New top end is in place, just need to reassemble the rest of the bike which doesn't take long and see how the bigger motor does.
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New top end is in place, just need to reassemble the rest of the bike which doesn't take long and see how the bigger motor does.
Attachment 46645
Seeing as you know what this generation cylinder and piston normally look like... here's the new setup. :D
I dunno what it looks like!!!
Newer powerplant??
Much bigger piston than OEM. 6mm bigger bore to be specific,
What the hell lol
380 powerplant??
Hah, I wish, 292cc in it's current setup. I went big and got sent home anyways so now I'm going more bigger to see what happens. Without stroking the crank (which I'm not sure there is room in the cases to allow) this is as big as the stock cylinder casting can go. Any more material removal and you start getting into the water jacket. If I get a motor feel anything like my KTM300 I'll be loving life.
Attachment 47289
So... yeah... new top end, lots of new hardware on new top end 'cause I like to make things better as I work, new chain and sprockets for Boxshop, add coolant and... crack in the crankcase.
seriously, when do you and Patel get a netShow, cause i'm tuning in! :D
WTF, happened?
Given the prior repair work to that motor mount, repair work I did to one case half, the cylinder failure that prompted this rebuild, and the bent frame Kates fixed I suspect the bike had been hit HARD at some point. Some of the repairs were more cosmetic than structural, and as I wring the poor bike's neck on pavement the stresses are causing that prior damage to rear it's ugly head again. Let's not forget the pile of shit this bike started as, it's not like this is a two year old machine that is suddenly going pop, it's had a hard life and I've been trying to deal with it as issues crop up. I'd bet it had been weeping prior to now, I attributed the coolant staining I saw around there when I did my teardown to the cylinder crack. Because in theory I was going to be racing it this weekend and it's a fresh assembly I was being extra cautious going over it, including paper towels on the floor to act as tell-tales for any leaks and well... found one.
It's not a quick leak, the idiot in me says hang the bike by it's front end, dry and clean that area and just slather on some epoxy but I don't think I could bring myself to race it like that.
Down for a YouTube channel!!!!
But dang man...that is one of my worst night Mares
Does that mean it's just not a track bike?
+1 on the jb weld motion. Do it. Do it now.
Further review showed the seepage to be coming from the base gasket. Research shows this to be a semi-common 'thing' on Yamaha smokers, many suggest using spray gasket prep on base gaskets just as normal maint. (Blech!) So, being the idiot I am, in a time crunch, I did no such thing. I've just fired it up, lit on the 4th kick after sitting apart all winter, and got a lil heat in it to see what happens. If it stays reasonably dry I'll run it.
Should I also be worried about said seepage
I'm pretty sure I keep asking and keep forgetting but I still have a spare set of cases for the 1994 motor on the YZ will that work for you on your big cylinder....or just JB weld...or new power plant or bust
Bike survived, no leaks other than some exhaust spooge.
Oh, and Mistake and I are starting to figure each other out, today was my time sumoing it that it felt 'right'. Had a BALL at Boxshop today.
Cont. From Facebook...stock carb is very good on my '94...no hesitation...smooth roll on at any rpm and responds very well to tuning (ie. Jetting changes) in the direction it's supposed to
Got a video of said hesitation?
And your 94 has a completely different carb than my antique did before I tossed it. (VM vs TMX) What I'm dealing with on mine is four stroking at idle to just past light maint throttle. Open it up more and away we rip. I never noticed or cared about it in the dirt, and it may be a sign I'm just letting the revs get too low on pavement. I'm pretty certain I can eliminate it as well, the main question I had in that conv is if it was normal for the bike to seem to loose drive as you went from rich to closer to right, which on a two stroke appears to be the case. Now that I know that I'm all set to continue tuning.
Edit: More specifically, now that I know that is how two strokes behave, stock carb or mine, dialed in it will have less go off the bottom if tuned to be smooth than if it's fat and four stroking. I think I'm going to alter my gearing to adapt.
1.) isn't fat and 4 stroking the goal with a 292? get it to fart with torque down low like the exc...that's why I'm getting the other cylinder ported & WR gears put in
2.) or does fat/4t mean it's hesitating?
ya gearing sounds like it'll help...lose some top end speed in exchange for more usable/shorter lower gears
I'm guessing you know this, but in order to get off the line on all older smokers, you gotta just feather the clutch to get it into some sort of power delivery range:
https://www.youtube.com/watch?v=1TJm...ature=youtu.be
so I'm guessing you're saying bigger rear sprocket/smaller front will allow you to keep those rpm's up and spend less time in the lower rpm's
but otherwise, stock carb - you should be able to tractor it at low rpm's with smooth response all day...up inclines:
https://www.youtube.com/watch?v=WAPMsDXMNjo&feature=youtu.be
even on sumo/kart track:
https://www.youtube.com/watch?v=xfu7Cnz4gIE
I even short shifted after 2nd hairpin into chicane..only reason I was "ding, ding ding" around the hairpins were the tampons in my purse...bike will do it
3.) kinda feel like the smart carb isn't performing correctly...maybe sell it and get a regular stock carb? can you just fit a different year carb into the boots/airbox of the '92?
or, you got your answer - leaner = less go on the bottom. new gearing. done.
man even though I'm not slaying villages, these videos still making me feel all :wub: about 250 2-strokes...can't wait to go out again!
Or I just, you know, finish dialing in the carb I've got? :D I was making good progress, I just got spooked by old four stoke tuning expectations. Now I know those are wrong and will go back to adjusting. If I can find some place to play this weekend I will otherwise I'll adjust at the classic between sessions.
side note on carbs... if you guys know anyone looking for a 36mm TMX i have one with Hall's tweaks, spare brass and a rebuild kit. no longer needed and keep forgetting to post on the interwebs for sale.