1981 Atc 250r Mugen Build

[yaegerb]

Picked up this tricked out 81 from another member. If you remember, he had this posted for sale a few weeks back. After looking at the pictures, I had to have it so off to Indiana I went. There is more history on this bike than I will likely know, but I have spoken to a few members and here's some of the potential goodies to date. I say potential because some of these items are still an educated guess.

3 tanks came with the purchase.

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1. Is an OEM peanut tank with a cover
2. Could be a Malcolm Smith 250R tank
3. A fiberglass Tank. Could be a Fibertech out of southern california

3 Pipes came with the purchase. Currently on the 250R is a Bassani

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1. Could be an old school DG
2. Could be a Coffman's
3. Is an old school DG

Here we have a CalFab swing arm re branded as a DG SuperTrack and a Works Shock with MaxxTraxx + 5 axle

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Other goodies are a number plate re-pop, champion beadlocks, 300 cylinder and triples bored to accept 35mm forks
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Meet my new little buddy I have lovingly named "Rival".

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Currently, it doesn't run. I will be pulling the cylinder and head with a one way ticket to Selvy. I will also be mating up the 41.5 taper bore mikuni and will be repacking and running the 1 piece DG. There are a couple more odds/ends that I am going to shore up before I go and have some fun and I will be documenting it here.

More fun ahead...stay tuned.

[atc300r]

Awsome glad you got it. The first pipe looks like my old school DG.I think the second pipe is Phase 5.This is a realy sweet R. I remember when Jesse built it. The front forks are 83-84 250r.

[bkm]

That thing is so cool. Seeing it makes me sad I passed on the "Dirt Works" first gen Captain Weezy sold a few years back. My prediction is with Tecates and 3rd Gen R's becoming too expensive for the average guy, the 1st and 2nd Gen R's will start gaining value as the introductory hi-po 2 stroke trikes.



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[atc300r]

It also has one of the first Flotec modded 330 liquid R piston conversions.He milled the head surface and matched the ports.I agree about the 81-84 R becoming the next sought after trike. Glad I have my 81,83 and 85 plus some extra stuff.My 81 has a triple rate Works. Any plans on racing it. couple guys on AF had the one piece DG they sound awesome.

[Aulbaugh]

That has to be the sweetest 81 I have ever seen! I'm ready to see/hear it run!

[brandonlowe2]

The Rival...... you know superhero’s have rivals but the superhero always wins :) haha...... I am super excited you got this and can’t wait to see how it turns out


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[yaegerb]

It also has one of the first Flotec modded 330 liquid R piston conversions.He milled the head surface and matched the ports.I agree about the 81-84 R becoming the next sought after trike. Glad I have my 81,83 and 85 plus some extra stuff.My 81 has a triple rate Works. Any plans on racing it. couple guys on AF had the one piece DG they sound awesome.

Yes, I would like to race it next spring/summer. Hopefully someone I know, *ahem* will be joining me :)

[yaegerb]

The Rival...... you know superhero’s have rivals but the superhero always wins :) haha...... I am super excited you got this and can’t wait to see how it turns out


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Thanks man, yeah I hear this rumor of someone building a second gen that’s going to smoke the competition!? Any truth to that?

[brandonlowe2]

You hear of someone building it? You must be hearing echoes in your shop :)


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[xrider]

Great pickup! Lots of goodies on there. Mario made those number plates a few years back. I messaged him this week hoping he still has one left somewhere. That case saver is slick. Better polish up that bad boy and bolt it onto the Cammex motor lol.

[yaegerb]

Great pickup! Lots of goodies on there. Mario made those number plates a few years back. I messaged him this week hoping he still has one left somewhere. That case saver is slick. Better polish up that bad boy and bolt it onto the Cammex motor lol.

LOL, ya know, Paul said I would be an air-hammer hero if I ran a set of those. I may consider doing it for anyone who wants one.

[xrider]

I would definitely be in for one

[atc007]

Glad to see you got it Brendon :( . I offered to buy it Friday night,but he said a guy was coming down around Thanksgiving and he was not taking my money till you looked at it. I told him you were a good guy and wouldn't steer him wrong. That is one very cool grab right there.

[350for350]

Glad to see you back on three!

[Merge_88]

Very nice, I look forward to seeing your progress on it and at St. Joe possibly some day next year!

[ironchop]

Nice score...there goes all your spare change for the foreseeable future.

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[yaegerb]

I picked up these neat additions over the holidays to ensure rival will live up to its name....

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[bkm]

Where does a feller find a piston for that beast?

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[yaegerb]

Where does a feller find a piston for that beast?

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Great question. I have two leads. First is working with another member to have wiseco make some more Pistons in a group buy and the second is a little place in jolly old England that I have yet to call.

[Footy]

Let me know if you need any parts. A friend of mine has a 1982 model that he is parting out. No engine or carb though.

[atc007]

Where does a feller find a piston for that beast?

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Denny at Flotek, he will deck the cylinder for a TRX 330 piston ;)

[yaegerb]

Denny at Flotek, he will deck the cylinder for a TRX 330 piston ;)

I couldn’t bring myself to deck a Mugen cylinder

[HondaRidr]

Is flotek still around?

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[Doug8765]

Nice find !!


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[yaegerb]

Is flotek still around?

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I don’t believe so.

[yaegerb]

Been 2 years and some change but I have made decent progress the ol' 81.

The engine is nothing short of a beast. A ton of work (mechanical and aesthetic) has gone into the motor making it a fire breather once again. I scored a piston from England last year and then sent the cylinder off to get re nik'd. I then sent the piston and crank down to crank works for a complete overhaul and balance. Once I started assembly of the motor it went along pretty well until the piston was hitting the cases. I had to take .080 off the intake skirt which was only 1.5 grams which presents no issues to my balance job from crank works. The pressure test revealed the head was severely warped so I hand lapped it back to form. It holds 6psi all day if want it to. A couple big shout outs to ironchop and chris parciello. I scored a new intake from chris and then massaged it for better flow. I then had ironchop cnc grooves the NOS elsinore 500 intake so I could use O-rings. Here is some timeline pics and how it sits today. She won't be like this for long though. I have the swingarm coming in a couple weeks along with a 41.5MM taper bore PWM. My custom PEP, ZPS shock is also being made. I would like to have it back on 3 by late spring. Enjoy the pics.

[bkm]

That thing is going to be a work of art. It's sad......back in the heyday of this place, this thread would be 10 pages long already.

[ironchop]

Man, that looks fantastic already!

Are you going to get it dirty ever again?



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[yaegerb]

Man, that looks fantastic already!

Are you going to get it dirty ever again?



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You bet buddy! This one will be strictly a race bike.

[ironchop]

...... It's sad......back in the heyday of this place, this thread would be 10 pages long already.

Well it's hard to keep the lights on around here considering how much competition there is with Fakebook and all the Mugen builds going on in there.......................[emoji23][emoji23][emoji23][emoji23][emoji23][emoji23]



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[bkm]

Well it's hard to keep the lights on around here considering how much competition there is with Fakebook and all the Mugen builds going on in there.......................[emoji23][emoji23][emoji23][emoji23][emoji23][emoji23]



Sent from my Z958 using TapatalkYeah, I can see how a Facebook "no spark" on a 185s post would be more interesting.

[83ATC185]

That thing is sick already!!! Definitely watching this one! What axle are you going to run?

[yaegerb]

That thing is sick already!!! Definitely watching this one! What axle are you going to run?

I will be running a maxtrax.

[shortline10]

Looking good !

[Antreas Sp]

All i have to say is wow! This type of work really needs its time.keep up and post picturessss!!

[yaegerb]

Been a while since I have updated this thread. Since my last update I have received my tank back from dent removal and powder, the DG/calfab supertrack swinger back from welding/anodizing and my maxtrax axle back from refinishing. I have also received my tires and OMF beadlocks plus front 10" rim, rear OEM grab bar and made my own chain guard for the swinger. I have a lot more goodies currently being computer designed and others in restoration. This bike will definitely be a 1 off when I am finished. Enjoy the pics!

[yaegerb]

Been a while since I have updated this thread. Got the rear drum all finished, Max Trax axle refinished and installed, installed the rebuilt Fox shock, rear tires/wheels and chain. All bolts have been torqued. Next on the docket is rear fender, air intake fitment and front end work.

[psujeepguy]

Incredible to read about this trike and watch the progress. That engine is true jewelry. Great job!

[bkm]

So what are the plans for the front end and what tire are you planning on running?

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[El Camexican]

Any plans for tank decals?

[Aulbaugh]

Its looking really good, are you going to run any skid plates?

[Mr. Clean]

Looks great except the pictures need to be upside down, like my Nicholson thread.

[wild200x]

Incredible build! Very cool! Keeping track on money? Bling bling! Damn nice!

[yaegerb]

So what are the plans for the front end and what tire are you planning on running?

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For the front end I am having a set of billet triples made that would hold an 81-82 steering pin. The triples will be able to hold the 39MM 85-86 ATC 250R fork. I was wanting to go with inverts for the front but that idea got scrapped due to the enormous amount of strain it would put on the two downposts for the engine cradle. All other front end components will be 86 as well. For the front tire I am running the new hoosier flat track tire that came out last year. Should be a pretty slick front end setup.

[yaegerb]

Any plans for tank decals?

Yes sir, I have Bruce at Blue Line graphics making the remaining stickers for the tank/swinger and the rear fenders. The tank stickers will be the old school font with 360 instead of 250.

[yaegerb]

Its looking really good, are you going to run any skid plates?

Yep, I have the rear skid on the DG swinger now. It was a custom unit that the previous owner had built. For the engine cradle I will be running a polished OEM skid.

[yaegerb]

Incredible build! Very cool! Keeping track on money? Bling bling! Damn nice!

Yeah, unfortunately I am keeping track of the costs on this one. Its a stunner and a wallet drainer all at the same time.

[El Camexican]

And now the big question....

What's with the upside-down grab-bar? Aerodynamics? Lower center of gravity? Improved downforce? Or could it be as simple as the parts fiche you're building off was posted by Mr. Clean in the upside down position?

Inquiring minds want answers!!!

[yaegerb]

And now the big question....

What's with the upside-down grab-bar? Aerodynamics? Lower center of gravity? Improved downforce? Or could it be as simple as the parts fiche you're building off was posted by Mr. Clean in the upside down position?

Inquiring minds want answers!!!

Ha! Old school way to put on your grab bar when racing.....and I think it looks cool.

[El Camexican]

Ha! Old school way to put on your grab bar when racing.....and I think it looks cool.

Might have had something to do with not ripping your junk off in a crash.

[BarnBoy]

Might have had something to do with not ripping your junk off in a crash.

Or snapping the ole back...ugh

[yaegerb]

Might have had something to do with not ripping your junk off in a crash.

Or getting your boot caught when throwing a leg to slide.

[ironchop]

"it puts the lotion on its skin, or it gets the Moo-gen again"

Any updates on this super rare machine?

Chop, chop Brendon

[Onetrackmind]

"it puts the lotion on its skin, or it gets the Moo-gen again"

Any updates on this super rare machine?

Chop, chop Brendon

Yes there is...show off her new backside bro!


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[yaegerb]

Been waiting 2.5 years for the rear fenders and another member on the forum was kind enough to sell me his set for this build. Big shout out to manbearpig. Dean isn't making these anymore.

[atc007]

And now the big question....

What's with the upside-down grab-bar? Aerodynamics? Lower center of gravity? Improved downforce? Or could it be as simple as the parts fiche you're building off was posted by Mr. Clean in the upside down position?

Inquiring minds want answers!!!

At our tracks it was simple. Much easier to load and unload out of pick ups. Always put pipe insulation on them also. Run em out of gas, stand them up, back the truck up to them, and throw them in. If Tanner Pies wouldn't have had his upside down at Ashtabula , Mac Moore might not have a hand. He was able to grab onto his instead of the chain and sprockets during a crash.

[yaegerb]

Decided I didn't like how wide and bulky the 81 seat is so I decided to call Matt Roby as I liked the way he narrowed his seat on his Cammex build. After some bansaw and welding work I think we have a very streamlined seat that fits nicely to the Sundahl Low Pro's. Now off to powder and then Tammy at Cosmic quads for new foam and cover.

[Gumbo]

Any more updates on the build, this is such a great looking bike!!! Nice work as always [emoji1305].

Any pictures of the Fox shock, it looks awesome


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[yaegerb]

Hey sir, thanks for the compliments. I am currently working on getting my trees cut for my custom front forks that I will be running. I should be wrapped up by the front end early next year. Below I have posted some rear shock pics along with the air box and carb wrapped up.

[shortline10]

Looking good !
Early next year ?
Reminds me of your 200x build lol , how many years did that take:wondering:lol:

[yaegerb]

5 I think, lol

[Red Rider]

Yeah, I agree. Looking awesome! Nice progress.

[Gumbo]

Looking great!! that swingarm and guard really pop!

What did you do to the shock, was it just a rebuild or an upgrade?
I have one that needs rebuilding for my project, did you find the parts easy to get hold of?
https://uploads.tapatalk-cdn.com/20220909/a2b8c54688ea2e618745f8a8df1af27b.jpg


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[yaegerb]

Yeah, I agree. Looking awesome! Nice progress.

Thanks sir!

[yaegerb]

Looking great!! that swingarm and guard really pop!

What did you do to the shock, was it just a rebuild or an upgrade?
I have one that needs rebuilding for my project, did you find the parts easy to get hold of?
https://uploads.tapatalk-cdn.com/20220909/a2b8c54688ea2e618745f8a8df1af27b.jpg


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I had everything rebuilt, polished and set up for my weight with all new springs. I sent it to Schmidty suspension. They did an awesome job.

[pipeline triker]

looking great, what are the details on that air box lid.

[yaegerb]

looking great, what are the details on that air box lid.

Airbox lid is an NOS mugen lid repopped on a 3-D printer with the slots cut out.

[pipeline triker]

very cool, if you ever get bored and make extras , I would love one.