Old Yamaha dirt bike restoration

To celebrate the new 2 stroke section, I figured I'd start a thread on my current restoration project.

I'm actually converting an enduro to a regular dirtbike. The enduro has been in the family since new so it's never going to be sold. I had it sitting in my shop office for a few years now but never really felt the burn to tear into it. I'm just not very into small displacement enduro bikes. After tripping over it one too many times i decided to just blow it apart and rebuild it as a dedicated off road bike.

Let me say right up front, I'm pretty extreme OCD . The guys at work call me Rainman.

The beginning. 1971 Yamaha CT1 175cc enduro.


Tear down to the bare bones.


Remove all unneeded brackets and tabs.




Powdercoated in Super Mirror red.


I'll try to update this thread each day until I get caught up to current status or the bike gets finished, whichever comes first. I figure I still have about a month of work left before completion as of right now.

Can I be the first to subscribe? Lookin good already.

Can't wait to see how this turns out.

I have a picture in mind of how I want the finished bike to look, red frame, white sheetmetal, and lots of little details.

To that end, I started on the rear fender. It had a couple of things that were no longer needed for the dirtbike application so I removed them.

Wiring channel for taillight wire harness.


Clip for turn signal wiring harness.


I powdercoated the fender in mirror white, along with the fender brackets.New factory rubber mounting grommets in the little baggies there.


The mud guard is the original plastic one that cleaned up real nicely. The mud guard retainer is also the original which I powder coated in Paccar semi gloss black.


Installed. All hardware on this bike is replated original stuff (more on that in later post).

Any traditional powder coat I've seen is usually a little orange peely. I don't see any orange peel in yours at all - I checked your blog page too. Skill? New process? Both? Will you powder the tank and side covers too?

I make every effort to make my powder work as smooth as any paint job. No real secret ingredient really, just technique and attention to detail. I will powder coat the tank to match but there are no side covers on this bike. What you see in the picture of the bike on the trailer is the oil tank for the factory Auto-Lube system. I did away with all that and it's associated frame bracketry and will run pre-mix fuel like a normal dirt bike.

Make sure the auto-lube on this bike just injects oil into the fuel-air mix; I know there are some engines that lube the bearings directly via auto lube, and the bearings will die quick if you run premix.

Nice job on the powder. When you do Candy with powder, is it like a traditional multi layer base/translucent colour/clear Candy paint, or is it all one coat? (And do you have a Candy Topaz Orange recipe?)

On these Yamahas, the oil pump has a single line that inject oil into the intake port, which I removed and plugged when I did the engine. The crankcase has it's own oil with fill plug and dipstick. Thank you for the thought though.

Candy powdercoat can be tough. It's either two or three separate stages. The problem with candy powder is that it is not translucent until fully cured. Unlike paint, if you have dark or light spots, you'll never know until it comes out of the oven fully cured and has to be completely stripped to bare metal and redone. I haven't done any Candy Topaz Orange stuff yet. I'm sure I can get close (my supplier has 5500 colors which can be further tweaked depending on the basecoat color), but I need a dead nuts original colored part to judge it off of.

On to today's installment.

The engine was typically greasy and needed a lot of cleaning to look nice. First stage of cleaning was plug all holes and degrease thoroughly, then dry it off and soda blast it. I'm a huge fan of soda blasting. McNoob, if you look closely in the third picture, you can see the oil feed line, which is the long one from the tank, that goes through the side cover to the oil pump, then a smaller short line from the pump that goes to a banjo bolt on the cylinder adjacent to the intake port. There was a brass jet pressed into the passage behind the oil line banjo, which I removed and plugged with a plain 6mm screw.




After all of that, the engine was clean enough to put up onto the workbench and tear into it so I could get serious about detailing.



I also sent all of the hardware on the bike out to be re-plated. I'm so fortunate to have a local shop that does it for me. For everything, it was 50 bucks. I take them dirty, greasy, rusty hardware and a week later I get this back (spokes not shown in picture, but they were replated too)

I started detailing the engine. The bike had only been ridden three months when it was bought new then stored for 40 years in a shop, so the engine wound up being very solid. In the end, I just replaced all engine seals, inside and out, honed the cylinder, soda blasted the piston and new rings. I hate any kind of leaks or seeps so basically anything that was rubber got replaced.

Since I removed the Auto-Lube oil pump system I had to make a block off plate for the pump. Yamaha sells them, but all you're buying is a flat piece of aluminum.

Make a pattern.


Chunk of old dump truck "naked girl" type of mudflap.


Finished. After the pictures, I did replace the screws with new ones. The ones in the picture are kind of chewed up.


Both engine side covers powdercoated in silver metallic with clear.

OOOOOOOHHH SHINEEEY fresh zinc plated hardware! Me like. Looks to be a good build. I have just gotten started in powdercoating, and admire other fellow's work. Do you have a home-made oven to do the frame?

wow nice job...Im on the other end of the spectrum...crank seals and carb clean is a "restoration" for me...

Look forward to seeing the end product!

Mike

I've got a 4 foot by 6 foot oven. It has been a good one. I can't count how many hundreds of hours it has been in use.

Thank you Mike. I'd bet you have more fun with yours than I do mine. When you invest so much effort into one, you get fussy and protective of it which cuts down on the fun dramatically.

I know you're going minimalist and that's why you want to run premix, but I've had past experiences with both premix (Bultacos and Suzukis) and oil injection (Kawasaki and Yamaha). IMO the bikes with oil injection ran cleaner and fouled plugs less often, but to each his own.

The cylinder was in super good shape so I just honed it. Same with the piston. I soda blasted it and got a new set of standard rings. Cylinder and head powdercoated and fins polished.



Since I'm doing away with the lighting system and battery on this bike, I removed the entire lighting coil section off the stator and rebuilt the remaining ignition wiring with all new stuff from www.vintageconnections.com . That's a great source for original type grey wire loom and connectors for old Asian motorcycles.

Sorry for the phone pics.



Started reassembling the frame. All the black stuff is powdercoated in Paccar semi gloss black.



Front head bearings looked brand new so just cleaned and re-greased before re-installation.


I also replaced all of the crank and trans seals too. Then, engine back into the frame.

Wow, great build!!

Thank you Willie. I've drawn a lot of inspiration for my bike from reading your build threads here and on the Yamaha enduro site.

I wish we where closer, I would totally tear my bike down and redo all the paint, BTW I have folowed several of your fine work, and you sir do some fine work

First, let me say, I really appreciate the praise.

This might be the stage where the build starts to bore the readers. I'm pretty anal about details so at times there doesn't appear to be much progress being made, but the little stuff can be tedious.

Since I've done away with the switch gear on the handlebars, I needed a kill switch. I ordered a Moose brand one that's for a CR Honda dirtbike.



Remember I warned you about the details. I spent a lot of time and effort on the brakes on this bike. The stock enduro front brake plate had the typical speedometer cable drive and the brake cable was oriented to route straight off the back of the plate. That caused a long cable and unsightly routing. I wound up scoring some MX bike brake plates off eBay pretty cheap. They don't have the speedometer provisions, and the cable routing is completely different, routing straight up the fork leg. As an added bonus, they are Magnesium and quite a bit lighter in the hand than the original aluminum ones.




Being Magnesium, polishing wasn't really an option so I coated them in the same silver with clear that I used on the engine cases.

We dare you to try!

What are the colored bottles in the background of the fender pick all about?