CB360 - Monoshock Brat

[Autotek]

I completely understand. If the dies are not snug they will crimp, which limits you to one diameter bend per pipe size. It is often so tight in the die after a bend that it can take a bit of pressure to release. For a one time thing, you made the right call.

 

[compoundcycles]

One thing I noticed before removing the stock handlebars during the tear down was how mushy the steering felt. I want to blame the old rubber isolators in the triple trees. I pulled them out and they look in decent shape. Does anyone have a lead on replacement isolators? Or suggestions for tightening up the play in the handlebars?

Thanks in advance.

 

[compoundcycles]

Update: Just found replacement over at Bikebandit.com

I'm hoping fresh ones will stiffen things up.

 

[Tim]

Many of those rubber bits can still be bought directly from Honda at reasonable prices. Check with your local dealer on things to avoid shipping etc.

 

[crazypj]

Stick a 10mm flat washer on the mount, then rubber then fit as normal
OD may need to be ground down so it fits 'inside' the diameter of rubber, I use SS washers

 

[compoundcycles]

Tim, yes the dealer! Thanks for reminding me about free shipping when ordering through them.

crazypj, just so I understand correctly, you're talking about a washer sandwich. Going down through the hole where the handlebars mount it would be washer, rubber mount, upside down rubber mount, washer?

Thanks for the suggestions, a combination of new rubber and some stainless washers sounds good to me.

 

[compoundcycles]

Started in on mounting the shock tonight. I used some 1/8in plate to reenforce where the shock mounts are to go. Just tacking everything up for now. I still need to see if the chain will clear the swingarm with the bottom end in the frame.

The swingarm brace isn't mounted, just barely hanging on by a string. I'm happy to see it come together a bit more. I wish I had a little more space between the brace and the tire but it's still a good amount to work with. I'll have to get creative with a rear fender a bit later.

 

[compoundcycles]

Thanks for all the suggestions and thanks for looking. More work to do.

 

[stroker crazy]

Remember the DTT engineering rule: If you're going to use string it needs to be reinforced with either cable ties or duct tape!

Crazy

 

[compoundcycles]

I'll make sure to add some JB Weld next time too Crazy

I learned the word "Photochop" today. I've been doing them for years, in fact, its my day job. Here's a quick one of shortening the seat further and losing the rear supports. I'll probably relocate some renforcement closer to the seat.

 

[neevo]

What's the length of that shock eye to eye? I am surprised its mounting so far back with the brace against the tyre.

You've got me worried about my build now. Hopefully you've got the 320mm version instead of the 290mm, if so you might have some more room to play with if you look at the shorter RD version.

Would also be keen to see how much sag the rear has when the shock compresses under the weight of the bike.

 

[compoundcycles]

From center of eye to eye I'm at 315mm (depending on where you are supposed to measure from its probably the 320mm version). The shock was said to have come off a 1982 Yamaha RD350LC.

The shock itself isn't labeled with much information.

I wouldn't worry about your bike, looks like you've done your due dilligence. I went back and looked at where your top shock mount is. You're mounting yours slightly more forward on the frame that I intend. That combined with my shock being longer puts it further against the tire.

I'm mounting my shock back further on the bike to make sure I clear the stock carbs. I have a stock CL360 that I was looking at for reference and if I mount the shock any further forward I run the risk of the stock carbs not fitting. Although with some Mikuni's on there I should have plenty of room. To me it seems difficult to plan this without reassembling the motor (which I'm not ready to do yet). So I'm mounting it back slightly just to be safe.

Even with the swingarm brace that close to the tire it still has more clearance than the tire does in the stock swingarm. So I'm hope I'm good...am I missing something?

Also, I'm mounting the shock up on its lowest compression setting that way if it sags too much I can add some preload. The tight look of the brace around the tire is kinda growing on me.

Thanks for the questions, It's really good to think about this stuff from every angle.

 

[crazypj]

crazypj, just so I understand correctly, you're talking about a washer sandwich. Going down through the hole where the handlebars mount it would be washer, rubber mount, upside down rubber mount, washer?

Thanks for the suggestions, a combination of new rubber and some stainless washers sounds good to me.

Yep, you may only need 1 washer at 'top' though, it's surprising how much it tightens things up

 

[Pattheswede]

Really nice work!
What gauge/dimension has the pipe you used?
// Z

 

[compoundcycles]

Thanks Pattheswede. Really cool work you're doing in your cowl as well.

The swingarm brace is 1" tubing @ 0.095 thick.

 

[crazypj]

360 is a pretty small bike, are you going to have enough room with seat that far forward?

 

[compoundcycles]

I'm still debating that. Gonna think about it a bit more.

On one hand I want a comfortable ride. On the other hand, I think it would look awesome if you could barely see what I was sitting on, like I'm floating above the back tire.

I really need to get the shock mounted, slap some bars on, and have a seat and see how it feels before committing.

 

[compoundcycles]

Well, I've run into a bit of a snag in my build.

Where I need to mount the top of the shock, the shock won't clear the carbs. I can't raise the mount point because the bolt to mount the shot won't have clearance to come in and out. Mounting it any further back results in a less than ideal position against the back tire.

So I'm stuck. I'm guessing some aftermarket Mikuni carbs would have more clearance than the stock ones...but how much I don't know. Replacing the stock carbs is an idea I'm willing to entertain. I just need to know if they'll give me the clearance I need. Anyone have a picture of the two side by side?

Seems like I can't move forward on this project, everything issue I run into is always dependent on something else. Frustrating.

 

[neevo]

Don't forget the 290mm version of that shock.

Not sure how different our frames are but I should have clearance for the shock against the rear tyre and still space for stacks:

That bit of 40x40mm stock is drilled at 290mm and the wheel is adjusted as far forwardas possible. You also get a bit of that length back (maybe 10mm) when the bike is dropped and the shock compresses under the static weight of the bike.

 

[compoundcycles]

Thanks for the photos neevo. It does look like you have more clearance between the carbs and the area where I/we mounted the shock. The 290mm shock is an option, but an expensive one for me as I can't only find new ones, no used ones on ebay.

I tried a few different configurations tonight and came up with a new plan because there has to be a way to make this work. I'm going to flip my mounting plate upside down and fit it into the middle of the frame rather than on top or bottom. This seems to give the shock plenty of clearance from the carbs, and gives the rear tire more room. The new problem is...the gas tank won't sit flush with the top of the shock rising slightly above the frame. I think I can fix that by altering the tank.

In the last picture imagine the plate sitting further forward and low enough in the frame for the shock mount bolt to be removed. I'll tack it up tomorrow and see.