Author Topic: fl 350 mods  (Read 20717 times)

Fat Bastard

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Re: fl 350 mods
« Reply #15 on: February 15, 2013, 10:55:15 AM »
Without being able to weld, it is going to be difficult or expensive to put any other engine in. A 583 or any twin for that matter ends up with the recoil starter through the frame on the right side when you line up the clutch. The Pilot frame is wider and you have probably seen more Pilot engine swaps than 350s.

It is feasible to put a CR500 cylinder on an FL350 bottom end. The cylinder has to be cut down both on top and bottom. A longer rod needs to be used because otherwise so much would need to be cut off the bottom of the cylinder it will cut into the reed block. Just like the Pilot conversion, the studs need to be moved out wider in the cases. The 350 transfer ports are wider than the Pilot and they line up better with the 500s but there will still need to be porting done on the cases and the cylinder to line them up. The ports also need to be altered to compensate for the 11mm difference in stroke.

I have an engine sitting on my bench that is 68cc over standard bore. I have yet to install it and fire it up. A standard bore CR500 cylinder would put it at 96cc over standard FL350 bore.

Go here for  FL350 fenders.

Flipping the wheels is bad. The yoke will get ripped out of your hands when you hit a hole. You want the wheels to have as similar offset to stock as possible.


Hey Mr. Live wire you say right here 11mm is possible. What's up with that?

LiveWire

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Re: fl 350 mods
« Reply #16 on: February 15, 2013, 06:49:49 PM »
...The ports also need to be altered to compensate for the 11mm difference in stroke.
...
A standard bore CR500 cylinder would put it at 96cc over standard FL350 bore.
...

Hey Mr. Live wire you say right here 11mm is possible. What's up with that?

I think you need to read more thoroughly. Nowhere does it say anything about stroking the crank. It also says a 96cc increase, not 150cc increase.

Fat Bastard

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Re: fl 350 mods
« Reply #17 on: February 15, 2013, 09:57:27 PM »
What would it do to the 490 if you shaved it down? What's the bore of a cr500?

LiveWire

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Re: fl 350 mods
« Reply #18 on: February 16, 2013, 04:05:10 PM »
I would think the same thing could be done to the YZ490 cylinder. A CR500 is 89mm with overbores to 91. My thoughts back then were to use a max overbore YZ490 piston in a standard bore CR500 cylinder and NiCom plate that cylinder when it wore out.

Fat Bastard

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Re: fl 350 mods
« Reply #19 on: February 16, 2013, 10:15:49 PM »
Would be nice to use the 490 jug. It bolt right on the fl350 bottom end and an fl350 head will bolt on as well. Just need to open the cases to fit the sleeve. How do you shave don the bottom of a cylinder? Do you also trim the bottom of the sleeve? Sounds pretty difficult.

LiveWire

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Re: fl 350 mods
« Reply #20 on: February 17, 2013, 01:52:00 PM »
I would do it on a CNC mill because I have one. You could also do it on a lathe making sure to get it mounted to the spindle true to center and flat. If you use a long enough rod, assuming one can be found, you would not need to cut at all. It is easier to make a spacer plate if needed.