CB360 - Penelope

[The Red Wonder]

Well after another long adventure break, I am back at it!


I made some shock mounts and finally got them welded in.


She stands on her own once again! The rear spring was pretty stiff and I was barely able to make it move.

The spring was set to its highest pre-load setting, so I needed to make a spring compressor.
The ID of the old sprocket is about .030" larger than the OD of the spring retainer! It was meant to be! I welded nuts on to the bottom of the all thread and used the air ratchet to compress everything....which means I didn't have to do any work to compress it ;D . I put the spring in its lowest pre-load setting, opened the rebound and compression all the way and was able to get some decent motion out of the shock, it still needs some work though. I think with the weight of the motor in there, it should be pretty good

I also painted the engine silver, put the pistons in, and bolted the head on. I will have some better pictures soon, and more detailed of the shock mounts. Thanks for looking!

 

[JRK5892]

what size are those rims? you plan on lowering that at all? looks kind of high... love the spokes

 

[The Red Wonder]

Thanks, I like em too!

Yea, it is kind of high, but its not too bad...the front is a 19 and the rear an 18. The rear has a slightly larger tire 120-90 vs. 100-90 in front, but the OD of both tires are the same. I have thought about lowering the front a little but the GSXR fork legs are tapered all sorts and it would require some shims or spacers, which wouldn't be too difficult, but I will worry about later if it comes to it

I guess I look at this way, higher up = better peg clearance when leaning in to corners

Once I get the exhaust underneath the frame, it will take away some of the dead space under there. The top of the seat frame rails is right about 30.5" which is about 2" higher than stock...oh well, I am happy with it and it fits me pretty well.

 

[JRK5892]

lower the internals of the forks now drop them though the trees, will look so much better and a lower stance will help the over all look of the bike.

 

[JRK5892]

plus the weight of the motor is not in there yet either

 

[The Red Wonder]

Right, that will sink it a little, but not too much.

And do that by shortening (chopping) the internal springs?

I have also thought about lacing up a different front rim (18") to better match the rear, and with a smaller OD tire, that would drop the front a little too. I would love to give it an aggressive stance, but I want to just finish it right now and come back to little details like that can wait later. Thanks for the ideas Joe!

 

[JRK5892]

you can not just chop springs on inverted forks bud you would have to go with a lowering kit like Ohlins for example... that is prob what i am going ot use on the CB750 we are building we have CBR1000 froks on it, they have that same taper... but not sure if we are going to lower it yet or jsut tear it apart and coat the tubes

 

[The Red Wonder]

I didn't think you could do that, thats why I asked...haha! I will worry about it later, but I think I would build the front rim with an 18 incher before doing that, thanks for the info!

 

[crazypj]

I would like to get at least $30 (shipping included) for each of them, in your choice of brass or aluminum.

Damn, I'm way too cheap, been selling tach plugs $10.00 plus $2.50 shipping

How did you remove the anodizing on front rim?.
came out real good.
Patching tubes isn't a problem as far as I'm concerned, but, your results may vary ;D
What wws the rear shock off?
If it was designed for a link system the spring will probably be way too hard and need changing.
Most link systems use a 3 or 4:1 ratio, last Yamaha cantilever I measured was 1.7:1 ratio, you probably don't have enough leverage
BTW, cutting springs increases the rate (makes them stiffer, you have less working coils)

 

[The Red Wonder]

Ha! I was waiting for you to chime in on that...I would justify it as "with age you gain speed and confidence with machining". I am pretty slow, but can usually hold a thou in doing so....probably doesn't need to be that tight, but I'm OCD when it comes to that.

The front rim is stock Harley. I didn't do anything to it. The rear however was a PITA! Paint stripper, then lots of sanding to get it shiny.

The rear shock is from an R1. It is a link system and you are right, that it was close to a 3:1 ratio and I am able to get close to a 2:1, so it is still a little too stiff. Also, not to mention that the shock from Yamaha was suggested for a 250# rider...100# more than me!

I was looking at the shock from a Kawasaki EX650, it is nearly identical to my setup, but it is a super lame gas emulsion shock, and finding one that isn't worn out is going to be difficult (Kawasaki recommends changing them every 5 years!). It might be an easy way to get a cheap lighter replacement spring if the ID is similar. The damper would be a little over damped still, so I am again stuck looking for a nice cheap used "performance" cantilever setup style shock damper.

PJ...do you know of any shock that fits the bill? Also, if you haven't seen or used this site yet, it is suuuuper handy! They have just about every spring rate for stock springs:

http://old.racetech.com/evalving/menu/searchstreet.asp

 

[analogue vanity]

dang,
this build is next level. makes me very self conscious.
Great Work!

 

[crazypj]

I like Racetech stuff but find it a bit expensive for me (I used to work with one of the guys there, he quit to work for them)
Have you looked at aftermarket coil springs for automotive use?
They sell them by length, diameter and spring rate, usually in increments of 5~10 lbs.
Damping isn't really too much of an issue, you can always re-build shock and fit lighter oil if minimum damping rate is still too much for spring.
Silkolene has highest viscosity index of easily available oil, 2.5wt Pro Suspension Fluid is around 400 V.I. (it doesn't thin down much when it gets hot)
I can't re-gas them but strip/re-build isn't a problem

 

[The Red Wonder]

dang,
this build is next level. makes me very self conscious.
Great Work!

Thanks man! Your bike is beautiful though! I am jealous that you are riding right now...

 

[crazypj]

I just realised what looks so odd.
The swing arm is too much of an angle and looks too short
Would it be possible to extend it a couple of inches?
I had same problem with a CB400f I built several years ago, had to relocate shock mount on frame and make 'higher' mount on swing arm to change leverage ratio.
It worked fantastically well when finished though, the modified fitting angles gave a rising rate without linkage or multi rate spring

 

[JRK5892]

PJ i think you are spot on... i think that is what is making it look so smooshed, even if he did stretch blocks like the sport bikes do i think that 2 - 3 inches would make a huge diff... but again till that motor gets in we will not really know the stance of the bike

 

[JRK5892]

what about jsut cutting a coil out of the rear shock?

 

[crazypj]

Cutting spring that's already too stiff will only make it worse. (see earlier post)
Needs relocating and swing arm stretch. That will change leverage ratio and allow spring to work properly
The motor isn't very heavy and isn't going to make much difference.
Personally I think it will look even more 'squashed' with motor in

 

[The Red Wonder]

Pictures:


Annealing the copper head gasket:

Annnnd QUENCH!

Upper shock mount started life as a piece of angle iron. A few cuts, bends, and re-weld got it here:

I was waiting until testing the motion to see how the shock moved before adding some more bracing up here...turns out the shock stays absolutely stationary through out all of its travel! Thats what I call an effective line of motion!

Here is a crude photochop with a MotoFiaccone crack pipe that will be similar to what I end up making in conjunction with Chris. The angle of the two shots weren't perfect, but it gives you an idea.

Here is a graph of wheel travel vs. shock travel, resulting in a ratio that is SUUUUPER linear, and about 1.9:

I was also able to remove even more preload from the spring and with the engine in, it seemed just a hair too stiff. I might order a spring from Eibach, they sell them pretty cheap and in just about any size you could need, including mine


I have also been pressure testing the tank and there are a ton of tiny little pin holes. I was hoping to seal them with out the use of a tank sealer, but the welding, grind, re-weld, grind...is getting kind of annoying, so I think I may just do that....would anyone recommend POR-15?


Thanks for looking, Hope you guys like it!

 

[cleoncleon]

Haha, man this Scoot looks good.

 

[scarlson06]

Your build is definitely a favorite of mine, makes me want to go back to school for engineering, or have access to the kind of resources you do...well, both.

To me the proximity of the filters to the shock is a bit cluttered. Maybe use a fitting to point the pods down at the same angle as the shock? I'm not sure that that would help considering how close the pods are to the frame on either side / the size of the pods.