Topic: 1982 Honda CB 650 / engine mounts same as cb500?

[Wnbasac]

I have an oppertuinty to purchase a 1982 Honda CB 650 but will it or does it have the same mounting points as the CB500?

It will be going in an Amen Plunger Frame which now has a CB500 in it

Exhuast systems same or different as I have a set of NOS headers for the CB500

I'm more concerned with the mounting points, exhuast , chain sprockets and such

Tks, Lou

Have a HondaFul Day

[Scott S]

 It will bolt right in but you'll need the clutch cable for the CB650. The sump is also larger/deeper. In a stock frame, it's best to remove the valve cover so you can lift the engine up high enough to clear the sump. If your chopper frame is low, you may drag the sump.

 CB 650 exhaust has a larger diameter and very slightly wider spacing. While you my BE able to make the 500 exhaust fit, I wouldn't do it. The 650 head breathes MUCH better and needs the larger exhaust.

 Sprockets will fit, but spend some time with a gearing calculator. The 650 transmission ratios are different and it came with a different size rear wheel. You'll have to figure out what sprockets you need to get the RPM's where you want them.

[MiGhost]

Just a note on the sprockets.
Info from JT sprockets shows the front sprocket on the 650 to be 2mm narrower than the 500\550\750 sprocket.

stock front sprocket
79-81 CB650 16T
82 CB650 17T
The front 18T 500\550\750 sprocket can be used by milling the outer face, and adjusting the clearance of the chain guard in the case cover.

[Wnbasac]

tks guys probably better staying with a 500 or 550..

tks again for your impute u guys ROCK!

Have A HondaFull Day

[cb650]

And there are the charging diff issues.

[MiGhost]

You could certainly use the head from the 650 on a 550 motor, but you'll still have the exhaust issues, but gain in the performance.

Using just the head will result in low compression on the 500\500. Better to use the cylinders, pistons, and head.

[trueblue]

You could certainly use the head from the 650 on a 550 motor, but you'll still have the exhaust issues, but gain in the performance.

Using just the head will result in low compression on the 500\500. Better to use the cylinders, pistons, and head.

Then fit some 750 pistons

[trueblue]

The 650 head has a much larger chamber and domed pistons to match. The 500/550 run flat topped pistons. It would be a great option for decompressing purposes in a turbo application but in a N/A engine you would lose far more than you gain from the extra flow.