Not another "New Bike" thread...

[pbr206]

First off, I have a 1980 XS400G (That's what the PO told the other PO who relayed that to me when I bought the bike at least) but the VIN is 3F8, which the forum says is a XS400G Special 2 3F8 12/79 1980.

The PO posted on here for a bit (Hey Kyle), and it seemed as though there were some issues regarding the bike's ability to start and stay running. However, his last post seems to imply that it was running, and it ran long enough for him to take a trip from Seattle to Mt. Rainier (roughly 133 miles, and an elevation gain to 5400 ft.) as well as trips east of the mountains.

There were some pretty obvious maintenance issues to take care of first: I took of all the superficial parts, crankcase covers, gas tank, carbs, and set to work degreasing /cleaning and repeating (the drive chain cover and the sprocket had what looked like 100 years of grease and oil and pebbles and seeds [I think a squirrel must have hidden his stash up in there...])

I was happy to find that the sprockets for the drive chain looked to be in good condition, no uneven wear. Most of the electrical system is in decent condition except for the fuse box, which is fine because I intend to replace all the fuses for in-lines anyways, and there are a few wires with worn insulation which will need to be replaced.

At first my biggest concerns (apart from it not starting) were the general condition. The oil drain bolt has been rounded down (looks like somebody went at it with some vicegrips) the carb had many stripped screws. But I knew I was buying a 'project' bike.

My general plan is to take the bike down to it's components and replace/repair what I can. Anything that may require specialized tools or machining, I plan to take to a shop.

The biggest obstacle I face (and I think I will be able to fix this issue) is a misthreaded sparkplug. I think most people would say that that is the end of the bike, but I have seen thread repair how-to's and I think I can do it. Somebody please tell me if this is a fools errand. please.

With that cleared up...

About me: Never touched a motorcycle before last sunday. Don't know how to ride even. That I can learn.

As for repair, I am somewhat mechanically inclined... Motorcycles just kinda make sense in their (I am going to regret saying this) simplicity. After all, it is basically a bicycle with an engine attached and some wires and a complicated gear box.

The trickier parts of a motorcycle (i.e. the carbs and the deep inner workings of the alternator and ignition systems) still make sense in that they are mechanical (the crank turns, when the brass connector makes contact a signal is sent to the coil etc. etc. etc.)

Whatever I don't know, I can usually find information or how-to's on the interwebs...

But that is assuming I know what I am dealing with, and herein lies the problem: I am elbow deep in a set of carbs, and I don't know for sure what set of carbs I am dealing with...

I have looked at all (at least I think all) of the parts diagrams for all models of XS400 carbs, and none of the diagrams really look similar to the carbs on my bike. I can tell that one of the PO's did some DIY repairs to seal the carb boots, and someone went crazy with the sea foam... (that was a bitch to clean out...)

Anyways as I am reassembling the carbs, I have had to replace a number of stripped screws (Fuck you Yamaha/Mikuni.... Why Phillips head screws?!?!?!??) and in my haste, I lost the float plug drain screws.

This may be one of the hardest parts to find replacements for, but following some previous posts, I have found a few sites, plus ebay, that carry them. But before I spend 20 bucks for a float bowl drain plug screw, I want to make sure it is the right fit, and I am less than certain because I cannot for sure ID the carb...

Thanks for reading my novel. As a reward, Pictures!

http://imgur.com/a/U6pnG

 

[pbr206]

Well the good news is I found my float bowl drain plugs! I forgot that I left them to soak in a cup of vinegar.

Now, I am derusting the gas tank (it wasn't too rusty, but I just want to be certain it is clean, especially after cleaning the carbs) and I will need to replace the gas cap seal. 37 y/o old rubber and plastic does not hold up well.

Now for the push button ignition...

Hot Wire Mode!

 

[16VGTIDave]

For your peace of mind: There are NO Phillips screws on your bike. At least not from the factory. All the original hardware is JIS. Look for the dot stamped into the heads.

Get the correct screwdrivers or bits, or forever destroy the screws...

 

[pbr206]

I'm currently in the process of switching out all that I can for recessed allen bolts.

I guess one of the PO's must have made some modifications then... anyways, I have all the correct tools, it was just a pain extracting all the stripped screws that were already on there.

 

[BBS360]

Bike and carb photos for ID?

 

[pbr206]

Bike and carb photos for ID?

carb photos are in the link in the first post, I forgot to direct link to them.

I got the carbs back together, drained the oil, ordering replacement gaskets, new sparkplug cables, still need to clean out the contact points. lots of stuff to clean still...

 

[arfstrom]

That hole under the fuel bowl, is a drain spigot, for when/if you winterize your bike. or if you check the float level, you would attach a hose (clear, 8 to 10 inches) to verify that the float is set right. (see manual)
Tobie

 

[xschris]

The float bowl with the single bolt hole on the bottom is for a 80 xs400 the other is off a 81-82 sohc xs400.

 

[pbr206]

The float bowl with the single bolt hole on the bottom is for a 80 xs400 the other is off a 81-82 sohc xs400.

Great. So I have a frankenstein carburator. makes me wonder what other kind of fuckery is going on.

Since the last owner was able to get it running, I am hoping that the worst thing that will happen with this set-up is a confused mechanic if I have to take it to a shop!

Do you know if I can plug it? or is there a special screw/valve?

 

[xschris]

The bowls should not make any difference. But I would keep an eye out for any other weird stuff.

 

[pbr206]

HAHAHAHA, I'm a dumbass.

So I had a latex glove covering the intake to the right cylinder, and forgot about it when testing the starter/kill switch assembly I rigged up. Sure enough, the jerry-rigged starter switch worked, and that stupid glove got sucked into the intake.

From what I can tell (and feel) it is caught up in the intake valve. SO, me being naive, started to take the valve cover off, but herein lies another problem....

Transistorized ignition... I find the walkthrough in the service manual a bit lacking, and since they are referencing drilling out a blind plug (don't know what that is...) and tapping new threads, I was wondering if anyone had any experience doing this?

Since it's late now, I will add some photos tomorrow.

 

[arfstrom]

here is a blind plug, may be more of them. There are Youtube vids on this topic

 

[pbr206]

here is a blind plug, may be more of them. There are Youtube vids on this topic

I feel a bit stupid asking questions, only to find the answer later after a second search, however I think my problem may be terminology.

For example, i sheared off what i called a "tappet cover" and freaked out because when i googled the problem everyone was talking about how rare and expensive this part is.

However, after a few hours of investigation, i discovered that yamaha calls it a "cylinder cover" and it is widely available and cheap.

So i guess i have learned to find out the official part name before searching for information to avoid further confusion.

The blind plug scared me because the yamaha manual makes it sound like drilling it out is some massive operation, when in fact it is literally just a disc of metal infront of a screw designed to prevent tampering.

 

[xschris]

I feel a bit stupid asking questions, only to find the answer later after a second search, however I think my problem may be terminology.

For example, i sheared off what i called a "tappet cover" and freaked out because when i googled the problem everyone was talking about how rare and expensive this part is.

However, after a few hours of investigation, i discovered that yamaha calls it a "cylinder cover" and it is widely available and cheap.

So i guess i have learned to find out the official part name before searching for information to avoid further confusion.

The blind plug scared me because the yamaha manual makes it sound like drilling it out is some massive operation, when in fact it is literally just a disc of metal infront of a screw designed to prevent tampering.

You mean the valve adjustment caps? Yes those are easy to get. The part they screw into should only be replace with a number matching head.

 

[pbr206]

Okay, I am committed to this project now...

Rebuilding/inspecting the top end. Round 1.

So first of, I got the glove out. Amazing that it went in via the Right intake, but a majority of the glove was stuck in the left intake valve spring. So, Magic.

Here are some pics of my progress, I am still in the cleaning stage, however, today I will need to disassemble the valve rocker arms to give it a good clean. I also plan on taking apart the valves today, although, I need to go rig a valve spring compression tool. And I think I will need a bigger 'C'/'G'-clamp.

Since there is quite a lot of carbon build-up, I was thinking of taking a dremel to the valve surfaces with a light wire doohickey. anyone done this before? is it too risky in terms of reshaping the valve surface?

I will also need to do the same to the pistons as they are caked in carbon, but that will probably be next weekend.

I am nervous about trying to get at the pistons, so far I have not hit any problems that I have not been able to reassemble, except for the gas cap locking mechanism (why the fuck did I take that apart.. cleaning it was not worth the frustration of reassembly.) And in fact, the Gas tank has been giving me the most trouble of all.

The rust wasnt too bad to start, but to be sure, I emptied it, and cleaned with vinegar, and now the rust seems worse??? I am letting it sit, maybe I will come back to it when I get the bike ready to start up, but I worry the rust will progress further without any gasoline in it.

Here is picture dump.

I swear, next time, I will upload pictures, and have imgur resize them appropriately. sorry.

 

[arfstrom]

I swear, next time, I will upload pictures, and have imgur resize them appropriately. sorry.

Only problem with using a different hosting site for photos, is if the host decides to change something, and then in one swift move, unbeknownst to anyone else, Forums like ours, will have blank spots. On the the chrome interface (not cell phone) there is a way to just add photos to the post. Which with the current version of the forum software, my attachments have all made the conversion. other forums I have notice will double the work, (lovingly i am sure) by coping a PDF file with the photos placed in appropriate places, and then if future updates happen, the PDF file is still fine.

 

[Tate]

Try electrolysis rust removal. My tank was nasty. I did this a few times but worked very well. YouTube has videos how to do it.