Topic: Road racers- 550 or smaller

[DonDDR]

 
     Prepping my 74 550 for track duty next season. Looking to meet other road racers. Exchange ideas and talk.

                   Thanks.

[Triffecpa]

Don

Welcome to the club.

I have put together a couple of track ready CB550's and a few CB350F/400F bikes.

Stick with a stock engine and worry about the suspension in the beginning.

I use the Midi/Forsa shocks that are available several places on the 'net for about $80.  Buy the ones for the CB1100F as they are 14+" long and will raise the back of the bike.

Haven't needed to do any frame strengthening yet.

Tapered steering bearings are a must.

I use clubman bars and save the price of clip ons.

get a 4-1 pipe for it and run it with as minimal of a baffle as you can get away with.  I know that you have some noise restrictions at Portland though.

For forks I usually like to swap to a different Honda front end.  The 35mm forks are OK, but the brake options suck with the stock fork legs. 

I try and use the twin piston early 80's Honda calipers with HH brake pads.

So if you can find some early 80's forks and triple clamps you will be in business.  I typically look for Goldwing or CB900F forks.  They tubes are too long, but you can either run them up thru the triple clamps or shorten the tubes.

Shorten the stock front springs and put a solid spacer in there.  You can cut 3" or so off the stock spring (cut the closely spaced coils if there are any) and cut a piece of PVC pipe to replace the cut portion of the spring.  You want about 1" of preload on the fork springs with the cap fully seated.

18" wheels are best, but they actually work decently with a 19" front.  There was one or two years of CM450 Customs that ran an 18"x2.5" front comstar wheel.  Those work great and they have the thinner 5 bolt front rotors.

Run a Dyna S ignition and total loss system and you'll be good.  I typically run open velocity stacks, but if you don't feel comfortable with that then run pods filters on the stock carbs.

The two bikes attached are examples of what I have done.  The yellow bike now has a CB900F 18" black comstar on the back to go with the CM450C one up front.  Those are CB900F forks with shortened tubes.

The red bike has Goldwing forks with '78 CB750F wheels.  (19" up front)

Tracy

[Triffecpa]

Couple more items.

If you run a single front caliper (more than adequate with the twin piston Honda calipers with HH pads) then use a 1/2" bore MC and braided steel brake lines.

For rearsets I weld a piece of angle iron to the frame tube that runs up to the rear shock mount and bolt on a set of late model rearsets from a sportbike.  You can typically get complete stock rearsets for $50 or so off ebay.  Buy a second set if you can to have for track spares.

I use Bikemaster clubman bars.  They are cheap ($25 or so).  They typically bend if you crash the bike, but you can have a second set at the ready.  I have actually heated and straighted them if they aren't too badly bent.  They do not break.  depending upon the upper triple clamps that you end up using, the bars might not be wide enough to get to eitehr side of the triple clamp and rotate down to the proper position.  I usually just cut and weld a piece into the middle of the bars and widen the center section between the handlebar clamps.  If you can't do that yourself then clip ons might ultimately end up being cheaper.  Buy the ones that have replaceable bars.

20w fork oil in the forks

Tracy

[DonDDR]

    Hey Tracy,

            Thanks for the great response. Exactly what I was looking for. It was my plan to have a stock engine and tune the suspension. I want to learn on a slow bike so I can go faster on my faster bike. I really like your budget approach to the suspension. Didnt like the comstars till now, but what are the chances of finding a one or 2 year only wheel off the 450? I bet if I can find one, it would be cheap tho. Found a 18" rear on craigslist today for 20 bux. What about the front end off of a 81 CX650? Guy i going to email me pictures of the calipers later. Or can I just do a dual rotor conversion to the stock front end?

          Tapered bearing are a must. Clubmans to start, If I find longer forks might do clipons cause want them on top of the upper triple. Wifey is going to learn to ride it and she is not that tall.

         Agree on the 4 into 1.

         Dyna S ignition will be installed. No total loss yet. Gunna leave the system intact. Make the bike "modular" as in able to add/reomve lights etc if Wifey likes to ride and its sees some street duty.

         All over the rear set trick. Seen a few other members do exactly what you did. Affordable and effictive. Just like your suspension advice.

       Again Thanks for all the info. Im sure we will talk again soon.

Don

[Triffecpa]

the CX650 probably already has the five bolt brake rotor and the twin piston caliper.  They used them across the Honda range starting in the early 80's

The nice thing about swapping to another Honda front end is that they almost all use the same steering head bearing set.

Not sure on the size of the CX650 sanction tubes, but if they are 35mm then you can just use the CB550 triples and slide in the new tubes. 

Twin rotors and calipers just gets heavier (the single CB550 caliper and rotor are heavy enough already) and you can't easily get agressive brake pads for the old style calipers.  With the funky hinged caliper mount, you can't really mount a "real" caliper to those forks either.

TR

[DonDDR]

    I see what you are saying about the calipers. Only problem with the CX wheel is its 19". I really want the 18" front. Guy selling the CX stuff wants nothing for it, might get the 19" front for now, and when I the 18, I will have an extra rotor.

   A few questions about raising the rear with the 14" rear shocks. That will bring me up 7/8 from stock. The smaller 18" front might bring me down 1/4, inch or so net. If I do the longer forks off of a 80's up wing or what ever, does this give me a point of tuning by moving the tubes in the trees or is it not going to matter? Tapered head bearings and new swing arm bushings should keep it from self steering, like you said- never had to brace a frame yet- Its not like the bike will see Race tech fork stuff or some $400 remote rear shocks anytime soon. Just want something reliable and somewhat predictable.  Like I said, I want a slow bike to learn to ride a faster bike better.

    Thanks for your info, its very much apperciated.

[Triffecpa]

Raising the back and running a smaller diameter front wheel will quicken the steering, which is a good thing with these bikes.  I would plan on running pretty much stock length forks. 

Worst case is that you have to run a steering damper, but I have not found that to be necessary.

On the red bike with the 19" front Comstar, I think that axle center line to the top of the upper triple clamp is somehting like 22.5", but I'll have to double check that mesurement.  I have since sold the red bike, but it belongs to a friend of mine who will have it out at the track in another ten days or so.

The stock geometry on these bikes is really slow and stable compared to current sport bike stuff.  It's really hard to get more rake than the frame can handle with just longer shocks and shorter forks and an 18" front wheel.

Tracy

[Bluegreen]

I am looking to do 18" front and back, spoked, shouldered, aluminium wheels on my 550. What width would people suggest? 2.5 front and back?

[bwaller]

I went with WM3 up front for a 90/90/18 and WM4 in the rear. The narrower front tire does help them turn in.

[Bluegreen]

Thanks Brent!

[mokie]

Hi there, newbie question, but how do you shorten tubes on the front suspension? Cut them where? Any welding required? How much to shorten them for a 550? Sorry for all the questions, I'd love to put some new forks up front on my bike. Will the triple tree from the CB900 fit strait in with appropriate taper bearings?

Thanks

[fastbroshi]

You don't ever cut them;  When he alluded to stock length, that didn't imply you can change the fork tube length.   If you wanted to alter the suspension a bit you can raise or lower the fork tubes in the triple tree. 

[mokie]

"They tubes are too long, but you can either run them up thru the triple clamps or shorten the tubes."

How to shorten them?

PS sorry for my english. Third language.

[jpd748]

3RD language! I'm struggling with one

[fastbroshi]

You loosen the clamps in the triple tree that hold the fork tubes in position, then slide them upward.  Depending on what bars you have, you may be limited in just how far you can slide them up. 

[Bill/BentON Racing]

I went with WM3 up front for a 90/90/18 and WM4 in the rear. The narrower front tire does help them turn in.

This set up works well,I ended up with 2.50 x 18 front  and 3.00 x 18 rear on my Yosh kitted 590 racer.Before that I ran a 2.15 x 19 F and 2.50 x 18 R.Gold anodizied DID's from Buchannons wheels and H/D spokes. 18 and 18 the way to go.Good idea on the 14" rear shocks. Good luck,Bill

[Triffecpa]

"They tubes are too long, but you can either run them up thru the triple clamps or shorten the tubes."

How to shorten them?

PS sorry for my english. Third language.

I do actually cut them.  I cut the top inch or two off that has the threaded portion for the fork cap and then I cut a section out and throw it away (2" to 4").  Then I bevel grind the top piece and the remainder of the fork leg and weld them back together and grind the welds flush.  The welded portion sits inside or just below the top triple clamp.  I have done this numerous times on race track run bikes and never had a problem with them.  You can also buy new shorter than stock length tubes from Forking by Frank if the welding makes you nervous.  Just remember that our frames are welded together also. 

Tracy

[eclipselzjp300]

http://cgi.ebay.com/ebaymotors/88-00-Honda-Goldwing-GL-1500-fork-forks-set-/160647709813?pt=Motorcycles_Parts_Accessories&hash=item2567598475#ht_1118wt_939

would something like this work??

[fastbroshi]

That's newer than what was being discussed.  Do a search on GL1000 or CB900 forks.

[mokie]

I do actually cut them.  I cut the top inch or two off that has the threaded portion for the fork cap and then I cut a section out and throw it away (2" to 4").  Then I bevel grind the top piece and the remainder of the fork leg and weld them back together and grind the welds flush.  The welded portion sits inside or just below the top triple clamp.  I have done this numerous times on race track run bikes and never had a problem with them.  You can also buy new shorter than stock length tubes from Forking by Frank if the welding makes you nervous.  Just remember that our frames are welded together also. 

Tracy

Thanks for the great info Tracy, never before have I heard of this being done. I cannot weld myself but have a very good professional friend who also races motorcycles he builds. I assume the metal the tubes are made from is weldable and is not brittle after finishing of weld? Because your results have been good maybe I wish to try this as I do not like the look of the forks riding high in the clamping assembly.

[Triffecpa]

Thanks for the great info Tracy, never before have I heard of this being done....

I think that I invented it. 

Seriously.

TR

[turboguzzi]

Thanks for the great info Tracy, never before have I heard of this being done....

I think that I invented it. 

Seriously.

TR

In the famous cycle World mag  feature on the Yoshi GS1000 racer back in 79' there's a very clear picture of the fork tubes that pops would make longer by welding extensions to..... issue on that bike was to GAIN ground clearance as it would drag the engine covers  in corners, but welding can be done. 

[Scott S]

 How would these work on a '78 550K? They're '83 CB1100F Super Sport shocks and are ~13.5" eye to eye, or about 1" longer than my stock shocks. Value on something like these?

[fastbroshi]

For racing?  They'd be better than the stockers for the simple fact they're longer.  They should fit with no issues.  That one fella that built the black and gold 550 with the GSXR forks and original Yoshi header used those.   

[Scott S]

 What about on a street bike?