My 1986 ATC250R Adventure

[yaegerb]

Or be OCD like me and put all your manual pages in plastic sleeves...but I still grease up my iPhone from time to time.

[ironchop]

Very nice indeed. I assume you are putting in boyesen reeds? Does the drive sprocket still have life?

Yeah I bought some boyesen reeds to stay on budget for now with plans for a better setup later. May even go rad valve or Vforce right after I pressure test. I'm not set in stone on that yet. I left the reeds out after reading instructions for pressure test after some searches. They said to leave reeds off the cage and put the piston at BDC before pumping up. Is this correct?

The sprocket is almost new. Was sitting in a bucket with the bolt and spring washer with some other stuff that must've got water on it at one point when stored in the shed three years ago so it surface rusted some. Looks worse than it is and I didn't see a reason to waste it since it'll be permanently dirty soon after break-in. I could blast and repaint it but I don't see the point

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[ironchop]

My problem is that if I make this thing as shiny and new as I would like, I'll be furious at myself for getting it dirty. I went thru this with one of my 200Xs and I was riding around mud puddles on trails like a sissy until I just convinced myself to ride it like it's meant to be ridden. Garage queens do me no good since I don't like people in my garage therefore I won't show it off.

If I had a strictly dune bike, I'd go all out because that dry climate is WAY easier to clean but here in KY the red clay and the white clayment at TF just destroys a nice finish on everything in about 4hrs riding time

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[yaegerb]

Yeah I bought some boyesen reeds to stay on budget for now with plans for a better setup later. May even go rad valve or Vforce right after I pressure test. I'm not set in stone on that yet. I left the reeds out after reading instructions for pressure test after some searches. They said to leave reeds off the cage and put the piston at BDC before pumping up. Is this correct?

The sprocket is almost new. Was sitting in a bucket with the bolt and spring washer with some other stuff that must've got water on it at one point when stored in the shed three years ago so it surface rusted some. Looks worse than it is and I didn't see a reason to waste it since it'll be permanently dirty soon after break-in. I could blast and repaint it but I don't see the point

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No you can pressure test with the reeds in and the piston at any point in the stroke.

[wonderboy]

What head gasket brand are you using for this?

I have a cometic and I can't get the coolant to stop weeping from a couple points. The head is dead flat. I can't do anything to the top of the cylinder without pulling the studs, and don't want to open a can of worms so I'm hoping a different head gasket can help.

I've read that the cometic head gasket has too hard/firm of a ring around the cylinder and it doesn't compress enough when torquing the head to compress the rubber part of the gasket to seal the coolant.

[ironchop]

What head gasket brand are you using for this?

I have a cometic and I can't get the coolant to stop weeping from a couple points. The head is dead flat. I can't do anything to the top of the cylinder without pulling the studs, and don't want to open a can of worms so I'm hoping a different head gasket can help.

I've read that the cometic head gasket has too hard/firm of a ring around the cylinder and it doesn't compress enough when torquing the head to compress the rubber part of the gasket to seal the coolant.

It's an OEM CR250R head gasket. Single layer. "Thin" style

Got it from BDT....



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[ironchop]

Choose your poison. Greasy phone, which will wipe off, but may fly out of your hand, or greasy pages that are stained forever, and practically always obscuring important data.

I pick greasy phone.

Plus this ZTE phone was only $80 more than a used OEM paper manual from eBay and I cant text, browse, or call from my manual haha

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[wonderboy]

Now I feel stupid... knowing that you got an OEM gasket, I searched and see that the 250R OEM gasket is also available. I'm sorry if I missed it, but is there a reason you are using the CR250 gasket? <--(EDIT: No need to answer that stupid question... I can't read).

Is the thinner gasket part of your plan to bump compression a bit higher?

Also, do the OEM gaskets accommodate bored cylinders? The one I'm working on is bored at least the first oversize (don't remember exactly).

[ironchop]

....
Is the thinner gasket part of your plan to bump compression a bit higher?.

Yes

..Also, do the OEM gaskets accommodate bored cylinders? The one I'm working on is bored at least the first oversize (don't remember exactly)....

This one did and my overbore is at 66.50mm from a 66.00mm stock size but much bigger than that and it might be an issue



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[ironchop]

Well my gas pressure test guage with Schrader valved adapter finally got here today. 2 1/2 weeks from purchase. Pretty slow for eBay.

I had bought and assembled the PVC portion a couple weeks ago. I used a rubber cap that yeagerB turned me onto instead of a plug in the exhaust port.

He also warned me that even with sealant, the exhaust gasket is likely to leak air and F@#K with my pressure test attempt. I didn't listen very well and after an hour of correcting all the leaks in my rig, I still had bubbles at the exhaust spigot joint. Cheapass Vesrah exhaust gasket was the culprit. I texted Brendon to admit defeat. I used it in a pinch. Fortunately, I had ordered a hi-temp o-ring set from BDT a couple weeks ago. It came with one new hi-temp o-ring, one "spare o-ring", and a leaded looking exhaust spigot gasket all for just $13 shipped. Now you'll recall I machined a second groove in my OEM spigot so getting an extra o-ring in this kit was exactly what I needed....I popped that gasket in dry just to see how well it sealed. I figured on taking it back out to throw some sealant on there but since it looked like it was lead permeated or something similar, I was curious.

https://rover.ebay.com/rover/0/0/0?m...2F273239891641

Well......I pumped it up to seven psi and it held that for ten minutes with zero loss. What a great gasket!

So my first 2-stroke total rebuild was a success. My OCD paid off with no measurable air leaks and this makes me much more confident in my work.

Before I put the motor in the frame, the stator wiring came to me on the motor with the plug cut off. I found another 2.8mm 2-pin plug for a few bucks on eBay and soldered on the new female connectors and then snapped then into the male housing. Good to go. Simple and cheap fix. Fits like a glove into the corresponding connector on this new ps2fixer wiring harness.

Now I've started the final assembly just a bit early but I still need to finish refilling my rear shock this weekend and tear down the forks for new seals and bushings.

Special thanks to Yaeger Performance Machines for the phone support and walking me through this.

Stay tuned for more of my adventure to come. I feel far less ignorant than when I started.


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[yaegerb]

Looks awesome brother. You did an outstanding job!

[ironchop]

I like to chronicle my screwups as equally as my successes. Everyone makes a mistake or two the first time around and maybe it will help someone else who's afraid to crack into a major project for fear of jacking it all up. The only way to learn is to try...and find some relevant YouTube videos if you can. Granted, some people shouldn't touch tools at all and some people are just OCD and patient enough to do things correctly the very first time. I'm in the middle somewhere but leaning more toward OCD moreso than hack HAHA!

This next episode will resonate with some guys and be cringeworthy for others.

Filled up the rear shock with oil last night after the engine work. I felt like I was on a roll......Next time, I'll probably skip the $25/quart shock fluid on a shock that's not totally worked over and revalved. A quart of ATF as suggested by Honda would've been much cheaper. I bought this without even looking at the rear shock section of the OEM manual. There's a lesson. READ MANUAL BEFORE TOUCHING WALLET.

The o-ring between the reservoir and the reservoir hose is supposedly discontinued for the ATC. Usually, Babbitt's does a good job cross referencing the part with other models but they dropped the ball here. The o-ring is an odd sounding size...9.8mm x 1.9mm...however, I was able to find them OEM Honda for other models on eBay so I bought three to stash a couple away for future shock builds.

I filled the shock body with oil, filled the rezzy hose with oil, installed new o-ring, and bolted them all together. I turned the reservoir open end up in the vise and filled it halfway with oil and started pumping out the air bubbles.

So I get the air out pretty quick and it seems like everything went way too easy. I texted Fabio to ask how many times he had to pump his shock to purge the air because I had a nagging feeling that it was way too easy. So Fabs offers some comedy relief and I go ahead and pull the Schrader valve out of the rezzy end cap and installed the brand new shock bladder on the cap. I push in the whole assembly and the excess oil goes everywhere as planned...you can't avoid it if you're doing it correctly. I get the cap below the snap ring groove in the rezzy, install the snap ring, and use my valve stem puller tool to pull the cap back up against the snap ring. Then I screw in a new Schrader valve core that came with the seal kit from Schmidty.

So at this point I'm feeling all full of myself despite that nagging feeling lurking in my gut.....and then I look at the pile of old seals and Schrader valve and whatnot on the work bench and something out of place catches my eye......a random washer. "WTF is that from?" "I don't remember any washers in this assembly".....and then I did remember the washer. The rezzy side of the hose screws in 95% of the way into the rezzy and there's a lock nut on there that actually tightens it onto the reservoir and seals that o-ring. This washer goes between the locknut and the o-ring. I text Fabio again to say "I told you I forgot something"...laced an expletive in there and laid my shock oil covered cellphone in a dry part of the bench and walked away. After a peanut butter sammich and some meditation over a Bud Light Orange beer, I tore it back apart and spilled shock oil all over my garage floor and workbench...again.

The OEM manual is vague on this part because they wrongfully assumed people won't forget the washer. I'm exhibit A for the prosecution in this case.

I got it back together correctly the second time. Since I smashed that new o-ring with the locknut and no flat washer in between, it was roached after loosening the nut. Good thing I bought those spares.

Now it's ready for a nitro charge and reinstall the spring which I think I'm going to buy a heavier spring. The OEM offering is for riders much lighter than my 220lb self so I'll probably hit up Schmidty Racing for a new spring designed for my size.

Today, I'll attempt to not hack the fork rebuild, I think ... Off to read the fork section of the manual FIRST.

I didn't take too many pics. It was a messy process so I tried not to touch the phone much outside of cursing text messages to Fabioso McMasshole. Enjoy.



Yeah, I did all that and then noticed this....MOTHERF@#KER!!



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[El Camexican]

I swear I’m laughing with you and not at you, but only because I’ve found a “spare” piston pin circlip after finishing a rebuild and doing the first heat cycle. It sucks donkey junk when reality sinks in.

[Red Rider]

Don't sweat it chop. We've all been there. My moment was when I first split the cases on a 250R.

About 25 years ago, on a day trip to Dumont Dunes, while riding inside the big bowl, my brother's 250R threw a chain (no case saver), which of course wadded up, and busted the L center case at the clutch actuator arm. Unable to get the chain un-wadded, we tried towing him out of the bowl with two 250R's, which didn't work. We had seen some guy going pretty much everywhere in his early 80's lifted Toyota 4x4, with aired down tires, so we enlisted his help. It was a harrowing ride out of the big bowl, with my brother, his R, & I in the bed of this stranger's truck. My brother & I made up a plan of action, as far as which side to bail out of, if the truck were to flip over, but luckily we didn't need it. Fast forward a few months, and our annual trip to Dumont for Thanksgiving is approaching, and my brother's R is still down for the count, with no spare time to fix it. I offer to do the work, confident I can successfully tackle the job. I find a used set of matched cases, and swap the internals over. The re-assembly goes smooth, and I'm pretty damn proud of myself. A few days later, my brother comes by to check it out. He shifts the transmission through all six gears, and neutral too, with no issues. Then he picks up the old L center case, so he can inspect the carnage from the inside, and out falls an oily washer, that was still stuck to it's machined, mating surface. Needless to say, he was now wondering what else I screwed up.

It's a gut-wrenching feeling, when you go from the elation of tackling a difficult job, to the realization that you did it wrong.

[ironchop]

Rear master rehab and rebuild.

Looked like a mess when I got it.

Blast, thoroughly cleaned the insides, repaint, and put a new K&L rebuild kit in there but reused the OEM metal piston and OEM boot as they were both in great condition. Just used the new seals and return spring


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