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gdarrell

newbie with XS 400 Special - won't start

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Hi,

I just picked up a 1980 XS400 special that was sitting under a tree for about 2 years. Prior owner said it was running when he parked it, but poorly due to carbs. This is my first attempt at a restoration. I don't mind getting my hands dirty, and for $200 bucks, I thought how bad can it be??

Before I spent too much time and money, I wanted to make sure the motor would run. I drained and cleaned the tank and pulled the carbs. Well, carbs were pretty nasty. Took a really good chemical soak, but they look a lot better now.

I have new plugs installed and the old ones were carboned up some, but not rusty. Shined a light inside and didn't see any rust and valves go up and down when I turned it over.

My problem is that when I hook it up to battery, the motor will turn about 1 revolution and then the starter kicks out. I jumped across the starter solenoid with a screwdriver to make sure it wasn't the solenoid. Got same response. I have tried kicking it, but only get about what seems to be one turn out of it. Seems to have a good bit of compression. Motor also seems to turn freely - no noises or grinding, etc.

Help please!! Not sure where to start first on replacing parts. My first guess would be the starter, but I saw a part on ebay for a starter clutch. No idea what that is, but need some expert help and suggestions on how to logically trouble shoot and/or test parts before replacement.

I would post a pic if I can figure out how :-)

thanks in advance..

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Can you start it up via the kickstart?

No. It doesn't seem like it "spins" enough to have a chance. That is, it seems like I don't get a good "bite" with the kick and I only get about 1 revolution. Don't know if that is normal or not since I have no experience with this model (and its only been about 20 years since I had a kick start street bike. My old dirt bike spins well when kicked (of course its a single cylinder two stroke).

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unfortunatly the kick only turns the motor over 1 revolution. spray in some carb start and bump start the bike. As its not been running a while I suspect that every thing is gummed up. change the oil and filter first so the engine has a chance to be properly loobed.

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I am in the process of getting an old 81xs400 back on the road. It hadn’t been started in over 10years, however I have it idling now. Here is what I suggest, as I too had a similar problem.

-Check the fuse box underneath the seat. My fuses looked fine however the contacts were so dirty and corroded that they would work sometimes and not others, causing a bunch of confusion. I ended up removing the existing fuse box and replacing it with individual fuses between the wires. If the electrical is not making good contact it wont fire up.

-Remove the air box from the carbs and spray carb cleaner directly into the carbs. I rebuilt my carbs and replaced the jets however there were some passages that were still clogged after soaking for weeks. Make sure you can apply compressed air to all the holes in the carbs and ensure they are free. Initially my bike would only idle if I stood behind it and sprayed a carb cleaner into the carbs. It idles fine now that I cleared the passages.

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A very good point.

And if your feeling up to it, its worth going around all induvidual connections, and cleaning the rust/corrosion off just to ensure that every connection is completely reliable!!!

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I am in the process of getting an old 81xs400 back on the road. It hadn’t been started in over 10years, however I have it idling now. Here is what I suggest, as I too had a similar problem.

-Check the fuse box underneath the seat. My fuses looked fine however the contacts were so dirty and corroded that they would work sometimes and not others, causing a bunch of confusion. I ended up removing the existing fuse box and replacing it with individual fuses between the wires. If the electrical is not making good contact it wont fire up.

-Remove the air box from the carbs and spray carb cleaner directly into the carbs. I rebuilt my carbs and replaced the jets however there were some passages that were still clogged after soaking for weeks. Make sure you can apply compressed air to all the holes in the carbs and ensure they are free. Initially my bike would only idle if I stood behind it and sprayed a carb cleaner into the carbs. It idles fine now that I cleared the passages.

I finally got the oil changed as Drewpy suggested. For some reason, the owner before me rounded off the oil pan bolt on the bottom. I pulled the plug on the side near the pressure switch which didn't get much oil out. So, i pulled off the oil screen pan and that did the trick. oil was full, no water, but really really black. any ideas on how to get that old drain plug out?? i don't want to pull the screen pan every time I change the oil...

I checked the fuses and there were only two installed. The main (20 amp) and a start (10 amp). The others are all missing. I am not sure if they would affect it or not - do you know? These are buss fuses and I don't have any so I have to pick up some tomorrow. As you suspected, the terminal ends are rusty looking (not green corrosion) and probably don't make good contact. The tail light does come on when I turn the key on. no other lights come on but I have the headlight pulled and there are no other fuses installed :blink:

I replaced the plug wires with car type wire (7 mm) so I hope that works. The old wires looked really bad, but I was able to use the old caps.

Speaking of reliable connections, CharlyG, I found that the lead wires to both coils had been stripped back and there was one jumper between the two coils (left side to right side). The other lead was skinned back with no jumper. None of this was taped up and of course its right under the tank :o I don't get it?? What would that do for you? Any ideas why that would either make sense or even work? Seems like the coils wouldn't fire correctly if tied together.....

too tired to kick tonight..... will try tomorrow. Not sure who is the worse shade tree mechanic - me or the owner before me :rolleyes: Got the fire extinguisher handy just in case....

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you wil need to get another drain bolt. the new ones have a larger head on them to get a better purchase.

I welded another nut on top of the bolt, so with the heat and so forth, the drain bolt undid.

coils share a red/white +ve feed and have orange and grey from contacts or TCI (not too sure of tci colours)

BTW, clean out the oil strainer by taking off 6 X 6mm bolts under the engine (square alloy thing)

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IT' ALIVE!!

Finally got it started tonight. Not sure why tonight was the lucky night, but after a new battery and cleaning the obvious terminals with a stiff wire brush and repacing all the fuses, it decided to kick. Still no action from the starter (just spins without engaging).

Bad news - only one cylinder is firing. The left side is not. Maybe that is why the former owner wired the coils together?? Anyway, I found a couple of coils and a starter off ebay and should get them tomorrow.

At least now I will be able to get serious on the refurb work since I know it runs.

Oh, here is where the rescue occured!! Sad wasn't it.

xs400.jpg

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IT' ALIVE!!

Finally got it started tonight. Not sure why tonight was the lucky night, but after a new battery and cleaning the obvious terminals with a stiff wire brush and repacing all the fuses, it decided to kick. Still no action from the starter (just spins without engaging).

Bad news - only one cylinder is firing. The left side is not. Maybe that is why the former owner wired the coils together?? Anyway, I found a couple of coils and a starter off ebay and should get them tomorrow.

At least now I will be able to get serious on the refurb work since I know it runs.

I guess the carbs are comming to bits plenty of time on cleaning them will pay dividends but becareful with the mixture screws (if I remember correctly located on the top of the carbs engine side not intake side but as the bike is US spec (3F9 ?) or if it's the same as europe could be in the side of the carbs under a wierd white plastic cover). if they are screwed in to far the tip snaps off in the carb body :angry:. I've posted else where on how to set up ignition timing so have a look for that or let me know & I'll do a walk thro (it does need investment in some tools tho).

just let me know if you need help

regards Jim

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I guess the carbs are comming to bits plenty of time on cleaning them will pay dividends but becareful with the mixture screws (if I remember correctly located on the top of the carbs engine side not intake side but as the bike is US spec (3F9 ?) or if it's the same as europe could be in the side of the carbs under a wierd white plastic cover). if they are screwed in to far the tip snaps off in the carb body :angry:. I've posted else where on how to set up ignition timing so have a look for that or let me know & I'll do a walk thro (it does need investment in some tools tho).

If it's U.S. spec you don't have to worry about that as they don't have a sharp tip, but rather a flat tip. They also are under a plug on the top between the mounting boot and the vacuum slide cover. On mine the o-rings on the mixture screws were almost completely gone, and if they are bs34 III's according to what I've found they are almost impossible to get to idle right without good o-rings. The good news is that the o-rings and everything are pretty cheap and available from MikesXS. I could NOT get mine to idle right until I replace the o-rings, but once I did it ended up being easy.

Running on one side could be spark or fuel, that may take some troubleshooting, oh and making sure there is good compression on both sides as well. But sitting as long as it did I'm guessing it was not prepped. I prepped mine before it sat for 11 years and it still took a lot of work to get it going right again.

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I guess the carbs are comming to bits plenty of time on cleaning them will pay dividends but becareful with the mixture screws (if I remember correctly located on the top of the carbs engine side not intake side but as the bike is US spec (3F9 ?) or if it's the same as europe could be in the side of the carbs under a wierd white plastic cover). if they are screwed in to far the tip snaps off in the carb body :angry:. I've posted else where on how to set up ignition timing so have a look for that or let me know & I'll do a walk thro (it does need investment in some tools tho).

just let me know if you need help

regards Jim

Jim,

I cleaned the carbs pretty good before I attempted to start. took them apart and then did a chemical soak. But, I didn' take anything out but the float needle and main jets. Still though, the inside looked good and I could see easily through all the holes and flushed out with compressed air.

Could be carb, but I am guessing its not firing. Is there a good way to check the left coil or what other trouble shooting on ignition can be done?

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Running on one side could be spark or fuel, that may take some troubleshooting, oh and making sure there is good compression on both sides as well. But sitting as long as it did I'm guessing it was not prepped. I prepped mine before it sat for 11 years and it still took a lot of work to get it going right again.

I didn't try to start until I did an oil change, carb clean, new plugs and new plug wires. Also new fuses. I think its electrical since the carbs cleaned up good. I did not take out the mixture screw - maybe I should have but I was wanting to see if it would run without a total disassmbly. The left pipe is completly cold after running for a few minutes, so that is why I was thinking electrical. But, this is new to me.....

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I didn't try to start until I did an oil change, carb clean, new plugs and new plug wires. Also new fuses. I think its electrical since the carbs cleaned up good. I did not take out the mixture screw - maybe I should have but I was wanting to see if it would run without a total disassmbly. The left pipe is completly cold after running for a few minutes, so that is why I was thinking electrical. But, this is new to me.....

Not firing for any reason will have the same affect, but generally if for electical you should be getting a gas smell from that pipe. If your not getting a gas smell from the side not firing it may be that it's not getting any fuel. Among other things make sure your getting spark on that side as a first step and if you have a timing light, make sure it's coming up at the right time. Also check the spark plug after running it to see if it's wet, and whether it's oil or gas on it. If it's dry, or oily without a gas smell on it check the fuel system.

Also make sure it's not the spark plug by swapping them (had one go bad and found that by swapping them, then the other side didn't work). If that happens then get new plugs, their pretty cheap, I got new ones for about $1 each at the local auto parts store.

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you could get a colortune kit. that way you can see a spark and also if it is burning ( good for adjusting carb mixture as well)

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Not firing for any reason will have the same affect, but generally if for electical you should be getting a gas smell from that pipe. If your not getting a gas smell from the side not firing it may be that it's not getting any fuel. Among other things make sure your getting spark on that side as a first step and if you have a timing light, make sure it's coming up at the right time. Also check the spark plug after running it to see if it's wet, and whether it's oil or gas on it. If it's dry, or oily without a gas smell on it check the fuel system.

Also make sure it's not the spark plug by swapping them (had one go bad and found that by swapping them, then the other side didn't work). If that happens then get new plugs, their pretty cheap, I got new ones for about $1 each at the local auto parts store.

wow those plugs r cheap give me the address nearly worth the plane fare to pick them up :lol: as long as u pay

regards Jim

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wow those plugs r cheap give me the address nearly worth the plane fare to pick them up :lol: as long as u pay

regards Jim

Got em at Kragan's, actually I think they were like $1.99 (found the reciept) but they were really cheap, and exact OEM even. Kinda cool cause it costs more to get them on ebay even, and I only have to go about 2 blocks to get them. Go in with the original part number and they can cross them and give you several options, the OEM were actually the cheapest. I may try a premium plug next time to see if it makes a diff on the gas milage, I think they have a cross for a multi-tip plug as well.

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Not firing for any reason will have the same affect, but generally if for electical you should be getting a gas smell from that pipe. If your not getting a gas smell from the side not firing it may be that it's not getting any fuel. Among other things make sure your getting spark on that side as a first step and if you have a timing light, make sure it's coming up at the right time. Also check the spark plug after running it to see if it's wet, and whether it's oil or gas on it. If it's dry, or oily without a gas smell on it check the fuel system.

Also make sure it's not the spark plug by swapping them (had one go bad and found that by swapping them, then the other side didn't work). If that happens then get new plugs, their pretty cheap, I got new ones for about $1 each at the local auto parts store.

Got the new coils in and installed one on the left side. Started it up, but still firing on right side only. Checked plug as you suggested (good idea) and it was clear (white) but wet and smelled of gas. That would suggest its getting gas but not fire.

I couldn't get the cover off the ignition. But not sure if this has points or electronic (3f9xxxxxx). But, does anyone know if its electronic, is their a failure that would only fire on one side? Or I am I chasing the wrong rabbit here?

Finally found my timing light late tonight and will try that tomorrow. I am assuming I should see a strobe if the coil is firing??

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Got the new coils in and installed one on the left side. Started it up, but still firing on right side only. Checked plug as you suggested (good idea) and it was clear (white) but wet and smelled of gas. That would suggest its getting gas but not fire.

I couldn't get the cover off the ignition. But not sure if this has points or electronic (3f9xxxxxx). But, does anyone know if its electronic, is their a failure that would only fire on one side? Or I am I chasing the wrong rabbit here?

Finally found my timing light late tonight and will try that tomorrow. I am assuming I should see a strobe if the coil is firing??

if you have a smooth alloy points cover with plugs instaed of screw heads, you have TCI ignition. Ribbed with screws visible - points. check you are getting 12v to the suspect coil!

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Got the new coils in and installed one on the left side. Started it up, but still firing on right side only. Checked plug as you suggested (good idea) and it was clear (white) but wet and smelled of gas. That would suggest its getting gas but not fire.

I couldn't get the cover off the ignition. But not sure if this has points or electronic (3f9xxxxxx). But, does anyone know if its electronic, is their a failure that would only fire on one side? Or I am I chasing the wrong rabbit here?

Finally found my timing light late tonight and will try that tomorrow. I am assuming I should see a strobe if the coil is firing??

Did you swap the plugs? Those things do go bad and that can be a failure point.

Yes if you hook the timing light to the wire and get strobing then you have spark, but it could be not getting to the plug tip.

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