750 sohc - 130.7 mph
2016 AMA Record - 750cc MPS-CG HONDA CB750 sohc - 137.7 mph
Chasis Builder / Tuner: Dave Murre
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« Reply #250 on: November 26, 2012, 01:21:02 PM »

thanks, and yep. that's just held on with a hose clamp for mocking up but needs rubber hose to seal them up right.

not sorted tank yet but I'm running a fuel pump so should be ok hopefully with flow to carbs... fingers crossed and all that  grin
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wobblywalrus
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« Reply #251 on: November 26, 2012, 09:27:19 PM »

Enclosing the belt is a nice touch.  Lots of people here run open primaries on their street bikes and it looks to be trouble waiting to happen.
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SUMO
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« Reply #252 on: November 27, 2012, 02:11:18 AM »

to be fair I've run a lot of miles on chops with open belts

this was more an exercise in getting an outrigger bearing in place  grin

Enclosing the belt is a nice touch.  Lots of people here run open primaries on their street bikes and it looks to be trouble waiting to happen.
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Kansas Bad Man
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« Reply #253 on: December 01, 2012, 02:04:46 PM »



Hi Sumo.  Max here.

Like your build.  Pretty neat.  I've built three twin engine outfits and found that the hardest thing is to couple the engines and make the coupling live.  In theory, firing the two engines at exactly the same time is ideal; however, it is necessary to lead the front engine in engine to engine timing by 8o to 13o.  It won't be necessary to employ a manifold equalizer tube. 

        www.vincentstreamliner.com

Good luck.  BTW I used to own a sloper. 

                          Max
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Kansas Bad Man
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« Reply #254 on: December 01, 2012, 02:09:13 PM »


Check out 'Mockups and Test Beds' on my website.

           www.vincentstreamliner.com
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