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Got my first XS for FREE
- Thread starter bbd1983
- Start date
You need good solid grounds. The battery needs a nice fat wire going to the frame, and to the harness.
Get a manual and look at the wire diagram. They can be intimidating but its something you should know how to read and understand. Its hurts my eyes sometimes to read a diagram.
Looking at my manual. The RUN switch is the R/W(red/white) wires. The R/W wire goes to the Igniter unit and to the coils. It should be hot with the switch turned ON.The R/W wire should also lead into a 10A fuse.
The starter button, One side is connected to ground, the other wire should be L/W (blue/white) and that goes to the start solenoid.
Get a manual and look at the wire diagram. They can be intimidating but its something you should know how to read and understand. Its hurts my eyes sometimes to read a diagram.
Looking at my manual. The RUN switch is the R/W(red/white) wires. The R/W wire goes to the Igniter unit and to the coils. It should be hot with the switch turned ON.The R/W wire should also lead into a 10A fuse.
The starter button, One side is connected to ground, the other wire should be L/W (blue/white) and that goes to the start solenoid.
bbd1983
XS400 Enthusiast
The kickstand and clutch don't seem to change anything. My start button is gone, the rest is there internally but no button. I've been either kicking or using a screwdriver on the solenoid/batt to turn it. What can you tell me about the loose wiring above? I'm trying with the diagram but it's just complicating things further. All the wiring seems intact and proper except what's torn apart up front.
Best I could do. The fuse box is easy but I dont have it outlined. To make reading wire diagrams easy, MS Paint is a good source to trace wires and also using a pen/marker and a ruler. You will need to know this stuff for yourself or you will constantly be frustrated. Take your time and figure it out, trace wires one by one. XS400.com will not be there for you at 2am when youre on the side of the road over something stupid, no one will be there for you. Get your switches fixed or figure out a way to wire in your own switches. I dislike electrical work with a passion but its vital if you want a reliable bike
bbd1983
XS400 Enthusiast
I appreciate your time and the diagram. I'm not trying to find an easy way out here, I'm trying to use the forum to build knowledge so when I am broke down I can troubleshoot better. Truth is if I had a functioning bike to start with I'd be way better at diagnosing. I have solid grounds, great wiring to frame and harness. In fact I looked at every connection and every wire and this whole bike is super intact with the exception of the headlight bucket wiring and killswitch/pushbutton. I took the right side assembly apart for multiple reasons one of which to see which wires went where. Blue/white goes to pushbutton, Blue & blue/black go to on/off lights, red/white and BROWN to killswitch. I tried matching the colors of the cut wires front handle wiring to headlight bucket connector, you can see what I'm referring to if you look back at previous pics. I have no clue what the brown should be doing, there's nothing that matches. I read another post on here about bypassing the switch by connecting the 2 red/white together? I also pulled the button out the housing that's missing the pushbutton and tried to touch it on the bars to 'electric start' and nothing. I'm just gonna start searching the forum and do some more research cuz' what I'm trying isn't working.
A volt meter is your friend. You may find brown wires that are grounds. A volt meter can verify this. Those switches get nasty and need to be cleaned. They have small parts, be careful. The switches need to be firmly mounted on the bars, the shells act as a grounding point.
I just went through this on my bike and Im pretty sure I had some brown grounds, one of them leading the the rear brake switch.
The red wire at the start button should be powered when you turn the run switch ON. The red wire goes to the solenoid. The solenoid acts as a low voltage safety switch to activate the starter, since the starter draws a lot of power. The solenoid should have 2 posts and 2 wires, the 2 wires are the +/- to make the solenoid switch the starter on.
I just went through this on my bike and Im pretty sure I had some brown grounds, one of them leading the the rear brake switch.
The red wire at the start button should be powered when you turn the run switch ON. The red wire goes to the solenoid. The solenoid acts as a low voltage safety switch to activate the starter, since the starter draws a lot of power. The solenoid should have 2 posts and 2 wires, the 2 wires are the +/- to make the solenoid switch the starter on.
bbd1983
XS400 Enthusiast
It's runniiiiiiing!!! Suuuper stoked. I took the right side handlebar switch apart again, cleaned and pulled blue/white that went to the button out of the housing, re-attached housing after making sure it could ground well. Connected blue/white where it was cut which was starter button and after reconnecting the red/white together on harness I touched the button to the bars and it turned over. Brown is just hanging as is red/yellow which is headlights. I almost wonder if all those went to a terminal plug that was cut out. Went straight to checking for spark, big fat blue spark on right cylinder, then same on left. Mounted gaskets, intake boots, carbs and h-pipe, fed a little gas and she started up, smokin like crazy but it's running! Tank was already cleaned and ready but my petcock flows hard on prime, drips steadily on reserve or on. I cleaned and routed throttle cable when I had that open so it's ready to be attached to carb. Time to do some research on those carbs, settings and check float height. Will clean air boxes well and mount, I was surprise to see filters in there and in good shape. I'll start searching but any info on that stuff would be awesome. I also need to look into fuel line routing and what to do on those intake boot ports.
Good to hear. Everything you should know is here. Check out the tech section, I recommend buying the manual. Manuals are easier to work with IMO. The best option is to keep it stock or pretty close to it. I have aftermarket mufflers on mine but the carbs and intake is all stock. Keeping it stock will help you get the bike in tune easier and will give you the best results.
bbd1983
XS400 Enthusiast
I wanna invest in a copy of the manual, such pain on the phone or laptop when I'm at the shop. I'm trying to nail down my exact carb and I think I'm right as they were off an 81' so Mikuni BS34s. Already digging into info on those and got my fuel line/inlets sorted. Main fuel line is obvious and the extra on tank goes to boot inlet with the other one capped. Still not sure why my petcock dribbles on 2 settings and flows hard on prime. I get the settings of the vacuum petcock so I'll look into that more (dribbling) maybe hooking up that vacuum line helps? I'm guessing before I've researched, the only flathead on both left sides of carbs is mixture screw that should be 3ish turns out to start and go from there. I'm super excited and appreciate the help you and the members have been! Can't wait to dig in more in the tech section.
Your carbs have two pilot mix screws located at the top front of the carbs next to the intake boots. They came from the factory with brass caps on them. If your are still there you need to remove them. There are threads on this in the forum and also on the xs650 forum. The one flat head in the middle screw is the carb sync screw. I would leave it until you sync the carbs. Also threads on this. If the petcock leaks fuel without the engine on and the vacuum line hooked up it's in need of a rebuild. I recommend replacing with a manual one. Mikesxs has them as well as ebay. They are listed for the 80-84 xs650 specials. I use them on a few on my bikes.
bbd1983
XS400 Enthusiast
Right on, I got 2 vacuum petcocks in a parts bin that could be cleaned and may have better seals in them. I do have plugs on my carbs so I'm gonna pull, do more cleaning, float height etc and address that, fuel filter, clamps, bla bla. I think I may have the boots mounted wrong also I'll have to double check.
I would go with a manual petcock. Its just easier and rebuilding old petcocks isnt a guarantee it wont leak. Rebuild kits arent cheap either. Youll want to replace the seat/needle too.
bbd1983
XS400 Enthusiast
Ya, I'm kinda getting the cart ahead of the horse with the excitement of getting it running. Time to get more detailed. Only had a about an hour today to work and my biggest prob is the right carb isn't getting fuel and the left too much. There's multiple issues probably contributing rn but more on that l8r. Don't wanna ask a bunch of ?s I'll probably have answers for with a bit more time digging in. In short I'm not a fan of the vacuum petcock setup either.
bbd1983
XS400 Enthusiast
Spent a bit more time, hooked up the throttle cable and re-did throttle assembly. Super smooth but the cable is too short like there's no idle adjustment at all. Mounted the carbs with clamps, h pipe with clamps and the air boxes. Tried spare parts on the petcock but it's still dripping a bit so I'll probably just get a new one when I have the dough. I thought maybe it'd like everything mounted alot better and maybe feed that 2nd carb but no love, gonna have to pull carbs and look again, gotta be float related cuz the 2nd cylinder wakes up fine with some gas sprayed in intake. Smokes like all hell.
bbd1983
XS400 Enthusiast
Pulled my carbs this morning to inspect float issue. Pretty obvious, the left side carb float doesn't even move as one post (don't know proper verbage) that holds the side of the float is broke off. It has an aftermarket plastic float that also doesn't seem right as there's a tang that prevents it from moving even if that one post wasn't broke off. Super bummed as I paid for them to be in good shape, PO said he rebuilt and did new float needles/seats so I don't know how he wasn't aware. I tried a spare brass float I had but it was too wide. Was thinking if I had the correct float I could maybe put a spot of jb or something similar on that one side for now. Maybe bend that tang that prevents movement? So, everything's at a halt for now. I'm guessing that's why my left carb would just get full of gas and not send fuel to the right carb? Lemme know what you guys think...
Carb is no good. Not sure if the float you have would work if the post was ok anyway. I have never seen those style on a xs400 carb. By the looks they are dirty and need to be rebuilt anyway. Was this an ebay purchase? I would want a refund if they were listed as "rebuilt". Always get pics of the insides of carbs first! I think one of the reasons one side is firing and not the other may be they are out of sync. You said you turned the center slotted screw. That is for syncing. One side butterfly is opening more than the other. A bench sync then a sync with a manometer would correct that but your carbs have larger issues.
bbd1983
XS400 Enthusiast
I bought them from a user on here. Said they were rebuilt with new needles/seats so I don't know how you wouldn't know that post was broke. He said maybe it happened in shipment or when I went to start the bike but that's not viable and if so the chunk would've been in the bowl. Float was an ebay special supposedly compatible with the carb but that tab makes it so it won't even move up/down. I didn't adjust the sync screw it was the idle adjuster that I was referring to. Seller said he'll refund me 1/2 since I got one good carb out of the deal. ?? : / Frustrating but I'm moving on from it.
bbd1983
XS400 Enthusiast
Just for the record he did make it right, didn't wanna make a member sound sketchy. I'm gonna try to get a proper brass float and JB that post for the hell of it. I know it's not the best but neither is the bike in general and its gonna be a long-term project. Motor has awesome compression though. If anything I'll learn some along the way, also need to learn how to bench sync and manometer.
I think that person should be identified. Thats a BS deal and it aint right. The seat/needle werent replaced, brass is tarnished. Theres absolutely no way that person didnt see a broken float post and virtually no way for one to break during shipping. Theyre fragile, but not that fragile. Must not an active member of the forum.. Is there any min. requirements for posting in the classifieds?
Thats no way to be introduced to the forum or to the mechanics of a motorcycle. Obviously that person doesnt represent the forum or 98% of motorcyclists. Mistakes are mistakes I get that, but come on dude....seriously?
Moving on, I just purchased a set of carbs that I will rebuild and test and make sure they work. Forget about the carbs for now, work on other things. I will hold the carbs for you when theyre done in case youd like to buy them. Buy them, dont buy them, either way they will eventually be sold or used on my stuff.
PM me if you want to work something out. Im not looking to make a profit, I dont need to profit off of this.
Thats no way to be introduced to the forum or to the mechanics of a motorcycle. Obviously that person doesnt represent the forum or 98% of motorcyclists. Mistakes are mistakes I get that, but come on dude....seriously?
Moving on, I just purchased a set of carbs that I will rebuild and test and make sure they work. Forget about the carbs for now, work on other things. I will hold the carbs for you when theyre done in case youd like to buy them. Buy them, dont buy them, either way they will eventually be sold or used on my stuff.
PM me if you want to work something out. Im not looking to make a profit, I dont need to profit off of this.
bbd1983
XS400 Enthusiast
HUGE shout-out to NewHavenMike for helping me out with a set of solid BS34s. Thanks to him the XS is purring. Only took me 3 sets to get there but it's now a headlight and tailight away from being in the road. Came to me seized with the wiring torn apart, no carbs etc etc so I'm super stoked. Just want to throw an update on here of the progress. Another one back to life!
