Author Topic: CB550 Track Bike Goes Racing  (Read 9421 times)

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Offline Rocketman

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CB550 Track Bike Goes Racing
« on: July 04, 2015, 05:55:19 pm »
My first roadrace after a nearly 29 year break is in the books.  Back in the 70's and 80's I raced with the various clubs and AMA on a series of production roadracers.  When I stopped after the 1986 season I intended to take a break and then build something fun and to do the occasional track day and maybe a club race or two.  As often happens, one thing leads to another and suddenly 25 year had gone by.  I made up my mind it was now or never and decided a replica of the Honda's raced in the 60's would be the hot ticket.  The holy grail to me was the RC181 raced by Hailwood and Redman.  With that settled I embarked on an adventure to build a vintage roadracer based on the CB550.  The build is documented in the Project Shop section under CB550 Track Bike. 

My intention was to take a race school and make my first race back at Nelson Ledges.  I had raced there regularly and it is within 3 hours of home.  Unfortunately the weather did not cooperate and we were snowed out!  Next on the schedule was one of my favorite tracks, Road America and a race school was available.  So I loaded up the trailer and hit the road with a couple of buddies.  My brother drove in from Illinois and Thursday evening (after surviving Chicago rush hour) we met at Road America. 

Friday morning bright and early I was in class with 8 or so other students.  It was a cool and windy day, but dry.  The day found us alternating classroom sessions with track time.  The classroom work was informative and the instructors knowledgeable.  The track time was challenging!  Trying to learn a new bike that I had built myself, trying to remember how to go fast (relatively speaking), and relearning the track at the same time was a steep learning curve.  The carbs on my 550 are from a 78 CB750.  The lean spot between 3,000 and 6,000 RPM made the bike challenging to ride.  I was struggling out of the slow curves, particularly the new chicane just after the carousel.  Nothing to 6,000 and then she would clear out and pull great to redline.  The day ended with a mock race.  In addition to the students, the instructors and a few other competitors participated.  The mock race went well and my times continued to drop.  After the race, one last quiz, and I was the proud recipient of an AHRMA race license. 

During the mock race I had grounded one of the exhaust headers.  Not a confidence inspiring event.  I did not want to pick the tire up and low side!  In an effort to gain additional ground clearance I increased the shock spring preload and lowered the forks a half inch.  Saturday was warmer, but still windy.  Two practice sessions in the morning and then it was time to race.  I did not drag the exhaust in practice, but it was in the back of my mind. 

I was gridded on row two of the second wave for the race.  The first wave was 500 Premier and 500GP.  Only real RC181s are eligible for 500GP, so I raced in Formula 500.  Also in the second wave was Production Heavy weight.  My start was nothing to write home about and I hit turn one 5th in class.  By the end of the first lap I had passed a couple riders and was 4th in class and 13th overall.  The leaders in class were on 2 stroke twins, either air cooled TR or TA Yamaha's.  For the next couple of laps I diced with 3rd while the leaders disappeared.   we passed a couple of other riders and then while braking for turn 5 at the end of the second long straight he lost the front end and slid off the track.  It was a lonely ride from there and I crossed the finish line 3rd in class and 10th overall.  I was all smiles.  I survived my first race since 1986 and the first 4 stroke race bike I'd every built had ran well.  While I was well off the pace of the leaders all in all it was a most successful weekend.   :)  As I had to be back at work Monday and at 60 years of age all night drives no longer thrill me, we packed up and hit the road Sunday morning. 

Here are some pictures from the weekend.

In the pits.





Photos from practice, front straight.



Heading into turn one.



Turn five.





Talking strategy in the pits.



Racing with 3rd (1E), he lost the front wheel just after this photo.



Since the race I have added 30mm extensions to my shocks bringing the total length to 350mm.  The front forks have been lowered 26mm as I was looking to quicken up the steering.  I also have given up on the CB750 carbs.  Needles to address the lean spot are not available and no amount of shimming works.  So, Christmas came early and a set of Keihin CR29 smoothbore carbs are on the bike.  Dyno time will be after Mid-Ohio next weekend, so the jetting is what Dynoman recommended.  Hope it is close.  Planning one more race after that at barber and hope to do the Ohio Mile in September for top speed.  See you at the races.
« Last Edit: July 04, 2015, 05:59:41 pm by Rocketman »

Offline scunny

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Re: CB550 Track Bike Goes Racing
« Reply #1 on: July 04, 2015, 06:21:56 pm »
Thanks for that. I haven't raced since the early 80's and now thinking maybe.
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Offline turboguzzi

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Re: CB550 Track Bike Goes Racing
« Reply #2 on: July 05, 2015, 10:41:22 am »
hello rocketman. good to hear about your successful comeback, specially on a DIY bike. my first race was also the bike's shakedown, so kind of identify with much of what you have gone through. also good to hear that a 550 can be competitive (though the logic of running a mid 70's CB550 with drum brakes and four pipes eludes me a bit:)  )
and dont worry too much about age.... i am 53 but we have a few 70 yrs old that still go pretty quick.

Offline Rocketman

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Re: CB550 Track Bike Goes Racing
« Reply #3 on: July 05, 2015, 06:07:29 pm »
Thanks for the replies.  Trying not to take this too seriously this time around.  There is no logic to drum brakes and 4 exhausts.   Just having fun and reliving 60's racing.  Looking forward to getting the full fairing so the bike really looks the part.    ;D

Offline bwaller

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Re: CB550 Track Bike Goes Racing
« Reply #4 on: July 05, 2015, 06:38:36 pm »
Nice Martin, I hope you have a blast racing this time around. We're the same "vintage" and getting back into it after a long absence makes it thrilling all over again. Can't beat that!

Offline Ravie

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Re: CB550 Track Bike Goes Racing
« Reply #5 on: July 05, 2015, 07:34:16 pm »
VERY cool!

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Offline Justind97

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Re: CB550 Track Bike Goes Racing
« Reply #6 on: July 06, 2015, 03:58:57 pm »
The bike looks awesome! 

What tank is that?

Offline Rocketman

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Re: CB550 Track Bike Goes Racing
« Reply #7 on: July 14, 2015, 01:26:15 pm »
The tank is an Airtech CR7503 tank that has been extensively modified.  There are photos in the Project Shop under CB550 Track Bike.  It was cheap on eBay and I knew I would be cutting it up.   I think if you started with a CR7503M the only changes needed would be moving the filler and changing it to a Monza cap.  http://www.airtech-streamlining.com/hondaz/CR7501969-77SINCAM.htm
« Last Edit: July 15, 2015, 05:43:30 pm by Rocketman »

Offline bwaller

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Re: CB550 Track Bike Goes Racing
« Reply #8 on: July 14, 2015, 07:24:47 pm »
Have fun at Mid-O?

Offline Rocketman

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CB550 Track Bike Goes Racing
« Reply #9 on: July 15, 2015, 05:57:20 pm »
Mid-Ohio was another step forward.  The Keihin CR29 carbs are a hugh improvement over the CB750 carbs.  I'm not to far off on the main at 120, but stumbling in the mid-range.  Need to get it on the dyno to see if it is too lean or rich.   Extending the shock and dropping the forks cured the ground clearance problem.  One of your countrymen was racing, Scott Mackenzie.  He and Ryan Hunt went at it all race long on Saturday.  Ryan had the upper hand on Saturday.  Not sure who prevailed Sunday as I pulled out due to the rain.  The best part was the 500 GP class had to start in a second group behind the Clubman 750 and GP 750.  If I could have kept a Norton 750 behind me it would have been a 1, 2, 3 overall for the 500's.   :)  Still a long way off the pace, but it is slowly coming back.  Hoping to get a track day in, then do the Ohio Mile and round out the year at Barber.

Here are some photos.





Scott Mackenzie (617) and Ryan Hunt (76)

« Last Edit: July 17, 2015, 06:09:12 pm by Rocketman »

Offline MRieck

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Re: CB550 Track Bike Goes Racing
« Reply #10 on: July 15, 2015, 06:47:10 pm »
 Get some different needles for the midrange problem.
Owner of the "Million Dollar CB"

Offline Rocketman

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Re: CB550 Track Bike Goes Racing
« Reply #11 on: July 17, 2015, 06:19:19 pm »
Just not sure if I am rich or lean.  If I can't get on the dyno will play with the jetting at a track day. 

Here is a link to photos taken of roadracing at the AMA Vintage Days.

http://gallery.americanmotorcyclist.com/AMA-Racing/2015-AMA-VGC-RR/50606241_C9bgKd#!i=4203506396&k=X4JNNvr

Offline Rocketman

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CB550 Track Bike Goes Racing
« Reply #12 on: October 26, 2015, 05:19:53 pm »
Last race of the year is in the books.  Before heading to Barber more dyno time was booked and the jetting further dialed in.  The power spread is now 43 HP at 6,500 and 42 at 10,250 with a peak of 48.1 at 8,500.  Interestingly the CR29 carbs did not make anymore peak power than the CB750 carbs.  The big difference was more power in the midrange to drive out of corners.

While I have been to Barber several times this was my first time racing there.  What an incredible racing surface, smooth as a billiard table with great grip.  Practiced on Friday and raced on Saturday.  The Formula 500 class was wave one with the 350 GP next followed by Production Heavy Weight.  Started on row two and by turn two had moved into 2nd place.  The rest of the race was a slow slide backward and I finished 5th in class and 7th overall.  Two of the 350 GP racers caught me including Dave Roper on his Aermacchi 350.  He passed my on the penultimate lap.  I had top speed on him, but tucked back in going into turn one in an effort to learn from the master.  Dropped another 2 seconds in the race and am looking forward to next year.

Here is a picture waiting for my practice group.



Getting ready to race.  Dave Roper, Chris Spargo (winner Formula 500), and myself.



Here are some pictures from the pits and various bike shows.







M3 Racings CB750 flat tracker



The real deal.  Rick Hocking's CB750 flat tracker.



This how we used to go racing!



























« Last Edit: October 27, 2015, 06:46:14 pm by Rocketman »

Offline Retro Rocket

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Re: CB550 Track Bike Goes Racing
« Reply #13 on: October 26, 2015, 06:05:07 pm »
Thanks for the report and great pics... ;)
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Offline Tintop

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Re: CB550 Track Bike Goes Racing
« Reply #14 on: October 26, 2015, 06:42:44 pm »
+1 8)
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Offline bwaller

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Re: CB550 Track Bike Goes Racing
« Reply #15 on: October 26, 2015, 07:02:04 pm »
Nice finish Martin. Great pics too, you're in good company with Spargo & Roper.

Offline bear

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Re: CB550 Track Bike Goes Racing
« Reply #16 on: October 26, 2015, 11:46:06 pm »
Good stuff.
We might be older.
We might be a tad slower
But we can still compete..............well some of us can. :( ;)

Cheers,
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Re: CB550 Track Bike Goes Racing
« Reply #17 on: October 29, 2015, 03:14:26 pm »
Great pics!  What are the limits on the GP500 class?
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Offline Rocketman

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Re: CB550 Track Bike Goes Racing
« Reply #18 on: October 29, 2015, 07:24:11 pm »
AHMRA has three classes that allow GP style motorcycles.  I am racing in Formula 500 which allows production based motorcycles along with a few true factory racers.  To race in 500 GP you need a real RC181, no replicas!  Like Honda is going to let one out of their museum.  :o Other bikes eligible for Formula 500 include Kawasaki H1R, Suzuki 500 Titan Factory racers and GT 550, Yamaha RD350, RD 400, TR2, TR3 and R5 TR based replicas.  There is also 500 Premier which allows the same bikes as 500 GP.  Here is a link to their rule book, look in Section 10.

http://www.ahrma.org/about/ahrma-rule-book/

Offline Rocketman

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CB550 Track Bike Goes Racing
« Reply #19 on: June 20, 2016, 05:41:28 pm »
The first two events of the year are in the books.  I had planned an upgrade to higher compression pistons and hotter cam over the winter.  When I tore the motor down I found the head had been damaged and would need replaced too.  It is only money, right?   :D  Mike Rieck came through with one of his outstanding port and valve jobs to get me back on the track.  The dyno confirmed the wisdom of using Mr. Rieck when the motor made 60 HP.  A 20% increase from last years 49 HP!  Off to the races.

Road America with AHRMA was first.  The Honda ran great all weekend and I scored two 3rds in Formula 500.  The competition was Ryan Hunt and Dave Morrow on their Yamaha twins.  My lap times were significantly better than last year and as well as the bike was running, they both out rode me.  Also pulled my RGB500 Suzuki out for the first time in 30 years and had a go on it too.  Finished 2nd behind Dave Crussell on his TZ750 both days.  Here are some photos.

Road America Pits



Ready to race the CB550



Suzuki RGB500 MK7



Suzuki X7



Kenny Cummings NYC Norton



Norton Twin



Manx Norton



Honda CBX



Dave Crussell's pits.  Kawasaki A1R, Yamaha TZ 750, and Kawasaki H2R in the transporter.



Dave Roper and his Moto Guzzi Dondolino



Dave Crussell's Kawasaki Big Horn



F37 Kawasaki



Sunday I ran the CB550 at the Ohio Mile and ran a 130.662 with a 5 to 6 mph head wind.  That put a big smile on my face!   ;D

Next up is Vintage Days at Mid-Ohio.  Look me up in the pits if you are there.




Offline bwaller

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Re: CB550 Track Bike Goes Racing
« Reply #20 on: June 20, 2016, 06:51:24 pm »
Thanks for the update Martin, glad the bike is running stronger too.  You'll have Ryan & Scotty to deal with at Mid-O again but get em hell!

EDIT, your Gamma must have been put away in good shape to drag it out of mothballs & race it right off? It would be a tad different that riding the 550!
« Last Edit: June 21, 2016, 07:12:27 am by bwaller »

Offline Trad

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Re: CB550 Track Bike Goes Racing
« Reply #21 on: June 20, 2016, 07:52:04 pm »
Great photos. Nice to see you putting that beauty to work.
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Offline slikwilli420

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Re: CB550 Track Bike Goes Racing
« Reply #22 on: June 21, 2016, 07:13:38 am »
I was at RA a few weeks ago, wish I would have known to look out for you. Which sanctioning body do you race with? AHRMA was at RA, but does not compete at Mid Ohio any more, only WERA. Do you race both?
All you gotta do is do what you gotta do.

Vintage Speed Parts Mashup: http://forums.sohc4.net/index.php?topic=133638.0
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AHRMA CB750 Racer: http://forums.sohc4.net/index.php/topic,158461.0.html
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Offline Rocketman

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Re: CB550 Track Bike Goes Racing
« Reply #23 on: June 21, 2016, 08:09:08 am »
Getting the RG running took 2 years and too many thousands of dollars.  Parts have gotten more expensive over the last 30 years.  Most parts come from England, mostly Padgett's, Nigel Everett did the cranks.

Running RA and Barber with AHRMA, Mid-Ohio with AMA/WERA, and hope to make Mosport with VRRA.  Look me up if you make any of these.

Offline slikwilli420

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Re: CB550 Track Bike Goes Racing
« Reply #24 on: June 21, 2016, 08:30:29 am »
Will definitely be at Mid-O this year and will keep an eye out in the pits.
All you gotta do is do what you gotta do.

Vintage Speed Parts Mashup: http://forums.sohc4.net/index.php?topic=133638.0
Rickman CR Parts Kit Refresh: http://forums.sohc4.net/index.php/topic,154837.0.html
AHRMA CB750 Racer: http://forums.sohc4.net/index.php/topic,158461.0.html
AHRMA Superbike Heavyweight Racer: http://forums.sohc4.net/index.php/topic,173120.0.html
'76F CB750 Patina Redemption: http://forums.sohc4.net/index.php/topic,174871.0.html

 

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