Author Topic: CB500/550 Bottom End Swap (Read 2549 times)

Greggo · « **on:** February 09, 2011, 09:35:16 PM »

Anybody swapped a 550 bottom end onto a 500 top end? Are there gearing issues? Would I be able to keep the top of the 500's bottom (with the engine number on it)?? I think I've read fitment isn't an issue, but I searched and searched unsuccessfully to find the thread. The top end of my 500 hums along happily, but she's skipping gears sometimes.

Thanks

bryanj · « **Reply #1 on:** February 09, 2011, 11:11:13 PM »

Cases HAVE to go as pairs plus the 550 has a completely different transmission and clutch cover.

A 550 engine will fit as long as you have the 550 RH rear engine mount for the clutch cable stop and a 500 cylinder and head set will fit on a 550 bottom

dave500 · « **Reply #2 on:** February 09, 2011, 11:58:37 PM »

the 500 has a 34 rear sprocket,the 550 has 37,itll have a tall gearing if you dont change to a 37,the different transmissions have different gearing internaly,heres a photo of the clutch bracket youll need for the 550.

Greggo · « **Reply #3 on:** February 10, 2011, 12:03:52 AM »

Thank you for the info guys, and the photos are very helpful Dave!

dave500 · « **Reply #4 on:** February 10, 2011, 12:09:58 AM »

no worries greggo,im putting a 550 motor into a 500 frame at the moment,i have a 500 i ride alot and it takes a little knack to shift,if it gets too bothersome ill use another 550 motor i have for the bottom end.

Greggo · « **Reply #5 on:** February 10, 2011, 01:00:24 PM »

Quote from: dave500 on February 10, 2011, 12:09:58 AM

no worries greggo,im putting a 550 motor into a 500 frame at the moment,i have a 500 i ride alot and it takes a little knack to shift,if it gets too bothersome ill use another 550 motor i have for the bottom end.

Exactly. Mine is beginning to get bothersome. I could spend a fortune undercutting gears, machining stronger clutch lifter rods, and finding new adjuster parts, but It would still be based on an inferior design.

domer · « **Reply #6 on:** February 10, 2011, 01:05:52 PM »

Quote from: Greggo on February 10, 2011, 01:00:24 PM

Quote from: dave500 on February 10, 2011, 12:09:58 AM
no worries greggo,im putting a 550 motor into a 500 frame at the moment,i have a 500 i ride alot and it takes a little knack to shift,if it gets too bothersome ill use another 550 motor i have for the bottom end.

Exactly. Mine is beginning to get bothersome. I could spend a fortune undercutting gears, machining stronger clutch lifter rods, and finding new adjuster parts, but It would still be based on an inferior design.

mine too.... occasional pop out of 2nd, finding neutral between 2nd and 3rd...

dave500 · « **Reply #7 on:** February 13, 2011, 01:00:34 AM »

hey heres something else ive discovered with this swap,the 550 kicker arm fouls the 500 side cover even before the locking detent clicks in,the 500"straight arm"kicker goes straight on and is well clear of the side cover and the 550 clutch action,lucky i have both,or just use electric start only.

Greggo · « **Reply #8 on:** February 13, 2011, 08:38:11 AM »

Thanks Dave, good thing I've got two 500 motors

. Any chance you can show me a pic of that engine/clutch cable mount?

bradweingartner · « **Reply #9 on:** February 13, 2011, 11:17:28 AM »

Any reason you want to swap a 500 top end on to a 550? Externally, the top end is pretty much identical. Best bet is probably just swapping a complete 550 motor. The extra displacement never hurts!

Not all the 550 kickers fowl either. The early 550Ks have identical side covers and frame as the 500, so any early 550K will be a 100% bolt in affair as long as you use a 550 clutch cable and a 550 clutch cable/engine bracket mentioned earlier. The later bikes with the different side cover have the bent kicker. Either one can work, the later 550s have the updated rocker cover though so it's probably not a bad idea to run one of those.

Greggo · « **Reply #10 on:** February 13, 2011, 11:58:48 AM »

Quote from: bradweingartner on February 13, 2011, 11:17:28 AM

Any reason you want to swap a 500 top end on to a 550? Externally, the top end is pretty much identical. Best bet is probably just swapping a complete 550 motor. The extra displacement never hurts!

Not all the 550 kickers fowl either. The early 550Ks have identical side covers and frame as the 500, so any early 550K will be a 100% bolt in affair as long as you use a 550 clutch cable and a 550 clutch cable/engine bracket mentioned earlier. The later bikes with the different side cover have the bent kicker. Either one can work, the later 550s have the updated rocker cover though so it's probably not a bad idea to run one of those.

If I had a nice, complete 550 motor, I would just swap it. But, this is a cheap solution to replacing a f*d up 500 transmission, as those parts are harder to find, and the design is inferior. Nice 550 motors can be 'spensive, and I'm not really concerned with displacement. I've read about one guy who did this swap to get the better tranny, but still stay within the displacement requirements for his racing class...

dave500 · « **Reply #11 on:** February 14, 2011, 12:13:29 AM »

Quote from: Greggo on February 13, 2011, 08:38:11 AM

Thanks Dave, good thing I've got two 500 motors . Any chance you can show me a pic of that engine/clutch cable mount?

i did already?scroll up.

Greggo · « **Reply #12 on:** February 14, 2011, 08:18:46 AM »

Quote from: dave500 on February 14, 2011, 12:13:29 AM

Quote from: Greggo on February 13, 2011, 08:38:11 AM
Thanks Dave, good thing I've got two 500 motors . Any chance you can show me a pic of that engine/clutch cable mount?

i did already?scroll up.

OOPS!

I just got a lock on a $50 550 motor, picking her up tomorrow!

dave500 · « **Reply #13 on:** February 15, 2011, 01:42:56 AM »

having a fiddle here hooking up the clutch cable,ill have to use the 550 cable as bradweingartner mentioned and lever end adjuster also,the 500 cable seems to have too much free length,maybe to reach a little further down and into the case to hook up,where as the 550 lower end of the cable sits a bit higher and has less distance to reach the hook?500 clutch cable number is 22870-323-020,the 550 is 22870-374-000,500 adjuster bolt is 53192-312-000 and the 550 one is 53192-268-000.

Scott S · « **Reply #14 on:** September 05, 2011, 10:31:37 AM »

Dave, your pic links no longer work.

I'm going to be putting a '76 550 engine into a '71 500 frame. I have 400F rear sets/levers and a 550F kicker (as part of the 400F swap over). Should all work OK, right?

dave500 · « **Reply #15 on:** September 05, 2011, 12:49:59 PM »

sorry,i cleaned up photobucket it was cluttered,i might still have some pics,what do you need?

Scott S · « **Reply #16 on:** September 05, 2011, 12:56:15 PM »

I believe they were pics of the kicker and what would/wouldn't work, but that's all a moot point if I'm using 400F pegs and a 550F kicker, right?

dave500 · « **Reply #17 on:** September 05, 2011, 12:59:44 PM »

yeah just see what fits,,the important part is the cable bracket and a 550 clutch cable,(those photos are still up)your rear sprocket will have to go from a 34 to a 37 for the 550.

faux fiddy · « **Reply #18 on:** September 06, 2011, 01:15:31 AM »

What about the 650 into the 5oo frame. They seem plentiful in cruiser style, and a bit beter displacement can't hurt .

News:

Author Topic: CB500/550 Bottom End Swap (Read 2549 times)