Author Topic: Bench designing a Bonneville bike (Read 12222 times)

Don R · « **on:** November 24, 2009, 01:32:27 PM »

If you could build a SOHC bike to compete at the salt flats or another top speed event what would you build? Could it be competetive?

Sam Green Racing · « **Reply #1 on:** November 24, 2009, 02:19:20 PM »

Frank 754 was talking about running his 750 with a sidecar on it last year. I offered to ride in the S/C but it didn't happen.
There are lots of classes, I'm sure a 750 would fit into one of them, It's not easy though, just ask Burt Munro.

Sam.

Old Scrambler · « **Reply #2 on:** November 24, 2009, 05:09:02 PM »

With today's piston and valve technology, almost any class is up for graps. One big secret is to build a bike that will adapt to several classes just by making minor alterations. Another trick is to find a 120 lb. rider that knows how to handle the sometimes soft salt. A fully-faired bike requires the side profile of the rider to be fully visible. If you build the rear enclosure as part of the seat, it can stay on for un-faired runs. As the bikes are built with increased power, adding weight to the swingarm seems to aid traction. To make the bike more slippery in the air you may want to remove the front brake or run a small brake in the hub.

I was clocked by my friend's Toyota at 90 MPH on my XR650L pit bike. (officially probably a little slower) If I geared it properly and lowered the bars to get me out of the wind, I think it would do 110. That kind of speed with a 220 lb. rider runs against conventional thinking about getting low to the ground. Be sure to leave a lot of seat room so the rider can adjust weight position to cure any speed wobbles. Here's some inspiration.......

BLUE71TURBO · « **Reply #3 on:** November 24, 2009, 05:29:44 PM »

Add some taller gears and a body to fit my big a$$ plus my motorcycle............

754 · « **Reply #4 on:** November 24, 2009, 08:03:59 PM »

A turbo 750 sohc ran around 147 or 149 back in 75 ish..
actually talked to the guy at the flats in Aug..

he has bigger fish to fry now, going after an absolute record..
he is also on the tech crew..

There was I think a 750 sohc at Bub this yrear but I could not find it.. either broke and left early or did not make it..

I would like to run there, but have not been able to afford, it be totally honest.

Sam Green Racing · « **Reply #5 on:** November 24, 2009, 08:08:34 PM »

Quote from: Old Scrambler on November 24, 2009, 05:09:02 PM

With today's piston and valve technology, almost any class is up for graps. One big secret is to build a bike that will adapt to several classes just by making minor alterations. Another trick is to find a 120 lb. rider that knows how to handle the sometimes soft salt. A fully-faired bike requires the side profile of the rider to be fully visible. If you build the rear enclosure as part of the seat, it can stay on for un-faired runs. As the bikes are built with increased power, adding weight to the swingarm seems to aid traction. To make the bike more slippery in the air you may want to remove the front brake or run a small brake in the hub.

I was clocked by my friend's Toyota at 90 MPH on my XR650L pit bike. (officially probably a little slower) If I geared it properly and lowered the bars to get me out of the wind, I think it would do 110. That kind of speed with a 220 lb. rider runs against conventional thinking about getting low to the ground. Be sure to leave a lot of seat room so the rider can adjust weight position to cure any speed wobbles. Here's some inspiration.......

Hey Dennis, #2 picture is by far the best, is the ladies name Debbie ?

Sam.

bwaller · « **Reply #6 on:** November 24, 2009, 08:22:32 PM »

I know she inspired me.

754 · « **Reply #7 on:** November 24, 2009, 08:27:06 PM »

She lives here in Kelowna BC.. I got a better pic of her.
i dont think it Debbie, trying to remember her name

wannabridin · « **Reply #8 on:** November 24, 2009, 09:58:42 PM »

well lets see that better pic of her!!!

BLUE71TURBO · « **Reply #9 on:** November 25, 2009, 12:39:29 AM »

Here's a BONNEVILLE BABE .....

Here name is Leslie Porterfield. Holds a bonneville record over 200 mph.
Here's a better picture....

voxonda · « **Reply #10 on:** November 25, 2009, 12:58:19 AM »

I know which of the two I like best...........and it aint that bike! She is COOL

Rob

BLUE71TURBO · « **Reply #11 on:** November 25, 2009, 01:09:49 AM »

You missed the second picture !!

754 · « **Reply #12 on:** November 25, 2009, 07:51:42 AM »

We got a cool pic of Leslie, and me and my buddy wearing our Hawaiin shirts at Speed Week..

she is very nice..
Didnt see her at all during Bub, I mean not at the pits..

Fritz Egli was sharing the same pits, I saw the stickers on the bike with sidecar, but did not realize he wass running it.. should got off my bike and had a better look..

Old Scrambler · « **Reply #13 on:** November 25, 2009, 08:45:09 AM »

I chatted with Leslie for quite some time in the starter's shelter while she waited to run on Thursday. She is very calm and knows her business. Notice how the 'seat' area on her bike allows her to move. When she is starting out her butt is almost a foot from the rear of the seat, but at speed she is all the way to the rear and hugging everything very closely. Leslie also rides other bikes for the owner.

Notice the front width of her bike is approximately the same as a 750 with the standard dyno/starter clutch removed. Another consideration is a rev-limiter to save the motor. Several soft spots on the salt caused numerous bikes to lose traction. Tom Moeller uses an aircraft-engine balance gauge on his '69 Triumph Triple to tell him at the end of each run if the rear wheel turned more revs than the front.

Don R · « **Reply #14 on:** November 25, 2009, 12:44:08 PM »

I've also thought of converting our dragster into a lakester, it has rear suspension but would need proper cooling, tire/wheel combo and gear ratio. My 120lb driver has been 177 in the quarter mile but she isn't a bike rider. My preference would be to start with a smaller cc sohc depending on the rules. Any good reason to get there really.

Old Scrambler · « **Reply #15 on:** November 25, 2009, 07:08:41 PM »

The BUB event has a 'run what you brung' event. No Excusses!

seaweb11 · « **Reply #16 on:** November 25, 2009, 07:53:47 PM »

............and she has gone over 200mph!!!!!!

Sorry where was I?

BLUE71TURBO · « **Reply #17 on:** November 25, 2009, 10:13:05 PM »

Stairing at that bonneville 200 mph club tank top !!!

lordmoonpie · « **Reply #18 on:** November 26, 2009, 05:10:07 AM »

Where can you find the list of Bonneville classes and current records?....one day

Don R · « **Reply #19 on:** November 26, 2009, 08:02:09 AM »

The BUB event sounds like a good way to get started.

754 · « **Reply #20 on:** November 26, 2009, 09:09:43 AM »

Bub is all bikes, Aug 28th to Sept 2nd for 2010

if you run it will cost a bit of money, entry fee, leathers, correct helmet etc.. get a rulebook, and do what you need BEFORE you get there..

Run What ya Brung..RWB.. is good up to 175mph.. so that covers even most stock Busas.. remember if your bike does 190mph at sea level, it MIGHT hit 170mph at Bonneville.. it is a different game there..

For endless info regarding slat Flats or any other speedtrials events, check out www.landracing.com.. an excellent forum, that will help you out with all you need..

Run by Seldom Seen Slim and the lovely Nancy.. who is also in the 200mph club.. they both ride Kawis.. got to meet them at Speedweek this year..

Sam Green Racing · « **Reply #21 on:** November 26, 2009, 07:49:04 PM »

Quote from: lordmoonpie on November 26, 2009, 05:10:07 AM

Where can you find the list of Bonneville classes and current records?....one day

Here ya go me Lord.

http://www.landracing.com/index.php?option=com_content&task=view&id=3&Itemid=17

This is the place Simon but the Bonneville records are not coming up at the moment for some reason or other.

Sam.

Don R · « **Reply #22 on:** November 26, 2009, 09:01:28 PM »

So it seems a SOHC750 could be bored from 736 to 750. But it appears we compete against 750 twin cam engines. For a serious record attempt we may be at a disadvantage compared to later 750's. For a fun run however is another story.

lordmoonpie · « **Reply #23 on:** November 27, 2009, 01:12:22 AM »

Quote from: SamCB750A on November 26, 2009, 07:49:04 PM

Here ya go me Lord.

http://www.landracing.com/index.php?option=com_content&task=view&id=3&Itemid=17

This is the place Simon but the Bonneville records are not coming up at the moment for some reason or other.

Sam.

Sam - thanks for this, I just need to find a class that no-one else goes into and get me a record LOL!

Don R · « **Reply #24 on:** November 29, 2009, 11:37:28 PM »

Ok then let's say you have a 75F 750 and you were planning on going to the BUB just to see how fast you could go. how would you prep the bike? speed rated tires, steering dampener, good neck bearings and swing arm rebuild go without saying. what else? Gear ratio? dragbike style or road race style? I'm thinking lowered with weight on or in the swingarm. would you need an O2 sensor for jetting when you get there?

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Author Topic: Bench designing a Bonneville bike (Read 12222 times)