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I will attend Mosport this Sat. Aug. 13 as a limping spectator . Joe Peck and Jack Sennett will take me in a car thing. Nice of them , see people there if attending these races. 
Racing Mosport
- Thread starter Doug MacRae
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Changed from Sat. to Sun. for our Mosport day of racings.
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I suggest that cracked crankcases might have a lot to do with balance factor. When the balance factor is higher and the motor is rigidly mounted, it is possible to get the situation where the motor is almost vibrationless right through the operating rev range (in my situation 5000 RPM to 7000 RPM ). The isolastics might insulate motor destroying vibration from the rider, but what else might be happening ? My bike actually rocks backwards and forwards when it is idling. Perhaps the internal forces are less at very low revs ?
Doug MacRae
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I will be racing of course at Mosport this weekend, I usually pit inside turn 1 somewhere if anyone makes it out.
I like to use Steve Maney cases but I blew up a couple sets of them in a row (and alloy barrels and everything below the head actually) and when we built up the short stroke we spent a lot of time and money doing up the internals so when it came to cases we used some late 850 stock cases. They will not last, they will crack up with the hp we are making but they should be OK for a few more weekends and I will get another set of Maney cases when we have to take it apart for inspection.
I like to use Steve Maney cases but I blew up a couple sets of them in a row (and alloy barrels and everything below the head actually) and when we built up the short stroke we spent a lot of time and money doing up the internals so when it came to cases we used some late 850 stock cases. They will not last, they will crack up with the hp we are making but they should be OK for a few more weekends and I will get another set of Maney cases when we have to take it apart for inspection.
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I've watched that video of you crashing at Daytona when the motor exploded. With a commando, the big bang has to happen, it is not IF but WHEN ? Some of your on-board stuff horrifies me, that weak long-stroke motor revving so hard and for so long, it would play on my nerves. My theory is that however fast you go when you race, that is the speed you have to be prepared to get off at. In my opinion the commando motor is excellent if used within it's limitations - high revs for too long is asking for trouble. On a short circuit, the combination of torque, gearing and handling can make a commando-based bike very competitive. However the big straight-line drag is not on. I would never race my 850 on a big circuit like Daytona. If the fail happens on a short circuit, the outcome might be much better.
lcrken
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I kind of understand your concern over the risk, but thatt seems to be the price of competing at the top. We keep squeezing more horsepower out of an old design until something breaks. Then we fix that, and keep making more horsepower until we find the next weak point, and repeat the sequence pretty much endlessly. That's just the name of the game. And for the serious engine builders, that's the challenge that keeps them going. All other things being equal, more usable horsepower means better race results. If you just want to have fun on the track, you don't have to go to those limits. Racing in mid-pack, or even at the rear, is just as exciting, as long as you have someone to race with, (ask me how I know). But if you want to run with the big dogs, you have to step everything up to that level. We can't all do that, but we can certainly appreciate the accomplishments of those who can.
Ken
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Doug MacRae said:
You've probably got the one of the fastest if not the very fastest Commando on the tracks. Even though its so pumped up - I think it will stay together (I hope) because of the stress reducing internals you are using and Herb's careful assembly.
Good luck and have fun this weekend.
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I suggest that with a commando-based bike it is easier to run with the lead bunch on short circuits than on a large circuit. The advantage lies in the torque characteristic. On a big circuit it is necessary to use higher gearing which makes the commando slower in the tighter parts of the circuit, where good handling and rider ability usually pay off. If you were racing against something such as a CR750 Honda, their disadvantage is more evident in the slower parts of the circuit. In Australia our CB750 Hondas are on methanol and many are over 1000cc capacity - all use 4 into 1 pipes. My Seeley is still better in the slower parts of circuits, especially when it rains.
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I know exactly what you mean , on the shorter circuits with more twists and turns my norton is better ( standard motor and four speed box ) most of the bikes in my race are Japanese ranging from 600,s to 1300 Kawasakis . Here is a video from Anglesey in Wales .
p.s excuse the poor quality 8)
https://www.youtube.com/watch?v=N3pj4BCdLJQ
p.s excuse the poor quality 8)
https://www.youtube.com/watch?v=N3pj4BCdLJQ
I dont want that case back
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The four speed box in a Commando puts you at a severe disadvantage when racing. If it is wide ratio, everything happens too slowly. If it is close ratio, you can choose where you want to lose a race - off the start or at the ends of the straights - depending on whether you set the overall gearing high or low. A while ago, I sold a very good TZ350 Yamaha to buy the 6 speed TTI gearbox - a conscious decision to go with the Seeley and not race the two-stroke. I still have not been able to afford another practice day, let alone a race day. The new gearbox should make a big difference when I get to race the bike again. My problem is that the family crises just seem to keep on coming along - cannot last forever ?
I'd make one suggestion - if you road race, the bike must do something for you. If you are getting a hard time, change the bike - modify or replace. When you adjust to your machine's deficiencies, you are not doing yourself any favours, even if you learn a lot of hard lessons.
I'd make one suggestion - if you road race, the bike must do something for you. If you are getting a hard time, change the bike - modify or replace. When you adjust to your machine's deficiencies, you are not doing yourself any favours, even if you learn a lot of hard lessons.
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I was just watching this video about the Superbike race at Anglesey : https://www.youtube.com/watch?v=N3pj4BCdLJQ
The bike was being very well ridden but if it is a commando, the guy was getting on the gas too late in most of the corners. That is what happens if the bike does not tighten its line in corners. What it means is you end up playing the same game as the guys on the four cylinder bikes - you cannot win a drag race with a commando. Unless you have got the run on them under braking and coming out of corners, you will end up nowhere. The thing is that it would be possible to make a four cylinder superbike tighten it line in corners, however the risk of getting the hi-side would be much greater. We all need to play to our strengths. With a commando, it is light weight, loads of torque and nimble handling.
It is really great to see guys such as Doug Macrae persevering with Commandos. I never believed in my Seeley 850 until I tried racing it and recognised it's potential. It had sat unraced for 20 years after I built it. It's a very strange bike, however I really love it even with it's limitations.
The bike was being very well ridden but if it is a commando, the guy was getting on the gas too late in most of the corners. That is what happens if the bike does not tighten its line in corners. What it means is you end up playing the same game as the guys on the four cylinder bikes - you cannot win a drag race with a commando. Unless you have got the run on them under braking and coming out of corners, you will end up nowhere. The thing is that it would be possible to make a four cylinder superbike tighten it line in corners, however the risk of getting the hi-side would be much greater. We all need to play to our strengths. With a commando, it is light weight, loads of torque and nimble handling.
It is really great to see guys such as Doug Macrae persevering with Commandos. I never believed in my Seeley 850 until I tried racing it and recognised it's potential. It had sat unraced for 20 years after I built it. It's a very strange bike, however I really love it even with it's limitations.
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Yes Acorel it is my rickman commando , and it has a stadard ratio four speed box . After riding a friends bike with five gears it was a revelation .
Doug MacRae
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Sorry for the late post, I was away for a few weeks.
Mosport was a bit of an anomaly this year with Saturday's heat races being completely cancelled due to dense fog all morning and heavy thunderstorms in the afternoon. I registered late as usual which meant I would be gridded near the back - normally this would not matter as you just get up near the front in your heat and then you be up there for the final, but now I would have fight from the back in the finals Sunday in races that were shortened from 8 to 5 laps to squeeze in cancelled races.
Period 2 heavy is my normal class- this year there was some interesting competition with two CR750's- one that almost always beats me at the high HP Mosport track and the other a very special bike up from the U.S., ridden by an Brit Superbike rider. There was also Crussell on the H2R Kawi 750 triple two stroke (who has won every time he has come up from California) and the fast Yammando, run on the dyno before the weekend was putting out a reputed 85 HP. I got a decent start, the CR750's disappeared, and by the time I caught the Yammando which had started on pole, the race was run so, 4th place.
The Period 3 Superbike M class (bikes to 1982) is a class above me that I bump up into- was very full with 26 bikes on the grid. I got a very good start from the 6th row and fought up close to the third place rider by the end of 5 laps and had to settle for another 4th.
The bike was pulling great through the mid-range, better than before- still not quite revving out as high as it should but that monster mid-range is fantastic. Some minor issues with the motor fouling some plugs but other than that all was good.
Mosport was a bit of an anomaly this year with Saturday's heat races being completely cancelled due to dense fog all morning and heavy thunderstorms in the afternoon. I registered late as usual which meant I would be gridded near the back - normally this would not matter as you just get up near the front in your heat and then you be up there for the final, but now I would have fight from the back in the finals Sunday in races that were shortened from 8 to 5 laps to squeeze in cancelled races.
Period 2 heavy is my normal class- this year there was some interesting competition with two CR750's- one that almost always beats me at the high HP Mosport track and the other a very special bike up from the U.S., ridden by an Brit Superbike rider. There was also Crussell on the H2R Kawi 750 triple two stroke (who has won every time he has come up from California) and the fast Yammando, run on the dyno before the weekend was putting out a reputed 85 HP. I got a decent start, the CR750's disappeared, and by the time I caught the Yammando which had started on pole, the race was run so, 4th place.
The Period 3 Superbike M class (bikes to 1982) is a class above me that I bump up into- was very full with 26 bikes on the grid. I got a very good start from the 6th row and fought up close to the third place rider by the end of 5 laps and had to settle for another 4th.
The bike was pulling great through the mid-range, better than before- still not quite revving out as high as it should but that monster mid-range is fantastic. Some minor issues with the motor fouling some plugs but other than that all was good.
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