Other Yzx500 Cali plated

Last night I used a dremel, a file, and tap magic to remove 0.315" from the inside chain side of the swing arm because the kx motor is quite a bit wider at the rear mount that the yz motor. Test fitted, and the sprocket looks like its centered pretty good with the rear sprocket. But there should be a slight gap between the swingarm and the engine. So I will remove material to get to .375" total material removal. This is very easy to do, just slightly time consuming.

Now the holdup and the hard part is removing this 0.375" from the bearing pin. I couldn't even scratch that with my fancy file, it is extremely hard material. Ill have to take that to a machine shop to throw on a lathe. I found a bearing online that will replace the 2 bearings that are currently in each side of the swingarm, except of course it is .375" shorter that the 2 oem bearings total width together.

Once the rear mount is sorted out, I can move on to the front mounts. Then figure out what carb I want to run.

As a side note, there is a slight bit of slop on the flywheel. Like its not tight on the crankshaft and it rotates until the key stops it. I don't have a flywheel puller for this yet but if you guys think thats pretty weird Ill have to just pull the flywheel and make sure the key isn't sheared then lap the crank and flywheel to fit more snugly.

Any thoughts or suggestions are appreciated. I don't know what I'm doing here

You're doing great. There should be no movement in the flywheel. It will have to be pulled and inspected. Crank, flywheel and woodruff key.

It Sounds like you have lapped a few flywheels. You probably know that if it is lapped right you should be able to set it in place, strike it at a right angle with a plastic mallet, and then need a puller to get it off again. We used to use a light valve grinding compound and finish up with a polishing compound. Kept the old easily distorted rotors from coming off.

Sigh, Okay. Flywheel puller in the mail now. I don't have too much experience lapping flywheels. Just done 1, but it worked out. Ive also jammed q tips into my dremel, coated in chrome polish, and stuck it in my carbs needle valve to polish it smooth and it doesn't leak any more. I had no idea that I should be able to hit the flywheel with a hammer and have it hold so strongly! I will use that as my test method for when I can stop lapping it. Thanks for the info on what compounds you use. Ill give it a shot!

Ive been trying really hard to find a needle bearing inner race that is 17mm id x 22mm od x 45mm long (stock is 55) but it seems like they don't make them that long. Im sure they probably have a different name if they are over a certain length, so Im just not searching the right keywords. Ill keep trying. This would save me the time and money of having a machine shop cut mine down .375" and not worry about heat causing a distortion of the dimensions. I don't know anything about machining hardened steel.

Thats all I have for now, hopefully Ill have some time tonight to finish removing material from the swingarm and get a shot of it all lined up

PS. Someone please convince me not to polish the swingarm since its off

Best or fastest and simplest way that i know to line up the sprocket is to suspend the bare frame with the swingarm pivot and axle downward. If you already have the motor mounted, suspend the plumb bob over the countershaft sprocket and see where it hits on the axle or mount the wheel and and see if they line up. if you want to go from the wheel being mounted to an empty frame go ahead. use levels to make sure that your pivot and axle are parallel if in doubt. you can do that anywhere with literally nothing as a string and a nut or any other kind of weight can become a plumb bob and you can use a glass of water or a clear tube and some water to see if the pivot and axle are on parallels.

ossagp that is awesome! thank you for sharing that tip on letting the swingarm hang, I can definitely do that! I was unsure how I was going to accomplish a good alignment, and you just solved my headache You lost me with the second part, about using levels and water. I can't visualize exactly what you mean there.

Last night I was able to ream the hole in the engine. used a grizzly 43 64 drill bit. (17.07mm, I read about this on the forums as a good overbore to allow clearance, not my idea) sorry my slash button is broken on my computer. its a hss chucking reamer so it was easily able to bore the hole in the soft magnesium. I also started removing .25" of material from the clutch side of the engine mount, so as to let the engine fit in there. I got tired and wanted to eat before I got all the way to .25". I have .125" to go. Unfortunately I am an idiot and in my stupor didn't realize that the swingarm bolt changed from 17 to 18mm from '01 to '02, which my bike is, so the swingarm pivot bolt still doesn't fit in. So I ordered a 23 32 chucking reamer (18.25mm)to bore it again to the next size.

Also, I removed the flywheel, used some valve lapping compound (the kind that breaks down from low to fight grit) and worked the flywheel on the crank. both the flywheel and crank had surface rust. Now they're polished clean and after a hit with a mallet (thanks ossagp!), it is locked on there. stator looked good, though i have no experience with kx500s so that comment is pretty useless.

Waiting for parts or tools sucks!! Its so close, the hole is going to be very clean indeed. Today i should be able to finish cutting the motor and getting it fit in the swingarm. Cant wait to get this rear mount figured out and get going on the other mounts. hell i can't wait to spark it up.

Im just lost with how I want to fuel it. I have the kx500 carb and the yz250 carb. But I've read that 500's are hard to tune (and I'm nothing special at carb tuning) and I'm trying to spend my time riding not tuning. not to mention if I'm riding at gorman its freezing then I go out to the desert and its 100 degrees out. because of that a lectron sounds very appealing. I just keep going back and forth. If any one has some advice on this matter, Id appreciate it. Pics to come tonight.

usually when the frame is suspended from the steering head, it hangs pretty straight. once you have it up there i like to make sure that the swingarm pivot is really at a right angle to the line the plumb bob is going to create. so you put a level on that pivot and set the frame completely perpendicular to it. those small torpedo levels work pretty nice, but you can actually do a little bit better with a piece of hose about 20 inches long with some fluid in it. clear with some of that pink rv antifreeze is my choice (it shows up good and wont kill the cat). a half inch piece of clear and that is set about 3/4 full of the fluid works fine. hold one end of the tube with the meniscus just in level eye sight with the up side of the pivot at the countershaft side. hold the other end of the hose to the other side of the pivot and see where the meniscus is in relationship to the top of the pivot. use a cord wire etc from a bench etc to hold the frame in place until it the pivot is level. put the axle in and do the same thing. this time tape the hose in place once you adjust the axle until it is level. full forward or full back may achieve a perfect level, but seldom has when i was doing it. now you can mark the pivot by putting the wheel on and hanging the plumb bob and now you are probably straighter than it's been since before it was ridden. if you want to do it by putting the engine in place and marking the axle you can do that too. in the later you can get about as close by simply making sure the pivot is level and therefore at a right angle with the plumb line

On the Lectron. I still have some. I used one for a race up a really tall in the rockies nearly 35 years ago. big elevation change. I wasn't happy with it. probably the best carburetor that EVER came on a dirtbike came on the kx500. really easy to tune. the factory 39.5 is hard to find and I would buy yours if you decide to use something else. gives the cr500 just a taste more overwind on the older porting arrangment.

@Scottysg the bike is looking sick!

ossagp:

On the Lectron. I still have some. I used one for a race up a really tall in the rockies nearly 35 years ago. big elevation change. I wasn't happy with it. probably the best carburetor that EVER came on a dirtbike came on the kx500. really easy to tune. the factory 39.5 is hard to find and I would buy yours if you decide to use something else. gives the cr500 just a taste more overwind on the older porting arrangment.

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@ossagp Do you think one can gain more performance on the yz250 engine with the factory kx500 carb?

Yes. if you cut about 8mm out of your header and put some stiffer reeds in it at the same time you will get some overwind you don't have now. Trades some low end. Start retarding the spark as you lean down and you would have something for supermoto and ovals. the carburetor with the throttle position sensor that the 250 has is actually a sweet unit. if I run onto a spare one I think I will size it out just for fun. That 39.5 when put on a cr500 makes itself noticed really fast.

On the 250 it just depends on what you are going to do with it.

ossagp thank you so much for your detailed responses. they really helped me get this going, couldn't have done it without ya! looks like ill be trying the oem keihin from what you've said.

haha where can i get some of that cologne! all the girls would want me (to mow their lawns)

are you suggesting that i try the tps carb on the kx500 motor? in that case would i run the complete ignition that from the 250?

on a similar note, can I run the kx500 cdi into the yz250 coil? its just a capacitor basically right? the reason i ask is the kx500 coil is much shorter bolt to bolt so it doesn't bolt into the yz250 stock coil location. i could make tabs easy, I'm just wondering if i even need to. Thanks for your wisdom!

@Scottysg I'm Looking forward to seeing this beast in ACTION!!