Bring out your dead!

[Paul_E_D]

THe serious answer is that you will go slower for many years with this technique. Now, a flattracker or motocrosser for life will go faster this way. THe only person I saw go really fast foot out at loudon was Doug Henry. I chased him and Jeff Wood for many laps on my 125. Doug had to carry crazy lean angles and dragged hard parts and slid the bike in literally every corner because of it. It was natural to him, but it won't be to you, or anyone who wasn't weaned from breastmilk directly to 2 stroke oil.

[lrrs313]

There was a discussion of this, years back. I believe it comes down to loading the front wheel, which is accomplished by putting a foot out. In very slow corners, it is beneficial; however, in higher speed corners (all of LRRS), it can tend to overload the front. Also, because of the effect on the center of gravity, it requires much higher lean angles to achieve the same cornering arc. This is the reason Doug Henry was dragging everything everywhere at NHMS, while J Wood and others were not (as much).

I could be completely wrong, but I believe this is what I was told by some of the fast riders with last names like Wood.

[Kurlon]

Ok, that's solid logic I can get behind.

[Paul_E_D]

I got plenty of molten titanium down the front of my leathers chasing Doug. That's pretty much the only reason I ever beat him. To get out of the lava flow coming off of his footpegs.

[Kurlon]

Bob Stengel of 22 Photos.net makes me look good even when I'm not.

[Kurlon]

If you had 'two LRRS rounds' in the 'when will it blow up pool', you win!

Cracked the cylinder, ear says the big end bearing on the crank is failing as well.

[Pittenger5]

As for the knee out ...
Ask Clark about the foot I broke (still don't remember it) in turn 11.

- - - Updated - - -

As for everything else ...
Go buy an R6 or CRF.

[breakdirt916]

whoa-ly chit!!

[carsick]

Too much NOS, bro! What are you going to swap in to replace it?

[nhbubba]

Find a busa mill. I know a guy with a bandsaw. You'll have three spares.

[breakdirt916]

ours same cylinder??

I think I might have 3 spare...would likely need re-plating, but if you wanted to punch to 265 anyways...

edit: and any idea why? hopefully not a "stock is best...over power it and $hit breaks"...

[Kurlon]

Playing the lazy card: Pics of the initial tear down are on my FB page - 771 Racing - Initial tear down and diagnostic on the sumo.... | Facebook

Short recap - I can't find any signs I assembled anything wrong. No signs of coolant going where it's not supposed to, looks like my 'leak' is more due to crappy radiator hose clamps than anything terminal. Crank is nice and wet with oil, no signs of getting warm. There is no up/down movement at the big end, I can wiggle the rod side to side slightly, and more worryingly I can tilt it left and right slightly. The small end might just be starting to develop some play. So, that leaves me still trying to find the knocking noise, I'm thinking possibly clutch basket dampers have given up?

Cylinder is absolutely cracked, you can see the crack in the transfer ports. I don't think it goes into the water jacket, I can't see any signs of such, but I don't have much hope it can be salvaged even if it doesn't.

[Kurlon]

Lazy streak over, pics now in the thread.

[breakdirt916]

hmm...internal knocking while engine parked?

not any sort of transmission bearings?

I can't imagine many places on a 2-smoke that would cause a knocking noise...exhaust valves look good w' no sign of hitting piston? crank bearings? maybe water pump impeller?

but on a scale of "meh, that's common" to "wow, I've never seen that before!"...sometimes the absolute worst can happen...for the hell they put down, the insides of these motors are fairly delicate

[Kurlon]

I can reproduce it by grabbing the flywheel and rocking it forward and backward. That's what led me to think it was the big end initially.

The good news is, so far I don't think I overstressed the motor...

[breakdirt916]

sweet!

she will live again!

gonna pressure test the yz today...need mo' street smokah in my life

[Kurlon]

In one form or another it will. It may be with a rebuilt motor, motor swap, frankenstein motor, or with everything transferred to a newer base bike. Dunno yet. I really want a second motor now just for mocking up a few ideas.

[csmutty]

IT490!!

That rattle will bring out your dead haha!

[Kurlon]

The 450 Killer!!!! The 2011 YZ490 - Yamaha 2-Stroke - ThumperTalk

Don't think I haven't considered it.

[breakdirt916]

aren't there more options for overbore with the newer motors?

or ya want to keep the 265/295 in a WR config?

the yz I posted in #102 was a monster...people would come by and talk about how fun it was to watch this guy

[Kurlon]

The only things on the market for the 88 to 98 motors are +2mm (265cc) overbores. I found one place mentioning at 295cc kit for that generation but no details what so ever which has me suspicious. I don't see how you can go +4mm with a stock cylinder casting, and the price is WAY too low to include any crank stroking. If I had a loose motor to poke at I'd be able to quickly determine if there is any room for stroking the crank to get closer to a modern bore/stroke ratio.

Current gen, 99 and up has stroker mods on the market, overbores to 345cc, etc. WR transmission swaps, or just using the new YZ250X gearbox provides a 'WR' transmission option. I've no idea if a current gen motor can be made to fit without pulling my hair out.

In the end, I want the bike to run. If I can improve on it's reliability and spread of power at the same time, even better. But ultimately all I care about is it running so I can at least sumo it.

Edit: The bike in post 102 is sporting an ESR cylinder, the power valve preload tension adjuster and head give it away. It could be anything from 325 to 360+ cc.

[csmutty]

Can you pleaseeee do a YZ490 project just like that link?

I soooo want to ride that thing!!

[breakdirt916]

does the '93-95 yz cylinder fit?

I got a couple used...needs re-plating & punch to 265...1 came on a junk motor so I'd let it go cheap

[Kurlon]

Can you pleaseeee do a YZ490 project just like that link?

I soooo want to ride that thing!!

If someone else is funding it, I'll do it.

[csmutty]

If someone else is funding it, I'll do it.

I'll start off the 490 fund with $1.fiddy