Author Topic: Dr. Tom Marquardt's 550 Hybred AHMRA Racer (Read 12569 times)

Tommy Neimeyer · « **on:** September 19, 2006, 07:23:28 PM »

Several people have asked for more info about a pic I posted in another thread, so here it is.

This year I have had the opportunity to help Dr. Tom race his CB550 and CBX at Willow Springs and Mid Ohio. He did real well in 8 races (4-CB550, 4- CBX) he got 4-firsts, 1- second, 2-thirds and a DNF (ran out of gas while leading). It was a real steep learning curve for me as I have never pitted for road racing.

The bike was originally assembled in 1977 and raced. It is still very competative in AHMRA racing today. It has a tri-anglelated (braced) swingarm, magnesium forks, magnesium wheels. The motor is close to 700cc, fitting just below the class limit. It is a 550 case and uses a Kenny Harmon cam, 64mm Kawi pistons, 750 liners and a 650 head. 31mm CR carbs feed the gas real well and it uses a 650 oil pump. Motor makes about 85 RWHP. The liners were so large that it effected the oil passages to the head. They were plugged and oil lines ran to the head from the lower oil galley.

As you can see, it has a lot of racing mods. Pegs, brake arm and shift arm are modified. Clutch cover has kick start welded shut, we bump start the bike. On the left side, the engine side cover has been cut out so gear changes can be made without removing the cover, it was done nicely so it looks good.

The only problem he is experiencing is some oil seepage around the top of the case and cylinder bottoms.
If you have any more questions, let me know and I will try to get them answered.

Cheers, Tom

bill440cars · « **Reply #1 on:** September 19, 2006, 08:12:05 PM »

Outstanding Bike

Totally Outstanding!

Later on, Bill

OldSchool_IsCool · « **Reply #2 on:** September 19, 2006, 08:22:41 PM »

Are you saying that this started as a stock '77 550?? That my little 'ol rat bike is a brother of this beast??

Tommy Neimeyer · « **Reply #3 on:** September 19, 2006, 09:45:05 PM »

Here he is at Daytona.......

Sam Green Racing · « **Reply #4 on:** September 19, 2006, 11:03:35 PM »

Tom, congrats to you and Dr Tom for a very well turned out motorcycle.
What class dose he run in, is it a modified street class ?
Can you let me know how the front sprocket locks onto the splined gearbox shaft.

Sam

ohiocaferacer · « **Reply #5 on:** September 20, 2006, 04:15:03 AM »

I remember seeing you guys at mid-ohio this year......dam fast!!!

Wasnt he the guy who got off the grid last(think it stalled or something). Cant remember which day it was......he was last off the grid...way behind everyone. Then lap after lap.....he was passing people left and right. Everyone keep saying watch the guy on the silver bike with the gold wheels. Dam good racing to watch.

Later,
Greg

Tommy Neimeyer · « **Reply #6 on:** September 20, 2006, 05:57:57 AM »

Thanks for the comments, Dr. Tom deserves all the kudos, I was just there wrenching and helping out. I originally went to wrench on the CBX (most of my experience lies here) but fell in love with the SOHC and that started me building my current 550/650 project.

SAMCR750,
I think we ran Vintage Superbike, Middleweight class with the 550.
We ran Vintage Superbike, Heavyweight class with the CBX.
Depending on what gearing we ran, the way the sprocket was "locked" onto the shaft was different. All the sprockets are splined, if you look at the pic above, you will see a large spring "C" clamp holding the sprocket in place. Most of the other gears had the stock plate with the two bolts.

Greg,
You are correct, I think it was race 9 on Sunday, we had a little "slip up" at the start and had to get bumped off about 7-8 seconds after everybody else left, he then wheelied his way into the first cornor. In this race, Tim Mings was the rider, Dr. Tom had raced the race before on the CBX and did not feel like running back to back races. Tim is an excellent rider and over the course of the race made it back to third place almost getting second (lost by less than a wheel). It was a very good race.

Cheers, Tom

SteveD CB500F · « **Reply #7 on:** September 20, 2006, 06:04:27 AM »

Tom.

We have a Gallery (here: www.sohc4.us/gallery/v/custom/cafe/ ) for customs where I have collected pictures of these bikes.

Email me some hi-res pics and I'll put them up (or go to the Gallery and do it yourself). These threads are buried very quickly in the Open Forum.

By the way, is the "CR 323" based on the model I/D (323=500/4) ?

Tommy Neimeyer · « **Reply #8 on:** September 20, 2006, 06:50:22 AM »

SteveD,

Very good deduction. The story I'm told is that Honda never "kitted" the 500/550 like they did the 750 (CR750) but if they did, it would have been like this machine. Dr. Tom is somewhat a Honda Historian, below is a short bio........

Dr. Tom started racing in the AMA sanctioned Mountain Roadracing Association in 1976. In 1977 he raced a TZ250 Yamaha in the AMA Novice class, and scored enough points in AMA Nationals to earn his AMA Expert License. He was the Overall Champion in the 1976, 1977, and 1978 Aspen Endurance Races.

Also in 1979 thru 1982, Tom was the Builder/Tuner of a Yamaha TZ250, Suzuki GS1000, and Honda RS1000R for rider Rusty Sharp, who was the top AMA National Privateer in 1980-1981.

Tom raced various bikes and classes thru 1984, then retired from active riding and began a restoration and hobby business – EYEBALL ENGINEERING. He restored a 1980 ex-Ron Pierce Factory Honda RS1000R, and a 1973 ex-Steve McLaughlin Factory Honda CR750 racer.

Once a racer, always a racer - in 1989 Dr. Tom started racing again, this time with the AHRMA vintage organization. Throughout the last two decades, he has raced in various classes and built and tuned for several riders; two of the most notable riders he has tuned for are Tim Mings and David Roper – both former AHRMA National Champions.

Tom continued to race in various classes and events through 1997. Due to his success and reputation through the years, he was invited to Japan to participate in the “Time Tunnel” and “Suzuki Historic” events in Tsukuba , Japan in 1994, 1996, and again in 2002. Dr. Tom was the Rider for the 1994 and 1996 events, on Honda Revival built CB72 and CB77 Racers, and he then sponsored rider David Roper in the 2002 event. Roper raced a Yetman Super Hawk based CB77 racer built, tuned, and owned by Dr. Tom, and their association continues to this day; they are still one of the most formidable teams in the AHRMA 350 Gran Prix Class.

A side note for all you car type gear heads – in 1997 Dr. Tom “retired” again from racing for a few years – in order to take the time to build a Ford GT-40 replica. It is a beautiful car, and I can imagine what a hoot it must be on the winding roads in the Rocky Mountains .

In 2002 Dr. Tom resumed racing on a restored Honda CB550 racer in the AHRMA Middleweight Superbike class (a bike that he had also raced back in the late 70’s and early 80’s).

SteveD CB500F · « **Reply #9 on:** September 20, 2006, 07:25:56 AM »

Ahh 1976-1978...

I was at Uni and spent my time going to bike race meets in England. Our favourite was the John Player Transatlantic Trophy each Easter, which was basically US vs UK (but extended to Europe later - bit like the Ryder Cup) and was held at Easter each year at Brands Hatch, Mallory Park and Oulton Park.

I'll scan some old pictures if I can find them and put them up. Barry Sheene, Kenny Roberts et al.

MRieck · « **Reply #10 on:** September 20, 2006, 07:52:53 AM »

Quote from: SteveD CB500F on September 20, 2006, 07:25:56 AM

Ahh 1976-1978...

I was at Uni and spent my time going to bike race meets in England. Our favourite was the John Player Transatlantic Trophy each Easter, which was basically US vs UK (but extended to Europe later - bit like the Ryder Cup) and was held at Easter each year at Brands Hatch, Mallory Park and Oulton Park.

I'll scan some old pictures if I can find them and put them up. Barry Sheene, Kenny Roberts et al.

Those sure were the days Steve.

Sam Green Racing · « **Reply #11 on:** September 20, 2006, 05:10:27 PM »

TomN, I thought it was a C clip when I first looked at it, the more I looked the less it looked like one.

Think I need new specs.

Sam.

RSV12K · « **Reply #12 on:** September 20, 2006, 06:53:04 PM »

What swas done to get those mags on the bike? I can't get a look at the swingarm. Is it stock or a whole nuther thing?

SteveD CB500F · « **Reply #13 on:** September 21, 2006, 01:11:30 AM »

The pictures are now in the Gallery for a more leisurely, hi-res perusal...

Thanks to TomN for forwarding the (big) jpeg files.

www.sohc4.us/gallery/v/custom/cafe/cr323/

jtb · « **Reply #14 on:** September 21, 2006, 05:12:00 AM »

The AHMRA season final is here at Barber Motorsports in Birmingham Oct 20-22, along with the Barber Vintage Motorcycle Festival and swap meet. Anybody going?

MRieck · « **Reply #15 on:** September 21, 2006, 06:32:20 AM »

Quote from: jtb on September 21, 2006, 05:12:00 AM

The AHMRA season final is here at Barber Motorsports in Birmingham Oct 20-22, along with the Barber Vintage Motorcycle Festival and swap meet. Anybody going?

Yup....rub it in John.

bill440cars · « **Reply #16 on:** September 21, 2006, 06:54:12 AM »

Quote from: SteveD CB500F on September 21, 2006, 01:11:30 AM

The pictures are now in the Gallery for a more leisurely, hi-res perusal...

Thanks to TomN for forwarding the (big) jpeg files.

www.sohc4.us/gallery/v/custom/cafe/cr323/

Nice shots, makes it a lot better to check it out. Later on, Bill

tmht · « **Reply #17 on:** September 21, 2006, 07:20:56 AM »

Two questions.

1. Who makes that exhaust? It looks like one of the new Micron GP units.

2. Is the belly pan home brewed? If so how long and what were the steps to make it?

SteveD CB500F · « **Reply #18 on:** October 18, 2006, 07:40:04 AM »

Dr Tom is in November's Classic and Motorcycle Mechanics. There's an article on a recent AHMRA meet with a passing reference to "a bloke with a CBX and a 500 racer". Also a nice phot of the CBX with the front of the CR323.

Sad that they didn't even try to get the details (they are supposed to be a mag for enthusiasts of 70s and 80s bikes...)

Kevin400F · « **Reply #19 on:** October 18, 2006, 01:42:04 PM »

Link to the online version of the Classic Motorcycle Mechanics mag article:

http://www.classicmechanics.com/article3.htm

Nate · « **Reply #20 on:** October 18, 2006, 01:55:27 PM »

Quote from: SteveD CB500F on September 20, 2006, 07:25:56 AM

Ahh 1976-1978...

Yeah 78 was a great year. The year i was born

mlinder · « **Reply #21 on:** October 18, 2006, 02:17:00 PM »

Ive been looking at the ahrma rules. Not a lot of areas the 750 can race. pretty much has to be a cr replica to race. :/

http://www.ahrma.org/rulebook/sec08.htm

Kevin400F · « **Reply #22 on:** October 18, 2006, 03:24:59 PM »

Novice Historic Production - Heavyweight would be a fine class for a basically stock CB750.

mlinder · « **Reply #23 on:** October 18, 2006, 03:26:18 PM »

Quote from: Kevin400F on October 18, 2006, 03:24:59 PM

Novice Historic Production - Heavyweight would be a fine class for a basically stock CB750.

Right, but you'd have to leave it pretty much completely stock. And, if you are too good to be a novice, they bump you up into some other class, where a stock cb750 is not going to be competitive, more than likely.

Chris Liston · « **Reply #24 on:** October 18, 2006, 04:00:06 PM »

Quote from: TomN on September 19, 2006, 07:23:28 PM

If you have any more questions, let me know and I will try to get them answered.

Cheers, Tom

Can Dr. Tom build me one of those beasts. I'll supply the 550

News:

Author Topic: Dr. Tom Marquardt's 550 Hybred AHMRA Racer (Read 12569 times)

RSV12K

tmht