theTRUTH

See cars and bikes being built for the salt

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momec3
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Joined: Tue Mar 01, 2011 10:36 pm
Location: Cedar Grove Qld

Re: theTRUTH

Post by momec3 » Thu Jul 13, 2017 8:05 pm

I have used several of the Davies Craig pumps and they work fantastic.
Chris

russelllowe
Posts: 92
Joined: Mon Jan 06, 2014 2:21 pm

Re: theTRUTH

Post by russelllowe » Thu Jul 13, 2017 11:31 pm

Just weighed the flywheel, clutch and pressure plate: 32.75kg ... the shipping weight of the whole motor is only 198kg!

The more I look at it the more I want something simpler and smaller.

Cheers

russelllowe
Posts: 92
Joined: Mon Jan 06, 2014 2:21 pm

Re: theTRUTH

Post by russelllowe » Thu Jul 13, 2017 11:35 pm

Hi Chris, which sizes have you used? Have you tried the aluminium as well as the plastic? They say the aluminium are good for the dragsters and high horsepower on one of their promo videos ... but they don't say why; other than it will polish up nice...

Cheers

momec3
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Location: Cedar Grove Qld

Re: theTRUTH

Post by momec3 » Fri Jul 14, 2017 9:56 am

The biggest one is the alloy one. Price difference is marginal. You need the highest gal/hour unit for a V8. Pump pressure is more important than flow. One advantage of electric pumps is they give constant pressure. Don't bother with the ecu controller, just run the pump full time in a race setup. I run one on our D Windsor engine in the F100 with no issues. The bike it will handle easy.
Chris

russelllowe
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Joined: Mon Jan 06, 2014 2:21 pm

Re: theTRUTH

Post by russelllowe » Fri Jul 14, 2017 3:23 pm

Thanks Chris, yes noticed there wasn't much difference in price, looks like I'll go for the 150 then. Cheers

russelllowe
Posts: 92
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Re: theTRUTH

Post by russelllowe » Fri Jul 21, 2017 7:07 pm

Hi Everyone,

After considering your advice, and reading a little more through Tony Foale's book, I've decided to go down a more conventional route re the front end design.

The killer information from Foale re the virtual steering axis was this (from section 7 page 32):

"The centre of the contact patch moves rearward as the steering is turned, this is in contrast to the head stock design where the patch moves forward. As any drag and road disturbance forces are likely to act in a general rearward direction, the link system will have a tendency to turn away, whereas the head stock design will be more stable and tend to straighten up."

Hoofhearted's bike has a great reputation for stability which confirms the above. And once you have all the power in the world stability seems useful for going fast.

So, I bought a GSF650 ...

Image

This guy has been sitting in the carpark where I work for the last year or so. It has been used by some Road Transport Safety researchers who wanted to build a virtual model of a motorcycle and validate it with the real thing. You can read about it here if thats your thing: http://www.tars.unsw.edu.au/news/2017/M ... erence.pdf

The steering stem is really heavily gusseted and the frame tubes look to be about 35mm diameter. So all nice and strong. I'll cut that part of the frame off ... at about 300mm down the frame (more at the back) and tig it to the horizontal frame members I have shown in the previous models. Some additional gussets at the connections will make sure the two bits don't come apart. I'll go for a 45 degree rake (like Hoofhearted).

I'll use the rear swing arm (which I'm pretty sure is steel) and rear wheel out the back. The narrow rear wheel might make me go faster I think ... Bones, don't you use a rear wheel off a SV650 on your bike?

The swingarm will be welded solid to the frame rails. So still no suspension front or rear.

The motor (only done 17,000km apparently) will go in my 1972 CB750 ... because the original SOHC won't make any oil pressure. Walkingpace, is that a CB750 in your avatar picture?

So it's a little like one of those fancy restaurants where they advertise eating all parts of the animals they kill. Or like being an Eskimo.

Should speed up the build a bit too ... I'm on a deadline!

Cheers, and thanks again everyone for your input!

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walkingpace
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Joined: Mon Jun 04, 2012 11:19 am
Location: Central Coast NSW

Re: theTRUTH

Post by walkingpace » Fri Jul 21, 2017 9:24 pm

Yes that is a CB750 in my avatar. Built it as a road bike first then converted it for nostalgia drags. It was pieced together out of a couple of crashed bikes and three damaged engines. Once it was built, just could not break it despite flogging it mercilessly. And that sound......

Sadly I no longer have it and still feel like a bit of a goose every time I think about the fact that I sold it.

Pretty sure I have a good oil pump in a box somewhere if that will help yours. Assuming I can find it you can have it if it's useful.

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BONES
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Joined: Wed Mar 15, 2006 4:28 pm
Location: Killara Sydney

Re: theTRUTH

Post by BONES » Fri Jul 21, 2017 11:14 pm

Hey Russell
Yes--I use an SV 650 wheel on the rear.
What you might need to check is the load rating of the tire you want to use-- that engine is a big weight on the rear tire.

cheers Bones

Stayt`ie
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Location: Mackay

Re: theTRUTH

Post by Stayt`ie » Sat Jul 22, 2017 8:44 am

IMO tyre size makes Jack Shite difference on high horsepower machines :mrgreen: ,,

I have always run 180's, this year on Sams "Production" ZX12 we had a 210 on there, she ran a comfortable 203mph at a conserative 10600rpm (12+ redline) 8)
First Australian to ride a motorcycle over 200mph at Bonneville,,,

russelllowe
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Joined: Mon Jan 06, 2014 2:21 pm

Re: theTRUTH

Post by russelllowe » Sat Jul 22, 2017 10:25 am

Walkingpace; Yeah, love that sound ... I ran one with the original 4 open headers and loved every minute of it. That bikes in Salt Lake City waiting for another go some time. I had assumed that my main bearings were shot on the CB750 I have here. Could be a shitty oil pump though. Now I have the gsf650 motor it makes it a moot point though ... so if you need another motor to build up another drag bike let me know; free like the pump.

Bones; I like running slicks ... which probably don't have the highest load rating ... might have to use a touring tire on the back this time.

Saty'ie; Yeah, probably not a big difference, but I'll take all I can get. Will need to go to proper land speed racing tires after 2018 anyway with a bit of luck (Slicks are only legal up to 265mph). Actually, a LOT of luck!

Cheers!

grumm441
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Re: theTRUTH

Post by grumm441 » Sat Jul 22, 2017 4:54 pm

russelllowe wrote:
Sat Jul 22, 2017 10:25 am
Walkingpace; Yeah, love that sound ... I ran one with the original 4 open headers and loved every minute of it. That bikes in Salt Lake City waiting for another go some time. I had assumed that my main bearings were shot on the CB750 I have here. Could be a shitty oil pump though.

They have a sumping valve in the oil pump
If it gets stuck, and it does, no oil pressure
You can get it off without taking the motor out of the frame

265 you say?
Hmmm

G
They make it
I make it work

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walkingpace
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Location: Central Coast NSW

Re: theTRUTH

Post by walkingpace » Sun Jul 23, 2017 7:52 am

Hmm the gracious offer of another project is always tempting...but experience has taught me exactly how many worms are in the CB750 can. Best not open another one. Grumm you are correct about the oil pump. It can be removed with the engine in the frame. You just drop the sump, undo 3 bolts (I think from memory) and it drops straight out the bottom.

Stayt`ie
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Joined: Fri May 13, 2005 11:47 pm
Location: Mackay

Re: theTRUTH

Post by Stayt`ie » Sun Jul 23, 2017 8:33 am

Have built quiet a few dragbike chassis ('ole skool laydown type), from experience 45* with a low c of g and weight, the steering on that thing, with a conventuial rounded motorcycle tyre, at low speed, will be way too heavy, increased rake promotes "flop",, Hoof's bike weight compared to yours is light, also that wide tyre in frount would negate "flop" due to its wider/flatter contact patch,,
First Australian to ride a motorcycle over 200mph at Bonneville,,,

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gennyshovel
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Location: Broken Hill

Re: theTRUTH

Post by gennyshovel » Sun Jul 23, 2017 4:07 pm

Stayt`ie wrote:
Sun Jul 23, 2017 8:33 am
increased rake promotes "flop",,
I think it's the increased trail that comes with the increased rake, that causes the "flop" Ronnie, unless the trail increase is reduced after raking a frame, you will need forearms like Popeye.
The " Silverton V8 bike " had 37 degrees & 4", no flippin' , floppin' , or handlin' problems with that one
Tiny DLRA# 484
Postiebike Racing , created & funded by TwoBob Engineering

Stayt`ie
Posts: 905
Joined: Fri May 13, 2005 11:47 pm
Location: Mackay

Re: theTRUTH

Post by Stayt`ie » Sun Jul 23, 2017 4:58 pm

Yup Tiny,, Chris's bike was more like a stretched conventual bike with an "extremily high c of g", this animals dimenshions(dynamics) are a world away from it,, uuummmm what was his fastest speed ??
First Australian to ride a motorcycle over 200mph at Bonneville,,,

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