CJ360T/XR600R, Possibly Monoshock "RoadRunner"

RoadRunner said:
So real life got in the way of this project for a little while but I am back and making some headway.

A buddy of a buddy of mine is going to help me do the frame work, motor mounts, and the monoshock conversion.

So right now I need to figure out what shock to use.

I know that the Wilkinson Bros used a Ducati Monster shock for their CL360 conversion, and CompoundCycles used a RD350LC for Doris.

Is there a rhyme or reason to choosing a monoshock? Or do y'all have any suggestions for which one to use?

Thank you
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I understand how life gets in the way for sure. It's happened to me far too many times during the 360 build I've had going for far too long.

Anyway, the asymmetrical aspect to the 360 frame is to facilitate getting the engine in and out. I don't see any reason why you couldn't make a crossbar that's done at an angle and have different height tabs. I'm afraid I can't really address your questions about what shock to use. There are many more on here w/ far more experience and knowledge who'd be able to give you accurate info.

As for grinding off the various tabs and extemporaneous stuff. I really doubt that, as long as you are careful, you are really going to have to go completely nuts w/ the grinder to actually compromise the frame. Speaking from experience I can tell you that what you have to be careful about is the smoothness that you end up w/ when you do your grinding. Much of the grinding I did on mine left me w/ a large amount of filing and smoothing to attempt to get things looking like my bike's frame wasn't built out of a bunch of corn cobs!
 
ridesolo said:
extemporaneous
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That one word is worth more money than a couple of my bikes...

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trek97 said:
That one word is worth more money than a couple of my bikes...

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I feel like Rodney Dangerfield. (I did use the wrong word, though.) You made a fortuitous ascertainment of my improper praxis.
 
Re: CJ360T/XR600R, Possibly Monoshock "RoadRunner"

My buddy of a buddy finally finished work on the monoshock conversion!

Chopped the seat real short and removed all of the extra stuff on the frame I didn't want.

I need to do a fair amount of work on the motor, and once that is done, I'll be focusing on motor mounts, an intake manifold for two new carbs, stainless high exhaust, and tabs for some rearsets.
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It’s looking good, I’m locked in now. Are there gussets welded in where the cross members meet the swing arm?


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cb250nproject said:
It’s looking good, I’m locked in now. Are there gussets welded in where the cross members meet the swing arm?


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Sorry CB, didn't see this until now. I'm not sure what you mean? We didn't reinforce that area, it just stock CJ360T frame there.

Also, as per usual, real life got in the way, and I've barely touched the bike. I've since gotten a house, and between that, moving in, and other responsibilities, I've been too busy to wrench on her.

However, the motor is safely seated in, with all new motor mounts, and it looks great in the frame. Once its nice enough to wheel her outside and take pictures for y'all I will.

However, I have some questions for now. I did a GSXR swap on my Suzuki SV650S and I wasn't planning on doing one here but I found a pair of forks, triple, and calipers locally for $100 so I picked it up. I know I could get a stem to press into the GSXR triple and a new set of bearings to make it all work, but Cognito Moto offers a "Fixed Offset Retro Triple Tree" that looks absolutely awesome and while expensive, I am considering it.

My question is, what exactly is "offset" and how does it affect handling? Am I better of just getting the new stem and using the GSXR triple or would it be beneficial to change the offset using Cognito Moto's triple?

Also, along the same lines, now that I'm converting the front end to juice brakes, how hard would it be to convert the rear wheel to juice as well?

I asked my buddy the fabricator about it, but he said something along the lines of needing a bracket that will track off the axle so the calipers move with the axle for chain adjustment. He recommended that I try and take a setup off of a bike from the era already set up for that.

Any suggestions? I still want to maintain spoked wheels both front and rear. I know Cognito Moto offers lacing ready huns for the GSXR, and I've read that Harley Narrow Glide wheels work as well. However, the rear end seems to be the toughy. Any bikes that use spokes and juice brakes y'all think I could use?

As always, sorry for the wall of questions, and any and all help is greatly appreciated.

Thanks!

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Others can jump in here and probably will, but essentially if you want to put a disc brake on the rear of your project for esthetic purposes that's one thing, but from a pure practicality standpoint it wouldn't be necessary nor worth the time and expense. The vast majority of your braking power is from your front wheel because of the physics of inertia and weight transfer. Way back when I first bought and started riding my old CL360 as a commuter I was concerned by it's lack of disc brakes because for many years and many miles I had been riding much higher performance bikes with much higher perforamce brakes. As I got use to the 360 and got more spirited with my riding I was surprised and pleased to find the standard brakes were more than adequate. Bottom line, in my opinion you'll really enjoy the juice brakes on the front and won't notice much practical difference with having them on the rear.
 
ridesolo said:
Others can jump in here and probably will, but essentially if you want to put a disc brake on the rear of your project for esthetic purposes that's one thing, but from a pure practicality standpoint it wouldn't be necessary nor worth the time and expense. The vast majority of your braking power is from your front wheel because of the physics of inertia and weight transfer. Way back when I first bought and started riding my old CL360 as a commuter I was concerned by it's lack of disc brakes because for many years and many miles I had been riding much higher performance bikes with much higher perforamce brakes. As I got use to the 360 and got more spirited with my riding I was surprised and pleased to find the standard brakes were more than adequate. Bottom line, in my opinion you'll really enjoy the juice brakes on the front and won't notice much practical difference with having them on the rear.
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Thank you, and welcome back to this project ridesolo!

That is pretty much what I figured, but at the same time I am a huge huge fan of symmetry and I am honestly leaning towards disc in the rear for that reason, as well as just ease of use.

You really helped me out earlier in this project so I appreciate your input!

If I were to go disc do you have any suggestions? Or anything about offset in the front?

Just trying to pick your brain a little!

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RoadRunner said:
Thank you, and welcome back to this project ridesolo!

That is pretty much what I figured, but at the same time I am a huge huge fan of symmetry and I am honestly leaning towards disc in the rear for that reason, as well as just ease of use.

You really helped me out earlier in this project so I appreciate your input!

If I were to go disc do you have any suggestions? Or anything about offset in the front?

Just trying to pick your brain a little!

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One issue that you may run into on a disc rear conversion mated to an xl600 motor would be that you would want to find a cush drive disc hub. There are plenty of options for a dirbike style disc rear wheel, but not necessarily with a cush drive. People who put street tires on the xl/xr 600's have commented on excessive countershaft wear due to the lack of cush drive. If the knobbies are retained, they tend to flex and add a bit of "cush" to the driveline, but sticky tires do away with that.

A setup i would look out for is a dr350se rear wheel. Careful, not all dr350 wheels are cush, but certain years street models are. @irk miller could likely give you more details on those. Also, any 96 and up dr650 uses the same hub as the cush drive dr350, only with a bigger rotor and a 17" rim instead of the 18" of the dr350.

Another option is the honda xr250l cush drive rear rim, but those seem to command even a bit more money than the dr350, as they are a fairly easy swap into a xr650l and other honda dual sports.
 
Offset is a word that is used in two different ways. The first relates to the wheels or specifically the amount that a hub is offset to one side or another. Older British bikes often had a hub offset to one side to align chain and rims and so on.

The other way the word is used relates to front forks and it's a measure of how far the fork legs are in front of the steering stem. Forks with shallow rake angle (eg 27-28 degrees) need a lot of offset in order to have the correct trail. Steeper fork angles on modern bikes need less offset to maintain appropriate trail. Fitting modern forks designed for a bike with a steep steering head angle will emd up with more trail than either the stock forks or the bike that the forks came from. More trail gives more stability and slightly harder steering.

Shorter forks or raising the rear, tilts the bike reducing fork angle (rake) and trail.

http://pinkpossum.com/GT750/phattrakka/part4a.htm gives you a better idea of how some things change but teh trail wasn't measured in that example.
 
My 360 now has front and rear disc brakes but that's because I'm using the forks, swing arm, wheels, brake discs, and calipers from a Kawi EX500 Ninja on my build. I understand what you are saying about symmetry, but there were (and maybe still are?) lots and lots of good and successful bikes from the factory w/ front disc brakes and a rear drum. Bottom line; build it your way for your tastes and make yourself happy. @teazer & @Hurco550 both have great input above. ^^ Smart and experienced dudes, both!
 
@teazer Thank you for the information! So I'm guessing I should measure the new forks and compare it to the old forks to see what I should do?

@Hurco550 Thank you! Thats one of those things that I would never have even thought about until you mentioned it. I should now see how those wheels measure up to my current one and see how the sprockets line up...or if they do at all.

@ridesolo To be honest after reading Hurco's comment I started to think about lining up the sprockets with this new rear wheel and now I'm not so sure about this whole venture. Thank you!

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Option C: all of the above !!

You need to align the wheels as well as the chain line. For chassis measurement, it's often easier to just fit the parts and measure what you have to work with. That's the experiential approach. If you prefer aq more theoretical approach, measure stock and new parts and draw the whole thing up - to scale - and see where that leads you.
 
RoadRunner said:
@Hurco550 Thank you! Thats one of those things that I would never have even thought about until you mentioned it. I should now see how those wheels measure up to my current one and see how the sprockets line up...or if they do at all.
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I have a complete dr350 cush rear wheel in my possession (sorry, not for sale) but i would be happy to measure for you if you need. I know it is VERY close to fitting in my stock swingarm xr400, with a bearing swap and a few spacers made up. Now, how that translates to an xr600 motor in a cb360 frame, i dont know, but i dont think it would be out of the realm of reason that it could fairly easily be made to work if you have someone local with a lathe and basic metal maker bits.

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Hurco550 said:
I have a complete dr350 cush rear wheel in my possession (sorry, not for sale) but i would be happy to measure for you if you need. I know it is VERY close to fitting in my stock swingarm xr400, with a bearing swap and a few spacers made up. Now, how that translates to an xr600 motor in a cb360 frame, i dont know, but i dont think it would be out of the realm of reason that it could fairly easily be made to work if you have someone local with a lathe and basic metal maker bits.

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Honestly, that would be awesome.

If you're willing and able I think overall width, axle diameter and length, as well as distance from center to the sprocket would be just about all I need.

Thank you!

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brad black said:
of course. depends how well you want to do it.

the predominant issue is that with the shock at the pivot end of the swingarm, any force resisting the rear wheel travel is much greater at the mount points than with the shocks at the wheel end of the swingarm. so you need a much stronger swingarm to handle the much larger bending load it will see, plus the now unrestrained twisting effect.

the frame also needs to be stronger at the swingarm pivot, which is where the twisting force is now handled. the frame also needs to be stronger and possibly modified in shape at the top shock mount, and even up to the steering head.

if you are using a linkage system, you either need to design your own with characteristics as you desire, or if you remove one from a bike you need to replicate the various pick up points to keep the system working like it was designed.

if you have an xr600r, look at the rear of that and how the frame goes to the front. you could use the xr600r bits and have someone restrict the shock travel.

the main issue with any of this is that someone will declare their intention to make this happen, then buy parts from various bikes on the assumption that if it worked on x,y or z it'll work just fine on their cobbled up piece of shit, and go ahead. for instance, someone here had a linkage setup which someone else modelled and showed them how, if it compressed toward the maximum allowed, it would go over centre and collapse. that sort of stuff. it's not that hard, it's just geometry really.
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Just curious but wouldn't the force required to bend the swingarm vertically be greater than the force required to compress the shocks/springs and wouldn't this mean that the shock placement would not affect the swingarm vertical to make it flex? Also, when you refer to twisting at the swingarm pivot do you mean twisting and not rotating, right? To me, it just seems that the shocks/springs will always compress before the frame vertically flexes?
 
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