Re: Cobrafreak's board track racer project, never ends!
Very nice build. I love what youve done with it.
Very nice build. I love what youve done with it.
Cobrafreak's board track racer project, has ended
- Thread starter cobrafreak
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Re: Cobrafreak's board track racer project, never ends!
now its got about the same horses as an old school board tracker :mrgreen:
now its got about the same horses as an old school board tracker :mrgreen:
Re: Cobrafreak's board track racer project, never ends!
I found a motorcycle speed calculator on line that allows the input of various ratios, tire sizes, and rpms. At 3600 rpm's the bike is capable of 74 mph, at 6500 rpm's it is capable of 132mph. Salt Flats anyone? :shock: So this set up, if you had motorcycle tires and a long strait, and you were tucked in laying on the tank, you could go as fast as a real board tracker of the day, no problem. If vintage motorcycle tires are available through various outlets they would need to be put on a motorcycle rim because they can't fit bicycle rims.
I found a motorcycle speed calculator on line that allows the input of various ratios, tire sizes, and rpms. At 3600 rpm's the bike is capable of 74 mph, at 6500 rpm's it is capable of 132mph. Salt Flats anyone? :shock: So this set up, if you had motorcycle tires and a long strait, and you were tucked in laying on the tank, you could go as fast as a real board tracker of the day, no problem. If vintage motorcycle tires are available through various outlets they would need to be put on a motorcycle rim because they can't fit bicycle rims.
Re: Cobrafreak's board track racer project, never ends!
That sounds fast Cobra
Is the 26" motorcycle rim you speak of a different diametre to a modern 26" bicycle rim? Are they available at a reasonable price? And what about the tyres? And are you considering these for your project?
That sounds fast Cobra
Is the 26" motorcycle rim you speak of a different diametre to a modern 26" bicycle rim? Are they available at a reasonable price? And what about the tyres? And are you considering these for your project?
Re: Cobrafreak's board track racer project, never ends!
Man that is very fast.
Do you allready have a tachometer (correct spelling?)
When are you going to test your machine? I'm very anxious to know what your set up is capable of.
cobrafreak said:
Man that is very fast.
Do you allready have a tachometer (correct spelling?)
When are you going to test your machine? I'm very anxious to know what your set up is capable of.
Re: Cobrafreak's board track racer project, never ends!
No, same diameter but the bead is different. I am not really seeking fast. I was seeking great reliability and quickness to legal speeds. I have a cobra if I want to scare myself! Lol.harry76 said:That sounds fast Cobra
Is the 26" motorcycle rim you speak of a different diametre to a modern 26" bicycle rim? Are they available at a reasonable price? And what about the tyres? And are you considering these for your project?
Re: Cobrafreak's board track racer project, never ends!
No tach yet. Mabey later. I am the wrong guy to ask to go fast on two wheels. I want to live!stocksucks said:
Re: Cobrafreak's board track racer project, never ends!
I wasnt thinking outright speed either. But you did mention your brakes were a litlle weak. I thought u may have been considering new wheels and hubs. I wont be interested in setting land speed records either. But my brother runs a car club and every now and then they have car shows at the local racetrack.... they have the static show with street machines before lunch, at lunch the cars are allowed to do laps on the track before they start having timed laps in the afternoon. I was thinking it would be cool to take my bike there when its done, then do some laps of the track on it. And it would be nice to have a little insurance policy with tyres that can run at speed.
Although you did mention that quality bike tyres could be capable of these speeds. If you have any knowledge on this subject id love you to share.....
cobrafreak said:No, same diameter but the bead is different. I am not really seeking fast. I was seeking great reliability and quickness to legal speeds. I have a cobra if I want to scare myself! Lol.harry76 said:That sounds fast Cobra
Is the 26" motorcycle rim you speak of a different diametre to a modern 26" bicycle rim? Are they available at a reasonable price? And what about the tyres? And are you considering these for your project?
I wasnt thinking outright speed either. But you did mention your brakes were a litlle weak. I thought u may have been considering new wheels and hubs. I wont be interested in setting land speed records either. But my brother runs a car club and every now and then they have car shows at the local racetrack.... they have the static show with street machines before lunch, at lunch the cars are allowed to do laps on the track before they start having timed laps in the afternoon. I was thinking it would be cool to take my bike there when its done, then do some laps of the track on it. And it would be nice to have a little insurance policy with tyres that can run at speed.
Although you did mention that quality bike tyres could be capable of these speeds. If you have any knowledge on this subject id love you to share.....
Re: Cobrafreak's board track racer project, never ends!
The Government does not require bicycle tires to be DOT speed rated like every other kind of tire is. Ratings of tires are done by putting them on a machine that simulates high speed driving over a specific length of time with the weight of a vehicle on the tire as is operates. The temperature of the tires after the sustained test determines the speed rating of said tire. If the tire is cool it goes to the next higher speed test and on and on and on until the particular tire shows heat from the friction deemed unsafe. It is heat that causes tires to explode and shred at speed. The lowest rated speed rating is 70 mph sustained speed. I read that a bicycle tire would easily pass the sustained test to achieve a 70 mph speed rating. It makes sense as bicycle road racers often reach speeds of 50 to 60 in downhill portions of the Tour de France and downhill racers often hit 70. Now as in safety ratings, they degrade over time. In airplanes, dive watches, and tires. The older it gets, the lower the safety rating. So if you are going to do a high speed test, do it on brand new tubes and tires at the max pressure on the tire to reduce the friction on the contact patch between the rubber and the road.
My double drum brakes are equal to the best brakes of the day in the vintage motorcycle world. If you ride slowly, carefully, and safely you will not have any problems. A high speed run doesn't require good brakes because hopefully you are going in a long strait line and you can coast for a long time before needing the brakes. It's just a test in a controlled environment. I'm just happy operating my machine at residential street speeds with maybe an occasional ride on a 45 to 50 mph road.
The Government does not require bicycle tires to be DOT speed rated like every other kind of tire is. Ratings of tires are done by putting them on a machine that simulates high speed driving over a specific length of time with the weight of a vehicle on the tire as is operates. The temperature of the tires after the sustained test determines the speed rating of said tire. If the tire is cool it goes to the next higher speed test and on and on and on until the particular tire shows heat from the friction deemed unsafe. It is heat that causes tires to explode and shred at speed. The lowest rated speed rating is 70 mph sustained speed. I read that a bicycle tire would easily pass the sustained test to achieve a 70 mph speed rating. It makes sense as bicycle road racers often reach speeds of 50 to 60 in downhill portions of the Tour de France and downhill racers often hit 70. Now as in safety ratings, they degrade over time. In airplanes, dive watches, and tires. The older it gets, the lower the safety rating. So if you are going to do a high speed test, do it on brand new tubes and tires at the max pressure on the tire to reduce the friction on the contact patch between the rubber and the road.
My double drum brakes are equal to the best brakes of the day in the vintage motorcycle world. If you ride slowly, carefully, and safely you will not have any problems. A high speed run doesn't require good brakes because hopefully you are going in a long strait line and you can coast for a long time before needing the brakes. It's just a test in a controlled environment. I'm just happy operating my machine at residential street speeds with maybe an occasional ride on a 45 to 50 mph road.
Re: Cobrafreak's board track racer project, never ends!
I might just see how you go..... so maybe a Fat Frank or Thick Brick tyre may be up for the task. Thanks and keep up the top work.
Not rushing you but are you going to get a chance to make a video?
I might just see how you go..... so maybe a Fat Frank or Thick Brick tyre may be up for the task. Thanks and keep up the top work.
Not rushing you but are you going to get a chance to make a video?
Re: Cobrafreak's board track racer project, never ends!
This weekend I have lots of time and the weather will be great. A video can happen
This weekend I have lots of time and the weather will be great. A video can happen
Re: Cobrafreak's board track racer project, never ends!
Video of Cobrafreak and his 1911 Indian in the Garage! Double click on the picture to peek into my world
Video of Cobrafreak and his 1911 Indian in the Garage! Double click on the picture to peek into my world
Re: Cobrafreak's board track racer project, never ends!
So glad you posted the video. Thanks Cobra. Youre bike is looking great. Very inspiring.....
I was happy to see that you said the wind from the flywheel pushes wind over the barrell hopefully eliminating a need for a shroud. And you live in California. If so, California would have a hot climate much like where i live for comparison, wouldnt it? In Australia we are just starting our winter but in Summer we get temps up to 35 degrees celcius (95 degrees fahrenheit) and quite humid.
I meant to ask does the flywheel bother you when riding. Do your feet come near the flywheel when pedalling, not that you would need to pedal this beast. Just wondering....
So glad you posted the video. Thanks Cobra. Youre bike is looking great. Very inspiring.....
I was happy to see that you said the wind from the flywheel pushes wind over the barrell hopefully eliminating a need for a shroud. And you live in California. If so, California would have a hot climate much like where i live for comparison, wouldnt it? In Australia we are just starting our winter but in Summer we get temps up to 35 degrees celcius (95 degrees fahrenheit) and quite humid.
I meant to ask does the flywheel bother you when riding. Do your feet come near the flywheel when pedalling, not that you would need to pedal this beast. Just wondering....
Re: Cobrafreak's board track racer project, never ends!
Yes, my right foot gets close to the flywheel, but it's not the flywheel I'm worried about, it's the pull start barrel. My buddy's friend got 90 stitches in his right leg from falling down and the barrel shredding his calf :shock: . So I ride with my right foot in the rearward position. I may put a set of pegs on the chain stays so both my feet are far away. I'm also thinking of an end cap for the barrel to plug it up. You know, like a handle bar plug. I'm not even concerned with engine temp now. Just have the fan on and it will still trickle air over the barrel. Now remember, I have the billet flywheel with different blades in mine. I don't know if the stock flywheel fan would do the same thing. On my flywheel there are fewer blades but they are taller and more pronounced than stock.
Yes, my right foot gets close to the flywheel, but it's not the flywheel I'm worried about, it's the pull start barrel. My buddy's friend got 90 stitches in his right leg from falling down and the barrel shredding his calf :shock: . So I ride with my right foot in the rearward position. I may put a set of pegs on the chain stays so both my feet are far away. I'm also thinking of an end cap for the barrel to plug it up. You know, like a handle bar plug. I'm not even concerned with engine temp now. Just have the fan on and it will still trickle air over the barrel. Now remember, I have the billet flywheel with different blades in mine. I don't know if the stock flywheel fan would do the same thing. On my flywheel there are fewer blades but they are taller and more pronounced than stock.
Re: Cobrafreak's board track racer project, never ends!
Here is an old video of my bike with the former 2 stroke engine for comparison.
Here is an old video of my bike with the former 2 stroke engine for comparison.
Re: Cobrafreak's board track racer project, never ends!
Would shorter cranks help?
Would it help when building mine, if i positioned the motor further forward then yours to move my feet away from the flywheel?
I was really hoping to runthe stock flywheel without the plastic veins. But from what you and others have said it may overheat. So i guess ill either try the palstic veins or save up for a billet flywheel like you have.
And you said a friends friend of yours got 90 stitches from a barrel...... was that on a MB or a motorbike? OUCH!!!!!!!!!!!! SCARY
cobrafreak said:
Would shorter cranks help?
Would it help when building mine, if i positioned the motor further forward then yours to move my feet away from the flywheel?
I was really hoping to runthe stock flywheel without the plastic veins. But from what you and others have said it may overheat. So i guess ill either try the palstic veins or save up for a billet flywheel like you have.
And you said a friends friend of yours got 90 stitches from a barrel...... was that on a MB or a motorbike? OUCH!!!!!!!!!!!! SCARY
Re: Cobrafreak's board track racer project, never ends!
-mini bike on the lawn. They were little kids at the time in the early 70's.
harry76 said:
-mini bike on the lawn. They were little kids at the time in the early 70's.
Got her up to 35 mph today
I have taken her to work for the last two days (24 miles round trip) and am happy to report no problems at all. The milage is fantastic. I didn't fill up after the first day (1 1/4 gallon tank) and there is still plenty left. Much better milage than the China Girl. I would estimate 120 miles per gallon. Freaking cool. I can justify this $$$ project to my Wife, Lol. It will pay for itself in a few years. I was bad because I broke the law and rode with traffic most of the way home. I really need to register this as a scooter because I can do it no problem. I was at a stop light and I'm sitting there idling and a convertible pulls up next to me and the Black dude asks me," How much would it take you to sell that old motorcycle?" I said, *It's not for sale ever, ever, ever, but if I did part with it I would say 80K", and he said "freaking awesome". Lol. The sound of the new engine is authentic for sure. Lots of fun. I am going to put on the full 100 year old outfit tomorrow and ride around. Way too much fun.
I have taken her to work for the last two days (24 miles round trip) and am happy to report no problems at all. The milage is fantastic. I didn't fill up after the first day (1 1/4 gallon tank) and there is still plenty left. Much better milage than the China Girl. I would estimate 120 miles per gallon. Freaking cool. I can justify this $$$ project to my Wife, Lol. It will pay for itself in a few years. I was bad because I broke the law and rode with traffic most of the way home. I really need to register this as a scooter because I can do it no problem. I was at a stop light and I'm sitting there idling and a convertible pulls up next to me and the Black dude asks me," How much would it take you to sell that old motorcycle?" I said, *It's not for sale ever, ever, ever, but if I did part with it I would say 80K", and he said "freaking awesome". Lol. The sound of the new engine is authentic for sure. Lots of fun. I am going to put on the full 100 year old outfit tomorrow and ride around. Way too much fun.
Re: Cobrafreak's board track racer project, never ends!
Congratulations Cobra..... Glad to see your bike is running trouble-free.
You mentioned a shorter crankarm on the CVT side would make things worse.... How do you mean?
Congratulations Cobra..... Glad to see your bike is running trouble-free.
You mentioned a shorter crankarm on the CVT side would make things worse.... How do you mean?
