how to install new wires and caps?

Tombo

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I have a 1980 xs400 special ii. :bike:Got a lot of the issues hammered out at this point (hopefully!), but I want to replace the caps and wires. I have the new caps and wires on hand from mikesxs, and I want to insttall them tomorrow morning before work.

:confused:Anything special I need to know? I've heard that original wires are glued to the coils, is that true for this bike? I need to strip the cap end of the plug before I screw it in? What's the best way to do that?

As soon as this thing is fully reliable, I can move on to the aesthetic/ weight saving mods, which will be MUCH more fun for everyone?:thumbsup:
 
If you have an 80 then the wires should just unscrew from the coils, its very easy to do.
 
@xschris - awesome dude, that's all I needed to know! :D

PS, chris, unrelated, but do you happen to have a stock tach for my bike you'd sell? :wink2: Mine works, but the PO must have tried to "de-gunk" it while she was trying to get it to run, as there is a chemical burn on the face of the thing.:doh: I am also getting a decent amount of oil seepage from where the cable connects to the head, not sure if theres much I can do about that - but on my XJ, I replaced a rubber donut that wrapped the tach drive gear itself.
 
Unscrew and pull the cap at same time. To ensure best connection you can trim 1/8 inch of the insulating off before screwing/pushing on the new caps. Then check resistance to make sure at spec.
cap end of new spark plug gets unscrewed or cap wont fit over plug - like you probably already have done on the spark plug

Tach cable oil seal should be replaced. On ebay for $8, part 93102-06254

http://www.ebay.com/itm/NOS-YAMAHA-XS400-XS-400-TACHOMETER-GEAR-OIL-SEAL-/200452100945?hash=item2eabe05351&item=200452100945&pt=Motorcycles_Parts_Accessories&vxp=mtr
 
I got the wires and caps installed - and it solved an "arrhythmia" issue I was having. I used to hear what sounded like a misfire during idling and especially warm up - that when cold, and throttle left unattended, the bike would die like 1 in 10 times. With new plugs and wires, not only is the arrhythmia gone from the idling sound, but it seemed to start much easier than before (first kick on half choke with no throttle added). Looking through my colortune plug before and after the plug wires and caps is like night and day - MUCH more excited spark going on here!

There are lots of people here running on one cylinder - I was one of them too when I first bought the bike - even after rebuilding carbs, new exhaust gaskets, inline fuel filter, mix adjustment via colortune, and lots of tuning, adjusting, and miles on the motor - I still had the arrhythmia going on (which was ridable but annoying). I would recommend ANYONE who is running on one cylinder - try caps and wires FIRST (and new plugs if you haven't already)- it's a cheap and easy fix, and it will pull a variable out of the equation. Though I think it was certainly necessary to take all the other steps - in hindsight, I believe this should have been my FIRST step, not my last.

I am using kick start only because my daily commute is only about a 10 to 15 minute drive through the city - and even with my recently rewired alternator, I don't think my ride is long enough or consistently high rev enough to recharge what my starter takes. When I go on a pleasure cruise, or doing a longer ride, I spoil myself with the electric start! But for commuting, the much more excited spark seems to kick over a bit easier.

For those of you who also wonder about your plug wires, here are some search words:

replacement sparkplug spark plug wire wires new install cap caps coil coils mis fire misfire weak spark 1980 80 special xs400g xs400sg one cylinder
 
@xschris - awesome dude, that's all I needed to know! :D

PS, chris, unrelated, but do you happen to have a stock tach for my bike you'd sell? :wink2: Mine works, but the PO must have tried to "de-gunk" it while she was trying to get it to run, as there is a chemical burn on the face of the thing.:doh: I am also getting a decent amount of oil seepage from where the cable connects to the head, not sure if theres much I can do about that - but on my XJ, I replaced a rubber donut that wrapped the tach drive gear itself.

I do have a tach it works fine. I opened it up last year when I got the bike to fix the face screws inside so that has been done and should never fall out again:wink2: $25 shipped paypal only.
 

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I just ordered some new plugs, caps, and wires from Mikesxs:thumbsup: and I noticed you mentioned specifically the 80 year was easy to replace.

How about the 79s? Anything different worth mentioning?
 
Not positive on the 79 as far as whether we use the same coil - but if we do, then the wires just unscrew from the coil, then pull out. The caps come out easy - they "screw in" to the wires. You will want to strip and expose about 1/4 inch of the wire on each side, fold them over on both ends. Then just push the wire into the coil and tighten the little "nut" to secure it. Then screw on your caps, plug it in, then fire it. Up
 
The 77-79 bikes used one of these. They have the wire fixed into them. You could cut the bad parts off and use a wire splicer. You can get a 4ohm coil for cheap from mikes or ebay:)
 

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If you have an 80 then the wires should just unscrew from the coils, its very easy to do.

Hey @xschris I just picked up a 84 XS400 DOHC... it seems like it's running on one cylinder.. (I'm no expert but a buddy that knows more than me said so) I read through this threads an others and I think I will replace the existing NGK spark plug cables.... I can see that the cables are twist off but I could only manage to squeeze two fingers in the opening let alone grip the cable and twist it off... When you say easy.. is there a easy way to twist the spark plug cable off of the coil?? Without taking these huge plates holding the engine off.

Adding picture for clarity.
 

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Hey @xschris I just picked up a 84 XS400 DOHC... it seems like it's running on one cylinder.. (I'm no expert but a buddy that knows more than me said so) I read through this threads an others and I think I will replace the existing NGK spark plug cables.... I can see that the cables are twist off but I could only manage to squeeze two fingers in the opening let alone grip the cable and twist it off... When you say easy.. is there a easy way to twist the spark plug cable off of the coil?? Without taking these huge plates holding the engine off.

Adding picture for clarity.

You can take one plate off and then just pull the entire coil out. It makes it easier as I cant get my fingers up in there on my DOHC bike. remeber people with little hands built these bikes........
 
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