81 ATC250r Hybrid Build

[anon3]

Picked this basket case up from a local guy along with the 200x. I don’t have a lot of photos from before hand but it’s fair to say it’s in really poor state.

Engine had a cracked case on the clutch adjuster side.

Came with two back ends. Both had been hacked up and fitted with crappy car disc brake setups.

Had the 200x front end on it as well.


Plan for this one is to:

Repair the frame
Fit a Trx450r back end
Stock front end with progressives
Stock motor +1 oversize
DG exhaust
Possibly going to experiment with an electronic shock
New plastics

[anon3]

Started ripping it apart, engine is in bits at the moment, waiting on my piston to come so I can have the cylinder bored before going out to Vapor blasting.

Ground off all the extra brackets and crap that had been fitted to the frame.

[anon3]

Found a complete 04 Trx450r back end and mocked it up to give to the fabricator.

I’ll be using the back brake and pedal setup as well.

At the moment the plan is to cut back into the main brace at the engine side to allow the swingarm to clear the back of the engine.

Also relocate the caliper stopper to the other side and fabricate a new chain guard as it’s on the other side.

The bearing carrier will go in backwards which should be fine. Everything switches over easy enough.

If the back cut causes cracking I’ll order a chromoly 450r swingarm from stellar or someone and ask them to clearance for the engine.

Few photos show the issue.

Also need to weld in a new frame cross brace below and behind the current one to allow the linkage to attach.

Last just need to machine the bushes to fit with the old swingarm to engine bracket.

Shock will sit a bit further forward on the frame to make the geometry work out.

[sledcrazyinCT]

Good start on your hybrid

[anon3]

Decided to go straight to the custom mild arch swinger from Stellar, reasoning being that if I made the mods to the frame for a custom TRX450R swinger I’d be stuck with having to cut and weld each time I need to replace.

Ordered some bits, and sending the engine out for Vapor blasting this week.

Found a 300r kit on ebay, which is now over at CT racing getting things sorted before heading my way. Needs a sleeve and a re-dome plus piston.

Picked up a durablue 2+2 for the backend for $200 on ebay, and a LSR billet carrier for $80.




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[anon3]

Built my own Vapor blaster in the end. And settled on a colour. Building now.

[anon3]

Build list:

Stella swingarm, 450r with sides reversed (if he has time)
Dura blue rear axle, 450r carrier and brakes
Original front shocks
Hill climber rear
Standard bottom end with 300 kit
Clake two lever
Brake pedal delete
Keihin carb upgrade

Paint and panel, though mainly paint. Keeping it fairly raw.

[wild200x]

looks good. following.

[anon3]

Thanks, bit more progress today. Paint is duplicolor metalcast anodizing spray. It’s a real pain in the ass to apply, has to go on really thin.

Worked out a process that works for me in case anyone else is suffering through using it.

Blast parts back to metal
Heat part to 75C
Apply 2 light base primer coats followed by two wet, 5 mins in between
Back to 75C
Apply 4-5 light colour coats 5 mins apart
Back to 75
Apply 4-5 more colour coats 5 mins apart
Bake at 105C for 24 hours

Colour changes with more application so consistency is key. I like the finish, and I’m going to use it on the frame as well. For that I’ll blast it, light base coat so I can still see the frame patina, and then relatively light coats of colour. Should be able to see the patina through the coating.

My shock has D/G stamped on it, were they made by DG?

[jasong_10]

That red is awesome

[patriot1]

I am ready to see this finished. Very interesting build

[anon3]

Bit more done.

[anon3]

How do you get this drum stopper on? Any tips? Spring is a pain.

[dieseldigger]

That bottom roller is a pain in the ass. Just keep fighting it carefully. You'll win. I usually use a flat head screwdriver and a pick set. No to mention a lot of choice vocabulary. Just make sure the spring is sitting properly on the bottom collar or when you put the top roller on, it won't fit properly on the post. Honda used this roller detent system on a lot of their earlier 2 strokes.

[anon3]

After many a choice word I managed to get it on. Then realised I’d missed a washer in the trans. Easier the second time around.

Just waiting on my spec bolt kit now.

Frame is next, just need to finish up the welding and get it painted up.