I'm thinking about starting on a motorcycle project and was wanting some input on how straight forward it is to put a newer engine on an old bike.
Just for purpose of discussion there is a 1973 Honda CB450 local with a bad motor and a 2007 R6 engine/transmission set up with about 850 miles.
Can you bolt pretty much any engine on the frame or is it easier if you stay within the same family (Honda engine on a Honda frame)?
I have done a few swaps. The main things that you must take into account are IMO, the height and width of the new engine. As in, will it actually fit in its new home, or do you have to modify the frame. You will also have to align the output shaft/sprocket of new motor, and the rear sprocket of bike. I have found that it is beneficial to have the complete donor bike for the odds and ends that you will need as you build. To answer your question, I don't think staying in the same family is necessary or beneficial.
I rode motorcycles off and on in college but never did any real work on them.
Are the mounts more or less the same from bike to bike? I'm assuming that I would have to weld on the mounts for whatever engine I would be using. I'm also assuming that for balance reasons that I would want to make sure the engine is centered on the frame.
Is there a good place online to find engine dimensions or is that something that's best just done with a tape measure when you're considering what your going to buy?
The mounts can be very different. Newer sportbikes use frames that wrap around the engine, whereas an older standard style bike will hold the engine in place with a top mount, and two or more points in the bottom cradle. Making a bottom mounting plate is easy, but not having an R6 in front of me, I'm not sure how you would make a mount for the top. You do want to keep the engine centered, and large drive offsets can be remedied by using a jackshaft. I'll see if I can find a pic, and hopefully someone with more expertise than I will chime in...
Easiest bike motor swaps EVAR. 1979-1982 Honda CB750 DOHC, stick in a 1983 CB1100F.
I guess I should clarify my question a little on what I would like to do.
I've been seeing old bikes (like Honda CB's) with bad motors for about $200-300. I was thinking that if I could find a newer motor that could easily swap into the older bike I would have an engine that I could just bolt and go (no rebuild) and a little more hp.
Any recommendation for newer motors that could easily be swapped into an older bike?
Something else I just noticed.
It looks like on small bike (under 500cc) the front of the frame only has one bar and the bigger bikes (750cc and up) have dual from bars.
Would it be easier to do an engine swap into something with dual bars?
The CB is a skinny bike, with a skinny frame and skinny tires, while the R6 is the opposite. To get the sprockets lined up, the engine would be hanging way out on one side of the bike. As far as the frame goes, single or twin downtubes aren't necessarily related to the bike size - some big bikes have a single downtube, while some small bikes have two (and some bikes have none at all.)
http://www.roaringtoyz.com/KING280/pages/KING7.html
I don't think that swap would be a good idea. 07 sportbike power, with 73 standard handling and brakes...
A good option MIGHT be a single cylinder 2-smoker from a dirtbike. I've been contemplating this swap for awhile. Narrow, light, and just enough more power than stock to make it fun.
Most bikes have one mount in common that the rest can be based off of, and that is the swinger pivot bolt. after you get that one figured out, the rest should be easy.
You'll have huge packaging problems. The R6 has what are basically downdraft carbs and will need a big airbox on top of those. That's about the same real estate where your current backbone frame and gas tank reside. Also you're going from maybe 40 hp to about 120 hp. No way the frame, fork, brakes, wheels, etc will be up to that.
Many modern sportbikes are on a two/three year cycle. So frames and engines will typically change every couple of years, meaning that engine mounts will most likely change that often as well.
Find a modern motocross/enduro thumper 450, put that motor in there and build a nice cafe bike a la Honda GB 500.
Modern bikes make a lot more power with a lot less engine, so maybe swap a 250 into where a 400 was or 600 into where a 750 was?
Of course if you were to buy my Midget I could probably toss in a low miles '01 Katana 600 engine and no-title frame you could play with for not a lot of cash....
You're not that far away, really, and I can deliver. You know you want to...
If you need to unload the Midget that bad you could always just drop it by my house. The Miata powered Midget idea is currently on hold for various reasons.
How much would you sell the Katana for without the Midget? Would it fit in the back of a 92 GTi? I'm going to be picking up a GTi from your area in the near future.
It's not a whole Katana, it's a frame I bought in one deal, an engine I bought in another, and a carb stack from yet another. Was planning on a two wheel in the front, one in the back, trike project that never happened. Engine might be as old as '96, they were all the same up 'til '06, the only differences being in the carbs which are '98+ for sure. I'll have to double check on theyear, I honestly don't remember now.
Two frames available, would like to keep one, one is pre-'98 and one is post, both hold the same engine but little different body work for the tail means a couple of different accessory brackets. Both frames are steel, though, so welding is easy enough.
Brought everything home in the back of my Scion XB, so should fit in a GTi.
Engine $200, carbs $50, frame $25. Carbs and frame tossed in free if you buy the Midget. ;)
I'll think on it. Do you have any pictures?
Sounds like I just need to stop by next time I'm through the area and see what all you have since you keep offering up stuff for my projects. 
jwdmotorsports wrote: Sounds like I just need to stop by next time I'm through the area and see what all you have since you keep offering up stuff for my projects.
Probably the ticket right there. I'll see if I can wrestle the motor out from under the bench tonight and get you a pic or two.
xci_ed6 wrote: I don't think that swap would be a good idea. 07 sportbike power, with 73 standard handling and brakes...
No kidding, this sounds like a rather scary sort of bike even for an experienced rider.
A modern twin might have the sprocket in a more appropriate location, and be a bit easier to control to boot. Maybe something out of a GS500 or Ninja 500.
MadScientistMatt wrote:xci_ed6 wrote: I don't think that swap would be a good idea. 07 sportbike power, with 73 standard handling and brakes...No kidding, this sounds like a rather scary sort of bike even for an experienced rider. A modern twin might have the sprocket in a more appropriate location, and be a bit easier to control to boot. Maybe something out of a GS500 or Ninja 500.
You missed the fact this thread is 4 years old.......and was bumped last night by a canoe who has since been deleted.
D'oh. I wonder if he ever tried it.
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