It lives
Moderator: DLRA
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- Posts: 3
- Joined: Sun Jul 15, 2012 9:50 am
Re: It lives
I was the other Nitro bike and it was "fill it to about half way then add two cups of nitro, shake well and serve". Didn't blow up!
Re: It lives
1/2 way in a postie bike is ?? 2 cups. Big or small? You running very fat jetting or is this an educated guess? Glad to hear its still running. I havnt messed with Meth before so am on a steep learning curve.Michael Riddell wrote:I was the other Nitro bike and it was "fill it to about half way then add two cups of nitro, shake well and serve". Didn't blow up!
Dave
Last Minute Racing
DLRA #928
2010 MPS/G 250 118 MPH
2011 Washed Out
2012 Washed Out
2013 MPS/G 250 131 MPH (RECORD)
2014 MPS/G 250 140 MPH (RECORD)
2015 MPS/F 250 DNF
2016 MPS/F 250 114 MPH (RECORD)
2017 MPS/F 250 DNF
- gennyshovel
- Posts: 866
- Joined: Tue Mar 29, 2005 10:10 am
- Location: Broken Hill
Re: It lives
It's a pitty you didn't get an official "big" track time MichaelMichael Riddell wrote:I was the other Nitro bike and it was "fill it to about half way then add two cups of nitro, shake well and serve". Didn't blow up!
Tiny
Tiny DLRA# 484
Postiebike Racing , created & funded by TwoBob Engineering
Postiebike Racing , created & funded by TwoBob Engineering
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- Posts: 3
- Joined: Sun Jul 15, 2012 9:50 am
Re: It lives
The fuel mix wasn't quite hit and miss but Ross was involved. It worked out about right with 16%.The jetting was worked out and then we used what we had. Over geared it for some test runs so it wouldn't go bang. And the non-timing run was a bit disappointing but didn't want it to buggar up a bloody great week. There's always next year! (got to stop saying that)
Re: It lives
Got my new rods, waiting for bearings and seals then its time to rebuild a crank for my new motor. New rods are 5mm longer so ive tracked down some pistons with a -3.5mm compression height, the rest of the height, 1.5mm, will be used to move the barrels up to create more of a top end port timing.
Last Minute Racing
DLRA #928
2010 MPS/G 250 118 MPH
2011 Washed Out
2012 Washed Out
2013 MPS/G 250 131 MPH (RECORD)
2014 MPS/G 250 140 MPH (RECORD)
2015 MPS/F 250 DNF
2016 MPS/F 250 114 MPH (RECORD)
2017 MPS/F 250 DNF
- AuotonomousRX
- Posts: 729
- Joined: Wed Jan 06, 2010 10:05 pm
- Location: Eyre Peninsula SA
Re: It lives
Dave
They certainly are a more substantial Con Rod.
Pete
They certainly are a more substantial Con Rod.
Pete
Still trying to decide if I am a procrastinator
Pete
DLRA #866
Pete
DLRA #866
Re: It lives
Is the new rod heavier? Will you have to re-balance the crank?
Re: It lives
Piston is 16g lighter and rod is about 14g heavier, so saving of 2g.
Dave
Dave
Last Minute Racing
DLRA #928
2010 MPS/G 250 118 MPH
2011 Washed Out
2012 Washed Out
2013 MPS/G 250 131 MPH (RECORD)
2014 MPS/G 250 140 MPH (RECORD)
2015 MPS/F 250 DNF
2016 MPS/F 250 114 MPH (RECORD)
2017 MPS/F 250 DNF
Re: It lives
Bit happening out in the shed over the w/end.
New piston and rod V old.
Some case flowing and port matching.
Next is building the crank and a dummy assemble of the motor to see what the 5mm longer rod is going to do to the port timing.
Ive found a piston with a 3.5mm lower compression height so only have to make up 1.5mm under the barrels.
Dave
New piston and rod V old.
Some case flowing and port matching.
Next is building the crank and a dummy assemble of the motor to see what the 5mm longer rod is going to do to the port timing.
Ive found a piston with a 3.5mm lower compression height so only have to make up 1.5mm under the barrels.
Dave
Last Minute Racing
DLRA #928
2010 MPS/G 250 118 MPH
2011 Washed Out
2012 Washed Out
2013 MPS/G 250 131 MPH (RECORD)
2014 MPS/G 250 140 MPH (RECORD)
2015 MPS/F 250 DNF
2016 MPS/F 250 114 MPH (RECORD)
2017 MPS/F 250 DNF
- AuotonomousRX
- Posts: 729
- Joined: Wed Jan 06, 2010 10:05 pm
- Location: Eyre Peninsula SA
Re: It lives
Got my carby's yesterday. Might have made a bit of a mistake when I ordered them. They turned out to be 40 mm not 38. Might be a touch too big.
Could probably get them to work but I wanted to keep the same size so I dont have to alter my air box, and I would have to make a pretty big bracket to hold these suckers on. Anyone want a pair of 40mm VM Mikunies?
Dave
Could probably get them to work but I wanted to keep the same size so I dont have to alter my air box, and I would have to make a pretty big bracket to hold these suckers on. Anyone want a pair of 40mm VM Mikunies?
Dave
Last Minute Racing
DLRA #928
2010 MPS/G 250 118 MPH
2011 Washed Out
2012 Washed Out
2013 MPS/G 250 131 MPH (RECORD)
2014 MPS/G 250 140 MPH (RECORD)
2015 MPS/F 250 DNF
2016 MPS/F 250 114 MPH (RECORD)
2017 MPS/F 250 DNF
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- Posts: 475
- Joined: Mon Nov 20, 2006 12:18 pm
- Location: Melbourne
- Contact:
Re: It lives
How do you calculate the size of the carb required? I have seen on an online calculator somewhere (can't remember now) where they spat out the size of the carb required for a given Hp. I based my single 38mm on what was standard and then added some. Is there a formula that you are using?
Paul
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DLRA #647
89.664 mph (aiming for 100mph+)
www.vespalabs.org
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DLRA #647
89.664 mph (aiming for 100mph+)
www.vespalabs.org
Re: It lives
Hey Paul, Ive got a excel worksheet, "useful 2 stroke tuning sheet 3" Its got a fair bit of stuff on it. There are some GP bikes running 40+ carbs so I will have a look at how much messing round it will be to fit them. They are quite a bit bigger than the 38's im running.
Dave
Dave
Last Minute Racing
DLRA #928
2010 MPS/G 250 118 MPH
2011 Washed Out
2012 Washed Out
2013 MPS/G 250 131 MPH (RECORD)
2014 MPS/G 250 140 MPH (RECORD)
2015 MPS/F 250 DNF
2016 MPS/F 250 114 MPH (RECORD)
2017 MPS/F 250 DNF
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- Posts: 475
- Joined: Mon Nov 20, 2006 12:18 pm
- Location: Melbourne
- Contact:
Re: It lives
Yes they look big You might be able to make a couple of different manifold types to produce different characteristics - I might be interested but I'd only need one and only towards the end of the year (pending other mods).RGV wrote:Hey Paul, Ive got a excel worksheet, "useful 2 stroke tuning sheet 3" Its got a fair bit of stuff on it. There are some GP bikes running 40+ carbs so I will have a look at how much messing round it will be to fit them. They are quite a bit bigger than the 38's im running.
Dave
Is that spreadsheet available online anywhere?
Paul
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DLRA #647
89.664 mph (aiming for 100mph+)
www.vespalabs.org
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DLRA #647
89.664 mph (aiming for 100mph+)
www.vespalabs.org
Re: It lives
Not sure where I got it from, send me ya email and ill shoot a copy off to ya. Ive got a heap of different ones for all sorts of things. Head calculations, chamber design, n stuff.
Dave
Dave
Last Minute Racing
DLRA #928
2010 MPS/G 250 118 MPH
2011 Washed Out
2012 Washed Out
2013 MPS/G 250 131 MPH (RECORD)
2014 MPS/G 250 140 MPH (RECORD)
2015 MPS/F 250 DNF
2016 MPS/F 250 114 MPH (RECORD)
2017 MPS/F 250 DNF