Project Lowbucks 1978 Yamaha YZ250, Part 3

Jul. 08, 2014 By Rick Sieman
Here’s what we ended up with after full day of cleaning. Looks pretty good here, but it sure didn’t start out like that.

The first few steps of our newest Project Lowbucks story (Part 1, Part 2) were pretty much straightforward. We took things apart, saw what we had, figured out what needed to be replaced, and did a deeper strip of the parts.

It was right around then that we noticed this was the filthiest bike we had ever worked on in our life. There was a coating of grease and dirt on the frame rails underneath the engine that almost defied imagination. Further inspection revealed crud all over the frame and swingarm, which was at times almost an eighth inch thick in places.

This demanded a deep clean before we could even think about painting the frame and the swingarm. Luckily, we had a parts washer nearby. With the aid of a wire brush and about an hour of scrubbing, we were able to get most of the crud off.

But closer inspection revealed a whole lot of stuff left to remove before we could even think about painting. Every place there was a knuckle or joint on the frame, dirt was packed in. It was necessary to get in there and pry the dirt out with a screwdriver.  Even then, there was still so much crud on the frame that we had to resort to a number of techniques to get it clean.

So follow along as we take on the crud factor.

This is quite possibly the filthiest frame we’ve ever worked on.  The rails under the engine were coated with a layer of crud that was truly amazing.

We put the frame in our parts washer and tried to break down the crud with a liberal dousing of diesel fuel and parts degreaser.

A wire brush was very helpful in getting much of the crud loose.

When we removed the frame from the parts washer, it was worlds better but still not ready for painting.

We resorted to some time proven stuff to assist us in the cleaning.  At Walmart, for less than two bucks a can, we got this carb and air intake spray that worked wonders.

Liberal applications of the spray helped get most of frame rails clean. It took four cans to get the job done.

The main part of the frame housed the monoshock, and it still had more than its share of hardened muck on it.

A very stiff-bristled brush helped us get most of the hardened muck on the swingarm free.

The chain guide and protector were removed get to all the impacted dirt free.

A fresh coat or two of aluminum paint had the swingarm looking like brand new.

Back on the mainframe tube, we tried peeling the hardened crud off with a single-edge razor blade.  It worked okay but was not perfect.

We finally resorted to a wire brush in a drill to get the hardened debris off.

Before any paint was applied, we masked the bits and pieces that we wanted to keep clean, such as the spark plug cable and the wiring connections.

To make sure that everything was nice and clean, we gave it one last blast of the carb spray from Walmart.

Take a look at our results! The frame looks like brand new.

The tail section of the frame got the same attention to detail as the major components.

Even those previously miserable looking frame rails under the engine shone like new.

A huge amount of time was spent cleaning and painting this area.

A job well done! What started out as the filthiest bike we’ve ever seen is well on its way to becoming a keeper.

Here’s a shift-side view of the now clean frame and swingarm. Newsletter
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