Author Topic: New BUB's build 2013  (Read 15560 times)

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Offline Koncretekid

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Re: New BUB's build 2013
« Reply #30 on: April 18, 2013, 10:33:10 PM »
Marty,
I, too, have been running spoke wheels because I always loved the look of spoke wheels.  My front one is a high shouldered Cosmo 1.85 x 17" (like Borrani) and the rear is a used junkyard 2.5 x 17" DID.  I laced both of them myself, but find that at least with the old rims, I cannot get the rims to run any closer than about .050" out of round at the weld (where the factory welded the joint in the rims).  You would think the tire would even that out, but apparently not, as I have checked the wheels with the tires on and they still run .050" out of round.  Last year I cracked my frame in several places starting near the rear wheel (rigid frame with a single cylinder BSA which vibrates like hell).  So I have decided to try cast aluminum ones which I have found to have less than .010" of run-out.  I really can't explain why my frame broke, but I just don't want to take a chance again.  Maybe new Excel or Sun rims are better, but not the new Akront/Morad ones, as I have laced up a few of them as well.

Another reason I am changing is the difficulty I've had mounting ZR rated tires on my old narrow spoke rims.  I have pinched a fair share of tubes getting these new tires (Avon AM26's are just as hard) mounted on the rims.  What if the tubes I'm running now are only pinched half way through?  Cast aluminum rims, no tubes.  Those are my thoughts.  I will be posting info on my new rims shortly.

Tom
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Life's uncertain - eat dessert first!

Offline Marty

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Re: New BUB's build 2013
« Reply #31 on: April 20, 2013, 10:36:58 AM »
Thanks Tom for your post. Yes Avon AM 26 are the tires I am going to run with speed rating of 149 which is just what I need for class. I thought a spoked wheel look is very clean when done right so thats one reason. I easily could have bought mags, but chose not to. Yes the rims do have some slight run out from production and I am doing my best to get rid of that but there will be some.I am running a 2 cycle vibrating machine also, but built the frame with 1 1/4 by .095 and some .120 wall to compensate for any structual issues, should be fine and also  rubber mounting engine to motor mounts, its a challenge but one i am willing to take. I have taken another step used by Top Fuel drag racers in frame building and that is to pressurize the frame to keep an eye on structural cracks did you do that as well?? Been doing that for some time and really keeps mind at peace.

Offline DND

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Re: New BUB's build 2013
« Reply #32 on: April 21, 2013, 03:12:32 PM »
Hi Tom

In my engine building days i ran into harmonics a few times, that might be causing some of your frame cracking problems.

One time a customer took his boat to another state to race and did not wan't to show up his friends, so he ran it at a lower rpm. I was checking things out and saw the starter ring gear was shook loose from the flywheel and was eating the alum motor plate, also had a few broken inner valve springs lucky we did not break a valve

After that he ran it flat out like the engine was designed to run

At the Traco dyno one day they told me that SBC harmonic's at about 5550 rpm, so they would pull power and skip a 5500 rpm pull.

Maybe your BSA single is running in a harmonic range that is causing your frame to get some cracks, like the other post says a rubber mounted engine just might help the problem.

Hope you find the cause, Don

Offline Koncretekid

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Re: New BUB's build 2013
« Reply #33 on: April 21, 2013, 05:39:23 PM »
Hi Tom

Maybe your BSA single is running in a harmonic range that is causing your frame to get some cracks, like the other post says a rubber mounted engine just might help the problem.

Hope you find the cause, Don
Don,
Not my build diary, but I believe the BSA 500cc single cylinder running on a 250cc crankshaft vibrates because it's a single (can't balance without a balance shaft) and the flywheels are too light for the larger piston and connecting rod.  I don't know if anyone has tried to run a single cylinder motor with rubber mounts, but I think it would play heck with the chain!  Norton got away with it with their 360 degree twin (as bad as a single for balance) but they mounted the swing arm on the same subframe so there would be no relative movement between the motor and the rear wheel and sprocket.  Mine is a rigid frame.  The new frame is chrome moly and better braced at the back, and I will be running aluminum wheels this year, so I expect it should be better, but who knows?  I'll at least know what to look for after each run.
Tom
We get too soon oldt, and too late schmart!
Life's uncertain - eat dessert first!

Offline Marty

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Re: New BUB's build 2013
« Reply #34 on: April 23, 2013, 08:59:28 PM »
update on new photos, decided to use this tail section, this one off my drag bike, but like the looks. motor mounts about to be tacked in, pipe is a monster ,but nothing I can do with this pontoon!!! maybe use it as a side stand?

Offline wobblywalrus

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Re: New BUB's build 2013
« Reply #35 on: April 23, 2013, 11:49:11 PM »
The spokes cross each other at last twice.  It is good to wrap zip ties around them where they cross.  They usually break at the bend on the hub end.  The zip ties keep the spoke from flailing around if it breaks and it prevents it from puncturing the tube. 

Offline Koncretekid

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Re: New BUB's build 2013
« Reply #36 on: April 24, 2013, 08:32:56 AM »
Your tail section looks like it was made to fit, but the exit from the exhaust looks like it would cook the "mountain oysters" if left as it is!  What is the motor?
We get too soon oldt, and too late schmart!
Life's uncertain - eat dessert first!

Offline Marty

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Re: New BUB's build 2013
« Reply #37 on: April 24, 2013, 06:35:28 PM »
Konkrete, The motor was to be a rz350 stroker383cc,AAF-500cc but bought a bad motor that was suppose to be good, (typical ebay) so I have changed my class to a AAF-350, I have a honda trx250r motor bumped to 310cc and I am going to spray it with some giggle gas, not to sure about a record(its pretty stout) but going to have fun anyway, then next year come out with my stroker RZ motor. the 500 cc AAF record is only 3 mph more than 350cc. Got motor mounts welded today, Pipe will actually exit out tail section and my riding position is completely laid out so other than LOUD it it will be good. Thanks for replying.

Offline Marty

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Re: New BUB's build 2013
« Reply #38 on: May 01, 2013, 09:10:51 PM »
Got a couple more photos for folks. Have all motor mounts made and nitrous bottle bracket support,put it on the wheels again to weigh it.I am wondering if the stage its in at 136lbs is a bit light but I am making provisions to hang 45 lbs right in front of rear wheel and on lower frame rail of chassis. Have rear tailsection on order going with a 86 gixxer 8 inch over. It seems to be the right look and shape for any trimming needed, will post photo when it arrives. All the little brackets and tabs take so much time now, got 3 months to make my schedule shake down runs. Thanks for looking.

Offline John Noonan

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Re: New BUB's build 2013
« Reply #39 on: May 01, 2013, 10:10:05 PM »
I crashed in '66.........so am well acquainted with stainless-steel parts :-D

Have not been down on pavement or salt...........but somewhat regularly tip-over in the dirt............last time was in 2011.

The good news about sharing everyone's concern about safety is that 'when you go down' I hope its just like I watched at the 2009 BUB.........rider down in the timing zone and slid for 1/2 mile............I talked with him about 2-hours later as he was zipping his leathers for another run 8-) 8-) 8-)

Who slid for 2640 feet at Bubs and was getting ready for another run soon thereafter ?  He must of been going 300 mph and I would have figured I wouldnhave heard about that?

Offline Koncretekid

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Re: New BUB's build 2013
« Reply #40 on: May 03, 2013, 08:48:02 AM »
"I have a honda trx250r motor bumped to 310cc and I am going to spray it with some giggle gas"
Marty,
Before you go to far with that motor, make sure it's acceptable.  Has to be a motorcycle motor.  Is it the same as a Honda motorcross bike motor?
Tom
« Last Edit: May 03, 2013, 08:50:42 AM by Koncretekid »
We get too soon oldt, and too late schmart!
Life's uncertain - eat dessert first!

Offline Marty

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Re: New BUB's build 2013
« Reply #41 on: May 03, 2013, 05:46:59 PM »
Hey thanks for the reply. Good thinking KonKrete, but yes it is same as honda CR250 back in the day. Thanks for the input. I hadnt thought about it until you said something. Good call.

Offline Marty

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Re: New BUB's build 2013
« Reply #42 on: September 15, 2013, 03:18:42 PM »
Hello folks, just thought I would repost the new post for 2014 build. Had huge financial burden that did not allow me to finish this year, so I am going balls to the wall with build now. have lots to share but just tinkering with a new sketch tell me what you think, will keep a full on post of new stuff. Thanks

Offline Koncretekid

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Re: New BUB's build 2013
« Reply #43 on: September 15, 2013, 05:30:51 PM »
"Innovative designs are encouraged"  I think it looks like what it's supposed to be - - fun!
Tom
We get too soon oldt, and too late schmart!
Life's uncertain - eat dessert first!

Offline Marty

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Re: New BUB's build 2013
« Reply #44 on: September 16, 2013, 09:26:16 PM »
Thanks Tom, Yes I agree it needs to be fun! I am redesigning the backbone to a dual backbone so I can hang fuel cell in between rails and also allows it to be a bit lower in the front,trying to get out of wind in a horizontal position. Look forward to parts coming in so I can complete the roller.