Author Topic: cb750/ vf500 cafe hybrid mono shock w/ oiled swingarm w/ pics (Read 12341 times)

cafebob · « **on:** November 09, 2007, 10:45:56 AM »

this is one of my current projects....

1978 cb750f/vf500 hybrid...

includes vf500 front end, breaks, rims, rear swing arm sealed and used as oil tank, mono shock conversion, vintage Rickman tank/tail, custom rear sets (which i may toss..and go with a Yamaha r6 set).

Motor will be 78f base, 1973 jugs, rebuilt F head with racing springs, airas 836 kit, mega cycle 125-65 cam, final CR adjusted to about 9:1. Dyna 2000 ignition w/ spark retard. Was going to use a set of 29mm mikuni smooth bores, mac 4-1, and a 20 shot of nitrous, but now am leaning to building a turbo kit for it.

The oiled swing arm is about a 3.5 inch stretch over stock, and holds just over 2 quarts of oil. It took some real machining to get it mounted. I was a little worried about oil temp, but the swing arm has significantly more surface area than the stock tank, and much more air flow. But now that im probably going to turbo it, i will be adding a oil and water cooler anyway...

anyway take a look let me know what you all think...i'm building the bike for me...not a client so time is not a really factor...

oh can anyone help me get my pics to not cut off the right 1/4?

and

and

and

link to full album

http://s239.photobucket.com/albums/ff137/cafebob/cb750%20vf500%20hybrid/

bob

scondon · « **Reply #1 on:** November 09, 2007, 11:22:46 AM »

Now that's just silly, Bob

(def. "silly"- bad ass to the extreme, over engineered rocket ship from the past, wish I could put something like that together

)

+1 on using modern rearsets. Terry helped me get a set of gsxr 'sets on my '78 and fitted some adjustable pegs to'em for fine tuning the position. Cheap new replacement parts available if needed.

Are you going to run a total loss system or fit a small battery under the seat?

Does the bike sit much lower with the vf500 suspension added? I remember seeing one of the cbr600 conversions which looked pretty awesome but dragged parts in the corners cause it lowered everything so much.

Definitely like the newer brakes. Better composition pads available for the newer calipers. Certainly oughta help that monster haul down from the speeds it should attain. Hope to see more of your progress in the months to come. Nice work

cafebob · « **Reply #2 on:** November 09, 2007, 11:34:03 AM »

actually all the electronics and battery fit in tail....i just got some r6 rear sets for 40$ off of ebay...im building a cb350/vf500 cross for my girlfriend and was going to use them on that bike, but I think i will use them on this project. I have actually test fit a motor in to her and she rides really nice...the shock has adjustable pre-load too, so we can boost her up a little if need be.

I have all the parts for the motor, just need to rebuild the head and button it up...i hope to have the motor in by thanksgiving...

In talks right now to get a IHI RHF4 turbo for it....well see maybe ill have it all mocked up my thanksgiving.

bob

dusterdude · « **Reply #3 on:** November 09, 2007, 11:43:54 AM »

i like it

ColinMc · « **Reply #4 on:** November 09, 2007, 11:44:46 AM »

Cool idea, I know why it isn't running yet though...that rear tire needs to be replaced

scondon · « **Reply #5 on:** November 09, 2007, 11:47:42 AM »

Quote from: cafebob on November 09, 2007, 11:34:03 AM

actually all the electronics and battery fit in tail....

That's what I meant. Can never seem to get my terms right (seat?tail?)

Two weeks to get it mocked up? Wish I had that kinda time to invest in my hobby. Sounds like you get to do this stuff for a living/stipend, lucky bastard

Did I see ya post that you were in Denver? When I get the 900 project rolling next year we could meet in the Arizona desert for a fuel burning fiesta. I should be able to keep ya in sight for a mile or two

legendary · « **Reply #6 on:** November 09, 2007, 12:09:48 PM »

Cafebob,
You have probably a 1 yr head start.... but I am heading in a similar (but milder) direction.
I love what you are doing with that! Keep posting updates!!

Steve

cafebob · « **Reply #7 on:** November 09, 2007, 12:15:36 PM »

thanks guys...actually I'm in medical school right now (2nd year) but most of the work on this bike was done over the summer while i was off, and in between working on paying projects...my time now is very limited...im lucky if i get 8 hours a week to put into it.

il have the motor in her by thanksgiving...if i have the turbo in hand it may be mocked up, but i am going to have to make my own exhaust header and intake plenum. those will NOT be done by thanksgiving

bob

flipprboi · « **Reply #8 on:** November 09, 2007, 08:02:34 PM »

WOW BOB! Very impressed. great idea! Now this is more like it. Very original! I just hope you dont get your project mixed up with med school, and start coming up with ideas of using CBRR inverted forks to humans as legs or the other way around.

But seriously nice work mahn. Keep us posted. Would love to see how everything turns out. Good Luck!

754 · « **Reply #9 on:** November 09, 2007, 08:18:20 PM »

How is the oil going to get in the motor??

jtb · « **Reply #10 on:** November 10, 2007, 05:26:42 AM »

Man, what a cool project! Looking forward to watching your progress, Bob.

754 · « **Reply #11 on:** November 10, 2007, 07:29:07 AM »

I must be missing something,

First it will only have 2/3 of the original oil capacity.

Then where will the pickup be, in the middle??
If its at the front, it may not get oil under acceleration.
If at the rear, what happens when the swingarm arcs up over centerline??..and where are you going to return it so that it has even a few seconds to cool before getting right back into the pickup hose ?? The vent line is the absolute least of the problem..

jreich · « **Reply #12 on:** November 10, 2007, 07:33:45 AM »

Would be interesting to put the oil tank in the tail, and run some braided lines down.

ekim98 · « **Reply #13 on:** November 10, 2007, 09:05:39 AM »

Quote from: jreich on November 10, 2007, 07:33:45 AM

Would be interesting to put the oil tank in the tail, and run some braided lines down.

Yes, but with the electrics up there and then the oil your putting a lot of weight up high on an already top heavy bike?

cafebob · « **Reply #14 on:** November 10, 2007, 03:10:40 PM »

......First it will only have 2/3 of the original oil capacity.....well that's just not true.

Actually the stock oil tank, when filled properly to the high mark on the dipstick holds about 44oz...1.375 quarts. I have cut open tanks, measured them, and fill tested them to confirm this. So 2 quarts is actually a larger tank than stock. People throw the 3.5 number around, but it is my belief this is for the entire bike. Try it for yourself if you don't believe me, drain the oil from your tank only and see how much comes out.

To answer some of the other questions...the pickup is on the bottom of the swing arm on the right side. Returns are at the end of each arm of the swing arm on the top. There will be a vent on the top right. The swing arm actually will probably have a longer mixing time than the stock tank, because of this current flow. This, plus the very large surface area, and air flow will probably keep the bike cooler than stock. As for loosing pressure while accelerating. If the tank (arm) is keep full, the pick up should always be submerged, because returning oil is filling the arm ends. But i will run a pressure gauge to make sure...

bob

scondon · « **Reply #15 on:** November 10, 2007, 03:30:13 PM »

Quote from: cafebob on November 10, 2007, 03:10:40 PM

Actually the stock oil tank, when filled properly to the high mark on the dipstick holds about 44oz...1.375 quarts.

Certainly true with my F2. I learned early on not to add a full quart no matter how low the level looked on the stick. Too easy to overfill

KB02 · « **Reply #16 on:** November 12, 2007, 05:40:36 AM »

Quote from: cafebob on November 10, 2007, 03:10:40 PM

To answer some of the other questions...the pickup is on the bottom of the swing arm on the right side. Returns are at the end of each arm of the swing arm on the top. There will be a vent on the top right. The swing arm actually will probably have a longer mixing time than the stock tank, because of this current flow. This, plus the very large surface area, and air flow will probably keep the bike cooler than stock. As for loosing pressure while accelerating. If the tank (arm) is keep full, the pick up should always be submerged, because returning oil is filling the arm ends. But i will run a pressure gauge to make sure...

bob

Okay, now I have a question (I was with you until you posted this):
If the pick up is at the bottom of the right side, but the return is positioned at the top of each side, won't you have a bunch of unused oil just hanging out on the left side of the swing arm all the time? Seems to me that the pick up would just pull from the returns leaving the oil on the left to just sit there and not circulate at all.

Everything else I am down with.

Any specifics on what was need to make the mono shock arm fit the bike?

cafebob · « **Reply #17 on:** November 12, 2007, 08:36:50 AM »

so the oil returning from the motor is actually coming out under pressure and at a very good rate. If you want a demonstration take off your oil return line at the base of your motor....good way to make a mess and quickly drain a motor. there may be a little preference for the right side, but it will not stagnate on the left, and the pickup is not way on the right, just to the right of center....ill post more pictures when the motor is in and the lines are plumed. The vent is going to run very high, and i have worried a some about over pressurization....but if it happens, ill deal with it by putting an small expansion tank on the vent line...

Fitting the swing arm....was not easy. I got one of those deals of a century and picked up 2 vf500's for 100$... broke one down to parts and started prepping for the conversion. the 500 swing arm is about 1/4 inch narrower than the 750 at the arm mount point so that was very nice. However the 500 swing arm mount with 2 bolt pivots that ride in bearings on the swing arm, not a single bolt that runs through the arm. This is what allows me to run a sealed swing arm for oil...If it used a center bolt, sealing the arm would have been so difficult to be not practical. I built a standing jig that held the frame and arm in place, cut out the swing arm mounting shafts from the 500's frame, drilled out the 750 frame at the swing arm bolt hole, and welded in the 500's mounting shaft in place. the jig allowed me to make sure everything was square and the arm traveled well before the full welds were in place.

To get the mono shock in place, I pulled the second 500 up right next to the jug, and mocked up the shock mounted to the 750/500 swing arm, such that the 500's original geometry was duplicated. from there it was relatively easy to build mounts on to the 750 frame to hold the shock....the top mount drops about 1' from the top of the 750 frame. the bottom mount comes off the bottom of the 750, from cross beam that sits right behind the lower motor.

I actually made the rear mount so that i can increase the rear ride height if i want...but i really like the look of the bike when the top of the frame is perfectly level....the look wacky when people jack up the rear...

long post but maybe it will clear up some more issues...

754 · « **Reply #18 on:** November 13, 2007, 09:37:17 AM »

Cafebob, sounds like you have put a lot of thought in it. As long as you keep an eye on the guage you will know.. I think the vertical height inside the arm though might be an issue, stock tank seems to funnel it to pickup and regardless of angle and slosh seems to keep oil over the pickup.

Hope everything works but I am thinking you dont do a lot of balance point wheelies, least not with that one!!

3 1/2 over on the arm, that will sure make for a longer wheelbase, will change your steering a bit I would think..
(not as bad as my 6over)

cafebob · « **Reply #19 on:** November 13, 2007, 10:18:14 AM »

the degree of stretch is really adjustable...the vf500 has quite a bit of adjustment built into the swing arm...another reason i went with it. And no, im not doing alot of wheelies

.

bob

cafebob · « **Reply #20 on:** June 21, 2008, 10:02:35 PM »

just wanted to update this project. After a 2 tear downs and rebuilds I now have the motor ready to put into the bike. The short story on the motor is it is a 836 w/ compression ratio of 8:1, which will be getting a blow through turbo set up of my own design on it. There is a along post on the motor build here http://forums.sohc4.net/index.php?topic=28576.0 I will post the complete stats on the motor if people are interested. Right now i have it on my test stand, and the motor starts right up.

An interesting note is that I am using cd650sc carbs on the project. I highly recomend these carbs to anyone looking to replace the pain in the ass 750 carbs, they are a bolt on!. The original thread on the carbs. http://forums.sohc4.net/index.php?topic=28898.0 All i have done to carbs to date is rebuild them. The motor starts right up and idles and revs perfectly so far. Once I get the motor in the bike I report the exact tuning I do to it. I can not say how surprised I am at the performance of these carbs so far.

CB

cafebob · « **Reply #21 on:** March 19, 2009, 04:40:17 PM »

wanted to resurrect this as I am now working on it again and will be posting more pictures.

The motor is in, after two rebuilds. It is designed to be a turbo motor.

836 w/ 8:1 compression
DOHC rods
F2 head
F2 cam
F2 transmission

83 CB650SC CV carbs (a bolt on mod i highly recommend, they idle beautifully, although I still need to rejet the mains)

oiled swingarm (works great as a stand alone, but I might end up adding a small surge tank.)

Dyna2000 w/vf500 coils

Major TO DO:
Install Turbo
Install IC
Exhaust header for turbo
Turbo pipeing
Install Fuel pump and regulator

I am planing to tune the carbs with a 4-1 on it then install the turbo. This is going to be a blow through setup as CV carbs are ideal for this application.

I will post so pics of the bike with the motor in tomorrow.

CB

rachet · « **Reply #22 on:** March 19, 2009, 08:03:09 PM »

Exciting build! Can't wait for pics!

Rachet~

kos · « **Reply #23 on:** March 20, 2009, 01:49:01 PM »

Sure is a ....pretty bike.

KOS

Caferacernoc · « **Reply #24 on:** March 20, 2009, 02:59:23 PM »

Quote from: cafebob on November 09, 2007, 11:34:03 AM

actually all the electronics and battery fit in tail....i just got some r6 rear sets for 40$ off of ebay...im building a cb350/vf500 cross for my girlfriend and was going to use them on that bike, but I think i will use them on this project. I have actually test fit a motor in to her and she rides really nice...the shock has adjustable pre-load too, so we can boost her up a little if need be.

I have all the parts for the motor, just need to rebuild the head and button it up...i hope to have the motor in by thanksgiving...

In talks right now to get a IHI RHF4 turbo for it....well see maybe ill have it all mocked up my thanksgiving.

bob

$40 for rearsets? Man. I look on ebay at least once a week for cbr, r6, anything.... and I never find a full set for anywhere near that cheap.

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Author Topic: cb750/ vf500 cafe hybrid mono shock w/ oiled swingarm w/ pics (Read 12341 times)

legendary