Author Topic: CB500 Conversion to 650 New Motor and CR 29 (Read 9754 times)

Scott S · « **Reply #25 on:** November 18, 2012, 04:34:48 am »

I did the 650 cam in a 550 swap and had to swap the tach. That's why I asked. This was on a '78 550K and it wasn't a problem finding a matching tach.
However, I'm thinking about doing this engine swap into my '72 CB500 (early production date, 1971) and the tach/speedo are the smaller style. I don't want to lose the gauges, but not sure what to do about the tach.

Scott S · « **Reply #26 on:** November 18, 2012, 06:28:09 pm »

Picked up a 650 engine today and now have two more questions:

1) How in the WORLD did you get it in the frame without that removable bar the 650 frame has?
2) What did you do about a clutch cable?

Tews19 · « **Reply #27 on:** November 18, 2012, 06:30:32 pm »

Quote from: Scott S on November 18, 2012, 06:28:09 pm

Picked up a 650 engine today and now have two more questions:

1) How in the WORLD did you get it in the frame without that removable bar the 650 frame has?
2) What did you do about a clutch cable?

AHH #$%*..... New build thread Scott? I have been searching for a 500/550 frame since reading this.... Curious how the hell his swap was so easy... Do you think the frame would need additional bracing as you are jumping up almost 15 hp from stock

Scott S · « **Reply #28 on:** November 18, 2012, 07:00:44 pm »

The frames seem very similar, other than the removable part. I'd guess the 500/550 frame would be just fine. I still have lots of research to do and some small parts to pick up, but I'll definitely update my old thread on the CB500 whenever I get around to making this swap.

Tews19 · « **Reply #29 on:** November 18, 2012, 07:17:53 pm »

How much did it cost you if you do not mind? I am thinking the weight to HP ratio would make it faster then a stock 750?

pangloss · « **Reply #30 on:** November 18, 2012, 07:55:39 pm »

AAAAh...!! Gotta tell the truth here..!!

I removed the rocker cover.....!! Strapped a 4X3 by 6 ft bit of timber behind the barrels and two people lifted it into place in 31 seconds.. ALL bolts through in 2 minutes... I timed it..!! Heh Heh!!

It requires a 650 clutch cable which is a little longer. Its routed below the engine.. In fact. A MUCH better run than the 500.. It's beautiful.. Well compared to the bloody 500 clutch which was AWFUL

Cost (apart from the engine freight bill which was embarrassing) amounts to 2 x New Ignitors ($150) and CR carburettors (which are obviously special..! .Gulp>> $700 l) Regulator/rectifier ($50 ebay) and adaptors for the exhaust (case of beer)... and of course the mucking around with the fuel tap.... Thats it.

Scott S · « **Reply #31 on:** November 19, 2012, 03:40:02 am »

I paid $100 for an engine, two sets of CV carbs (that I'd be lucky to make one set out of), a non-titled frame, front wheel with new tire, and a set of Comstars, the front also with a new tire.

I still need a regulator, possibly ignitors, and an exhaust...I'm thinking the MAC 4-1. Oh, and a clutch cable.

Scott S · « **Reply #32 on:** November 19, 2012, 06:35:19 pm »

Will I need the CB650 regulator/rectifier or will the CB500 stuff work?

Scott S · « **Reply #33 on:** December 15, 2012, 01:07:00 pm »

Quote from: pangloss on November 18, 2012, 07:55:39 pm

AAAAh...!! Gotta tell the truth here..!!

I removed the rocker cover.....!! Strapped a 4X3 by 6 ft bit of timber behind the barrels and two people lifted it into place in 31 seconds.. ALL bolts through in 2 minutes... I timed it..!! Heh Heh!!

Do you mean the whole rocker cover, requiring a valve adjustment, or just the breather and two outer covers?

pangloss · « **Reply #34 on:** December 15, 2012, 01:39:18 pm »

The whole rocker cover... I wanted to check in there anyway, so yes, the umpteenth 6mm bolts.
I know a 500/550 motor will go into this frame complete, not sure about the 650. The rocker cover on the 650 is slightly taller

rb550four · « **Reply #35 on:** December 16, 2012, 11:26:47 am »

I'm just finishing up a 550/650 conversion. I always top load 500/550 motor into the 500/550 frame by hand, the 650 seems a little heavier so I lowered the frame over the 650 engine, takes less than 10 mins. Engine bolts and spacers from 500/550 works ,mounts up the same. I used the 650 wiring in it's entirety, much better than fooling around wondering what will work or work better. there is still some fitting issues, but not bad. I have a running thread now , it sounds like it's just about carbs but it's not.

Scott S · « **Reply #36 on:** December 16, 2012, 11:40:01 am »

rb550four, you have a build thread? Link?

I have a non-titled 650 frame that came with my pile of parts. My Dad has a childhood friend that's a world class hot-rod builder and fabricator (no, seriously....he's that good) and I'm seriously considering taking the 500 frame to hime while the engine is out and having him splce in the removable section of the 650 frame. I'm sure he could do it properly.

I have a little while before I attempt the actual swap, but I'm wondering if the shift shaft is in the same spot on both bikes? I'm running CB400F mid-set pegs and I'd like to use them with the 650 engine if possible.

rb550four · « **Reply #37 on:** December 16, 2012, 11:51:06 am »

Sorry , it's 80 pd's vs 81vb's carbs, it was an unexpected build, I was going to build another snow machine but this happened.
Don't know anything about the 400 pegs, I'm still switching parts between the 500 550 and 650 to see what works . I ended up with 550 pegs. the 650 shifter is longer, I haven't measured the difference if there is any between the 550 and 650 shafts yet.
I like the idea of the breakaway frame, I considered it briefly, but decided that there would be a possible issue with the rear brake pedal mount, don't know how extensive it could become, figured I'd get a bike operational and fool with the particulars later.

pangloss · « **Reply #38 on:** December 16, 2012, 01:00:39 pm »

The removable part of the 650 frame was only put there because the rear (seat level) section was lowered..its not requied in a 500/550 frame.. the gear shift spindle is exactly the same posn

Scott S · « **Reply #39 on:** April 16, 2013, 02:50:08 pm »

Did you do anything special to get the K&N filters to clear the side covers? I have different carbs (VM44) and I can't get the upper tab of my side covers to seat firmly in the grommet on the frame. The RH side is the worst.

pangloss · « **Reply #40 on:** April 16, 2013, 08:48:15 pm »

Same here.. misses the top front tab by 1/4 inch... Had to use a couple of small cable ties to hold it in..

Scott S · « **Reply #41 on:** April 18, 2013, 03:20:57 am »

Sent you a PM. Can you show me what you did to hold the side covers?

pangloss · « **Reply #42 on:** April 18, 2013, 05:19:52 am »

Bit tricky.. The bike is in Sydney.. I'm in Darwin 3000 Miles away I didn't get a detailed picture of my sidecover hold on cable ties. I put one tie around the tab, tight. This one also traps the second tie which goes around the tab hole. It's good as it provides security. I've lost sidecovers before

Scott S · « **Reply #43 on:** April 18, 2013, 05:57:50 am »

I might try that before trimming the covers. Thanks for the reply.

If this were a 550F with the triangular covers, it wouldn't be a problem....in case any of you 550F owners are thinking about this swap.

BTW, Pangloss, I found a 40T rear sprocket on ebay and that got the gearing nearly identical to the stock CB650 gearing. This little rocket hauls butt!
I really like the K&N filters. I was able to tune the carbs nicely. I think the linked carbs give a bit of a plenum effect.

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Author Topic: CB500 Conversion to 650 New Motor and CR 29 (Read 9754 times)