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Discussion Starter #1
Yes, it's done, I've finished my 230ccm engine after a much too long time.

The carb has a well setup, there is just a small hole from idle to less open thottle.



Now the technical details sorted from the inlet to the outlet:

- modified Airbox

- Mikuni VM28-418

- 200/225 cylinderhead

-> incl. cylinderhead optimisation with porting to 71mm and a bigger outlet

-> Webcam camshaft stage 3 incl. Valve Spring Kit With CrMo Retainers Beehive (Race)

- 225er cylinder

-> with 71mm piston from Wiseco, compression: 10,25:1

- 225 crankshaft (58mm stroke)

-> incl. 225 ballancer

- Akrapovic Racing exhaustsystem (complete system incl. headerpipe)

- 5 disk clutch (not std. at the 125ccm engine) with fitted pressureplate for springs froma 600ccm Yamaha engine



Here the results from the dyno (stronger as the feeling from my testrides):

Performance: 21,8 hp @ 8,091rpm

Torque: 20,9 Nm @ 6,643rpm



Here is the chart in comparison to a:

TW125 (+10,4 PS {+91%}/+12,9 Nm {+161%})

TW200 (+5,8 PS {+36%}/+4,9 Nm {+31%})





Click to zoom!



Here are the org. prints from the dyno:





Regards, Sebastian
 

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Significant gain from 3000rpm and higher. Excellent! The shape of the curves indicate potential for better fine tuning, which will net even more gain.
 

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Sebastian, by optimization do you mean you're opening up the combustion chamber to cover the full 71mm bore?
 

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Discussion Starter #4
Significant gain from 3000rpm and higher. Excellent! The shape of the curves indicate potential for better fine tuning, which will net even more gain.
I have a lambda sonde with display (shows air/fuel ratio between 12 and 16). This is very helpfully to find a good setup.
 

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Discussion Starter #5
Sebastian, by optimization do you mean you're opening up the combustion chamber to cover the full 71mm bore?
Yes, that's it. Plus a rounder shape from the combustion chamber and the bigger outlet (max. diameter from the headerpipe gasket).
 

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Do you check your air:fuel mixture while riding? Airflow from motion can change air:fuel ratios in the engine. It's actually common.
 

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Discussion Starter #7
Do you check your air:fuel mixture while riding? Airflow from motion can change air:fuel ratios in the engine. It's actually common.
Yes, I allways take a look on the display.

The setting will be never the perfect, but I can try to find a good middle.



It's goog to feel differnet settings, but it's better to see the differences (especially with small changes).



I use this one from Koso:

KOSO NORTH AMERICA MINI AIR/FUEL RATIO METER - BA005000



Highly visible LCD digital display in a compact size

Internal battery lets you move meter from sled to sled without messing with power wires; can also be hardwired into power source (backlighting requires hardwiring)

Display range: 12.1-16.8

Measures 2 3/8 in. W x 1 5/16 in. H x 5/8 in. D

Includes O2 sensor





Included Items:

(1) Meter; (1) Signal connect wire; (1) Oxygen sensor; (1) Oxygen sensor adapter; (2) Connect terminal; (1) Velcro set; (1) Manual



Note: For use on 4-stroke models only



www.chrome-addiction.com

Price: $168.96



 

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Very nice. Sebastian strikes again.
 

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Wow, that's the cheapest one I've seen yet. Very tempting. Is is waterproof enough to be left on the bike? Can it be calibrated?
 

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Discussion Starter #10
@ lizrdbrth



Much more better is a fuel injection system with lambda-sonde. I am thinking since 1-2 years about it.



@ PJungnitsch

Yes, it is water resistant. And you don't have to connect it to the electric system from your bike.

No, there is nothing to calibrate. It is just a display for a sensor (like a temp-sensor).
 

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[quote name='macbig2k1' date='27 June 2011 - 02:16 PM' timestamp='1309202193' post='21098']

@ lizrdbrth



Much more better is a fuel injection system with lambda-sonde. I am thinking since 1-2 years about it.



Have you thought about integrating the FI system from the yamaha YS 250 Fazer? That would be the ideal starting point in my opinion, the basic cylinder and head is very similar to the TW200. The major hurdle would be the fuel pump, the Fazer FP could not be used, but an inline FP that provided the right pressure and flow rate, may....



http://www.twowheelsblog.com/post/3894/2010-yamaha-ys-250-fazer-from-brazil-to-europe
 

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In the absense of fuel injection, Ronnydog has suggested a good ole' Dial-a-jet system could be used.



But rather than relying on a "butt dyno", plug readings or intuition, an O2 sensor and meter could be used to monitor air/fuel ratio in real time.



Poor man's "fuel injection" with on-the-fly feedback.



Neandrethal, but doable. Dial up your jetting to suit altitude and ambient conditions, verify with the meter, then dial it down when the balance changes. I could have used something similar when we were bouncing up and down from sea level to 8,000 ft. on our honeymoon.
 

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In the absense of fuel injection, Ronnydog has suggested a good ole' Dial-a-jet system could be used.



But rather than relying on a "butt dyno", plug readings or intuition, an O2 sensor and meter could be used to monitor air/fuel ratio in real time.



Poor man's "fuel injection" with on-the-fly feedback.



Neandrethal, but doable. Dial up your jetting to suit altitude and ambient conditions, verify with the meter, then dial it down when the balance changes. I could have used something similar when we were bouncing up and down from sea level to 8,000 ft. on our honeymoon.
Some people do exactly as you suggest.
 

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Discussion Starter #15
@ Arrowsmith

Turbo is too expensive, too many moving parts and too many pipes to bend.



And there is still the same problem:

- different hight (sea level) -> different setup needed

- different temperatures -> different setup needed

- different types of fuel -> differnet setup needed (timing for spark)

The best would be a system incl. knock sensor.
 

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Great job Mac. Sure would be nice to get all this (and other engine threads) condensed down and in one spot. You "Engine Guys" sure have a keen understanding of the machine. Gerry



 

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Sebastian, I have an old link to a do-it-yourself electronic fuel injection controller. I'll see if I can find it. If memory serves, it will control up to 4 injectors, but only 1 or 2 if that's all that need controlling. The cold start enrichment circuit is manual (switch on the handlebars) for cold starts, and the controller responds to a throttle position sensor and oxygen sensor. Tuning was via USB and a laptop, and the user could create his own fuel maps.



EDIT: Well, well, looks like the technology is alive and growing.
 

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Don't want to send this thread in some absurd direction. The meter system seems pretty straight forward, though I understand it's value as a 'tune-up' aid but beyond that I am unclear. I remember reading the posts on the dial-a-jet and gave much thought to purchaseing one, but so far I have gone no higher in elevation than about 5000'. Should one move towards the 'poormans' fuel injection, would this have anyvalue. Gerry











This is a bilge fan that I installed into my intake. I moves lots of air but not anything close to being a 'turbo'. It is controlled by a pulse modulator so input can be held steady at various volumns. Gerry
 

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Gerry,



The value of the meter is that it allows you to view your air/fuel ratio.



On a real fuel injection system its sensor talks to the ECM and makes air/ fuel corrections many times per second. The meter uses the same type of sensor, but merely converts the signal into a visible air/fuel ratio.



Ordinarily most of us jet to suit our home location, and this jetting serves a relatively narrow range in elevation. It goes lean at lower elevations, rich at higher elevations and there isn't a heck of a lot we can do about it unless we want to stop and rejet every 2,000 ft. The dial-a-jet is reasonably capable of giving us ideal jetting that can be varied to suit conditions, the meter just takes the guesswork out of knowing how far to turn the knob, and rather than making corrections hundreds of times per second as fuel injection can, you'd turn the dial-a-jet up or down say, every 1,000 ft. in elevation, based on the air/fuel meter. Or whenever it strayed from within a given range.



So rather than serving as a tuneup tool it would become part of your instrumentation. You would need to weld a bung into your exhaust header for the sensor.



There have been many attempts at electric fan superchargers, btw. Most of them homebrewed. Some of them actually work to varying degrees.
 

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I doubt a TW generates enough juice to turn a strong enough fan to actually make a difference for very long.
 
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