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Author Topic: Engine Centerline on a Cycle  (Read 3824 times)

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Offline TwinSpin

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Engine Centerline on a Cycle
« on: February 09, 2012, 04:45:56 PM »
I'm dreaming and designing about my first solo cycle build and I'm lost as how to measure the centerline of a cycle engine. Being new to building a bike I thought the centerline of an engine would be the centerline of the crank, no? However, most bike engines have the shaft in a transverse placement in the frame, or at 90 degree angle from the line between the front tire and the rear tire. Rule 7.I.2 Engine Location, for sidecars, (I want a side car as an option when I build), says "... engine centerline is located within the width of the rear tire." OK, I will do that but I don't have the knowledge of how the centerline is measured or determined. Is it the crankshaft, the mass of the engine (CoG), actual width divided in half, or some easy way I just can't see, to determine the engine centerline. This is about as new as I can ask a newbee question. Your thoughts are appreciated.

See ya at the NW Reunion.

Offline Stainless1

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Re: Engine Centerline on a Cycle
« Reply #1 on: February 09, 2012, 05:51:25 PM »
Bill, probably don't need to worry too much about that, if the bike is rideable the centerline of the motor will be within the width of the rear wheel.  I think the sidecar rule is there to prevent the motor being on the sidecar platform
Stainless
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MSA Bockscar Lakester #1000 my fastest mile 245 and change, 84 ci turbobusa motor... but Corey's 233 MPH H/BFL record is still 3MPH faster than mine.

Offline TwinSpin

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Re: Engine Centerline on a Cycle
« Reply #2 on: February 10, 2012, 05:13:09 PM »
Stainless - -

I was going to put the motor IN the sidecar.  :-o  I think a small block Chevy could have fit in a Steib original sidecar, no?

I now understand why the centerline rule was not mentioned under solo bikes too. Everyone says read the rule book over and over, I guess I read too much into this rule.

See you soon in Portland.

Bill

Offline Nortonist 592

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Re: Engine Centerline on a Cycle
« Reply #3 on: February 10, 2012, 05:30:04 PM »
  I think a small block Chevy could have fit in a Steib original sidecar, no?


At least you won't have to worry about the 10% weight on the sidecar wheel rule  : - )
Get off the stove Grandad.  You're too old to be riding the range.

Offline TwinSpin

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Re: Engine Centerline on a Cycle
« Reply #4 on: February 10, 2012, 05:49:35 PM »
Well Hello Nortonist - -

You are right, no worry now about the 10% sidecar wheel weight rule. I'm glad I didn't mention that the Chevy V8 was going to sit sideways and the flywheel was going to BE the sidecar wheel. Not gonna mention my three wheel drive idea either. You know under Special Construction they say "Innovation is encouraged. "  :-D

See you in May.

Bill

Offline 55chevr

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Re: Engine Centerline on a Cycle
« Reply #5 on: February 10, 2012, 06:16:43 PM »
On the Sportster engine I used the center of gravity of the engine to locate it in the drag frame. It is balanced in the frame but appears to be slightly to port side when viewing from above.     Joe

Offline Nortonist 592

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Re: Engine Centerline on a Cycle
« Reply #6 on: February 10, 2012, 07:56:59 PM »
Hello Bill.  Didn't realize that was you.  That rule should really read "Innovation, if the tech inspector likes it, is encouraged"
Get off the stove Grandad.  You're too old to be riding the range.

Offline oz

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Re: Engine Centerline on a Cycle
« Reply #7 on: February 11, 2012, 02:07:18 AM »
Not sure if you are serious about the V8 but if its a solo in special construction class "A" it must be a motorcycle engine.
It also mentions that other than Omega class it must be a motorcycle engine.
It also mentions only the rear wheel drving.
Sorry to rain on the fireworks coz it sounds like a fun build.
You can calculate the mounting for your engine by measuring from the centre line of the tire/wheel to the centre or edge of rear sprocket,this will give you the centre edge of the front sprocket away from the centre line of your jig/bench
make sure its the original equipment you are measuring If it aint as long as your chain run is ok it is usually fine as long as you havent massively gone away from stock.

cheersOz
« Last Edit: February 11, 2012, 02:15:40 AM by oz »
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Offline grumm441

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Re: Engine Centerline on a Cycle
« Reply #8 on: February 13, 2012, 05:05:49 AM »
Hello Bill.  Didn't realize that was you.  That rule should really read "Innovation, if the tech inspector likes it, is encouraged"

I thought it read "Innovation is encouraged, within the rules."
and that's a whole other thread

I would think if you were going to run a Chev, it would have to have come out of a boss hoss V8 bike
and I'm not too sure about two wheel drive, however if one was to run a Ural sidecar, it could be two wheel drive and production pushrod

I was just looking at Kenny Lyons 2000cc side car records for Bonneville.....
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Offline bak189

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Re: Engine Centerline on a Cycle
« Reply #9 on: February 13, 2012, 09:51:55 AM »
When I first wrote the sidecar LSR rules back in the 1970's for SCTA/BNI (certainly have been changed and modified since...not by me) I wanted to make certain, just like Stainless noted, that the engine was not mounted in the sidecar.......at that time there were several outfits racing in Europe in sprints that had the engine in the chair (still driving the rear wheel) and I felt in order it to be a "real" sidecar it should have room for a passenger .....passengers being  allowed at that time racing with SCTA/BNI.
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Offline dr j

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Re: Engine Centerline on a Cycle
« Reply #10 on: February 13, 2012, 11:01:57 AM »
When I first wrote the sidecar LSR rules back in the 1970's for SCTA/BNI (certainly have been changed and modified since...not by me) I wanted to make certain, just like Stainless noted, that the engine was not mounted in the sidecar.......at that time there were several outfits racing in Europe in sprints that had the engine in the chair (still driving the rear wheel) and I felt in order it to be a "real" sidecar it should have room for a passenger .....passengers being  allowed at that time racing with SCTA/BNI.
Thanks bak189!  That was an awesome post.  Great to get an explanation by the author of the original rule explaining both the intent and the reasoning.  Thanks again.
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Offline TwinSpin

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Re: Engine Centerline on a Cycle
« Reply #11 on: February 13, 2012, 02:59:39 PM »
Hello All -

My question about the engine centerline was true and accurate. I do want to build a solo bike with the option of adding a sidecar. Bill Anderson (Nortionist) has made me believe in the fun and Zen of sidecars. So my question about engine centerline rule confused me. After Stainless gave me the obvious answer that I didn't know, then I started to make a joke out of my lack of bike knowledge and rule understanding. So, in a sarcastic and fun way I said I was going to put the engine in the sidecar, only a monkey would do that? no?  :?

I am new to LSR and I am designing a bike for Bonneville and as a retired shop teacher, I am one that does follow all the rules in the book. I just need to understand them first.

I know about rear wheel drive only, and I know about motorcycle engines only in bikes too. I did build a street roadster with twin Chevy V8 when I was 19 years old, and that is where the reference to a V8 in the sidecar came to mind.

When Stainless answered my question so easily, I thought this thread was done, so I started to have some tongue and cheek fun. That is the kind of guy I am, but I'm new and few know me.

bak189  - - Thanks for giving me the honor of reading about my centerline question. I didn't know how to measure it. I do now understand why this rule was written. And thanks to you for putting the time in the rule book back then.  I hope to meet you on the salt or at Elmo someday. 

My engine design and mounting is unique, but it does fit into both solo and sidecar rules. Nothing on paper yet, still all in my head and having fun doing it.

Bill

Offline bak189

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Re: Engine Centerline on a Cycle
« Reply #12 on: February 13, 2012, 06:30:55 PM »
TwinSpin.......I would also like to meet you on the salt someday....but keep in mind you will have to attend the BUB Speed Trials....at this point in time that is the only event where we race our sidecar due to that both the AMA and the FIM allow for the option of using a passenger in the sidecar.....we choose to race with a passenger........(162mph in 2011)................................
Question authority.....always

Offline TwinSpin

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Re: Engine Centerline on a Cycle
« Reply #13 on: February 14, 2012, 02:11:57 PM »
Hello bak 189 again.

We will meet one day. I wonder if we already met? I was at BUB last August as a spectator (first time). I did try to see and visit most of the sidecar pits and ask questions. I plan to bring my 10 year old daughter again to this years BUB. I probably will be spending time in the pits of a fellow who has a special construction, Busa motor with a roll type cage over his head and up to the front end. His name is Robin and he is from Arizona.

BTW, I checked my notebook of important papers and pictures and I came across an email from you from 2 years ago. I had asked about center hub steering for a solo bike. You mentioned that it was no big deal for a solo on the salt flats but for a sidecar it was good, low and lean. You suggested I contact a center hub builder in the Netherlands called Bakker since you were not makaing them for sale anymore. So, if we keep bumping together on this forum, I guess we will do so at BUB.

Will look forward to that future handshake and some fun conversation on solo and SC designs and builds. And please don't ask me if I want to go for a ride on your sidecar. :-D

Till then,

Bill