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Discussion Starter #1
Has any one else seen this pic?



Looks like fun! I can't find any more info about it though.....Somewhere in Europe I assume.



I know someone one here was talking about putting a Turbo on the little Thumper!



I wonder how much HP's it puts to the rear wheel?





23o74g by Richard Todd Giordanella, on Flickr
 

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OMG that's ridiculous, in a good way! Haha I've entertained thoughts of turboing my DR200. It could get hilarious when you pull up next to some guy on a brand new 250 Motocrosser and smoke him in a drag race on your 15 year old budget dual sport lmao! I can't help but think though, that if someone were to pull off a turbo TW, the motor wouldn't last very long at all. But who cares I guess if you could do it to like an old 91 that you got for 800 bucks lol ;-)
 

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I can't help but think though, that if someone were to pull off a turbo TW, the motor wouldn't last very long at all. But who cares I guess if you could do it to like an old 91 that you got for 800 bucks lol ;-)


HEY! that sounds like an insult hurled in the direction of my mighty steed, a '94.... bought for $800!
 

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Discussion Starter #4
Does any one know if you have to jet the carb esp for a turbo? I always wondered that even for automotive applications, if you need the main jet's etc even larger than normal to compensate for the turbo?
 

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Does any one know if you have to jet the carb esp for a turbo? I always wondered that even for automotive applications, if you need the main jet's etc even larger than normal to compensate for the turbo?


Turbos add air. You would need to devise a way to add fuel as well. At least that is how it works with cars!
 

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JATO! JATO! JATO!....
 

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HEY! that sounds like an insult hurled in the direction of my mighty steed, a '94.... bought for $800!


Same here! Traded a dead Kawasucki KZ750 for my '94t. They thought they were getting a great deal. They wouldn't recognize her now, and I wouldn't trade for a newer year if someone offered.



Turbo dub, 0-60 in 4 seconds, 60-anyotherspeed in never.
 

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That particular installation has plumbing that looks quite vulnerable to damage. Okay for a street bike, but if I wanted a street bike I would get a bigger engine. i expect this rider is limited by license regulations.



Most of the time, any significant change to intake, exhaust, or internal engine parts can be improved upon by rejetting. Does not matter the engine or modification.



Easiest way to plumb a turbo is carb-turbo-engine, but off-idle throttle response tends to be somewhat lazy. Accel actually built a valve that operated on pressure that bypassed the turbo until boost was sufficient, providing better throttle response. Worked pretty well. A turbo-carb-engine configuration provides better off-idle throttle response, but longer turbo lag as the turbo has more intake to pressurize. Plus, the carb needs to withstand pressure, making the current gravity-feed system unable to deliver fuel.



The easiest way to pressurize a carb is to put it in a box and use a fuel pump with a regulator to keep fuel pressure just slightly more than boost pressure for adequate flow. A box creates a HUGE intake volume that needs pressurization, resulting in intolerable turbo lag. The right way to pressurize a carb is to seal all the carb vents and shafts, and forget using the late model carb as it operates the slide with vacumn.



Adding an intercooler merely creates a huge intake volume that results in huge turbo lag. Cooler, denser intake charge can make more power, and tricks like pop-off valves and such can be used to keep impeller rpm up during coasting, but making time through corners often requires throttle and brake at the same time to avoid a huge bog exiting corners.



The best solution for throttle response is a combination of direct port fuel injection, minimum intake volume, and a small turbo that spins up fast. For max power, cooler intake charge, bigger turbo that flows more air. Like any other engine tuning, it's all compromises.



I'm wondering how this builder oils the turbo bearings. They need a high volume of cool oil to avoid siezure from exhaust heat literally cooking the oil. Oiling is super critical to turbo life. This problem is all that keeps me from a turbo TW.



Finally, for maximum performace, a very low static compression ratio and camshaft with minimum overlap and duration are desirable. Pressurized competition engines generally have static compression ratios of about 8:1 and cam timing typical of engines designed for maximum fuel efficiency, but with more lift.



I've thought about a turbo TW. I'd be looking for better speed-holding capability on the highway, but I'm not willing to sacrifice the stock off-idle torque and throttle response. I already have a homemade direct port EFI that can replace the carb on a TW. It's been running on a 21hp riding mower since early last summer without problems. It is sized to adapt to the stock '01+ intake manifold. Not to difficult with DIYEFI.org as a resource. EFI would allow rapid off-idle throttle response without the pressurization issues of a carb. I'd use a slightly oversize turbo so boost at low rpm would be insignicant. ~6 pounds of boost at highway speeds would increase power by about 50%, but there would be plenty of air flow to keep the engine cool. It would be a lower-cost and more fuel efficient option than a stroke and bore, but it would add some weight.
 

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:That particular installation has plumbing that looks quite vulnerable to damage. Okay for a street bike, but if I wanted a street bike I would get a bigger engine. i expect this rider is limited by license regulations." Nope the bike was made in Japan. The whole reason why a TW never exceeded 250cc is because of Japan's laws. In Japan any bike 250cc or smaller does not need Japanese Car Inspection. I know it said car but thats what they call it. So the bike will never ever get a government inspection. The sky's the limit on Mods. No license regulations required.
 

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That's the point I was trying to make--in many parts of the world the government pretty much dictates maximum displacement. In Japan, it's the inspection issue. In much of Europe, it's an operator license issue--one must be licensed on small bikes before one can be licensed on big bikes. In the U. S. of A. we just buy bigger engines.
 

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That's the point I was trying to make--in many parts of the world the government pretty much dictates maximum displacement. In Japan, it's the inspection issue. In much of Europe, it's an operator license issue--one must be licensed on small bikes before one can be licensed on big bikes. In the U. S. of A. we just buy bigger engines.
I've been amazed at the information you share with all the rest of us... I look forward to reading what you have to say every time I see your name... I belong to totally yamaha snow mobile site.. On the site you have a twin... His name is Turk.. I bet if you two met you could talk for days and never repeat yourselves................. Thanks for so many great views on our dubs. I have learned a great deal.. OMM.
 

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I've been amazed at the information you share with all the rest of us... I look forward to reading what you have to say every time I see your name... I belong to totally yamaha snow mobile site.. On the site you have a twin... His name is Turk.. I bet if you two met you could talk for days and never repeat yourselves................. Thanks for so many great views on our dubs. I have learned a great deal.. OMM.
Turk and I have nothing to say to each other. I hate cold. Snowmobiles? *barf*
 

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Turk and I have nothing to say to each other. I hate cold. Snowmobiles? *barf*
You miss out on all that great white stuff...................... I hated snow for many years because I would have to put up my bikes... But then I decided to join in the winter fun since I live right next to a major trail here in mich.. Now I get bummed out if it doesn't snow. OMM.
 

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You miss out on all that great white stuff...................... I hated snow for many years because I would have to put up my bikes... But then I decided to join in the winter fun since I live right next to a major trail here in mich.. Now I get bummed out if it doesn't snow. OMM.
Make the best of what you've got.



Eat more 'que!
 

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Discussion Starter #19
I agree with OMM, it's always great to read all the info qwerty contributes to the forum, and for that, Thanks man!



I am also really stoked on that little turbo, Imagine it spooling up and boosting the TW to new levels! Perhaps when I do another build that is more street orientated I'll build in the turbo. A Tee-urbo OH-Dub 200. Haha! It really looks like FUN!



I'd be inclined to get the real Japanese Turbo though vs the chinese clone, just by principal....in keeping the TW legit!
 

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I'm with qwerty on this one.. I HATE the cold... snow is for kids at xmass!



z
 
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