87 CR125 Resto: Q:Trouble w/ corrosion and some random questions

[hellbertos]

You are fortunate to have one of two years that the ama made the pros race what came off the assembly line. At the time, they were factory bikes.

Thanx! Yeah, I really loved the bike. Even when it was a couple years old, it still felt as though it held its own. One of the reasons I thought it would be a good rebuild as well...

Thanx SMMWest! Let me know if you find any extra PJ-1 paint in Honda orange. I looked around a bit but didn't find any. I'll look at the Chev engine paint when I get to that point, but, in all likelihood, if I do paint it I'll probably go to an auto paint shop and see if they'll color match.

BTW, I had an 85 CR125 way back when also. Sold it to get my 87. Loved that bike too. Nice work keeping it alive... and, in my opinion, nice work returning the frame to stock. I remember guys doing their frames white back then and never really liked it. I recall it being the "Euro" look. The custom aspect was cool but I guess I just thought the white clashed too much w/ the rest of the bike + got dirty and ugly fast... my fashion rant for the year...

 

[Ol'89r]

At the risk of wearing out all the goodwill... I still have the corrosion issues which I am unsure about, as well as general rebuild questions (like how to remove the main bearings from the crank?? I guess I better start looking for a good machinist...) and I'm sure many future questions as the project goes on. Given this, I am not sure the etiquette for posting. Should I keep reopening this post or repost as new questions/problems arise?

No worries. You can keep this thread going for your project and we will check back in. If your friend is an AP mechanic he should be sharp enough to help you through most of your rebuild problems. Use heat to remove the crank from the cases. Your main cases are aluminum, not magnesium, so you can use direct flame on them without any danger of catching them on fire. You have to be careful not to overheat them because they will melt at a little over 1100 degrees. Heat them until you can sizzle a drop of water on the case. Then, your bearings will almost fall out. Reinstall them using the same method.

You will need a bearing splitter to remove the bearing from the crank. It is a wedge type of device that goes under the bearing and pushes it up off of the crank. Check with your local dealer to order one. You can also heat the bearing and try to pry it up by using two levers on opposite sides of the bearing. If that doesn't work, you will need the bearing splitter. Your local shop may remove the bearings for you for a small charge.

 

[SMMWest]

Thanx SMMWest! Let me know if you find any extra PJ-1 paint in Honda orange. I looked around a bit but didn't find any. I'll look at the Chev engine paint when I get to that point, but, in all likelihood, if I do paint it I'll probably go to an auto paint shop and see if they'll color match.

BTW, I had an 85 CR125 way back when also. Sold it to get my 87. Loved that bike too. Nice work keeping it alive... and, in my opinion, nice work returning the frame to stock. I remember guys doing their frames white back then and never really liked it. I recall it being the "Euro" look. The custom aspect was cool but I guess I just thought the white clashed too much w/ the rest of the bike + got dirty and ugly fast... my fashion rant for the year...

Haven't been able to track down any PJ-1 Honda Orange Paint, but I can find tons of 1988-1989 Honda Red.

I think I will put this whole thing back together with the "Euro" look White Frame (after tearing it all the way back down again) and get in some riding and racing on this thing and then right before Hangtown Amateur Day this year I will tear it all back down and get a Automobile Paint Shop to do my frame also depending on the price. If the price is too high then I will go with the Chevy Engine Block Orange paint and do it myself.

I think besides my old 1982 Suzuki RM125 that my 1988 Honda CR125 was my all time favorite bike and me getting this 1985 Honda CR125 is bringing back that feeling. It just doesn't sit the same as my old 1988 Honda CR125 in the Front. I am going to throw on some Answer Alumilite Honda CR HI Bend Bars and see if that helps.

 

[2strokerfun]

If your friend is an AP mechanic he should be sharp enough to help you through most of your rebuild problems.

His friend may very well be able and competent to help him. But I went through A&P school in late '70s and I have to say I wouldn't let about half the guys in my class change the water in my dog's bowl. A lot of people with A&P licenses are excellent mechanics, but certainly not all. Some people liked and understood working on engines and some just wanted a way to make a living working for a major airline. But almost every general aviation mechanic I've ever known is an excellent all around mechanic, too.

 

[SMMWest]

How are things going with this project?

 

[mas2de]

(kind of late but...)
Magnesium doesn't much like to ignite when it is in large chunks. filings and thin strips will blind you and won't blow out but as for open flame on big pieces of magnesium, you should be ok if you're careful. And welding magnesium is extremely difficult. I believe it is still a challenge for professional welders, but should be do-able. But it is not much for the amateur. The TIG easily burns through the magnesium and has other problems too.
And doesn't soda blasting leave a funky residue and work it's way into more crevices than sand? Guess it wouldn't much matter for around the impellar and if you're rebuilding the rest of the stuff.
You can get the bearings off the crank ok, it is putting them back on which is the problem. For that you need something a little more precision. A good machine shop really ought to be able to put it back together right.
Glad to hear it's going alright. and good luck.
see ya,
Mike

 

[SMMWest]

Had to sell the 1985 Honda CR125 yesterday that I had rebuilt from the ground up. Couldn't miss a Child Support Payment, so it had to go. Someday when I can get ahead I think I will purchase another one and rebuild it the same or grab a 1986 Yamaha YZ490 again. Sad Sad Day.

 

[2strokerfun]

Couldn't miss a Child Support Payment, so it had to go.

You're a better man for it.
Hope you get another one someday to rebuild.

 

[hellbertos]

Well... its been quite a while now since I posted anything, so I'd like to say right up front, sorry for lagging on all you guys here and, again, thanks for all the previous info which really helped me get passed some of those tough early moments of disassembly.

I thought I'd pop back in to let you all know, if anyone cares at this point, that I finished the project. I plan to post some photos to picasa soon to show some friends. I'll post a link here if anyone is interested. Unfortunately, shortly after my last post a little over a year ago, I ended up w/ a major family health problem. Suffice it to say, I spent a few months visiting the cancer ward w/ regularity. For someone who has never had someone close go through that, it was pretty hard. Riding, moto projects, etc. were the furthest thing from my mind.

Eventually, I got going again, around last summer and I am happy to say the project is complete! Well, I still have to bleed the brakes and deal w/ the CA DMV which will be ugly and time consuming I'm sure. However, it was kicked over a few weeks ago and sounded GREAT! Forks were disassembled and cleaned w/ new bushings/seals installed. Shock disassembled and cleaned, linkage relubed, etc... but the biggie was the motor. It was my, and my friends, first bottom end project, so we were happy that was a success... well, so far as we can tell to this point w/ just a couple laps around the block.

The corrosion issues were many. In the end, I bought a new right side case cover and all new water pump parts. The old stuff was shot. I soaked the rad hoses in 50/50 mix of CLR and water. Team Calamari Racing in Salinas, CA handled clean up of the h20 pump cover, cylinder and head h20 jackets w/ bead blasting... also bored the cylinder for me and balanced the crank. Myler's Radiators in UT cleaned my rads out and welded on new fittings. Found some parts on ebay, ordered most straight from Honda... many parts are still available, though some are long, long gone.

In the end, I have a pretty darn clean, nice running (so far) 1987 CR125R motocross bike. I look forward to getting it stickered so I can get it out for some trail time and start dialing it in. I hope to be able to race it in a vintage class for it at some point... though early searches haven't indicated much availability for it. I also have much more mechanical knowledge than before I started; partially attained through trial and error, reading, etc and partially through talking w/ the various people I contacted throughout this project... and some of that was here at dirtrider.net in the Vintage forum. Thanks again for all the input guys! Happy to post the pic link if anyone would like to see (once I get those pix uploaded).

@SMMWest: Sorry to hear you had to sell that 85 CR you'd worked on. Having recently finished mine project, I have an new perspective on what it means to restore one of these bikes. Couldn't have been easy, but like 2T'erfun, I think you made the right move given the circumstance. I'm sure another will come around... funny thing is, now that this one is essentially finished... I have this weird feeling like I need to wrench and caught myself cruising Craigslist for a broken down MX'er to work on, and they are out there! ...better just get this one out on the dirt first, eh?

Thx again to all. Enjoy the ride...

 

[Uchytil]

Looking forward to pics!

 

[_JOE_]

Looking forward to pics!

Yes, yes, yes!!!

 

[hellbertos]

Finally found the dang camera

Hi guys- sorry it took so long to get these posted... couldn't find that dang camera for the life of me; been busy too though.

Anyhow, I put a web album since I cannot upload pics... hopefully this link will work for anyone interested.

Thanks again for all the help I received from people on the board! This was a great learning experience but it was tough in the early going, so I really appreciate the input from you guys here early on.

Looking forward to the next one...

Here's the cut-n-paste link:
http://picasaweb.google.com/115026051672893121897

 

[Uchytil]

Nice job!

 

[whenfoxforks-ruled]

The bike looks killer! Nice job.

 

[hellbertos]

Thanks guys.

Took a lot of work but it was definitely worth it! Learned a ton...