650 on a 500 frame

5525 Views 92 Replies 12 Participants Last post by SirFoxx, Jan 17, 2022

SirFoxx

Discussion Starter · Jan 11, 2022

Hey--

Just wanted to start a general discussion about the thoughts, or personal experience of a cx/gl650 engine swapped onto a 500 frame. I've got a cx500 standard that I rip around every now and then, and I think the extra power from the 650 would be nice!

I've talked to murray about it several times, and I know he loves the extra power the 650 has to offer, even with the slightly longer gears.

What got me going on wanting to do this is, I picked up two GL650 engines from an estate sale for $100. One has the end of the camshaft snapped off, where the water impeller goes, and the other is complete. I need to stick my endoscope into the complete engine and see how the cylinders are, make sure the complete one is in decent shape and not blown up from lack of oil. Makes me curious why the PO was trying to take apart the other motor, and how hard he was prying at the impeller to break the cam.

I've been trying to get a 2nd starter as neither engine has one so I can also crank them over and listen for anything funny, but it seems they are becoming hard to come by and rather expensive. I'd use the one off my cx500, but I'd rather not drop the engine just to borrow a starter...

(if anyone has one they'd sell to me cheap I'd really appreciate it~)\

I think I have everything mentally written down that I am going to need / do for the swap:

Rae-San ignition, timing jumper to aggressive
12v coils
murray mid-pipes
rejet murray carbs
modify cx500 engine hangar
gl650 radiator + efan wiring
swap output shafts
inspect cam chain, replace mechanical seal while swapping output shaft
Swap over HD clutch springs?

I don't think I'm missing anything..but I probably am. If the cam chain tensioner isnt stretched to the max, I am going to leave it. No reason to change good parts. Same with the stator.

Only thing I have ordered right now is the 650 radiator, mainly because it was in great shape, came with the efan and the shroud for $70 shipped!

I may make a build thread once I get this project going. The hardest part will be modifying the engine hangar, but theres a video on youtube doing it, and its pretty easy if you have a welder (which i do lol).

See less See more

21 - 40 of 93 Posts

SirFoxx

Discussion Starter · #21 · Jan 12, 2022

jlbutler81 said:
That Nimbus is a 650 motor, right? If it's not terribly difficult to do I might be tempted. My problem would be sourcing a manual tensioner, I don't see any on ebay and I think the Turbo 500 I have is automatic.

@SirFoxx I'm putting my 650 into a 500 Turbo frame. I think the 650s drop into a GL frame with modifed GL650 hangers but on mine I may be fabricating completely new hangers because I hate the stamped sheet metal ones. What are your engine hanger plans looking like? If you've caught Murray's attention I'm sure he's discussed it with you I'm just curious.

the 650's, cx or gl, will drop onto the 500 frames with a modified 500 stamped steel hanger. you cannot modify the gl hangers as they are cast.

there are 4 bolts that hold the hanger to the motor. I believe the lower set needs to get modified--you cut the collar that the bolts go through off the mount, get new collars and move them down like a 1/4" and reweld them. its a very simple process. the reason for doing this is because the upper part of the mount that bolts to the frame is very different between the 500's and the 650's.

jlbutler81

· #22 · Jan 12, 2022

SirFoxx said:
the 650's, cx or gl, will drop onto the 500 frames with a modified 500 stamped steel hanger. you cannot modify the gl hangers as they are cast.

there are 4 bolts that hold the hanger to the motor. I believe the lower set needs to get modified--you cut the collar that the bolts go through off the mount, get new collars and move them down like a 1/4" and reweld them. its a very simple process. the reason for doing this is because the upper part of the mount that bolts to the frame is very different between the 500's and the 650's.

I know all that stuff, I meant with your bike, I thought you had an older CX500 frame? I didn't know what CX500s that worked on ^

SirFoxx

Discussion Starter · #23 · Jan 12, 2022

jlbutler81 said:
I know all that stuff, I meant with your bike, I thought you had an older CX500 frame? I didn't know what CX500s that worked on ^

I do. '78 standard. first year babyyy!

im not well versed on every flavor of the 500's, but the modification of the stamped steel 500 hangar should work on any of the us derived cx500 bikes. I am not sure about the gl500's, cx500e's, or the turbo bikes. i do know that it will work on mine as murray used to offer the modification service, but since stopped, but gave me advice on what to do, as well as finding a video on how to do it.

ChopperCharles

· #24 · Jan 12, 2022

Why can't you modify the cast hangers? They're just cast steel, not hardened or anything. They take a weld bead just fine.

Charles.

SirFoxx

Discussion Starter · #25 · Jan 12, 2022

ChopperCharles said:
Why can't you modify the cast hangers? They're just cast steel, not hardened or anything. They take a weld bead just fine.

Charles.

you're not supposed to weld to cast do to its porosity. You can braze to cast, though I wouldnt trust a brazed cast piece on something thats keeping the engine secured to the bike.

jlbutler81

· #26 · Jan 12, 2022

ChopperCharles said:
Why can't you modify the cast hangers? They're just cast steel, not hardened or anything. They take a weld bead just fine.

Charles.

In my case? It's just a preference to have something more attractive. And welding any cast is not something most people can do at home; I'd say the average guy has a mig welder and knows how to melt metal just well enough. The GL500 hanger that's sheet metal was just the easiest solution I think.

jlbutler81

· #27 · Jan 12, 2022

SirFoxx said:
you're not supposed to weld to cast do to its porosity. You can braze to cast, though I wouldnt trust a brazed cast piece on something thats keeping the engine secured to the bike.

It's a bitch and it can work you in circles when you run into issues, but done properly I'd trust it if it's just the one bolt hole on the hanger, as is the process for the GL500 sheet metal hanger. In my Turbo frame I'd have to cut and weld across the entire hanger on both sides and I wouldn't mind trying but I don't know that I'd trust it. For the aggravation some plate steel and tubes was my plan, and I can make it look nicer (relative to my tastes of course)

And now I actually really want to try it but it's 20 degrees in my work area so f that lol

SirFoxx

Discussion Starter · #28 · Jan 12, 2022

jlbutler81 said:
It's a bitch and it can work you in circles when you run into issues, but done properly I'd trust it if it's just the one bolt hole on the hanger, as is the process for the GL500 sheet metal hanger. In my Turbo frame I'd have to cut and weld across the entire hanger on both sides and I wouldn't mind trying but I don't know that I'd trust it. For the aggravation some plate steel and tubes was my plan, and I can make it look nicer (relative to my tastes of course)

And now I actually really want to try it but it's 20 degrees in my work area so f that lol

its both lower bolt holes, not just the one. I'll post the video here shortly.

I have a diesel heater for when its get nipply if I need to work in the garage lol

jlbutler81

· #29 · Jan 12, 2022

SirFoxx said:
its both lower bolt holes, not just the one. I'll post the video here shortly.

I've watched the video on it a while back, I thought they only had to do the top left one, my mistake.

jlbutler81

· #30 · Jan 12, 2022

He only specifies that one bolt out of alignment?

SirFoxx

Discussion Starter · #31 · Jan 12, 2022

jlbutler81 said:
I've watched the video on it a while back, I thought they only had to do the top left one, my mistake.

ill have to go back and watch it lol. all i remember is it needs to get modified (currently at work and cant view YT >.< )

Randall-in-Mpls

· #32 · Jan 12, 2022

There's no need to modify the cast hanger. Both the GL500 and GL650 use a two-piece cast hanger with identical attachment to the frame. You can hang a 650 engine on a GL500 frame using a GL650 hanger.
The one-piece, stamped metal hangers are all CX500. I'm not sure about the CX650C.

SirFoxx

Discussion Starter · #33 · Jan 12, 2022

Randall-in-Mpls said:
There's no need to modify the cast hanger. Both the GL500 and GL650 use a two-piece cast hanger with identical attachment to the frame. You can hang a 650 engine on a GL500 frame using a GL650 hanger.
The one-piece, stamped metal hangers are all CX500. I'm not sure about the CX650C.

We should compile this info somewhere on the motofaction site 🤔

jlbutler81

· #34 · Jan 12, 2022

Randall-in-Mpls said:
There's no need to modify the cast hanger. Both the GL500 and GL650 use a two-piece cast hanger with identical attachment to the frame. You can hang a 650 engine on a GL500 frame using a GL650 hanger.
The one-piece, stamped metal hangers are all CX500. I'm not sure about the CX650C.

Thats my problem, and I guess it was bad of me to jump into another's thread about it. I have a CX650C w/ cast hangers that are very different from the turbo hangers. I'm using a Turbo 500 frame; most don't. That might work for @SirFoxx

CXPhreak pointed me to the diagrams this morning; I was about to ask in the Turbo forum about the frames but this saved me from that post:

Line Font Auto part Parallel Engineering

See less See more

jlbutler81

· #35 · Jan 12, 2022

@Randall-in-Mpls So @SirFoxx could order these and they'd be a bolt in solution?

www.ebay.com

83 HONDA GL650 GL 650 SILVERWING ENGINE MOUNT BRACKETS #U21 | eBay

83 GL650 Engine mounts. Part is in good working condition. Any problems will be stated below. (11161) (4).

www.ebay.com

jlbutler81

· #36 · Jan 12, 2022

@Randall-in-Mpls @SirFoxx has a CX500 frame; they look different than a GL500 frame?

jlbutler81

· #37 · Jan 12, 2022

SirFoxx said:
We should compile this info somewhere on the motofaction site 🤔

AFAIK, there's only one CX500 frame mount pattern across all years; I think Randall's talking about a GL500 frame which is different and doesn't require modifications. The Red Rocket was built welding a GL500 frame to a turbo rear I think, and I've seen at least one other instance of that.

For your CX500 frame I think you're stuck modifying an engine mount.

SirFoxx

Discussion Starter · #38 · Jan 12, 2022

jlbutler81 said:
AFAIK, there's only one CX500 frame mount pattern across all years; I think Randall's talking about a GL500 frame which is different and doesn't require modifications. The Red Rocket was built welding a GL500 frame to a turbo rear I think, and I've seen at least one other instance of that.

For your CX500 frame I think you're stuck modifying an engine mount.

i mean, thats fine with me. it doesnt seem that hard to do.

reclinedrelic

· #39 · Jan 12, 2022

SirFoxx said:
-doesn"t the crankcase vent come out from the middle section of the motor, not from the back cover? what issue do you see with the venting?

Depending on the year of the engine the crankcase may be vented through the cylinder heads, CX500s, through the pulser cover, GL500 and others, and through a bottle breather at the timing inspection port.

Randall-in-Mpls

· #40 · Jan 12, 2022 (Edited)

SirFoxx said:
do you still have the link for the thread adapter?

www.amazon.com

Maslin M6 to M8 Inner and Outer Threaded Hollow Tube Adapter Inner Outer Threaded Coupler Conveyer Adapter - (Color: Zinc Plating, Size: M6 to m8 Pitch1.0, Thread Specification: 10 Pieces): Amazon.com: Industrial & Scientific

Maslin M6 to M8 Inner and Outer Threaded Hollow Tube Adapter Inner Outer Threaded Coupler Conveyer Adapter - (Color: Zinc Plating, Size: M6 to m8 Pitch1.0, Thread Specification: 10 Pieces): Amazon.com: Industrial & Scientific

www.amazon.com

Note that these are M6x1.0 to M8x1.0. The common adapter is M8x1.25.

21 - 40 of 93 Posts

This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.