Topic: CB550 racer - how to quicken steering

[vintage_racer]

I race my CB550 for 6 seasons now (2010 will be my 7th with 4 to 5 weekends each season).
It's a good reliable bike with some engine work (cams, porting Yosh pistons, etc..) and is quite competitive in it's class but not on very tight race tracks.
The bike doesn't turn very well even though I dropped the front forks about 1" and rear shocks are 1/2" longer than stock.
What should be the next step? should I get longer rear shocks?, if so from where?
Dan

[Bill/BentON Racing]

Might try 18 inch front wheel,lighter wheels,the 1100F shox are eye to clevis and 1-1.5 inc longer,I can measure for you,probably too stiff,I have Fox Superbike shox on my 590 racer.do you still have loose ball bearings in f/end,tapered much better,move rear wheel as far forward as possible.tire pressure? and size? I never did get mine like I wanted,I think it's easier to fix the rear.Good Luck,Bill

[bwaller]

There are lots of guys here racing these. Besides jacking the back end it seems the hot choice for front tire is a 90/90 on an 18". Apparently helps make them turn in.

[vintage_racer]

I use a 19" front on an alloy rim. Will be a lot of work to get an 18" on my hub.
Will try longer rear shocks first, so far couldn't find any.

[Laminar]

CB900f shocks are about 13.5" long, and have adjustable preload, compression dampening, and rebound dampening.

[vintage_racer]

Thanks for the info Laminar.
Unfortunately this CB900 shocks wouldn't be legal in the category I race (period 2).

[Triffecpa]

I use the Midi/Forsa shocks that are 14 3/8" eye to clevis on my CB550's.  One has an 18" front and the other has a 19".  Both turn well.  Partnsmore.com has the shocks for $75.  Look under the listing for CB1100F Hondas

Tracy

[Laminar]

I use the Midi/Forsa shocks that are 14 3/8" eye to clevis on my CB550's.  One has an 18" front and the other has a 19".  Both turn well.  Partnsmore.com has the shocks for $75.  Look under the listing for CB1100F Hondas

Tracy

Do you have problems with your chain hitting your swingarm? I noticed with my shocks that it's close, and it looks close in your pictures.

[Triffecpa]

I use the Midi/Forsa shocks that are 14 3/8" eye to clevis on my CB550's.  One has an 18" front and the other has a 19".  Both turn well.  Partnsmore.com has the shocks for $75.  Look under the listing for CB1100F Hondas

Tracy

Do you have problems with your chain hitting your swingarm? I noticed with my shocks that it's close, and it looks close in your pictures.

The chain drags on the top of the swingarm pivot if the bike is unladen.  But once you park yourself on the seat, it isn't a problem.

TR

[vintage_racer]

Thanks Tracy,
This is the solution I was looking for  .
Dan

[turboguzzi]

+1/2 inch will not give you the decrease in rake you are seeking.

I am up to almost 14" (with a little trick...)

and an 18" front of course,

dropping the front on the tubes will reduce the ground clerance and you dont want that, do ya?

thing is that at that point you might want to have also triple clamps with less offset. with the stock ones and 23 degrees of rake ive got now, the trail was greatly reduced and i've lost the "feel" of what the front was doing. clamps with -15mm offset restored that. 

Another tip i recently heard is switching to a 750 swingarm, seems to be shorter but cant confirm.

TG

[simon#42]

using yokes [ triple clamps to you ] with less offset increases trail and makes the bike harder to turn , not what you are trying to achieve . jacking up the rear to much will loose you rear grip , only do this if you have chronic ground clearance problems  and try to keep it to a minimum . for me your best bet would be to try a few different front tyres , the difference in profile between , say dunlop and avon can make a huge difference . dont think that bigger [ wider ] is better . i always had a spare wheel with a skinny front tyre on for tight circuits  . shortening the swinging arm will also loose you grip , the main reason moto gp bikes have stacked gearboxes is so they can run long swinging arms without long wheelbase

[ryder60]

By looking at your picture I think I'd drop the front a bit lower on the forks.  I have to run a belly pan and I set the height so that when I lean over in the hardest turn I just touch the front of the pan on the track then I go up about 1 inch.  Mission track is tight and I never thought I had any trouble turning in.  I'm running a BT45.  I have stock shocks and 19" wheels.

[vintage_racer]

well, I'm kind of stuck with Avons here in Ontario M22 90/90 front M23 130/65 rear. I will order the 14 3/8" chocks today (currently I'm using 13 1/2"). I do run into some ground clearance issues already so a taller tail will help. Never run into rear tire grip issues (at least on dry pavement) this Avons are very sticky.
Dan

[turboguzzi]

using yokes [ triple clamps to you ] with less offset increases trail and makes the bike harder to turn , not what you are trying to achieve .

Simon, in my experience, after you reduce the rake with 14" shocks, you just loose too much trail, the slightly less offset just restores the trail back to about 95mm, with the stock yokes/clamps youo are down to 80mm. look at specs of current sipersports and youo'll see that 23 degs/95mm are pretty common figures.

but to be honest, rake- trail - front end feel are so personal.

vintage, you might want to raise the rear first with stock clams and then see if you like it. in our 500 class most CB's are with reduced offset clamos but 1-2 very fast guys run stock clamps, so nothing is written in stone on the subject. All the 500's in the gird have seriously raised rear ends though. Personally never had a problem with rear grip even iwth my high tail, the situation might be different with bikes with more than 60-70hp.

 

[simon#42]

yes tg you may be right about the feel of the front end being a personal thing but to be honest none of the fast bikes over here [ in any of the classic classes ] use yokes with reduced offset .  i do disagree about rear end grip not being a problem on lower powered bikes [ its one of the main areas we worked on on our 125s and made big improvements to the lap times ]  if when you hit the apex of the corner you can have the bike on your knee and the throttle wide open [ in the power band ] then maybe you have enough grip but in my experience [ and with the benefit of a data logger on the 125s ] the people who are not sliding are not wining and the more grip you have the faster you can corner before you slide . when it comes down to it grip is everything , whether the rider is good enough to use it is another matter entirely !!

[turboguzzi]

simon, lets keep it in context of racing 500/550's fours and try to help this guy....

So yes, of course that if you are not sliding you are not going close enough to the limit but at 48 years old, I am happy to do it only once or twice a lap in the corners I feel good at. I applaud your young gun (or is it you?) for being able to keep it on the edge it all race long.

In any case, to put my comment in context, I did not experience any WORSE rear traction problems when I raised up the rear a good 1"-1.5", that was all I was trying to tell our friend.  I think that raising the rear in a 500 is beneficial, lowering your front instead will rob you ground clearance. (And of course you can never have enough grip   )

Then, a 100 kg, 50HP 125 with a 55 kg rider is very high power compared to a 150kg, 60hp 550 (if he has that kind of power in the first placer) with an 75kg (85kg in my case) rider in top. Your 125 has a power to weight ratio that is 50% higher, so yes, a a racing 550 is very low power compared to it and the type of problems are vastly different. Some info will apply, some not.

TG

[vintage_racer]

Thanks for the advice guys I ordered the long (14.3/8") rear shocks for now.
I probably have 45HP (estimate, never daynoed it)on a good day and despite lots of exercise and watching my diet (well, really like beer and wings) I can't drop under 72Kg. In my race category I run against a couple other CB550, some Kawasaki triples (up to 400cc) and air cooled Yamaha RD350/RD400 which seem to be the fastest.
Now, how do you get 60HP out of a Cb550 without casting a totally new head? The CB550 has such a terrible head design that it seems impossible to get good power.
I run Yosh pistons, a mild porting job, high duration camshaft with special springs and aluminum retainers and CB750 carbs with velocity stalks. My motor is a dead meat under 6500 RPM but then pools OK.

[turboguzzi]

Thanks for the advice guys I ordered the long (14.3/8") rear shocks for now.
I probably have 45HP (estimate, never daynoed it)on a good day and despite lots of exercise and watching my diet (well, really like beer and wings) I can't drop under 72Kg. In my race category I run against a couple other CB550, some Kawasaki triples (up to 400cc) and air cooled Yamaha RD350/RD400 which seem to be the fastest.
Now, how do you get 60HP out of a Cb550 without casting a totally new head? The CB550 has such a terrible head design that it seems impossible to get good power.
I run Yosh pistons, a mild porting job, high duration camshaft with special springs and aluminum retainers and CB750 carbs with velocity stalks. My motor is a dead meat under 6500 RPM but then pools OK.

Vintage, there are quit e few of us getting that kind of figures out of 500/550's, but we are talking about full on hot rodding here: 12:1 CR, 29mm keihin CR's, HEAVY porting, and careful setup. just check threads by Howel, CB500four, myself and others. not sure that you have indeed only 45hp, would wait for a dyno before being sure.

TG

[Rod]

Simon, it sounds like I could use your help when I finally get up to Mallory for a test session - do you hire out your services?  

[Sam Green Racing]

Come on guys, we've managed to get 5 pages in this forum without any of the crap that gets banded about in the open forum and causing people to close their accounts.
This forum was set up for the more serious members who were taking their hobby a little further than just a hot rod or cafe racer. People will allways have different opinions of how something should be done or made to work. Any advise be it from seasoned campaigners or from relative newcomers to the sport is greatly appreciated but it will always be down to the person that asked the question in the first place who's advice they listen to. Remember this, set up is a very personal thing and what works for one person won't always work for others.
On a lighter note, try setting up a 600bhp Super Street or Pro Street drag bike to run 7 seconds in the quarter where disregard for a one degree change in temperature can mean the difference in qualifying let alone winning or being runner up in a race.
Now kiss and make up, and don't make me use my super power.

Sam.

[simon#42]

Simon, it sounds like I could use your help when I finally get up to Mallory for a test session - do you hire out your services?  

send me a message when you are ready to test , i will meet you down there ..... your buying the tea!

[turboguzzi]

I know you already ordered your shocks but this is a simple solution I found to get any ride height you want with little work involved + lets you use non clevis type shocks in a 500/550, it will give you more choice in shocks.

The last pic shows a Delrin plate to avoid contact between chain and s'arm


Cheers

TG


 

[Bill/BentON Racing]

TG,remember seeing the shock brackets in another post.Did you machine them yourself ? Keep up the good work and heres to more podium finishes! Bill

[turboguzzi]

TG,remember seeing the shock brackets in another post.Did you machine them yourself ? Keep up the good work and heres to more podium finishes! Bill

"machine" them myself? oh yeah, in my HCHB center, that stands for: Hand Controlled Hacksaw Blade..... There is a bit of computing involved though in these, I build the geometry in a CAD program and then simply print the layout and tack it to the ally plate with spray glue.