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2021 Benelli Leoncino - 2017 CSC RX3 - 2017 SSR Buccaneer 250i - 1979 CX650 Street Scrambler
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Discussion Starter · #1 ·
So, with a 650 motor in the 78 Standard frame, the 500 carbs can not be put in between the motor and the frame without removing all the engine bolts and tipping the motor forward slightly. I know I didn't have this issue on the 82 Custom... anyone else experience the same?



Charles.
 

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You're running the 650 with 500 carbs?



Did you have pod filters on the '82? Eliminating the airbox boots would make a big difference.



R
 

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Discussion Starter · #3 ·
You're running the 650 with 500 carbs?



Did you have pod filters on the '82? Eliminating the airbox boots would make a big difference.



R


Yep, 500 carbs are required. 650 carbs won't work, they hit the center frame post. You need pliable rubber intake manifolds - it's kind of a stretch. But they work. Need an 85 slow jet and 130 mains with a stock airbox. Chopper was running that setup... I'm putting pods on my latest bike though, and the problem is actually the frame (there's no airbox installed). Well, the problem is that the 650's water pump cover sticks out a half inch more to the rear than the 500's. (Different impeller, different cover).



Charles.
 

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Charles make some new manifolds and use two into one cables for the carburetors? That would also free up carbureto choice geared towards increased performance. Jim mentioned VM round slides they are cheap and easy to works with. Most are spigot mounted. I have an XS650 that we made some really nice alu. carb mounts for the engne.

Cheers, 50gary
 

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Discussion Starter · #5 ·
Yeah, I've been thinking of buying the round slide carbs on eBay, which are usually listed for an XS650. I'd need to take measurements and see if I can source manifolds though. But for the time being, I'm going to use 500 carbs.



Charles.
 

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So, with a 650 motor in the 78 Standard frame, the 500 carbs can not be put in between the motor and the frame without removing all the engine bolts and tipping the motor forward slightly. I know I didn't have this issue on the 82 Custom... anyone else experience the same?



Charles.


Do you mean that to install the carbs you have to tip the motor slightly forward but once the carbs are installed you are able to bolt it back in place? So it would only be a problem when installing or removing the carbs.

If you removed the caps and sliders would it make a difference?
 

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Yeah, I've been thinking of buying the round slide carbs on eBay, which are usually listed for an XS650. I'd need to take measurements and see if I can source manifolds though. But for the time being, I'm going to use 500 carbs.



Charles.
For my XS650 Yamaha I bought new from "Sporting for Less" and had to change all of the jets. They said the carburetors would be jetted for the 650, lied to me and others not even close. Anyway I bought VM34 round slides and they work very well after jetting. I ported my heads, stock cam, and two into one selfmade headers.

Cheers, 50gary
 

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For my XS650 Yamaha I bought new from "Sporting for Less" and had to change all of the jets. They said the carburetors would be jetted for the 650, lied to me and others not even close. Anyway I bought VM34 round slides and they work very well after jetting. I ported my heads, stock cam, and two into one selfmade headers.

Cheers, 50gary


So you're sporting dual 34mm carbs?
 

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Discussion Starter · #9 ·
Do you mean that to install the carbs you have to tip the motor slightly forward but once the carbs are installed you are able to bolt it back in place? So it would only be a problem when installing or removing the carbs.

If you removed the caps and sliders would it make a difference?


Yes, that's it exactly. It would make a difference I removed the caps or the float bowls, yeah. Then i could get it in.



Charles.
 

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So how much modification was needed when porting the 650 to the '82 frame? It sounds like you had to keep a lot of the stock '82 items and just move the block.
 

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Hi,



my 81`CX500 also have (had) a 650 engine.

Also had problems with the carbs and found the following solution:

After extending the carb battery about 15mm it fits much better to the stiff engine manifolds, please have a look to the attachments. The bike has the stock airbox yet, the airbox boots are much more flexible (compared to the manifolds) and fit really good to the extended carb battery. No more problems while installing the carbs. The engine is converted to CDI-ignition. The clearance between water pump cover and the frame is big enough to install the carb battery.

I used 650`s Euro brackets with distance plates for front engine mounting.



Mayby someone is interested in....



Matze from Germany

...excuse my English
...
 

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Discussion Starter · #13 ·
Hi,



my 81`CX500 also have (had) a 650 engine.

Also had problems with the carbs and found the following solution:

After extending the carb battery about 15mm it fits much better to the stiff engine manifolds, please have a look to the attachments. The bike has the stock airbox yet, the airbox boots are much more flexible (compared to the manifolds) and fit really good to the extended carb battery. No more problems while installing the carbs. The engine is converted to CDI-ignition. The clearance between water pump cover and the frame is big enough to install the carb battery.

I used 650`s Euro brackets with distance plates for front engine mounting.



Mayby someone is interested in....



Matze from Germany

...excuse my English
...


That's a very interesting way of mounting the motor. You used GL650 hangers with a CX500 frame. (CX650 hangers don't even come close without extensive modification, I already tried that route). Do you have problems fitting the tank with that setup? When I tried using modifed 650 hangers they were just too wide for the tank to fit on the rubber grommets. So, I did what I did for the chopper - I just cut and welded the 500 hanger. No machining required.





Charles.
 

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Matze,



I can't tell in your avatar, have you done a spoke conversion on your rear wheel? If so, what method did you use?



Thanks,



R
 

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Charles:

yes, after mounting the steel brackets the tank needs to be widened a little bit around the front hangers area. Not a big operation, other problems I didn`t have with these front hanger solution.

Which water cooler did you use?



And in the end: in Germany we have tough regulations for modifications, nearly everything you do has to be inspected and approved by inspection engineers. Frame modifications like raking front ends are very near to a sacrilege and will be a good chance to lose the bike approval. It`s easier to screw on a new part than to modify a stock part by welding - that `s the reason I chose that way.

It was a hard thing and took a long time to get my bike legal on the road in this condition.



Randall:

For both wheels I used the so called "german method" with screwed rings and stock hubs. Those kits were distributed here in germany by AME (needless to say that they`re approved...
).

For some better pics please have a look here (in the lower section) :

Members Bikes 2

or here:

swing arm modification for wider rear tire



Matze
 

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Those kits were distributed here in germany by AME
Thanks, Matze.



Do you know if they're still available? I've considered having the rings machined, and shortening and rethreading the spokes, but a ready-made kit would be better.



R
 

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Randall,

these kits are still available, but ~350 (!) €/wheel - inacceptable...


10 years ago I payed the half price for the same parts.

I`m sure your self-made-kit is much better now ...
 
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