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Author Topic: Draw thru supercharger carb weirdness  (Read 14884 times)
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generatorshovel
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« Reply #15 on: September 01, 2012, 06:55:08 PM »

Once again, thanks to all for your valued input  cheers
There is no substitute for experience, and this forum has experience dripping from it's ears,
One of the best things I have gained from this build, is learning new skills, even if they were obtained the hard way sometimes, I'm an old dog, and have learned new tricks, hopefully I will be able to share some info and help someone my self one day ?
Tiny
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Tiny (in OZ)
I would prefer to make horsepower, rather than buy, or hya it, regardless of the difficulties involved , as it would then be MINE
generatorshovel
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« Reply #16 on: September 09, 2012, 01:55:53 AM »

The process of elimination took a giant leap forward today  grin
The ignition output is satisfactory, .036" plug gap, full throttle, 14000 rpm in 5th, no problem  grin  (although it began to nose over  after a while in 5th gear indicating fuel flow problems)
1 more gear, and 1000 rpm to go !
 cheers Tiny
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Tiny (in OZ)
I would prefer to make horsepower, rather than buy, or hya it, regardless of the difficulties involved , as it would then be MINE
guilfordin
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« Reply #17 on: February 16, 2015, 12:18:58 PM »

I think I read you are running a 250cc Suzuki 4 cylinder/water cooled engine?  I just picked up a bike here in Indiana, USA for use at the Bonneville Salt Flats.  I have a 500 cc Suzuki two cylinder air cooled bike that I ran in 2012.  I was considering a supercharged application for the little 250 but don't know if the AMR300 is a good choice.  All those 125, 250 350 and 500 cc land speed records are held by two stroke Yamaha's, so the only way to counter that is with boosted 4 strokes.  I have had good experiences with turbocharging, and may just go ahead and build one for this class.  To make serious power, is going to require at least 20 PSI, not sure if these little things can do that.  I see no problem turning the 250 at 18,000 + RPM with performance valve gear.  I use hastaloy exhaust and titanium intakes, with stiffer springs and titanium retainers. 

My fuel/air ratio is 4.6"1.  With alcohol, its very hard to figure how much to dump in.  [/img]


* 100_1964.JPG (460.59 KB, 1280x960 - viewed 165 times.)
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generatorshovel
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« Reply #18 on: February 16, 2015, 10:10:42 PM »

Close Guilfordin, I'm running a Honda 250/4, and have sorted out all my fuel issues now.
These Hondas are happy until an indicated 18,000 rpm (it's actually 17,200), then the valves tend to bounce (surprise !  rolleyes)although power peaks @ 15,200 (actual) , anything more is just for young bloke bragging rights,,,,,I have a spare engine (parts only) that had dropped a valve, all pistons had polished valve pockets from valves bouncing off 'em, Honda got the cutouts right, the valves hit square onto the piston cutouts.

The exh valves are Titanium standard, or more correctly, the tulips are, the stems aren't and they also contain a fair bit of unobtanium ( a set on evil bay UK at the moment for 50 quid each !)
Engine consumables are also rare, Honda NEVER made 0/S pistons, big end shells are impossible to buy (so far), as are mains.
When I rebuilt my engine, I used CB250F cams (zero overlap, .5 mm less lift), which upped the pre-determined boost from 9 psi, to 15, with no blower drive changes, the bike has done very little testing @ 15 psi, I re-geared the blower to drop back down to 10 lb, once I actually get a slip,,I might go for broke with 15 ?
Red cup racing from Canada have a turbo'd 250/4 they are sorting out now, plus a de-sleeved 250/4, which is now a 175/4  shocked
I with them well with their racing year.
Hopefully, I'll get some salt in my veins soon  cheers
« Last Edit: February 16, 2015, 10:29:23 PM by generatorshovel » Logged

Tiny (in OZ)
I would prefer to make horsepower, rather than buy, or hya it, regardless of the difficulties involved , as it would then be MINE
guilfordin
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« Reply #19 on: February 16, 2015, 10:29:13 PM »

When I decided to try the 250 Class, I went on Craigslist with a want ad for any four stroke 4 banger, Yamaha, Suzuki or Honda.  As you may not know, these were never sold for sale in the US.  I've never ridden any of them, I just based my quest for something that could handle the TZ's out there.  It would be nice if the sanctioning bodies broke out two stroke and four, but I think that 110-120 BHP is easily attainable with pressure and fuel.  Here is a link to a dyno run three years ago



, running straight methanol, 20% throttle setting, and 11,000 RPM rev limiter.  We crashed 200 several times afterwards, but I was plagued with breakage, which turned out to be from hydro locking.  Turns out the rev limiter was killing spark, but not fuel, and was twisting rods off at the pin.

On this 250, I really want to run one of those AMR300 units, but not as a draw through.  EFI is still the way to go, but there is a huge tuning curve to deal with if you start running anything other that E85 or race gas.  Regarding pistons, I have been using Ross forever, absolutely a great choice and they can make anything.  I liked reading about the desleeved 250, I was going to sleeve down one of my 400 bandits, but I wouldn't be able to get enough compression to run alcohol.  I couldn't find any crank builders who could destroke it either.  Those boys from IOM in England did that with the 600 Yamaha, and killed the 500CC record last year.
Adding a pic of what real detonation looks like ! Yikes, getting sick of this.


* 100_1254.JPG (402.56 KB, 1280x960 - viewed 167 times.)
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generatorshovel
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« Reply #20 on: February 16, 2015, 10:32:52 PM »

Thanks for assisting my post night shift wake up struggle ,,read this,,,
http://cbr250.com/forums/project-bikes/7307-project-cbr250rri.html
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Tiny (in OZ)
I would prefer to make horsepower, rather than buy, or hya it, regardless of the difficulties involved , as it would then be MINE
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