Topic: Rebirth of paulages' cb735

[paulages]

Yes...the larger the wheel the more accurate the timing.

i wish they made a 12" dial indicator though...   it's just as easy to be a degree or two off by misreading the indicator.

dont worry, it just moves the powerband a few thousand revs up or down....

regarding the bearing, these old fairings need a bracket to connect the two top corners to somewhere fixed, otherwise the fairing twits like hell, it,s usually done with a braket that has a littl simple bearing in the midle and connects to the top steering stem nut.

look at any of the new ducati paul smart replicas.

Yeah, I figured out that by "hinged" you were referring to a pivot mount at that point. I hadn't decided whether or not attach it at the top steering nut or off of the main bracket, but you paul smart reference gives me an idea, as a good friend of mine is the service writer at the local duc dealer. Maybe I can borrow a part? Otherwise, I was thinking of welding a mount onto the outside race of a sealed roller bearing, if I could do so without warping the race or burning the seal. Might be tricky...

Oh, and regarding the cam timing and powerband; I'm not as concerned with this (as I have lots of low and mid-range torque) as I am with valve to piston clearance... retarding the cam shrinks those up a bit.

[turboguzzi]

tried to be smart as you suggest and link the bracket to a fixed part but there's not much way around building the hinged bracket.

TG

 

[bikebitzofvt]

Gustafsson will make a screen for your Duc fairing:
http://www.bikescreen.com/
Great folks, a bit pricier than I recall...  Used his screens on ram air GSXR 7/11's back in the late 80's.
Your build is fantastic!   Great attention to detail!
Thanks again for the hook-up on 520 sprockets!
Tom

[paulages]

Gustafsson will make a screen for your Duc fairing:
http://www.bikescreen.com/
Great folks, a bit pricier than I recall...  Used his screens on ram air GSXR 7/11's back in the late 80's.
Your build is fantastic!   Great attention to detail!
Thanks again for the hook-up on 520 sprockets!
Tom

thanks! i'm gonna go get the used screen today or tomorrow, as the bike is almost ready, but i'm getting a little miffed about the wait on the new one. if i hadn't already paid for it, i would have just sourced one elsewhere and had it already. oh well.

might have the seat back today. all it needs is the pipes and it's ready to fire up. oh, and i still need a rear brake cable.

[Kemp]

though unable to access the article on frame design, here is a great tony foale link:

http://www.lortim.demon.co.uk/reviews/Foale/index.htm

Thanks Paul, I'll read it and hope to understand. In the very least it will provide a basis for ongoing discussions on how to fix the handling of these bikes. I`ve tried progressive springs in the front forks and progressive shocks on the back 1 inch longer than stock. The bike (CB500) steers much quicker and suspension compliance is light years better than stock. It is still twitchy though.

[Retro Rocket]

though unable to access the article on frame design, here is a great tony foale link:

http://www.lortim.demon.co.uk/reviews/Foale/index.htm

Thanks Paul, I'll read it and hope to understand. In the very least it will provide a basis for ongoing discussions on how to fix the handling of these bikes. I`ve tried progressive springs in the front forks and progressive shocks on the back 1 inch longer than stock. The bike (CB500) steers much quicker and suspension compliance is light years better than stock. It is still twitchy though.

Have you tried a steering damper, that should sort out the "twitch"...

Mick

[paulages]

though unable to access the article on frame design, here is a great tony foale link:

http://www.lortim.demon.co.uk/reviews/Foale/index.htm

Thanks Paul, I'll read it and hope to understand. In the very least it will provide a basis for ongoing discussions on how to fix the handling of these bikes. I`ve tried progressive springs in the front forks and progressive shocks on the back 1 inch longer than stock. The bike (CB500) steers much quicker and suspension compliance is light years better than stock. It is still twitchy though.

mine is a bit twitchy with 14" shocks on the rear, but it only really feels so at 100MPH or so. at slow speeds it handles much better than stock. i hope the steering damper solves this.

[voxonda]

though unable to access the article on frame design, here is a great tony foale link:

http://www.lortim.demon.co.uk/reviews/Foale/index.htm

Thanks Paul, I'll read it and hope to understand. In the very least it will provide a basis for ongoing discussions on how to fix the handling of these bikes. I`ve tried progressive springs in the front forks and progressive shocks on the back 1 inch longer than stock. The bike (CB500) steers much quicker and suspension compliance is light years better than stock. It is still twitchy though.

mine is a bit twitchy with 14" shocks on the rear, but it only really feels so at 100MPH or so. at slow speeds it handles much better than stock. i hope the steering damper solves this.

Hey Paul,

Maybe you need a bit more off-set (triple tree), think it is now 50 mm. On my replica I use the trees of the DOHC's with 60 mm. no need for steering damper (so far).

Hope I was clear and used the right descriptions.

Cheers, Rob

[turboguzzi]

paul, when you'll hit the track you'll see that your perception of handling will completely change.

on the track you are constantly hitting full throttle when exiting turns and in the lower gears it lightens the front end and makes it twichy

then there's the matter of top speed wobles but you kinda learn to live with them..... you surely dont want to slow down your steering just because the bike wobbles a bit at 120, right? 

with more than a click or two on the damper you really start to feel how it slows down sterring response.

[paulages]

with more than a click or two on the damper you really start to feel how it slows down sterring response.

yeah, i noticed that on the track bike. more than two clicks and you really have to work to turn the bars.

by the way, i went and looked at one of those duc sport classic fairing mounts. they had just installed it and attached the fairing, so i wasn't able to examine the bottom side. unlike what i had come up with, there is no bearing in the assembly at all. there is a plastic sleeve the upper part rides on (plastic bushing i guess?). great system, but the entire assembly is about $275 new. i got the bits to make mine for under $10. won't look as good, but eh...

[paulages]

got the rearset situation sorted out. the brake side required making a new cable and fabricating mounts for adjusters at both ends, but it feels good now and actuates smoothly.




...and the shifting side:



i just like this picture... down the barrel:

[Retro Rocket]

Hi Paul, could you possibly post some pics of the bracing you have done around the steering head part of the frame. Terry is bracing a frame i am buying off him and some pics would make it easier to explain.

Mick

[bill440cars]

      Hey Paul. Looks like, ONCE AGAIN, I'm running behind on things. I can't believe that I've gone without seeing this thread. As usual, with YOUR stuff, I am "SET BACK", as to the work and attention to detail that has been done to this one! MAN, if that sucker won't "WALK & TALK", NOTHING WILL!!!!!!! Can't wait to see how things go with getting it out there in the middle of things!


                                         Later on, Bill

[Kemp]

As to handling issues - what about the possibility of using a CB750 swingarm as a substitute for the CB550's. I've measured a few CB750's from various years and they measure about 18"-20" centre of swingarm to end/opening depending on the model. Some 750's are sort of welded square section 42x32mm(taper)approx while the CB550/500 is 35mm round and 20.5" long. Looks like you could adjust handling with a slightly shorter 750 arm and it might be stiffer as well? Again the issue might be that a shorter arm makes the bike more flickable but upsets the high speed stability.

[UnCrash]

Really looking great!  Nice to see the progress pics. (subscribed!)

[paulages]

As to handling issues - what about the possibility of using a CB750 swingarm as a substitute for the CB550's. I've measured a few CB750's from various years and they measure about 18"-20" centre of swingarm to end/opening depending on the model. Some 750's are sort of welded square section 42x32mm(taper)approx while the CB550/500 is 35mm round and 20.5" long. Looks like you could adjust handling with a slightly shorter 750 arm and it might be stiffer as well? Again the issue might be that a shorter arm makes the bike more flickable but upsets the high speed stability.

as is, i try and keep the wheelbase as short as possible, within the stock swingarm. i'd like to try and go even steeper now that i have a steering damper... we'll see how the current setup feels for now.

i was going to fire it up tonight, but i found that the battery had discharged a bit. must've left the ignition on at some point. anyway, everything's ready to go except that i need to mount the ignition module and add fluids...

 

[paulages]

IT'S ALIIIIIIIIIIIIIIIIIIIVE!!!
 

[paulages]

[Retro Rocket]

Looking great Paul, nice lines..

Mick

[paulages]

thanks! I'll to get some decent pictures soon, and detail some of the things i did. for now, the specs:

-718cc engine, making 70RWHP and 42# of torque (JMR stage 2 porting, megacycle 12620 cam, 64mm pistons,  10.6/1 CR
-dyna 2000 ignition, set at curve 3 with 37 degrees total advance
-14" progressive rear suspension
-race tech cartridge emulators in forks, with 20W bel-ray oil
-tarrozzi fork brace
-tarrozzi rearsets, with custom mounting brackets
-avon roadracer on the rear and pirelli sport demon on the front
-1976 CB550 frame, lightened of extras and gusseted- more bracing to come
-1979 ducati 900SS tank and half fairing
-hand-hammered alloy seatpan (yours truly)
-mac 4-1 header with glasspacked open baffle
-K&N intake filters

[coldright]

Sweet baby jesus, that thing is purdier than I imagined it would be.  I hope you've gone for a nice ride by now... and that it was worth the hell she put you through this summer.  Looks like it probably was. 

[paulages]

Sweet baby jesus, that thing is purdier than I imagined it would be.  I hope you've gone for a nice ride by now... and that it was worth the hell she put you through this summer.  Looks like it probably was. 

just got to spin around the neighborhood a few times and shake it down to find my mistakes... some advice: make sure that you put both cam tensioner mounting bolts back on. come to find out, a big hole in the engine leaks oil.  not sure if i dried everything up for sure, but i plan to hit skyline on it tomorrow and see how the suspension feels.

[Frankenkit]

She's gorgeous!

[paulages]

She's gorgeous!

Thanks!

[bwaller]

Great bike Paul.

You've made some changes, so how's the fit Paul?  No chance of grinding the pegs for sure. 

Did you ever find out what spring (or shim) your man used in the pump?