THE PLAN & THE PROJECT
It all started as an idea for a 50th birthday present to myself, I decided I wanted to go vintage bike racing with AHRMA.
About a year before the anticipated date, I started to get to work on an old ’72 BMW R60/5 airhead/boxer 650 twin that was missing the Left side top end and had been partially disassembled.
I found the replacement top end parts from a guy named Bruce (Boxers by Bruce) that I met at the BMOA New Ulm Rallye; he gave me a great deal on the head, pushrods, carb parts and a few assorted bits. It wasn’t that big a chore to clean up the stump that had been left open for nearly a dozen years, install the top end, overhaul the carbs and kick the little boxer to life. It ran well enough, but the thought lingered in the back of my mind that the engine internals might not be all that anxious to propel the rusty roller at race pace for any length of time without protest.
Nearly a full year came and went without another thought to the entire project, but as the calendar pages came away, my anticipatory notes started appearing with more frequency, so I started to formulate a more concrete plan. I applied on line to the most convenient sanctioning body, CMRA, for a racing license to be obtained after a track day and racing school presented by Lone Star Track Days at Texas World Speedway; as a happy coincidence, the scheduled date was September 10th, my 50th birthday (2007).
Then came the harder part – assembling a reliable road racer for the project. I wandered around my shop, garage and sheds, looking over the various bikes and parts parked, stacked and scattered around; I considered a couple of my complete running Bonnevilles in the garage, but decided I’d much rather leave them alone as they are mostly original. I considered my Yamaha RD400, but quickly determined I could never be competitive against the 500s I’d be running against.
My first choice fell to a ’63 Triumph Bonneville street tracker chassis that I had just acquired as a project bike for resale, with a fairly decent ’72 Bonnie engine that was the best of 5 Triumph lumps I had laying on the shop floor. I quickly got to work stripping the chassis to the bare essentials and readying the lump for cleanup and assembly, then it occurred to me that I ought to examine the rules for anything on the street tracker that might not be compliant, as the last thing I wanted was to be disqualified before I ever got to race. This decision proved fortunate, as the frame had been modified to accept the fiberglass bodywork, and the wheels were neither original nor factory options for the bike’s vintage. At this point, I had only lost two half-days’ work, but time was getting tight!
Pretty quickly I concluded that I had enough parts to build a rolling chassis that wouldn’t require much effort to put together, and a complete running ’68 Triumph TR6 650 engine with a ’67 dual carb Bonneville head that had been pulled from a running “donor bike” that I acquired about a year and a half earlier for a client project. I had been saving the engine for a ’68 Bonnie that I intended to refurbish to near-original condition “one of these days”, and the chassis parts were supposed to be for project ’69 Bonneville that I intended to sell; no matter, they were the best choices for the project.
It didn’t take long to get it put together, and then it was a simple matter to drop the engine in and bolt it in place. In just about a week’s time, I had what resembled a motorcycle cobbled together from scratch.
It took another couple of days to receive the new Dunlop Arrowmax GT501 tires, new cables, levers and a few other bits & bobs for the project, and I quickly got them installed. I pulled my best pair of used Amal concentric carbs off the shelf (I had previously overhauled them and set them aside for my ’68 Bonnie project), as well as a good used Boyer ignition box, and installed them. Then I decided on a set of big-bore exhaust headers over 2 other sets of stock headers with crossover pipes that had much better chrome, and a pair of slightly acid-etched original Bonnie style straight-through mufflers. I wanted to do something a little different with the exhaust, so I installed a pair of “kink adapters” from newbonneville.com for mounting old style mufflers to New Bonnevilles, which in my case resulted in a much steeper upsweep at the tailpipes; the final assembly resulted in pipes which didn’t need to be disturbed to service either the rear axle, suspension, or primary cover screws.
I then freshened up the front suspension with a good flush and inspection (which revealed seals, stanchion tubes and bushings in great shape), and re-assembled with new rubber fork gaiters. I had previously packed the steering head bearings when I assembled the rolling project, so I didn’t mess with the fork yokes. It was a quick and easy task to pull the ½ clamps off the street tracker (they are much better than the OEM “P” clamps), and a set of clubman bars I had on the BMW, and mount them up. I took the opportunity to inspect, clean & service the front brakes, and make sure I had good free play in the actuation pivot points, and full contact on the brake linings. I could have saved myself a day’s work by taking 10 or 15 more minutes on the front yokes and Swingarm, but a bit more on that later.
I had a nice 2-1/2 gallon Bonneville tank set aside for the ’68 Bonnie, but that would fall victim to the racing project, as would an almost new set of Hagon shocks and a slightly used set of Barnett clutch plates. A bit more scrounging around the storage room and I came up with a seat pan, a crusty, crumbling seat foam, and a mostly intact seat cover; I did a bit of trimming on the foam to minimize the dribbling dust and lower the front section height, then clipped it in with the cover onto the pan. I had to spread the hinges apart a bit to install the seat, as they had been welded onto the pan, then bend them back together and that part was done. The oil tank was in good shape, but the only spare sidecover I had needed some repairs and adaptation involving the “blue tipped wrench” (oxygen-acetylene torch); a bit of fitting & fiddling, welding and drilling, and it was neatly installed. I made a happy discovery there, as an empty bottle of transmission oil fit perfectly in the sidecover to serve as my crankcase vent catch tank.
At this point, all that remained was to wire the bike, which took one day, plumb all the oil & fuel lines, and connect all the remaining cables and wires (one more day). Now nearly two full weeks into the project, it was time to test-fire the engine. I used a ratty battery that held enough charge to produce a solid honk from my test horn (I don’t need no steenking volt meter), dumped in a gallon of gas and a couple of quarts of oil, turned on the switch and started kicking. After about the third kick, I got a couple of pops and a backfire; re-checking the static timing, and a bit of re-adjustment, and I got it to run on one cylinder.
I did the math in my head and calculated the remaining days ‘till my track day, and decided it would be best to eliminate the three biggest potential problems. I pulled the brand new set of Amal concentrics and Sparx ignition system off the shelf (yep, the ’68 Bonnie’s parts), and did the swap; only one additional day lost. After that chore, the bike fired right up and I was able to balance the carbs and set the timing.
The first test ride was only up to about 30 MPH on our private drive which is about a quarter mile long with 3 slight curves and a turn-around in a relative’s driveway; so although the bike felt okay, it was not nearly sufficient to reveal the pending issues with the chassis. The bike was starting, idling, running and stopping well, and there was virtually no oil leakage whatsoever.
The next step was to grab my helmet and take it out for a bit more of a shake-down run of about 4 miles around the more open stretches of road in the neighborhood. The first thing that became apparent was a bit of a rear end twitch once I was able to pour on some throttle, then another twitch as I snapped off the throttle to check the carb slide return springs. The twitch didn’t seem at all violent, so I continued on at a modest pace in order to see how the higher revs felt. The second thing that became apparent was some looseness in the front end that manifested itself under heavy braking; this wasn’t bad, either, so the test continued.
Back in the garage, I determined that the top yoke hadn’t fully seated on the steering stem, so a bit of nipping up was in order; that done, the looseness of the front end went away, resulting in a nice snug yoke with a good range of damping available from the OEM Triumph “faucet handle” steering damper.
The twitch in the rear end proved to be a good bit more troublesome, as a firm sideward tug on the rear wheel revealed a significant looseness in the Swingarm bushings. Thankfully, I realized that I could address the issue by simply pulling the footpeg/engine mounting plates, loosening off the lower shock bolts, and pulling the main pivot bolt. What I found was both amazing and extremely relieving; amazing in that one of the two main pivot blocks was missing entirely, and relieving in that If I had dismissed it, it would have caused a tech inspection failure and could have caused a nasty get-off.
So, almost two weeks to the day that I started the project, the bike was done, generally sorted, and running well; the best thing was that I had essentially completed the project just in time to load up and hit the road. The trip planning had formalized into one stop for a weekend at Port Aransas on the Texas coast with my family to scatter my Dad’s ashes in the Gulf of Mexico (his favorite fishing spot), Monday track day / racing school at College Station, travel to Austin to meet up with my friend Charlie and take advantage of his bolt-drilling drill press / bench vise setup to lockwire my bike, then two days of driving to Albuquerque for race weekend at the Sandia Motor Raceway.
continued...
It all started as an idea for a 50th birthday present to myself, I decided I wanted to go vintage bike racing with AHRMA.
About a year before the anticipated date, I started to get to work on an old ’72 BMW R60/5 airhead/boxer 650 twin that was missing the Left side top end and had been partially disassembled.
I found the replacement top end parts from a guy named Bruce (Boxers by Bruce) that I met at the BMOA New Ulm Rallye; he gave me a great deal on the head, pushrods, carb parts and a few assorted bits. It wasn’t that big a chore to clean up the stump that had been left open for nearly a dozen years, install the top end, overhaul the carbs and kick the little boxer to life. It ran well enough, but the thought lingered in the back of my mind that the engine internals might not be all that anxious to propel the rusty roller at race pace for any length of time without protest.
Nearly a full year came and went without another thought to the entire project, but as the calendar pages came away, my anticipatory notes started appearing with more frequency, so I started to formulate a more concrete plan. I applied on line to the most convenient sanctioning body, CMRA, for a racing license to be obtained after a track day and racing school presented by Lone Star Track Days at Texas World Speedway; as a happy coincidence, the scheduled date was September 10th, my 50th birthday (2007).
Then came the harder part – assembling a reliable road racer for the project. I wandered around my shop, garage and sheds, looking over the various bikes and parts parked, stacked and scattered around; I considered a couple of my complete running Bonnevilles in the garage, but decided I’d much rather leave them alone as they are mostly original. I considered my Yamaha RD400, but quickly determined I could never be competitive against the 500s I’d be running against.
My first choice fell to a ’63 Triumph Bonneville street tracker chassis that I had just acquired as a project bike for resale, with a fairly decent ’72 Bonnie engine that was the best of 5 Triumph lumps I had laying on the shop floor. I quickly got to work stripping the chassis to the bare essentials and readying the lump for cleanup and assembly, then it occurred to me that I ought to examine the rules for anything on the street tracker that might not be compliant, as the last thing I wanted was to be disqualified before I ever got to race. This decision proved fortunate, as the frame had been modified to accept the fiberglass bodywork, and the wheels were neither original nor factory options for the bike’s vintage. At this point, I had only lost two half-days’ work, but time was getting tight!
Pretty quickly I concluded that I had enough parts to build a rolling chassis that wouldn’t require much effort to put together, and a complete running ’68 Triumph TR6 650 engine with a ’67 dual carb Bonneville head that had been pulled from a running “donor bike” that I acquired about a year and a half earlier for a client project. I had been saving the engine for a ’68 Bonnie that I intended to refurbish to near-original condition “one of these days”, and the chassis parts were supposed to be for project ’69 Bonneville that I intended to sell; no matter, they were the best choices for the project.
It didn’t take long to get it put together, and then it was a simple matter to drop the engine in and bolt it in place. In just about a week’s time, I had what resembled a motorcycle cobbled together from scratch.
It took another couple of days to receive the new Dunlop Arrowmax GT501 tires, new cables, levers and a few other bits & bobs for the project, and I quickly got them installed. I pulled my best pair of used Amal concentric carbs off the shelf (I had previously overhauled them and set them aside for my ’68 Bonnie project), as well as a good used Boyer ignition box, and installed them. Then I decided on a set of big-bore exhaust headers over 2 other sets of stock headers with crossover pipes that had much better chrome, and a pair of slightly acid-etched original Bonnie style straight-through mufflers. I wanted to do something a little different with the exhaust, so I installed a pair of “kink adapters” from newbonneville.com for mounting old style mufflers to New Bonnevilles, which in my case resulted in a much steeper upsweep at the tailpipes; the final assembly resulted in pipes which didn’t need to be disturbed to service either the rear axle, suspension, or primary cover screws.
I then freshened up the front suspension with a good flush and inspection (which revealed seals, stanchion tubes and bushings in great shape), and re-assembled with new rubber fork gaiters. I had previously packed the steering head bearings when I assembled the rolling project, so I didn’t mess with the fork yokes. It was a quick and easy task to pull the ½ clamps off the street tracker (they are much better than the OEM “P” clamps), and a set of clubman bars I had on the BMW, and mount them up. I took the opportunity to inspect, clean & service the front brakes, and make sure I had good free play in the actuation pivot points, and full contact on the brake linings. I could have saved myself a day’s work by taking 10 or 15 more minutes on the front yokes and Swingarm, but a bit more on that later.
I had a nice 2-1/2 gallon Bonneville tank set aside for the ’68 Bonnie, but that would fall victim to the racing project, as would an almost new set of Hagon shocks and a slightly used set of Barnett clutch plates. A bit more scrounging around the storage room and I came up with a seat pan, a crusty, crumbling seat foam, and a mostly intact seat cover; I did a bit of trimming on the foam to minimize the dribbling dust and lower the front section height, then clipped it in with the cover onto the pan. I had to spread the hinges apart a bit to install the seat, as they had been welded onto the pan, then bend them back together and that part was done. The oil tank was in good shape, but the only spare sidecover I had needed some repairs and adaptation involving the “blue tipped wrench” (oxygen-acetylene torch); a bit of fitting & fiddling, welding and drilling, and it was neatly installed. I made a happy discovery there, as an empty bottle of transmission oil fit perfectly in the sidecover to serve as my crankcase vent catch tank.
At this point, all that remained was to wire the bike, which took one day, plumb all the oil & fuel lines, and connect all the remaining cables and wires (one more day). Now nearly two full weeks into the project, it was time to test-fire the engine. I used a ratty battery that held enough charge to produce a solid honk from my test horn (I don’t need no steenking volt meter), dumped in a gallon of gas and a couple of quarts of oil, turned on the switch and started kicking. After about the third kick, I got a couple of pops and a backfire; re-checking the static timing, and a bit of re-adjustment, and I got it to run on one cylinder.
I did the math in my head and calculated the remaining days ‘till my track day, and decided it would be best to eliminate the three biggest potential problems. I pulled the brand new set of Amal concentrics and Sparx ignition system off the shelf (yep, the ’68 Bonnie’s parts), and did the swap; only one additional day lost. After that chore, the bike fired right up and I was able to balance the carbs and set the timing.
The first test ride was only up to about 30 MPH on our private drive which is about a quarter mile long with 3 slight curves and a turn-around in a relative’s driveway; so although the bike felt okay, it was not nearly sufficient to reveal the pending issues with the chassis. The bike was starting, idling, running and stopping well, and there was virtually no oil leakage whatsoever.
The next step was to grab my helmet and take it out for a bit more of a shake-down run of about 4 miles around the more open stretches of road in the neighborhood. The first thing that became apparent was a bit of a rear end twitch once I was able to pour on some throttle, then another twitch as I snapped off the throttle to check the carb slide return springs. The twitch didn’t seem at all violent, so I continued on at a modest pace in order to see how the higher revs felt. The second thing that became apparent was some looseness in the front end that manifested itself under heavy braking; this wasn’t bad, either, so the test continued.
Back in the garage, I determined that the top yoke hadn’t fully seated on the steering stem, so a bit of nipping up was in order; that done, the looseness of the front end went away, resulting in a nice snug yoke with a good range of damping available from the OEM Triumph “faucet handle” steering damper.
The twitch in the rear end proved to be a good bit more troublesome, as a firm sideward tug on the rear wheel revealed a significant looseness in the Swingarm bushings. Thankfully, I realized that I could address the issue by simply pulling the footpeg/engine mounting plates, loosening off the lower shock bolts, and pulling the main pivot bolt. What I found was both amazing and extremely relieving; amazing in that one of the two main pivot blocks was missing entirely, and relieving in that If I had dismissed it, it would have caused a tech inspection failure and could have caused a nasty get-off.
So, almost two weeks to the day that I started the project, the bike was done, generally sorted, and running well; the best thing was that I had essentially completed the project just in time to load up and hit the road. The trip planning had formalized into one stop for a weekend at Port Aransas on the Texas coast with my family to scatter my Dad’s ashes in the Gulf of Mexico (his favorite fishing spot), Monday track day / racing school at College Station, travel to Austin to meet up with my friend Charlie and take advantage of his bolt-drilling drill press / bench vise setup to lockwire my bike, then two days of driving to Albuquerque for race weekend at the Sandia Motor Raceway.
continued...