Author Topic: 650 to 550 cam swap.. what year cam? (Read 2303 times)

A Grove · « **on:** April 16, 2009, 06:34:04 PM »

Will a cam from a 1985 cb650 swap into a '75550k? What is the range of years when searching for a cam to swap? thanks

mlinder · « **Reply #1 on:** April 16, 2009, 06:39:24 PM »

Quote from: A Grove on April 16, 2009, 06:34:04 PM

Will a cam from a 1985 cb650 swap into a '75550k? What is the range of years when searching for a cam to swap? thanks

No.

79-82

Shenanigans · « **Reply #2 on:** April 16, 2009, 06:41:14 PM »

You'd have a cam left over

B.O.X.N.I.F.E. · « **Reply #3 on:** May 13, 2009, 02:30:11 PM »

Hey, I read somewhere online that the '79 was a slightly hotter profile than 80 - 82. It's the same part number according to Honda, but were the measurements actually any different in '79?

j-conn · « **Reply #4 on:** May 13, 2009, 02:55:15 PM »

im still looking for one...

CBJoe · « **Reply #5 on:** May 13, 2009, 03:00:53 PM »

Quote from: boxnife on May 13, 2009, 02:30:11 PM

Hey, I read somewhere online that the '79 was a slightly hotter profile than 80 - 82. It's the same part number according to Honda, but were the measurements actually any different in '79?

There's an old thread that goes into this, but I thought that the 79-82 cams were the same but that there was a German Market model that had slightly lesser horsepower.

I'm pretty sure that Soos knows. I thought that it was one of his old threads that had the measurements and info.

Regards, Joe

CBJoe · « **Reply #6 on:** May 13, 2009, 03:03:05 PM »

Pretty Sure that it was this thread

http://forums.sohc4.net/index.php?topic=26492.0

Edit: Nope... similar thread, but I'm thinking it might have been on the Honda CB650 Site
http://www.hondacb650.com

cb650 · « **Reply #7 on:** May 13, 2009, 03:53:07 PM »

I've heard to that the 79 was the cam to have. Think it comes from that year being the fastest 1/4 mile times. I think it was more to the gearing. The manual list wear limits as the sam for all. But it dont mention the lopo german cam either.

B.O.X.N.I.F.E. · « **Reply #8 on:** May 13, 2009, 04:00:59 PM »

Oh, so 79 possibly has a slightly less powerful profile? Well #$%*...

cb650 · « **Reply #9 on:** May 13, 2009, 04:10:54 PM »

And who said that? German cam is the only lopo one I know of.

B.O.X.N.I.F.E. · « **Reply #10 on:** May 13, 2009, 04:24:41 PM »

Quote from: cb650 on May 13, 2009, 04:10:54 PM

And who said that? German cam is the only lopo one I know of.

Nobody, I read it wrong. I had also heard that there was a european cam to watch out for, but I still thought the 79 was hotter. Could be internet urban legend. I'll keep looking for the post with measurements.

B.O.X.N.I.F.E. · « **Reply #11 on:** May 13, 2009, 04:45:30 PM »

Well if I can pick up some measuring tools I'll do it, just got an 82 cam off ebay.

cb650 · « **Reply #12 on:** May 13, 2009, 05:25:41 PM »

I compared a 79 to 81 cam years ago and ther was no diff. But nobody listens to me

CBJoe · « **Reply #13 on:** May 13, 2009, 05:35:12 PM »

Quote from: cb650 on May 13, 2009, 05:25:41 PM

I compared a 79 to 81 cam years ago and ther was no diff. But nobody listens to me

If anyone actually listens to me I'll probably be wrong.

cb650 · « **Reply #14 on:** May 13, 2009, 05:42:58 PM »

Thats the only time I get heard.

Soos · « **Reply #15 on:** May 14, 2009, 07:24:39 AM »

Quote from: cb650 on May 13, 2009, 03:53:07 PM

I've heard to that the 79 was the cam to have. Think it comes from that year being the fastest 1/4 mile times. I think it was more to the gearing.

Yup, it's all in the gearing, minor differences, but 5th is still geared the same through the 650 lineup if I am remembering right.

Quote

Hey, I read somewhere online that the '79 was a slightly hotter profile than 80 - 82. It's the same part number according to Honda, but were the measurements actually any different in '79?

NO, no no... as cb650 said, the '79 is IDENTICAL in profile(including the opening and closing ramps) to the '80-'82 SOHC camshafts available in the US.
Yes there is a german 50hp version, but thats about it for the 650 cams.

l8r

Soos · « **Reply #16 on:** May 14, 2009, 07:26:35 AM »

Quote from: boxnife on May 13, 2009, 04:45:30 PM

Well if I can pick up some measuring tools I'll do it, just got an 82 cam off ebay.

Be careful, I have been bit in the arse buying a 650 cam off feebay, and got a 550 cam once(or a german 50hp 650 cam).

dude came through and re-paid the money, and I re-sent the cam.
So all ended well, but beware.

l8r

buffalogt750 · « **Reply #17 on:** May 14, 2009, 09:08:55 AM »

Well if I can pick up some measuring tools I'll do it, just got an 82 cam off ebay. (quote)

==================================================================

If you just got the cam on ebay for $7.75 that was a bargain. Make sure you measure it to be sure its within specs. A cheap dial caliper from Harbor Freight will work fine to measure it. Wear limits for 650 cam are 1.40 for intake and 1.39 for exhaust. Check for cam lobe clearance on your head. Lobes are about .030 taller then 550 lobes. I had no clearance problems on my '76 550 but some do. You have to use the 550 cam sprocket and a 650 tach drive and 650 tach with the 650 cam. Tach drive ratios are different. If you use the 550 tach drive with the 650 cam I'm sure it will chew the gears up. The 550 tach and speedo cables will work with 650 gauges. You have to beware buying 650 gauges also. You will probably want a 650 speedo to match your 650 tach and 1979 is the only year that 650's had a 120 mph speedo. 1980 to 1982 had the wimpy 85 mph speedos. The 650 gauges I got off ebay had warped plastic needles that rubbed the glass and would not read right. I lucked out and had an old set of Suzuki GT750 gauges with metal needles and was able to swap the needles (probably an easier job than trying to get my money back!)

B.O.X.N.I.F.E. · « **Reply #18 on:** May 14, 2009, 10:40:04 AM »

Yeah, I got that 7.75$ cam. The last 650 cam I saw had something like 10 bids, so maybe people had trouble finding this one. It was definetly a score.

As for the tach, I'm keeping an eye out for a 650 unit, but I had read 80's VF750 electronic tachs may work. Either way, I'll miss my green face guages.

Quote from: buffalogt750 on May 14, 2009, 09:08:55 AM

Well if I can pick up some measuring tools I'll do it, just got an 82 cam off ebay. (quote)

==================================================================

If you just got the cam on ebay for $7.75 that was a bargain. Make sure you measure it to be sure its within specs. A cheap dial caliper from Harbor Freight will work fine to measure it. Wear limits for 650 cam are 1.40 for intake and 1.39 for exhaust. Check for cam lobe clearance on your head. Lobes are about .030 taller then 550 lobes. I had no clearance problems on my '76 550 but some do. You have to use the 550 cam sprocket and a 650 tach drive and 650 tach with the 650 cam. Tach drive ratios are different. If you use the 550 tach drive with the 650 cam I'm sure it will chew the gears up. The 550 tach and speedo cables will work with 650 gauges. You have to beware buying 650 gauges also. You will probably want a 650 speedo to match your 650 tach and 1979 is the only year that 650's had a 120 mph speedo. 1980 to 1982 had the wimpy 85 mph speedos. The 650 gauges I got off ebay had warped plastic needles that rubbed the glass and would not read right. I lucked out and had an old set of Suzuki GT750 gauges with metal needles and was able to swap the needles (probably an easier job than trying to get my money back!)

B.O.X.N.I.F.E. · « **Reply #19 on:** May 16, 2009, 01:27:18 PM »

Hey guys, I'm finishing up my top end rebuild and it's time for the cam to go in. Because I don't have a tach yet that will work with the 650 cam, should I wait to install it until I find a tach? If it wasn't for the rebuild I'd just do it, but I'm afraid it might be a bad idea to try to go through the break in procedure without a tach.

cb650 · « **Reply #20 on:** May 16, 2009, 04:02:35 PM »

If it is all used I would say just be easy at first untill the used parts are properly introduced.
I have been wondering in all the swaps if anybody checked the journals. And the ones in the alum head.

buffalogt750 · « **Reply #21 on:** May 16, 2009, 06:43:15 PM »

I would think that anyone doing a cam swap would know to look at everything closely, especially when dealing with used ebay parts.

cb650 · « **Reply #22 on:** May 16, 2009, 07:09:34 PM »

Cool! Everyone must have a set of teloscoping gages and mikes. Not to be a ass (like I care) but to measure the head and cam cover it would need to be assembled without the cam and checked. Aluminumumum will wear faster than the hard steel cam. If you but a cam in specs and put it in a head that is junk wont matter in the long run.

buffalogt750 · « **Reply #23 on:** May 17, 2009, 07:53:47 AM »

I guess if we don't have access to a full compliment of measuring instruments and probably a full machine shop, we shouldn't even bother.

cb650 · « **Reply #24 on:** May 17, 2009, 08:28:13 AM »

I never said that I was just wondering if anyone had done it. I've never even checked mine when apart. And all you would need is plastigage.

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Author Topic: 650 to 550 cam swap.. what year cam? (Read 2303 times)