2004 RM “Corona” build - updated 11/1

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3/31/2020 7:44 AM

I picked this bike up late last summer in real rough shape. I found some recipes and a Ponca City bike check sticker that leads me to believe it was a former Am National bike for a local pro of the era, but when I picked it up it was primarily parts in a box, seized crank, trashed head/cylinder, etc. so the first step was to tear it down and start tracking down what I needed (and wanted).
This is what it looked like when I picked it up. Photo
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Here are some pics of the breakdown/cleaning process.

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3/31/2020 7:51 AM

Pretty much every bearing is roached, so that’s been fun. The bottom end included. While it’s apart every engine and transmission bearing is being replaced, the transmission is being polished in a buddies tumbler, new OEM crank, and everything is getting coated.

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3/31/2020 7:56 AM

Some goodies started showing up as well:
VHM Head cut for perfect tolerances with the Weisco GP flat top piston. Did I mention it’s also a Millennium built 144?
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New stainless bolts for the entire engine from Po-Bolt
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3/31/2020 7:59 AM

Also some other goodies like some carbon engine hangers and pipe brackets...and the X-fun tank 😍 Photo
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3/31/2020 8:02 AM

I also can’t recommend FasterUSA enough. These wheels are going to be killer. These are stock hubs with the casting lines removed, ceracoated, then laced up to bulldog spokes and excel rims with Galfer rotors. Photo
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3/31/2020 8:06 AM

This all getting mated up to a 2012 RMZ front end as well.
Here is where the project currently sits while I start on the motor. I wanted to have a lot of progress to post before I started the thread, but being in “self-isolation” will do things to a man lol Photo
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3/31/2020 2:21 PM

Looking good on the re-build ! Glad that you mentioned Faster USA...their customer service, knowledge, and products are top shelf, and Collin is a down to earth good guy. Also,where did the carbon fiber pipe bracket come from if you don't mind ?

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There's something happening here, what it is ain't exactly clear.

3/31/2020 3:16 PM

Holy smokes thats going to be amazing

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3/31/2020 4:18 PM

ledger wrote:

Looking good on the re-build ! Glad that you mentioned Faster USA...their customer service, knowledge, and products are top ...more

I got them from a member here on Vital. I’ll look for his name, but he makes and sells them in small batches. Really impressed with the quality of them!

I can’t say enough good about the guys at FasterUSA

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3/31/2020 5:13 PM

You should do an actual Corona bike.laughing
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3/31/2020 5:30 PM

EZZA 95B wrote:

You should do an actual Corona bike.laughing
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The thought crossed my mind! 😂😂

Here are some details on the “blued” frame 😎 Photo
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3/31/2020 6:12 PM

Tell us about the frame - did you have it bead-blasted then powder-coated in a clear? Looks outstanding, and unique.

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3/31/2020 6:48 PM

KGAspeed wrote:

Tell us about the frame - did you have it bead-blasted then powder-coated in a clear? Looks outstanding, and unique.

Thank you! I had it sand blasted which created the slightly rough dull grey. Originally I was going to do a light polish but liked the grey. I brought everything up to temp slowly and worked each section with a small propane torch, being careful not to get it too hot. The goal was to bring the welds and surrounding areas up to the colors they would have been when originally welded. I opted not to do some of the longer welds, but am overall very happy with the look.
I think had the same shop apply an 80% gloss clear powder coat. I am really happy with the results!

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3/31/2020 6:52 PM

KGAspeed wrote:

Tell us about the frame - did you have it bead-blasted then powder-coated in a clear? Looks outstanding, and unique.

Ryan625 wrote:

Thank you! I had it sand blasted which created the slightly rough dull grey. Originally I was going to do a light polish but ...more

You should be...again - way to think outside the box. Love it. Heating up the welds to give it that raw look is awesome. I may totally copy that!

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4/1/2020 9:20 AM

That frame came out really sweet! Nice build

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4/2/2020 5:54 PM

Slow to get some progress this week. Full time dad mode!
Got a little elbow grease in last night, and started setting engine bearings today but ran out of time. Ive been removing casting lines from everything and trying to go for the billet look. Photo

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4/2/2020 6:26 PM

This build looks great!

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4/2/2020 6:51 PM

Ryan625 wrote:

Slow to get some progress this week. Full time dad mode!
Got a little elbow grease in last night, and started setting engine ...more

Awesome. I’ve done that before too (remove casting marks). I used a right angle air grinder with a scotch-brite type of attachment. Lots of work. This is going to be good -

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4/3/2020 3:47 PM

Well I got all of the bearings in today, finding time for myself has been tough in isolation with a toddler!

Tonight I’ll assemble and dry run the transmission. I’m waiting on a couple small retainer screws that got misplaced then I’ll be setting the crank and transmission once I know it’s all 100% Photo
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4/4/2020 6:05 AM

Nice job on removing the castings! I got an '05 I'm going to start doing that to.

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4/5/2020 8:55 AM

Last nights fun...transmission assembly. It was all going smooth until I discovered a single very specific washer missing. So a midnight parts order...other than that I’m 99% sure it’s all there...gotta love getting a completely disassembled motor in a box 🤦🏻‍♂️ Photo
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4/16/2020 2:37 PM

All my bearings finally came in along with a couple of the transmission parts I still need. Got the bearings out of the linkage and swingarm only to find that the wishbone is absolutely shot. I’ll need to order a new one of those.

Got all the new bearings in where I could, and got the swingarm on for mock up. Still some cleaning left on the swingarm too. Next up is wheel bearings once all the other odds and ends show up for the wheel set.

I should have a roller here soon, and the motor shouldn’t be far away eother. Photo
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4/16/2020 3:29 PM

Looking good! I’m doing a build on a 2002 rm125 right now, think I need to start a thread for that.

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4/16/2020 3:51 PM
Edited Date/Time: 4/16/2020 3:52 PM

#1: Your stock front wheel hub won't work with those 2014 forks -You need an RMZ front wheel.
#2;The pics you are showing of the engine cases are of a case-reed engine - didn't the '04 RM250 have the reeds in the cylinder??

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4/16/2020 5:00 PM

mxracer666 wrote:

#1: Your stock front wheel hub won't work with those 2014 forks -You need an RMZ front wheel.
#2;The pics you are showing of ...more

#1. You are correct, I am using the RMZ front wheel and brakes with RM wheel spacers. Lines up perfectly using the RM250 triple clamps.
#2. I am not sure about the reed design on the RM250, this is a 125 build

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4/16/2020 5:12 PM

Good info! Nice job on the frame! The pic the other guy supplied of the actual "Corona RM" was a 250 , and led me astray ... carry on!

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4/16/2020 7:15 PM

Nice work!

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4/19/2020 2:33 PM

Engine will hopefully be getting put together barring any more setbacks. Every time I get to the next stage I’m missing something 🤦🏻‍♂️

Good news the transmission is ready! Two set screws and a washer and I’ll be able to drop the crank in.
Also got my galfer brakes on and a few shiny bits
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5/19/2020 10:39 PM

very nice

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"If you feel in control, you're not going fast enough" ~Mario Andretti

5/20/2020 12:15 AM

Awesome build...

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