My bike's got a plethora of issues. (Kickstart, e-start, carbs, etc.)

HiPurpleTurtle

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My bike's got a plethora of issues. Now it's my build thread.

Hey folks! I just recently picked up a '81 XS400 Special. It ran when I first got it, albeit very poorly. I rode her home then bought some new parts. I replaced the battery, oil, oil filter, spark plugs, caps and wires, air filters, and I took apart the carbs to clean them and installed a fuel filter. I also adjusted the valves.

The bike then ran phenomenally better after all that! However, it was still very temperamental. I had to adjust the fuel mixture and idle speed so that it could finally run without the choke on. I got it to that point, but then the carbs would overflow and fuel would constantly leak out of the left carb into the air filter. I took the carbs back apart and checked that float bowls but nothing seemed out of the ordinary..The carbs had never leaked before until I cleaned them, though! It doesn't seem to be leaking anymore. What gives?! :banghead:
Oh, I'm also pretty sure my petcock is broken. I know it's supposed to be vacuum fed, but regardless of which position the lever is in, gas will pour freely from it. I figured that's the cause since the fuel would never stop coming out and then obviously the carbs would overflow. And yet it's not leaking right now and there's some gas left in the tank? :wtf:

And here's the other issue: I'm fairly certain my transmission has now slipped or something. The bike is missing the electric start button so I've had to use a screwdriver to start it that way. I prefer kickstarting, so I try to use that most of the time. HOWEVER, now the kickstart lever is making an awful grinding noise. Here's the video of the noise.
http://tinypic.com/r/zssfwi/8


I think this is because the e-start would engage automatically even while the bike is running, causing the engine to turn over more then it should? I honestly don't know.
I would really love to get rid of the e-start and have the kickstart functioning again. How would I go about doing that?
 
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What kind of oil did you put in? needs to be safe for wet clutches or it will cause slipping.

if the carbs were leaking fuel might have gotten into the case and you will have to replace the oil anyway...

carb issue sounds like a sticking needle or ur float height is off. Will need to open them back up and really really clean them or replace needles and seats. also make sure float height is set to stock which i think is 27mm.
 
I used Rotella 15w40 diesel oil. I forgot to smell the oil for gas earlier, but I'm sure you're right.

I'm sure replacing the seats would help. Any idea as to why the kickstarter is so off?

Thanks!
 
Something is definitely wrong with the kick starter. You should not be able to kick the bike over with your hand. Is you clutch engaged when you are trying this? Or maybe it is out of adjustment at the motor. Download the manual and start reading how the kick and e-start works. There are threads on how to fix/work on both in the forum. Do a search.
 
The bike was in neutral when I attempted to do that. There's absolutely no resistance when I hold the clutch lever in. But that's normal, yeah?
It's probably out of adjustment at the motor at this point.
If I do put it in 1st gear, it'll move the bike forward, so it's still engaging the transmission, but yeah. I'll mess with it all whenever I get a chance again.
 
So today I got the bike back up and running!

The kickstarter is fully functional again. I took off the engine cover and reinstalled the kickstarter assembly in the correct position. I also adjusted the clutch line and that pretty much fixed that issue.
The bike is running soo much better now.

Next issue to fix is the faulty petcock. I will take it apart again when I get a chance. I'll wait on buying a rebuild kit for now.
I need to fix the electric start issue, too...

It's coming along nicely.
 
Today I made a new seat for my bike!
I'm temporarily using a denim shirt as the fabric. I'll reshape the foam and use brown leather next time.
Everything should be finished this week! I have euro bars, carb parts, a smaller battery, and some other goodies coming in this week. :D
I'm going to strip down the tank bare and leave it that way. ah I'm so excited.
 
http://imgur.com/a/LIYQQ
Here's how she's sitting for now!
cdMWxmK.jpg
 
I've got an inline filter, actually! I was worried that it was too big, but I'm waiting for my new petcock to arrive on Thursday before I put it back on. :)

It's not thaaat uncomfy. :thumbsup:
I'd definitely like to get it professionally upholstered after a while, though!
 
Got my tank back today from the sandblaster! I was expecting to be a nice bare metal finish, but it seems like there's a rough primer-like layer on it. Ah well, I still like it. I can polish it myself later on.
I replaced my petcock and float seat and valve so it doesn't seem like I'm leaking any more fuel! However, the bike now dies without the full choke on. I'm gonna have to tear it back apart and clean the jets again. Hopefully that'll fix the issue! I'm going to have to get a new fuel filter..the one I have now is too big and won't fit properly. -sigh-
That or the vacuum plugs I put on the carbs aren't working properly..
Either way, I should have it figured out and riding tomorrow!

Here's a picture of how she sits now. :)
 

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If they sand blasted the tank, that's not primer but small pits in the metal:( Not going to polish that out. You will have to sand it smooth first.
 
Lots of sanding ahead of me, then! Not a big deal.
I'll enjoy the finish as is for now. It's already dirty, but I'm okay with that. I'm just ready to get this back on the road.
 
I can't seem to figure out what the issue is. My spark plugs are fouled now, so I'll have to get new ones again. I need to figure out what the issue is first so I don't keep fouling the plugs, of course..

I took off the idle mixture caps today, so I'll try messing with that again tomorrow or Monday. I'm going to clean the carbs once more, but more carefully this time. I'll get to use an air compressor instead of a can, as well..haha

Anyway, the bike is starting and idling but only with the choke fully open. The bike also backfires every so often. If set to even 1/2 choke then the bike will die. No hanging idle or anything, so I'd like to think there isn't a vacuum leak and the float height is fine, but I'll double check all that again.

The bike ran well after the first time I cleaned the carbs, so I'm not sure what happened now..
Maybe I'll need to rejet? I'll find out if the bike still doesn't idle even with the mixture screws set 4 turns out.
And my front brake is just not engaging well, either. There's not enough pressure in the line for the drums to fully work.


Daaaamn. If I can't figure this out the next chance I get, I'll probably just order new jets and take a break from it.
 
If you are fowling the plugs it's too rich. What jets are you using? Before adjusting carbs you should make sure the valves are set correctly. The carbs may need another cleaning. Then sync the carbs with a manometer. Does the bike smoke? As for the brakes, are the shoes in spec for thickness?
 
I'm honestly not sure what jets they are. I think the PO said that someone had changed them at one point. There are indicators on them, right?
I'll check the valve clearance again, but I made sure that they were correct the first time I did them.

I haven't used a manometer yet. Only adjusted the fuel mixture screw and eyed the butterflies.
I do remember the bike smoking a tiny bit once or twice. Not recently though.
If it's too rich, then that could mean that my jets are too large, right? What else could it mean? Improper float height, too?
I'm pretty sure I have to replace the idle jet screw, spring and o rings, too.

Wait, if the bike is running rich, then why would it only idle with the choke fully on? It suddenly becomes too lean to run with it off?
I've ridden the bike up and down my street with the choke on, so I know that contributes to the fouling.
 
You will need to sync the carbs before going farther. Running the choke a lot will foul the plugs. After the sync you may have to adjust the idle mix screws. If the o-rings are bad for them it may be part of the issue. Also make sure they are assemble correctly. ( o-ring first then washer, spring then screw)
 
I haven't synced the carbs yet, but I played with the idle mixture screw today after cleaning the carbs pretty well and the bike is up and running! Runs fairly well now. Yesssss.

I'll get a manometer soon and see sync it properly soon.
 
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