Breaking the engine open

It could be put off no longer, it was time to dig into the engine.  I am using the factory service manual to disassemble the engine in the best order.  First up comes the heads and cylinders which are the last remaining engine components that need painting, the main case is supposed to be bare aluminum.  The state of the head and cylinders was rather poor, most of the paint was gone and there were old mud wasp nests between half of the cooling fins.

The first step was scrubbing 30 years of dirt and wasp nest off of everything.  I washed them with warm water and a stiff brush, which cleaned up everything and then took heavy cleaner/degreaser and q-tips and cleaned all of the dirt and oil out of all of the small crevices in the cooling fins.  Once that was done I used the soda blaster to strip the remaining paint and oxidation and went through the same hand cleaning process again to make sure everything was clean.  I then carefully masked off all of the opening and hit everything with 3 coats of high temperature engine paint.  Now as you can see below the edges of all of the fins are bare metal and semi polished, this proved to be a bit of a headache as there is no good way to mask that edge as the edge is no longer square.  I ended up painting it and the scraping and using a scotch pad to polish the edges.  Now scotch pads release small particles of aluminum abrasive, small enough to hide in engines and large enough to ruin bearings, so I had to make sure the masking was still good and wash everything a third time to get rid of the sanding dust, but they turned out pretty good in the end.

Next up is Clutch and engine gear disassembly and inspection.

Slow, but steady progress...

Well it has been a while since I updated, but I have been plugging away at the project.  I have been taking components off individually and bringing them inside all winter and cleaning them up and painting or zinc plating them as I go.  I now have the engine out now and all that is left to strip from the frame is the front suspension and a few other little bits.  I have decided to go with painting all of the components including the frame rather than powder coating.  I have been impressed with the chassis paint I bought in the spray can and it has done a really good job, so i think I will save some cash and do the painting myself.

For this update, I am going to go through the cleaning and refurbishing of one of the key little components that make this two stroke street bike a little more civilized, the oil injection pump.

Above you can see the side cover, which I also redid as part of this task, the pump is housed under the front of that cover.

What this little pump does is take oil from a tank and inject the correct amount depending on throttle position into the carburetors to lubricate the engine.  Before these pumps were created you had to premix the oil with the gas when you fill up which is a hassle and has the problem of starving the engine of oil at idle, so coasting down a hill could seize your engine!  So, this component is really vital to prevent engine damage.

Yamaha never meat this pump to be user serviced, in the service manual that simple say to get another pump from your dealer if yours fails.  Fortunately, these little pumps are near indestructible.  The problem is oil leaks getting oil all over my nice clean engine.  I found a few places that sell seal kits for about $35 that come with the 4 oil seals you need and new screws for the body and gaskets.  So I carefully took the pump apart and I see why they aren't user serviceable, it is full of some very, very tiny parts.  There are two gear retaining pins that are literally 2mm long and .75mm thick!  I managed to get everything replaced and back together and turned the pump by hand and it works, it was like watch repair.

Above is the finished product out of the housing, all new seals in place and the shiny new screws all tightened and cleaned up. Below is the pump installed back in the cleaned up, repainted and polished engine cover.

                                        

Below is everything back in place like I found it, I plan on getting new screws to replace those rusted 3 screws holding the pump cover on, but other than that it isa ready to go on the engine.

Next up is the rear swing arm assembly and followed by that soon by the engine inspection.  I have another bike in pieces right now in the garage, plus it has been super cold in Minnesota this winter which cuts down on my initiative to get out to the shop.

Adventures in Electrochemistry

So I know it has been a while since my last update, but before summer arrived in full swing and my other bikes started getting all of the attention, I spent a large portion of time trying to clean and replate some of the smaller specialty pieces I had taken off the bike with zinc.

This involved two steps, the first being trying to get all of the rust off of a part.  My soda blaster had been doing well for light to medium rust, but the heavy rust on this rear brake brace was rather stubborn.

 This is what I started with, heavy surface rust and pitting.  What I did was use an old computer power supply tied to four pieces of iron rebar on one lead and a piece of wire suspended in the middle of the bucket.  The part was attached to the wire and submerged in a salt and water type solution that would allow electric conductivity.  Simply turn on the power supply and the rust process is essentially reversed and the rust cakes on the rebar.  This doesn't fix bad rust pitting, which I had a lot of, but it is a start.  Once the piece ran for a day or so you pull it out and scrub it with some steel wool and you get this.

You can still see some of the rust pitting, but it is a huge improvement.  Once I had this I took a dremel and made sure I had all of the rust off (there were a few little spots that were still rusty from air bubbles being there etc) and dipped the whole piece in moderately concentrated HCl, this acts as a strip for the factory plating (in this case either Zinc or Cadmium) and makes sure your part is down to the bare metal.

Once this is finished you are ready for plating!  The plating apparatus I made is similar to the rust removing bath with high purity Zinc roof strips in place of the rebar and the polarity of the power supply switched so our electron are moving in the opposite direction.  the part is submerged and allowed to run for 10-15 minutes (you don't want all of you tolerances messed up by too much plating).  This is the result.

OK, that doesn't look very nice, but here is the trick.  If you take that and scrub it with a brass wire brush under some water you get this.

I then ran the part through the zinc plating process for a second time for a nicer finish.  Notice there is still some pitting that kind of lets the piece down, but it is a huge improvement and is more then adequate for this non concours restoration.

I am going to do this process and every currently zinc plated fastener that is surface rusted, but here is an example of the factory finish in good shape and the replate for some exhaust bolts.

Factory plating is on the top and the replate is on the bottom.  The black on the end of the replate nut is heavy pitting from rust, which is why I have the extra factory bolt.

Brake master cylinder

I have had the brake master cylinder of the bike for a while and have been putting off working on it since it is not a stock component.  From what I can tell it came off at mid 80's Yamaha, but isolating it enough to figure out which rebuild kit was difficult.  Even the dealer couldn't give me a decent idea.  Well I decided to tear it apart and inspect the seals and see if by some chance it didn't need to be rebuilt.

Here was the state it was in:

There was a lot of corrosion on the outside from the brake fluid sitting in the system, but I was happy to find out when I opened it up, that the bore was clean and the seal were still pliable and looked good!  Well this saved a lot of time and frustration.  So i soda blasted the body, and wire wheeled the rubber coating from the handle and repainted the whole thing, below is the result.

Next up is removing the rest of the front brake system and cleaning up those.

Finishing the gauge cluster

So the gauge cluster was my first big sub unit that needed to be reworked and repaired.  Here is the state of things before I started.

Cosmetically, it was in rough shape with most of the black paint gone from the gauge backs and the aluminum frame.  Underneath it got worse, each of the center four indicator lights sits in a rubber tube that at some point had filled with water and caused the bulb and holder to rust away in some cases!  Fortunately, there are several online suppliers that make many reproduction parts for this bike.  So I ordered 3 new bulb holders and cut and soldered new bulb holders in place.

Here is a new holder along side one of the rusted out holders.

Here is the finished product reassembled, looking good.  They do make reproduction face plates for the gauges and mine is slightly nicked up, but I like it that way and think I will keep it like that for now.

Exhaust pipes

Its been a while, lots of things over the summer, new bike, patio, Subaru head gasket job, baby on the way, motorcycle fell off the list.  I did get a chance to work on the expansion chambers, removing years of two stroke oil and dirt baked on to form a concrete like layer.

This side had some light surface rust, but it cleaned up real well, those other side on the other hand had a few surprises.  Here is what the final product on this side looked like:

The other side had a few issues.  It looked OK at first glance but as I scraped away the layers of grim i found several small holes that I could stick my screwdriver in.  In a 4 stroke bike this would be usable, but since the expansion chamber provides vital back pressure for the engine to run, holes are a big no no.  Fortunately, my new favorite place in the world, Sport Wheels salvage has a few bikes that are identical to mine that I can pull parts from.  I found a replacement that was in amazing shape for about $70.  Not cheap, but better than what I have been seeing on Ebay.

Next maybe I will tackle rewiring the gauge cluster, once I have fixed the gauge cluster in my truck that is.

Carburetors

So I finally got back to working on the bike after the commotion of getting things ready for spring and vacation.

Here are the carbs in place on the bike

Carb off and ready to be cleaned

Torn apart after being cleaned

Finished product

These carbs were originally painted all black, I'm not sure if I am going to paint them though since carb paint never holds up well.

In other news I have been cleaning the exhaust pipes and found the right one was rusted through in several places so I need to take a trip to the salvage yard and try to find a replacement.  I blame the anti dust spray they put on the roads near where my grandfather lived, this would explain all the rust spots on fenders too.