XS400: A ScottLuke Saga

ScottLuke

XS400 Addict
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Hello everyone, My name is Scott. This is my first street bike and restoration of one. For as long as I can remember, I have always been intrigued by these 2-wheeled machines. Like many of you, Steve McQueen's film On Any Sunday and his infamous jump scene in The Great Escape was what pulled me in. My Father was an old MX racer back in the 70's. You know those guys wearing the Darth Vader masks and leather boots.

I started off on a PW50 at the age of 6 years. As I grew little by little, the bikes and CC's did as well. Unfortunately, we had to sell our bikes when I was around 12 years old. Both my YZ125 and my father's YZ250 due to money issues and my father's many volunteered deployments around the World.

I wouldn't touch a bike again until I was 17. I was working my first job at a local Truck Tire shop here in Portland and saved enough money to buy a 2005 YZF450. Now, 10 years later we own a couple YZ250's, WR200, 2 YZF & YFZ450's.

Each trip we would take as a family to ride the dunes, or even just when I'm out driving my semi-truck down the highway, I'm always jealous to see how much fun you're all having riding your bikes out on the pavement. For years I have wanted to do that exact thing, but speeding tickets and money have always kept me from purchasing a street bike. My Wife too, I guess its because she has seen me ride off-pavement, and it scares her to the bones to think of how I would ride on the pavement.

Recently I have been very interested in older bikes. We are a strict Yamaha only family, Bleed Blue through and through. After many a talk with my wife, and her seeing some bobbers and trackers. We both have fallen in love with the looks of these bikes and their style. We set out on finding a "Mechanics special" bike on Craigslist. A few days of searching and we were lucky enough to find this classic gem.

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Its a little rough, but exactly what we wanted. Something we could build into our own.

So Let The Build Begin! :D:bike::bike:
 
Well the Next day I woke up and decided it was time to check out the bike, and it's issues. I pulled the Headlight first and took the seat off the PO had installed. This is what I found first...

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:yikes::yikes::yikes:
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I proceeded to wheel it outside into the sunlight, hoping it would change, but it didn't.:(
 
Drained the oil next, and started on her dress..:D

With the Engine out and bike disassembled, I sent the frame off to Sand blast. Yes, that is all truck bed liner on the frame, tank, forks, triple tree, everywhere....:banghead::banghead::banghead:

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Welcome Scott, the carb placement on those first three pics threw me off -eh that doesn't look right! Looks like you've got a fun project though, and a ninja turtle helper. Hopefully that bedliner stuff comes off with paint stripper easy enough.
 
:(Thanks everyone!

I am not sure which direction I am going with it yet. I am thinking a dirtbike-bobber style of look?

Yes, that carburetor picture had me scratching my head as well, because before purchasing I read they had dual carbs. The above picture shows the bike with a single carburetor.

I was called yesterday and told the sandblasters were having a rough time using walnut shell to strip the frame, and are now using a more abrasive type media. Bad news about that phone call was the extra $$ dollhairs it was going to cost me..:(

Tonight I am tearing the top-end off to inspect the valves, cylinder jug and bottom end. Pictures to come here later tonight. :thumbsup:
 
Strange they would use walnut shell to begin with on that and stranger still that it's going to cost more than another type of media? Walnut shell is not very abrasive to begin with and loses it's abrasiveness the more its reused and no cheaper than many other medias. I would have started with a crushed glass (dirt cheap and reuseable) or glass beads which are also reusable and about same cost as walnut shells.
 
walnut shell for the tank and small parts, is what I figured? Then something like you mentioned for that ugly Frame.. Not more for the different type of media, just more money for the time? Hopefully it doesn't cost too much more, because the price $300 for blast and powder and two different colors didn't seem to bad in the first place. Trying to keep the budget down for paint and more on parts :D Thanks again Hutch :thumbsup:. I'll be sure to ask them about the price and what media they started with.
 
Started the disassembly of the top-end tonight. Here is what I found...

Tear down of the cam shaft and sprocket removal.

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Cylinder removed and here are the pistons..:eek: look at all that blow-by. The rings must have been gone for quite sometime, along with the cylinder bore, it is like glass..

Left cylinder
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Right Cylinder
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Cylinder Bore
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Left Cylinder
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Right Cylinder
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It definitely needs to be honed, and new rings. The wear toward the bottom of the skirt, is this normal? I've never seen a cylinder bore look as this one does near the bottom.
 
Now onto the Head and removal of the intake and exhaust valves. They don't look any better. Poor jetting definitely must have been the culprit here, among other things as well.

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Next I used the old rubber mallet and socket trick to remove the valves. Once again, this wasn't the prettiest sight to see...

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Left side...Looks like it was running lean? The plug was white too, so I had the feeling that this is what I would find..

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Right Side-Not nearly as many pictures, because my phone died.:doh:
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Afterwards my buddy and I decided to walk over to his work shop and clean, inspect and Sonic clean the carburetors. Found a idle mixture screw completely worn beyond belief and a brand new one on the carburetor next to it. I did install new choke/s too. My question is why doesn't the choke lever stay stuck out? Never seen a carbon that didn't have some kind of detention ball or something to hold it "ON"

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Carburetor bath. :D:D
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Now please tell me if the screw on the left is supposed to be like this, but I have never, ever seen one where this would be considered "Normal". Please correct me if I am wrong..

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Our lame attempt to use some kind of "power foam" to de-carbon the valves, it didn't work at all. :(:(
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I think I am just going to purchase new Valves. Would I just lap the new ones to seat them. Or should I take my new valves and have a shop grind the valves and seats? Our 4-stroke bikes we have always just sent the heads into a shop. Seeing as the valves are hard to find, I would rather purchase them myself, do the work(if I can). I will take the New valves to a shop if you all think I must. Suggestions and feedback would be much appreciated and helpful. Thanks all - Luke
 
So, I just learned that white residue on the Exhaust valves totally normal. Tomorrow I am going to head on over to the parts store for a new kit. Probably look for some Berrymans B12 parts cleaner to de-carbon the pistons and valves.

Just ordered new Circlips and wrist pins. Funny how they (pistons) don't have any wrist pin bearings? never seen that before. Learn something new each day.
 
You can clean those valves carefully using carb cleaner, a wire wheel or scotchbrite. Carb cleaner will clean the pistons as well.

Also, the carbs should have little springs and ball bearings on the choke rod to keep it in place. You can see the holes they go in above the fuel mixture needles.

Those fuel mixture needles look like 2 different ones? and one seems to be just a hair shorter? Maybe not, they aren't lined up in the picture so could be just that. I'd have a look to see if the end broke off in the body. Did you also remove the washers and o-rings that would have been under those needles?
 
The one needle is worn out. The 77-79 xs400 carbs don't have o-rings for the needles. That left valve was running lean most likely because of the signal carb setup that was on it. These bikes don't work well with that setup.
 
Thanks fellas. Shoot, I new the holes on the carburetor where the choke rod slides through should have brass bearings(Balls) in there to stop the choke. Damn, the PO must have lost them when he "rebuilt" the carbs. We both were scratching our heads trying to figure out how the choke stayed open. :banghead:

Parts are soaking in this B12 parts cleaner I bought from the parts store this morning. I'll post pictures to show how it worked out.
 
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