B-8-D
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down to one car!!
Posts: 4,038
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raising and widening the exhaust ports will give you more power but will be higher in the rev range.. don't go too much as it will lower the effectice cr also.. drilling from the intake port strait to the crankcase will give u a little low range power but fittint a reed valve to the intake will be nessisary.. reshaping the combustion chanber and pollishing helps too. a decent expansion type exhaust is needed and where the power is made really on 2stokes.. a bit of a black art and an additional expantion area an extra pot with a butterfly valve to open at low revs will help give extra low range torque and effectivly make the expansion chamber bigger on low rev could be an idea?? flowwing all intake ports and knife edging any dividers helps too..
ive tuned a few 2 strokes in the past all bikes but all succsessfull had a dt50 with a 75cc big bore kit doing 75 to 80 mph back in the day.. lol si
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So realisicly what you going to do to it then? exhaust, bit of porting, bit of a compression rise too I hope! Lets inject it ![:D](//storage.proboards.com/forum/images/smiley/grin.png) you've about summed up my feelings. except injection, i've been warned off efi on 2 strokes. anything complex like that can wait anyway ![:)](//storage.proboards.com/forum/images/smiley/smiley.png) best two stroke tuner was stan stephens but he tuned bikes www.stanstephens.com/if need anyhting major maybe, but I reckon with a bit of help I can do most and slater can do the machining/welding. My first point is why the hell didn't you ask me last night...... cos I'm a braindead halfwit and I forgot ![:-X](//storage.proboards.com/forum/images/smiley/lipssealed.png) excelent advice and the pics are great! loving your old AR ![8-)](//storage.proboards.com/forum/images/smiley/cool.png) oldschool.co.nz/phpbb/viewtopic.php?t=8612flatmate's fronte. pipes made a fair bit of top end difference, even though he had leaks at the flange which goes against the head, and hadn't altered any jetting. runs a bit on the rich side anyway I believe. there's a few theories about on the volumes and such things, though. sounds so intensely awesome though. farking ace! ![8-)](//storage.proboards.com/forum/images/smiley/cool.png) he's nuttier than me ;D drop my ole man a line, rob(at)cobra-racing.co.uk if that doesn't work I'll pm his moby he tunes suzuki T500s for classic racing and is damn good at it. He can design and build expansions and port and squish and all the other stuff that strokers need ![:)](//storage.proboards.com/forum/images/smiley/smiley.png) He will probably enjoy this ![:)](//storage.proboards.com/forum/images/smiley/smiley.png) Al awesome man! thanks for that ![8-)](//storage.proboards.com/forum/images/smiley/cool.png) Then check whether the piston skirt interferes with the ports and trim to suit. hopefully you mean at tdc ![;)](//storage.proboards.com/forum/images/smiley/wink.png) if i remove the skirt at BDC it won't run ![:D](//storage.proboards.com/forum/images/smiley/grin.png) at TDC its a good idea though, ta ![:)](//storage.proboards.com/forum/images/smiley/smiley.png) You could look into some of the goodies Melkus made: expansion exhausts, triple Jikov's, that sort of thing. the triple carbs are mz250 ones, at least they are on the wart wr353. I want to go single carb as it is only a road car. Also people with DDR speedboats (panthers) frequently use these parts. They may be old and scene taxed, yet very retro-awesome. like this- galerie.trier-wunder.de/categories.php?cat_id=93&page=3you're right- very awesome! Just mod a basic K-jet system and you'll instantly cut fuel consumption in half. I'd rather not, efi would be my choice. also two strokes don't have much in the way of inlet vacuum so I don't know what you'd do to the curse word-flap in the meter head to get it to meter corectly? raising and widening the exhaust ports will give you more power but will be higher in the rev range.. don't go too much as it will lower the effectice cr also.. taken on board. I was only going to widen it. I've been looking at tuning for single speed 100cc karts as they have to have a wide flat torque curve to compensate for the lack of gears. oh, and I just won this- ![](http://i19.ebayimg.com/07/i/001/27/f4/38c8_1.JPG) yeah, sidedraft would be slightly better, but this was cheap ;D
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Jan 10, 2009 14:07:28 GMT
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I would probably start by matching the port shapes with the inlet and exhaust to improve flow, no point in just removing loads of material if its going to hit a step on the way through. Then check whether the piston skirt interferes with the ports and trim to suit. Polishing the ports etc will help with flow also. You really need to do just one thing at a time when tuning to see what is working and what isnt. Please don't shoot me if I'm wrong though! Yes i did mean checking the piston skirt at tdc, sorry about that.
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Jan 10, 2009 18:52:04 GMT
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no worries chap, its something I hadn't thought of ![:)](//storage.proboards.com/forum/images/smiley/smiley.png) the list of ideas - expansion chamber exhaust
- megajolt
- widened exhaust port
- headwork. mainly skim and increase the squish in tolerance and in radius
- weber carb only cos it cost £notalot
its supposed to be 50bhp stock, wonder what that would make it? I'm only going for basic mods for the time being. a balls out engine would be a way down the pipe line. oh, and take a look at this nutter. wartburg head converted to direct injection! ![:o](//storage.proboards.com/forum/images/smiley/shocked.png) ![](http://www-user.tu-chemnitz.de/~andrf/bilder/Sonderklasse/Zylinderkopf_DI_oben_2.jpg)
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