That first 2 stroke powerband...

[nerobro]

I just about pooped myself on friday. I was quite seriously reminded of how insane two strokes had become before the modern era of powervalves, electronicly variable ignition timing, and nice broad tuned pipes.

Two weeks ago, Skreemer and I took the dirtbikes out to play. Mine ran for oh... 2 minutes. And I oil fouled the plug. I had no spare and I didn't bring a plugwrench. so My bike was toast for the day. Steve rode his for all of 10 minutes. Breaking his clutch lever. ;-) My 30 mins of riding that day were entirely clutchless. Quite a time. I fell off twice ;-)

So, friday, Skreemer ditched work, picked up some sparkplugs.. and we went about making my bike run again. We put in the new plug, I half hearted kicked the kickstarter. It revved to life. I was grinning ear to ear. 5 minutes of running around the house to warm it up, and I pulled my bike out onto hte street. Last time I did this highly illiegal move I had the choke on, and the bike sputtered, bucked, and ran like doggie doo. This time I didn't make that mistake.

But a mistake I did make. I had forgotten that 2 strokes had gone from weak. (20 hp) To ok. (30 horsepower) To almost unridable. (40 horsepower) all without powervalves. Now to get more horsepower you end up with a sharper powerband. my bike makes 10-15 horsepower untill it comes up on the pipe, and then... well.. The front tire was 18" in the air before I could grasp the situation.

I was by no means expecting my bike to try to run away from me like that. It didnt' end in disaster, but I don't wanna hit that powerband on the street again. Without a powervalve, 2 strokes are vicious, evil, nasty, beasts.

I can't wait to ride it more ;-)

[Creative Mayhem]

I was by no means expecting my bike to try to run away from me like that. It didnt' end in disaster, but I don't wanna hit that powerband on the street again. Without a powervalve, 2 strokes are vicious, evil, nasty, beasts.

I can't wait to ride it more ;-)

hahah so true

[skife]

i'm getting a 350 banshee next month for $350... its a stolen recovery and needs a stator and some other stuff. a stator is like $350, my friend's sister ran out of inhertience money and doesn't have a job so she is selling stuff cheap.

[nerobro]

Stators aren't that expensive. Find an old one from say... a RZ350. and you'd be amazed at what's compatable. They are also rewindable. It costs about $15 in copper to do it. STators are a commodity item. The stator on my 550 may well fit a half a dozen other bikes from a half a dozen otehr companies.

[skife]

Stators aren't that expensive. Find an old one from say... a RZ350. and you'd be amazed at what's compatable. They are also rewindable. It costs about $15 in copper to do it. STators are a commodity item. The stator on my 550 may well fit a half a dozen other bikes from a half a dozen otehr companies.

i've called all the yamaha dealers around here and they all quote $300+ for a stator.

[PyRo]

i've called all the yamaha dealers around here and they all quote $300+ for a stator.

Is that installed? Check around on the interweb.

[turtlepaint]

bbrraaaaap

what kinda bike u riding nerobro. the powervalve only changes the performance on the top end to give you more of it and rev out better ,they do come on like a light switch without em though , like my cr500 or 250r that had the stump pulling torque but not the top end rush. gotta luv the two strokes so simple and fast. but ya cant beat the new crf's
- oh and if i think of it ill look up that stator at work tomorrow

http://www.msnusers.com/t2em5a7de6ub6h05ju39hue927/Documents/Pictures%2Fquad%20pics%20001.jpg

[Dubstar112]

165 horse ... with powervalves of course.

One of the guys from our sponsor D&D made a 500cc two stroke dirtbike. I forgot the specs, but i guess it was nearly impossible to kick start.

[nerobro]

what kinda bike u riding nerobro. the powervalve only changes the performance on the top end to give you more of it and rev out better ,they do come on like a light switch without em though , like my cr500 or 250r that had the stump pulling torque but not the top end rush. gotta luv the two strokes so simple and fast. but ya cant beat the new crf's
- oh and if i think of it ill look up that stator at work tomorrow

WELL... not quite. Powervalves lower the timing of the exaust port. Effectively what that does is it retunes the engine to make more torque at lower rpms. The 1983 RM250 I have has the exhaust port wide open, so it makes jack and squat on the low end, but as I found out, pulls like god up top. You'd get the same effect by disabling the powervalve servo on your CR250 and wiring the powervalve wide open.

[hitech]

bulltaco 400, ah the memories...

[nerobro]

Dubstar... 500's aren't imposable to kickstart. Especially 2 strokes.

http://www.atkusa.com/ProductsIntimidator.aspx Even THOSE aren't imposable to kickstart. ;-)

The thing is 2 strokes have static compression of only 6.5:1 or less. So are fairly easy to kick. Relitively speaking. The PITA's are say.. 640cc 4 strokes like a KTM LC640 ;-) Even the 450's now have compression release so you can boot them over despite their 11-13:1 compression ratios.