Honda CR125 frame restoration

[retrobuilder]

Finally finished an 87 Honda CR125 motocross frame refinishing plus minor repairs.

Main frame and subframe was painted by a previous owner in white, we wanted back in factory Flash Red.

Had to repair and strengthen the subframe seat tabs which were cracked and bent. Added thicker reinforcement gusset plates by cutting/bend and TIG welded. Stronger than factory for AHRMA races.

All finished in automobile custom enamel match paint and ready to reassemble

 

[safetyman665]

Very slick. Many years ago I rebuilt Dad's old '85 CR250. Man, that bike could flat out haul ***. It was heavier but felt faster than my '01 Suzuki RM250 that had the usual reed valve and exhaust upgrades. Rode it hard and put it away wet and finally ditched it into, well, a ditch (with water).

 

[Cdstahlman]

Do you have a build thread going anywhere? Or is this it? Always enjoy seeing motocross bikes


Sent from my iPhone using Tapatalk

 

[countryroad82]

Those subframes were always cracking great job on that frame! I always hate painting bike frames and rollbars, anything round. It's a pita for me to get everything covered with no dry spots or horrible runs!!

 

[retrobuilder]

Those subframes were always cracking...

I attempted to find another sub frame- most were worse or broken entirely. Designed the gusset plate to bridge the stress areas and also for easy TIG welding with bend and a welding notch. Made it a simple 2 minute weld task for the welder.

The trick to frame painting- both bicycles and motorcycles or roll bars is to first
"cut in spray all the tube intersections, tube ends, brackets and compact spots.
Apply a small spray pattern close to the spot and fast. Medium wet coat.
At weld joints with tiny guset gaps I may even spray close and FAST but localized wet coat.
Then proceed to spray the long tubes in one pass starting at the bottom or top. Overlap into the "corners".
Do not expect a one pass spray coverage- allow the first cover coat to flash a few minutes. Then repeat as needed.
Final coat should be a overall wet/medium wet coat on the large exposed visual areas. (If you have flashed orange peel a fast wet coat can melt it smoother).

I spend most of time getting the surfaces free of cry spray paint and scratch marks. The entire metal on outer surfaces should be primed one color as some colors can show thru with need for more coats. A thin but smooth primer sealer makes for less costs and better finish.

Hint- a good suspending paint fixture helps with making the job easier and assure access for paint spraying the undersides as they can be the thinly covered or not at all.

Done painting- after the paint flashes a several minutes remove masking tapes. i f the paint thickly bridges the tape edges you may need to use an exacto knife to cut the painted edge. Peel the tape at a low angle to the tubes- less paint lift and ragged edges.

Than walk away and let the paint dry or cure. avoid wanting to rush the handling unless you use heat lamps.

Tip #2- avoid rainy days or heavy humid days as blushing is a problem. A little humidity and cool temps in the mid 70's to 80's is perfect. Avoid sun exposure- In hoter weather use a slower solvent or curing system.

85% prep- 15% spraying, thanks for comments.

 

[penca]

hi, beautiful job man. also like restoring old bikes

i would like to ask you what type of gun you find more adequate for this job (gravity, suction, pp)

can you post a pic of the painting fixture you`re using?

do you think a coat of a corrosion inhibitor (here we use copper phospate acid for some exposed piping) would improve paint adhesion and overall life of a frame paint job (always had a problem with chipping)?

thanks for sharing

pete

 

[RedRob]

Looks great !!

 

[countryroad82]

Very good tutorial! I normally do a very similar procedure when painting that stuff, I just hate it! Takes waaaayyyy too long when I'm used to just running up to flat panels (well nothing's truely flat but it's not round!!) and just run with it. It's like when I paint a tractor, I go around with my detail gun and get all the books and cram us covered first my succeeding coats are with my normal gun. Usually it works for me, sometimes I might have a dry spot or 2 in a deep recess that you jus can't get to without splitting the machine, but it's a tractor for crying out loud!! Unless it's a showpiece I don't panic.

 

[zmotorsports]

Nice job. I bought a 1986 XR600R years ago that had a cracked frame and worn piston/cylinder that I tore all the way down and did a very similar build-up. I welded up a couple of cracks, replaced a few ugly looking tabs with nicer looking ones and used some PPG epoxy primer followed by some PPG polyurethane Honda red paint. The bike turned out fantastic and I rode it for about 8-years until I sold it last year. Loved that bike.

Thanks for posting and keep the pics coming.

Mike.

 

[retrobuilder]

Thanks all for positive comments.

A few quick responses to questions-

Spray gun types for bike frames? gravity feed "detail guns" are my preference. I have a Devilbiss EGA and a newer Sharpe Finex 1000. Sharpe refinishing guns are excellent and less $ than many pro guns. For tube frame painting almost any brand can do well as long as the jetting and pressure is sized for the paint used.

My paint fixture was made from 1 1/2" PVC with a leg formed in a up side down TEE and use of T fittings at each end for stability. Then put another T on top to run a long rod thru. That allows the frame engine mounts or swing arm pivots to suspend in air. as I only glue the pieces under load so I can disassemble. To support the front I have another tall inverted TEE to support the steer tube bearing race. (need PICS??)