Bikes with two engines?

speirmoor

speirmoor

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Something I've always wondered. Those race bikes with two (sometimes three) motors like the Hogslayer etc. How do they work? Do you get twice the power with 2 motors? How/where are they linked together?
 
Usually linked together with chain or belt linking front and rear engines together at drive side crankshaft ends, sometimes with added outboard bearings on the crankshaft ends, and then normal primary chain or belt to drive transmission on rear engine. One of the problems with that is reliability of the transmission and clutch under twice the power. Some, like the Hogslayer, use a stronger transmission in place of the old Norton box. Easier with pre-unit engines than later ones, because you don't have to deal with the extra transmission lump. If you hunt around on-line, you can find quite a bit of detail on some of them.

Ken
 
I see, and thanks for the simple explanation. Theres alot online alright. Sometimes too much as if you're supposed to know the basics already..
 
These pictures of a Norton twin engine bike show one way to do it. Notice that he is using a Harley big twin transmission. I have seen a video of him somewhere actually kick starting it and riding it around a bit, but I don't have a link to it.

Bikes with two engines?


Bikes with two engines?


Ken
 
When you double the number of cylinders, you don't usually get double the power. 'Because I can' is never a good reason for doing anything. What you pick up on the merry-go-round, you often lose on the hurdey-gurdey.
 
Bikes with two engines?
lcrken said:
Usually linked together with chain or belt linking front and rear engines together at drive side crankshaft ends, sometimes with added outboard bearings on the crankshaft ends, and then normal primary chain or belt to drive transmission on rear engine. One of the problems with that is reliability of the transmission and clutch under twice the power. Some, like the Hogslayer, use a stronger transmission in place of the old Norton box. Easier with pre-unit engines than later ones, because you don't have to deal with the extra transmission lump. If you hunt around on-line, you can find quite a bit of detail on some of them.

Ken
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I took this pic in the NATIONAL MOTORCYCLE MUSEUM ,Birmingham in the Uk, almost 2 years ago, apols for not getting all in , but as u can see, it is a bit special
 
I have always wondered..........
Since no two engines are identical, does the more powerful engine carry the weaker one or does the slower of the two hold back the the better running?
 
I have no experience of twin motors, I would suggest ……..

I have run a model railway loco with 2 identical motors wired independently -it ran rough, yet when they were wired together it ran smooth, so there's your answer... of sorts.
 
Mark said:
I have always wondered..........
Since no two engines are identical, does the more powerful engine carry the weaker one or does the slower of the two hold back the the better running?
Click to expand...
I’ve often wondered the same and kinda why I started this thread.
 
Mark said:
I have always wondered..........
Since no two engines are identical, does the more powerful engine carry the weaker one or does the slower of the two hold back the the better running?
Click to expand...

The engines are staggered timing-wise. So, in effect, it is no different than a 4 cylinder engine with one common crankshaft, each cylinder 90 degrees apart in timing. Each cylinder is doing all the work, during its' power part of the 720 degree cycle.

Slick
 
Hogslayers tranny was a 2-speed Rambler overdrive unit. First Top Fuel drag bike to have more than one gear. Clutch was made from an earthmover brake.
 
Danno said:
Hogslayers tranny was a 2-speed Rambler overdrive unit. First Top Fuel drag bike to have more than one gear. Clutch was made from an earthmover brake.
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John Gregory was (and still is) a mechanical genius. TC was the one who had to pull the trigger on that beast. TC is in the AMA hall of Fame. John should be. They are also very nice guys. It took a long time and a great deal of campaigning to get the AMA to put TC into the Hall of Fame despite the fact that they were world champions for 4 years running. They (the AMA) had a bad attitude, as drag racing was sanctioned by the National Hot Rod Assn. and not the AMA. Besides what Danno stated, they were the first ones to use a chrome moly frame and the big rear slick. They consistently beat bikes that had more power. It took 5 years for the other guys to catch up to their engineering mastery. The triple engine bike was in development when the British bike industry fell to pieces. This changed the financial situation for British bike dealers like TC and the triple project was stopped. TC still has that bike.
 
I think John Gregory has or had a Manx or Atlas racer on disp;ay at Anamosa. I saw both, just can't remember which one was his,
 
Oh yeah, I am pretty sure that they were the first to use fuel injection too. It was fortuitous for them to be in Kenosha, WI. With the American Motors car plant right there. There was a lot of local talent in small independent shops.
 
Bikes with two engines are a waste of an engine. If you need two engines to win a competition, find yourself a different competition. I look at those photos of the Hogslayer and wonder why some dick would want to do that. If I had one of those motors, I'd build a second bike. Beating a Harley cannot be that important. - All you need to do is get them onto a small road-race circuit and any Commando will make them look stupid.
 
Thank you you acotrel for your insightful contribution to this discussion.
 
Alan only has one mine and thats road racing on a circuit and anything else is a waste of time, if Alan watched the video of the Hogslayer then he minght see what they achieved and the things they built to out perform anything that went up against them and they did it on a small budget not like the rest of them and the amount of runs they done without a rebuild is outstanding.

Ashley
 
XTINCT said:
Oh yeah, I am pretty sure that they were the first to use fuel injection too. It was fortuitous for them to be in Kenosha, WI. With the American Motors car plant right there. There was a lot of local talent in small independent shops.
Click to expand...
I think the fuel injection was a mechanical unit from a 4-cylinder Offenhauser engine-cut in half for the two twins. The only thing wasted was the competition.
 
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