Street Legal 2-Stroke Aprilia SXV Project
07-09-2009, 10:01 PM
#11
Thread Starter
Well, after placing the engine high and tight in the frame, the front sprocket center is about 35mm above the swingarm pivot center, so the idler sprocket is looking more interesting. I've never seen a bike in person that uses something like this and I don't know how much HP the idler can take - and I don't know how much HP it might rob.
07-09-2009, 10:09 PM
#13
Thread Starter
Also checking out a jackshaft setup.
The blue part on the left would need to be chopped out for the sprockets, and the blue part on the right would need to be added for support. A solid plate could also be welded in to support the cut area.
Driven chain on the left, drive chain on the right.
There may not be enough clearance for the sprockets and chain - I can't get good measurements without the rear sprocket in place and better alignment of the engine/frame/swingarm.
The blue part on the left would need to be chopped out for the sprockets, and the blue part on the right would need to be added for support. A solid plate could also be welded in to support the cut area.
Driven chain on the left, drive chain on the right.
There may not be enough clearance for the sprockets and chain - I can't get good measurements without the rear sprocket in place and better alignment of the engine/frame/swingarm.
07-09-2009, 10:14 PM
#15
Thread Starter
Similar idea to eliminate chain slack on the newBMW MX bike.
[I]Perhaps the single most impressive design element of the G450X is the exclusive implementation of a coaxial swingarm pivot/countershaft. A hollow countershaft serves as the swingarm pivot bolt hole, allowing the countershaft sprocket to rotate around the swingarm pivot point. This completely eliminates the need to adjust the chain to accommodate the wild variations in tension due to 12 inches of rear wheel travel. It
[I]Perhaps the single most impressive design element of the G450X is the exclusive implementation of a coaxial swingarm pivot/countershaft. A hollow countershaft serves as the swingarm pivot bolt hole, allowing the countershaft sprocket to rotate around the swingarm pivot point. This completely eliminates the need to adjust the chain to accommodate the wild variations in tension due to 12 inches of rear wheel travel. It
07-09-2009, 10:22 PM
#17
Thread Starter
I was lucky enough to speak to an engineer in Honda motorcycle R&D and got this info:
The chain heats up when it goes around the small circumfrence of the front sprocket at speed. It's not a problem because the chain is cooled as it travels to the rear sprocket and returns to the front.
If the jackshaft sprocket is only a few inches away from the front sprocket, the chain won't cool by the time it hits the jackshaft sprocket - which could heat it up even more, and so on - until the chain burns up the seals & lube, and then blows itself up.
The chain heats up when it goes around the small circumfrence of the front sprocket at speed. It's not a problem because the chain is cooled as it travels to the rear sprocket and returns to the front.
If the jackshaft sprocket is only a few inches away from the front sprocket, the chain won't cool by the time it hits the jackshaft sprocket - which could heat it up even more, and so on - until the chain burns up the seals & lube, and then blows itself up.
07-09-2009, 10:32 PM
#18
Thread Starter
Ordered Marchesini supermoto wheels with custom gold finish and Michelin Power One tires on June 9. Already received the tires, but got bad news today on the wheels.
Evidently the entire country of Italy stops working for the month of August, so the custom gold supermoto wheels won't be available until around mid-September.
Evidently the entire country of Italy stops working for the month of August, so the custom gold supermoto wheels won't be available until around mid-September.
07-09-2009, 10:35 PM
#19
Thread Starter
On the topic of making ground clearance for the downpipes - I don't think flatening the pipes in the belly (a little) will hurt performance much.
Check out the pipes on Eddie Lawson's OW81. I'm sure the engine will make more HP with round pipes, but probably not much more.
Check out the pipes on Eddie Lawson's OW81. I'm sure the engine will make more HP with round pipes, but probably not much more.
07-10-2009, 04:49 PM
#20
Awesome!