...The Motorcycle Diaries of Dave Moss
Updated: September 21st, 2007
2007 Journals
Project Bios: The People behind The Project
2007 Cummulative Update
With the announcement of Triumph's kit race parts for the 675, we decided to make the commitment to heavily modify the engine to make the bike absolutely class competitive in the power department and to make some suspension upgrades. We decided to order only those parts that were quick to install, but a package that would make for improved engine performance. We decided not to change the head gasket as this requires race fuel only such as Sunoco 100 unleaded or VP Ultimate 4.2. Project 675 race bike builder Jim Williams, long time Triumph tech, installed all the parts onto the bike.
Triumph Race parts installed were:
| A9600197 | Arrow Exhaust, Stage 2 |
| A9618055 | Intake cam |
| A9618056 | Exhaust cam |
| A9618057 | Cam sprockets |
| A9618058 | Valve spring kit |
| A9618059 | Cam chain kit |
| A9618060 | Cam chain tensioner kit |
| A9618061 | Valve kit |
| A9618063 | Velocity stack trumpets |
| A9618070 | ECU kit |
| A9618071 | Harness kit |
| A9618075 | Air filter kit |
| A9618076 | Manual idle kit |
| A9728028 | Carbon fiber clutch cover |
| A9728029 | Carbon fiber crank cover |
| A9728032 | Carbon fiber alternator cover |
After installing all the parts and setting cam timing at 104 degrees for both intake and exhaust cams, we installed a Power Commander as mapping is required after the kit parts are installed (Tune Boy is an alternate software choice). The first dyno run on pump fuel saw less horsepower than stock, but there was no surprise with that data. Using information from other tuners, we revised the map and saw an immediate jump to 102 SAE bhp. Pump fuel was removed and '76' 100 unleaded race fuel was added. This improved peak performance to 106.8 SAE bhp. The air fuel ratio was 11.8.
In order to further improve the chassis, we moved the rear axle 41mm from the front edge of the swing arm axle bolt location and Jim Williams designed new swing arm pivot point inserts and had them CNC machined in billet. This corrected the swing arm angle lowered the seat height by almost 2 inches! The improvement in swing arm angle also required a softer shock spring due to the change in leverage ratio, so the 600lb spring used with the stock inserts was changed to a 525lb spring (rider weight 195lbs, no gear).
The race bike had one day of track day riding with Keigwins at the Track to break the motor in and recalibrate my own mind given the significant power increase. There was far more power from 9,000 rpm so the Dunlop 209 180/55 x 17 was replaced with the 209 190/55 x 17 for more side grip. That required significant changes to the Elka shock ride height to correct swing arm angle and the shock was set 3mm shorter than stock. During testing the most noticeable difference other than improved drive and power was significant improvement in braking as the bike had more rake and trail with the fork caps being flush with the upper triple clamp. This required a little more effort to initiate the turn, but once tipped over the bike was rock solid allowing very early positive throttle roll on to get excellent drive out of the corner. By the end of the day I was very happy with set up and loaded the bike into the trailer.
The 675 was then taken to Infineon Raceway/Sears Point for the AFM race in August. As per usual there was no time for any practice on Saturday, so I had my usual warm up Sunday morning of 20 minutes. After three laps I knew the swing arm angle was a long way off in set up when the rear tire spun up every time I applied the throttle aggressively. SAG on the Elka shock was set at 31mm so I added 2 turns of preload, one turn of ride height and set low speed compression at 10 clicks out from full stiff. After two laps the rear tire only spun up at the bottom of the carousel (turn 6) where the most G load is found. Half a turn of preload was added, low speed compression was set to 8 clicks out from full stiff and half a turn of ride height was added to the Elka shock. The checkered flag came out after 2 laps, but the 675 could drive out of the corner and hold the line with aggressive throttle use, so the back of the bike was sorted for swing arm angle, SAG and damping.
Photo ©Gary Rather
In the first race at true race pace the swing arm angle was still too shallow and wheel spin came back. The forks with SAG of 45mm, 1.0kg springs and an oil level of 125mm also bottomed out in heavy breaking areas and in turn six. Another half turn of ride height was added to the shock, half a turn of preload was added to the shock spring. The forks were raised 2mm above the upper triple clamp, SAG was changed to 40mm and compression was set from 8 clicks out from full stiff to 6.
In race two the bike handled much better with no wheel spin, but the front end still bottomed in the same areas of the track. Fork compression was changed to 4 clicks out and half a turn more preload was added to change SAG to 38mm.
In race three, the bike felt significantly better in all aspects at every point in the track. This was reflected in race results in starting from 26 th and finishing 12 th, with a best lap time of 1:49.4, only a few seconds off AMA qualifying times. Very encouraging! The shock spring needs to be upgraded to a 550lb spring for the September AFM round, again at Sears Point.
To further improve engine performance and review fuel changes in SAE bhp, the bike was taken under the wing of Kevin at MCE racing. We put Sunoco 110 leaded into the bike and reviewed only bhp and fuel readings. Note that the cam timing was not changed prior to, during or after the dyno runs.
The base run gave 107.5 SAE bhp and air fuel ration of 11.8. Triumphs seems to need to run a little “fat” rather than lean on air fuel, so Kevin decided to lean the ratio out slightly. The beauty of the leaded fuel is that the lead lubricates the engine, and the running temp of the 675 dropped from 6 bars to 5, ideal in 100 degree plus weather in summer! After a couple of runs and some changes to the map, the bike produced 109.0 SAE bhp with an air fuel ration of 12.1 and a noticeable flattening of the fuel line between 9 and 14,000rpm. Also worthy of note was peak power stayed constant between 11,800 and 14,000 rpm with a very linear line from 8-12,000 rpm. This changed the power deliver from the original map to more of a tractor feel, encouraging early use of full throttle out of corners and made the bike much easier to ride overall.
The tank was emptied and Sunoco 100 unleaded was used next. Changing to a lower octane fuel provided a much faster burn, and Kevin was expecting a gain of 2-3 SAE bhp just from the fuel change. The initial run showed 111.3 SAE bhp at peak and air fuel ratio of 12.3, so Kevin’s prediction was correct. The most significant gains were from 7,000 rpm on up. The map remained unchanged, as Kevin believed there was not much to gain at any throttle position, so the bike was pulled from the dyno. On track, the seat of the pants feel was a lot more than 2.3bhp gain!
Well that brings us up to date on Project Daytona, make sure you come out and see us on Sept 29th at Sears!