Supercharged CBR250 build

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gennyshovel
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Re: Supercharged CBR250 build

Post by gennyshovel » Sun Feb 02, 2014 11:23 am

grumm441 wrote: He had replaced the oil tank with a round top fame tube that he was using as a fuel tank
It had a radiator cap on it and was running a bleed from the blower to pressurize the tank
G
I dunno 'bout feeding hot fuel laden air into a fuel tank under pressure ?

Clutch plate sets "A" & "B" are within specs, as good as new actually, but the springs I had in, although also within specs, were up to 1mm shorter than the spare set (sag), I looked around in the spare engine dept, and found some FZR 600 valve springs, a little heavier gauge and longer, so I tried them, unfortunately, they had spring bind when compressed, a quick rethink saw me using the FZR lower valve spring cups (1.2mm thick) under the "good" CBR250 springs, that made the effort to disengage the clutch about 20% greater, so hopefully, it'll be slip free.
Plan W would involve kevlar friction plates, but time won't allow that this year (they tend to stick together over night too)
Tiny DLRA# 484
Postiebike Racing , created & funded by TwoBob Engineering

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RGV
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Re: Supercharged CBR250 build

Post by RGV » Sun Feb 02, 2014 1:46 pm

I hit my steel plates with the wire wheel on my grinder at 90* to rotation to give the surface some texture. Not really roughing them up, just de-glaze really. Never had a slipping problem. I measured my friction plates thinking they might be getting worn but still well within spec. The clutch took a lot of abuse at Tailem Bend, must have done 20 or more runs.

Image

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Stayt`ie
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Re: Supercharged CBR250 build

Post by Stayt`ie » Sun Feb 02, 2014 10:28 pm

back in the seventies i was running a Mach 111 at the drags at Surfers, the clutch was slipping and i didnt have any spares, somewon suggested rubbing them in a figger of eight on the pit (bitumen) road, cured the clutch slip,, every bike since including the present ZX12 has the steelies done this way,, :D ,,
First Australian to ride a motorcycle over 200mph at Bonneville,,,

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dplecko
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Re: Supercharged CBR250 build

Post by dplecko » Mon Feb 03, 2014 12:29 am

Still under development but i have about 2 times standard clutch spring pressure, a couple of extra plates and a machined sleeve to contain the total travel of the weights.

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AuotonomousRX
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Re: Supercharged CBR250 build

Post by AuotonomousRX » Mon Feb 03, 2014 1:50 pm

I found I got some Clutch Slip using a Synthetic Gear Oil, Motul Expert Transoil 10W40.

I changed to Castrol MTX Gear Oil in the Gearbox/Clutch seems to work well in the RGV.

An EBC Clutch Spring Kit (they are a Heavier Spring) is a cheap option that helps in modded RGV's, it makes the Lever heavy, so using a mix of good Std and EBC springs is common practice, this is what I have and works great.

Pete :D
Metric Target 250 on a 250 on a Red Bike

Pete :shock:
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Greg Watters
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Re: Supercharged CBR250 build

Post by Greg Watters » Mon Feb 03, 2014 2:49 pm

Nearly the same as Ronnie i used to rough them up on the concrete many yrs ago
then for a while it was springs so heavy we had to help Kim after she hurt her hand
Now the 750 has a lockup and its light again and does not slip
if anyone wants to make a lockup i have drawings that you could adapt to your particular application

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gennyshovel
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Re: Supercharged CBR250 build

Post by gennyshovel » Fri Feb 14, 2014 9:48 am

Panic stations in the creation station,,,,as usual, work gets in the way of fun, I managed to wrangle another week off next week, so, if the rain misses us, test ride # zillion should happen Sunday.
After the last ride, I've been having nightmares regarding the newfound 15 psi of boost, so I've decreased the blower drive ratio, hopefully that'll get the boost back to where it was before the cam swap.
I had issues with the "test tank" and it's venting (almost none), the thermostat not opening as it should, and the slipping clutch, hopefully, all these problems have been cured.
I'm only 6 months behind where I'd like to be,,,,,,,,,,,
Tiny DLRA# 484
Postiebike Racing , created & funded by TwoBob Engineering

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gennyshovel
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Re: Supercharged CBR250 build

Post by gennyshovel » Sat Mar 29, 2014 7:32 pm

Back to work in the creation station, the power jet installed.
Image

I went for yet another test run with the pre holed piston jetting in, unfortunately once the throttle was cracked, the mixture leaned out on the pilot jet, freaking out the O2 gauge, but my soul needed therapy, so I worked thru the burbles and got onto the main, it felt like the power jet was working, I kept my thumb on the piston cooler/oiler/squirter button to help cool the piston crowns while I ventured into the danger zone.
Ill upp the pilot from #70 (the largest I have) to #90 (bigger if needed) when jet order number 39 arrives.
By fattening the needle jet a bit too much I think I hid the underlying pilot leaness prob, so I'll work thru all stages one by one, keeping within the O2 gauges range.


http://youtu.be/ZLhvS7SSfd0

#1 is still running hotter than the other cylinders, I might swap #1 and #2 egt probes 'round to eliminate error, later on I'll try and deflect the incoming A/F charge in the plenum to even things out.

This clip was taken the Sat before speedweek with 15 lb boost while the wot mixture was still too lean (regardless of main jet increases)
After seeing Dave Plecas' run (dplecko) with 30 lb boost on a stock Honda conrod I'm not so worried about 15 lb any more.
http://youtu.be/cS5dAJz90uo
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Tiny DLRA# 484
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hawkwind
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Re: Supercharged CBR250 build

Post by hawkwind » Sat Mar 29, 2014 8:38 pm

:D ....one thing to keep in mind you can go to rich on meth and it will run lean ...im running in the 4:1 range on boost and the oxygen sensor don't work to well if at all accurately at that level.
cheers
Vehicle......................A new creation.
Designed by................Troglodyte.
Engineered/ built by......Rustic.
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Johno Senior
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Re: Supercharged CBR250 build

Post by Johno Senior » Sat Mar 29, 2014 8:54 pm

Hi Tiny,
Hope that blast down the road made you feel good again and get rid of the post speed week blues :D

On my NGK oxy sensor it warns me that the reading will be lean at low RPM if the sensor is too close to the end of the pipe, they suggest by two points. ?

my sensor is about 100mm from the end so have a pipe extension ready for the dyno one day ,
ciao johno

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gennyshovel
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Re: Supercharged CBR250 build

Post by gennyshovel » Tue Apr 08, 2014 9:48 am

Johno Senior wrote:Hi Tiny,
Hope that blast down the road made you feel good again and get rid of the post speed week blues :D

On my NGK oxy sensor it warns me that the reading will be lean at low RPM if the sensor is too close to the end of the pipe, they suggest by two points. ?

my sensor is about 100mm from the end so have a pipe extension ready for the dyno one day ,
ciao johno
Yeah Johnno, it did, I even remembered to actuate my piston oilers :shock:
I've decided my brain needs frying, I'm in the progress of learnin' 'bout EFI setup :? so I'm ready for the next project, Wilso's 3 wheeler.
There's NO WAY Laslo will let me bring it up to today's technology , no room to shove injectors while the engine is in "that" frame.....Pity :cry:
Tiny DLRA# 484
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gennyshovel
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Re: Supercharged CBR250 build

Post by gennyshovel » Tue Apr 22, 2014 6:03 pm

I switched #1 & #2 egt probes,,there is a calibration error, not a lean cylinder,,good,,but,,,,
Stupid bloody O2 sensors,the ears say filthy rich, the gauge disagrees , then
goes out on strike (again),,,,,,,,,,,,,,,,,,After further research regarding
wideband O2 sensors, Iv'e reached the conclusion they suck when using methanol,
there are SO many variables affecting their operation like unburnt fuel giving a
false lean reading , missfires giving a false lean reading, thermal shock from
the H2O produced when burning methanol kills the ceramic heater element, they
can't be switched off while warming the engine enough to evaporate any H2O
droplets in the exhaust, this will foul the element also.
The makers neglect to mention the Innovate Motorsports Digital MTX-L Air/Fuel
Ratio Gauge will suffer these problems in the sales pitch, although the problem
is mentioned in "help"

" Wideband O2 Sensor is compatible with all fuel types (Leaded, Unleaded, Diesel,
Methanol, E85, etc)
• Ability to calibrate O2 sensor for increased accuracy "
Then,,,,
"When tuning a methanol engine, make sure the engine is warmed up before you
switch on the wideband system. (The short operation without heater power will not
damage the sensor.) Here's the reason:
Many methanol engines run very rich, not only because of the low stoich AFR of
methanol (6.4), but also because methanol has a very high latent heat value
compared to gasoline. On a cold engine only part of the inducted or injected
methanol even vaporizes and takes part in the combustion. The rest runs out of
the exh. ports still in liquid droplet form. This can be seen on the exhaust
ports that show traces of liquid methanol running out. This liquid methanol can
kill the sensor by heat shock (high latent heat, as said), just as water can.
In addition the EGTs of methanol are typically much lower than on a gasoline
engine, while the exhaust gas volume is higher. This causes the sensor heater to
not be able to keep the sensor at operating temperature and it will error out.
Even higher supply voltage will not help because the sensor heater has a limit to
how much wattage can be supplied to it. After all, these sensors are designed for
production cars with much lower power than a methanol fueled dragster. Using a
double height bung so the sensor is out of the direct exhaust stream will help
the sensor heater to keep the sensor in its operating temperature range."

Back to "feel" ,sound, & plug reading I guess (your right Ronnie,OLD SCHOOL RULES !)
Tiny DLRA# 484
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internetscooter
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Re: Supercharged CBR250 build

Post by internetscooter » Tue Apr 22, 2014 6:11 pm

Tiny - I haven't tried them myself but I am wondering if something like this would help?

http://www.carbtune.com/colortune.html

If they did then I always thought there must be a way (Vespa Labs patent pending) to turn the colour reading into a signal that could be displayed while riding.
Paul
---
DLRA #647
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Vespa Labs [url]http://www.vespalabs.org[/url]

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gennyshovel
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Re: Supercharged CBR250 build

Post by gennyshovel » Tue Apr 22, 2014 6:16 pm

Methanol changes everything Paul,,
If I shoved one in my earhole, it would turn brown(ed off) at the moment.
Tiny DLRA# 484
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Stayt`ie
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Re: Supercharged CBR250 build

Post by Stayt`ie » Tue Apr 22, 2014 6:27 pm

yup, :lol: ,,
First Australian to ride a motorcycle over 200mph at Bonneville,,,

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