The 2-stroke thread

Heres a bit of a breakdown...

The bike had changes every year..some more than others. Yamaha tended to stay with the same basic design and modify it rather than scrapping everything every few years. I remember working on a 1982 yz 250 and a 97 on the same day. You could tell the two engines were very similar.

The MAJOR points would be a new engine design in 99 that was revised from then until 2003. It basically stopped there. Previous to that, the engine was changed some from year to year, but many of the parts would change over.

The last chassis geometry change was between 1997 and 98 when the steering head angle was decreased by 1/2 degree. Basically the 2009 yz 250 still uses the same steering geometry as the 1998 model. The frame changed to aluminum in 2005, but the chassis geometry was not altered.

The plastic changed between the 2001 and 2002 bike. The 2002 tank, seat, and airbox is still in use. The front fender and numberplate changed between 2005 and 2006. The fork guards changed in 2008.

The suspension change to the SSS fork in 2006 is probably considered a major change as well.

 

Where at?? I need a backup bike in Havasu, its in AZ??

 

Not you I am just saying in the shootouts and tests they are saying the KTM has finally passed Yamaha

 

Interesting comparison of some newer ones.
http://motocrossactionmag.com/mobil...A-YZ250-TWOSTROKE-MOTOCROSS-TEST-IF-9991.aspx
And by the way, I'm just stirring the pot as I have some beers. I in no way even remotely dislike Japanese bikes, and we could all find an article here or there saying each bike is the best. There are two blue bikes beside the KTM's in my garage right now.

 

Gonna keep this for when I go to find an 05 as it seems all sorts of parts are interchangeable.

 

Get the 06, better shocks!! Anything 06' and after is damn near identical, I got an 05' with 06' suspension.

 

Phil, did you buy a smoker yet?

 

Fuck, damn close to buying one. Really want to finish my bobber first though as I could turn that around and sell it and get me a used rocket and smoker.

 

i was looking at videos from 2011 in hollister in northern california.
i cant wait to go back once my knee is feeling better. If you got time to kill go ahead and take a look.

http://youtu.be/QsuFNfFOYfU

 

Sweet video man that hillclimb at the beginning looks like a blast! I'd love to adventure out to Cali and ride sometime.

Here's some footage of me and a buddy braaping around the mountains here in Wyo. Sort of a long video but we covered some good ground and ended up riding all the way back in fog. I have the footage somewhere but it was so foggy you couldnt even see 50ft ahead and the GoPro lense would get covered in moisture almost instantly after i'd wipe it off lol. Choppy footage cause i had it in the wrong frame rate..woops

https://www.youtube.com/watch?v=dmTZCMDu5zE

 

THE AF500 is done, virgin test ride tomorrow!! I will get some GoPro of it in action!

Rode it around the block, mostly on the back tire! I think I am in love.....

 

700cc just waiting for warmer water

 

#In your bedroom?Your're my hero!I hope that's a waterbed!

 

Yeah, what he said.

 

I havent made the AF500 vid yet, gotta edit the shit out of if since my GoPro was on FOREVER! But since I blew up the YZ300 I will be racing this thing next weekend, sorry not a 2 stroke!

Its an 08' CRF488r big bore, Stg III Hotcams, porting, high compression, blah, blah..


Its a little loop I like to do in Ocotillo Wells.
http://www.youtube.com/watch?v=E_EiOisujyg&feature=youtu.be

 

Alright so I've always had issues with my bike taking like a million kicks to start. And when it's cold forget about it... Has a new top end now, basically tore it down to its frame and it's back together now. Still having issues with starting, exactly like before top end. Would reed valves be the cause of hard starting? I planned on doing them anyway and probably gonna order a vforce 3 reed system soon. I never even so much as looked at them so I'll probably pull the carb tomorrow and check em out.

 

Reeds are worth taking a look at. Make sure the carb vent tubes are clean. Clean the carb. If it's been a long time since it's been started, make sure the gas is mixed with the oil, and that the carb isn't gummed up. This tends to happen now with ethanol infused gasoline. I turn off the fuel and empty the float if I know the bike will be sitting for a few months.

What's the compression on the new top end? Should be anywhere between 160psi-200psi depending on your engine displacement.

If all of that stuff checks out. I'd start looking at the jetting.

I'm sure you have tried all the tricks (no throttle, wide open throttle, half throttle, blip the throttle, kick from top dead center, etc. etc.)

 

Crank seal?

 

I can see how a crank seal might cause some starting issues. But he hasn't mentioned any issues with the bike after it has already started. I think you'd agree that a bad crank seal would cause other problems beyond just the inability to start.

There are many other more simple issues that could be causing this problem.

IMO, the list of things to check is this, start simple and move to more complicated - I'm sure I'm missing something too:

1) Spark
2) Gas is on
3) Gas is fresh
4) Open vent hoses
5) Plugged up pipe/silencer
6) Clean carb
7) Reeds
8) Proper Jetting
9) Compression
10) Head/Base Gaskets
11) Crank seal?