The Journey of a wrench and his first motorcycle

Your right, I'll toss stock back in there. I may have induced symptoms messing with the jets. I have been doing manometer syncs but I'm starting to wonder about the accuracy of my homemade one.
Bike is on hold till replacement points and condensor arrive. Might trim .5in off spark plug wires in the meantime and re gap and time to practice my technique.
New points and new to me condenser is en route. Condenser is an ebay find from another 1978 xs400 that supposedly had 14k miles on it. I had to go this route after mikesxs sold its last one before i could fallow through with it. I'm doing this because i have noticed blue sparking on my left cylinder point, none on the right point but with mild pitting on both and sparking on the left i feel that im hot on the trail on this hesitation issue at 39 mph. Vehicle will remain covered in my yard where its been for the last month untill parts arrive.
Condenser is installed! Couldn't resist when i got home and found some packages with my name on them. After getting to know this machine for the last almost year now it yet again throws a curve ball. The condenser i took off did not look exactly like the one i put on. I've realized that i most likely have a completely custom wire harness... damn. "old" condenser had 2 male electrical connectors that plugged into 2 female ends which immediately plugged into 4 wires. "new" condenser had a plastic "molex" connector. Had to cannibalize the connectors off the old unit. Units do not look identical. "old" unit was taken off what appears to be the wrong side of the mount on the frame. "new" unit had small bent tab that only allowed me to install it one direction, on the opposite side of where the previous was. Bike ROAR's to life first kick and idles and sounds stronger then it had since what i suspect was a steady decent on the condition of my condenser.. Had removed the points cover and observed 0 sparking on right and a very small amount on the left. My left point is undoubtedly in much worse condition both in pitting and scarring. I had full choke on yesterday and for the past few months full choke was too much, i had to use a combination of none and half to get the bike started. With the new condenser the bike was acting like normal choke operation was normal. Which leads me to think that im hot on the trail of ironing out base operation expectations. fingers crossed my points are there when i get home.

I should mention, I have yet to come across even 1 fuse.
Points were not happily waiting my arrival yesterday but i couldn't keep away from the bike. Removed both original points and filed them flat again *within reason* gapped and timed and finally, finally after months of what im pretty sure has always been a failing condenser, the bike runs amazingly well. put on 60 light miles and the plugs have never looked this good with the starting 3 - 3.5 turns out on the fuel mixture screw. one was slightly rich and the other slightly lean but both had evidence of that mythical coffee tan we dream about. Full usage of all rpms under about 7. I didn't wanna go to wild with it. Zero hesitation, zero back fire and a strong consistent sound. O yea, the new points should be there tonight, I get to do it all over again!
Found a good quality H-pipe on ebay. The benefits observed immediately after install seem to make this piece absolutely necessary which if asked, the designers would say "yes, it is absolutely necessary". Full disclosure, my new points have not arrived, I have ordered another set but i have been keeping a close eye on my current set since some research has lead me to conclude that any serious pitting is grounds for absolute replacement. I just took some time with mine and cleaned them really well, I just don't think i have very many more dressings left and i'm not interested in putting more time into what others would not bother with.
Last edited:
Petcock gasket has been installed and zero leaking has been observed. This doesn't mean it didn't seem to affect the bike unexpectedly. Vacuum and petcocks and all the hoses and tubes running around that have to do with this thing unfortunately connect a lot of different parts of the bike and now it seems i might be re tuning due to this. I had raised the needle cir-clip up by one and without the carburetor H-pipe and fixed petcock the bike was running well. Not sure entirely sure why i decided to raise the needle but ride quality was perceived as improved. With the H-pipe the bike had continued to run well but as soon as i created a functioning petcock, things changed. The rubber seal on my gas tank is pretty well toasted and i tossed a little grease on it to help eek it along till the replacement arrives, but in doing so last night after a 25ish mile ride the bike started bogging super hard, sound deepend and i observed mild surging, presumably due to a functioning vacuum. limped it to where i had to be and tried not to lose sleep over it. Did some research and i had concluded that my deplorable points had caused my timing to degrade once warm. They have yet to be replaced after my original order was lost in transit, but to really cover my a$$ i picked up new points and a fresh shiny condenser, they are in transit.

After spending the morning working on it I think its more likely that the functioning petcock and enriched needle had caused the bike to create a bogging condition more related to over enrichment. Plugs looked great this morning so more head scratching, if anything they are slightly rich looking but they both had slight coffee tan-ness but looking at the plug color charts, you know the ones with like 30 plugs in different conditions they seem to be closer to cold and rich as opposed to hot and lean but they are both within the green "good" areas. Removed .5 inch from spark plug lines and tided up any wires just in case something had gotten loose, also reconnected all the h-pipe and carb fittings in case of leaking and reset the fuel limit screws to 3 turns out from lightly seated. Having not done so since changing my air flow may have attributed to last nights problem. Anywhos got it driving again this morn and it is feeling a ton better, the stock needle position seems to be closer to where it needs to be for that post 1/4 throttle sound and feel. Tonight i get to hook up the manometer again and check plug color.
Last edited:
So the brand new shiny points and condenser have been installed. 2 nights ago i got all the parts on and tried to putt it around the neighborhood. The bike was performing terribly, shuddering on pick up and slight popping on acceleration. Barely put a mile on it and limped it home to shed tears in solitude. Left it alone on on the trickle charger for the span of my day job shift and decided to double check timing and gap, re gaped to loose 0.012 snug 0.013 if memory serves and double checked all spots it appeared to be most open. I've been developing quite the feeler gauge technique. Re timed it, noticed and corrected my left cylinder and tided up the separation to coincide with the etching on the plate to obscenely accurate levels. Kick over and the bike is still sucking. So i'm thinking WTF during this period of time i notice my right cylinder is getting leaner and leaner.

Figure what the heck its only 830 pm lets do a carb rebuild, why not. I was about to shelter the bike till the weekend anyways and while blipping the throttle i had noticed a funny noise coincidentally from the right cylinder. Wet slurpy sound on throttle blip from idle, im thinking diaphragm is unhooked or out of its groove but what the heck i'll start from the bottom. Remove right carb bowl and all looks okay, flip it over and huh! my float wasn't moving, poke it and its really hard to move almost stuck feeling, I'm thinking its the rod that spans from the float valve goal posts and i notice the entire float seat is un threaded! YAY! a noticeable problem and i get to apply a fix! these are the best problems, i was expecting to find nothing.

So while driving it the past week my float valve seat was slowly coming undone creating most likely a ton of slurpy airy turbulence on almost all usable circuits on my right carb. Tidy up the right, check the other side, all good and button it up. Right cylinder is immediately a light brown and far from the sorry lean state i had put less then a mile on. Bike is running sooooo smooth, I think i've reached the end of what i can do beyond icing the cake on this one. Finally i get to leave my points cover on till about 2000 miles or whenever the manual suggests. Now i get to enact phase 2 after of course an immediate oil change this weekend. I've been running marvel mystery oil in the gas tank and i put a shot of it in the crankcase, the bottle says its fine for all gasoline and diesel, but it does not specifically say its cool to put in diesel oil, or the rotella that im running with. After that phase 2 begins. 50 bucks or less on 1 part per month starting with a high quality throttle. All the while i'll be building a new wire harness fallowing schematics that should improve the life of my electronics. You know how i said i haven't found a fuse? well still none and hear me out on this.

Is this whats happening. Can the bike really have no fuses? None, nada, no inline no fuse box. How? Is my under powered tiny battery that i can run dead in less then 30 mins of just the head light being on the secret? Hook up a system, get it to stay on as long as its not a dead battery but induce the system in a constant undercharged state, is my battery the fuse? Are all my electronics being tested to the extreme and somewhat okay unless the battery becomes fully charged while riding? Will my points detonate again as the bike continues to make slightly more charge then it uses since i happen to catch all green lights and i've been driving manual transmissions since turning 18. I bet were all the best drivers we know :laugh:. Is this why theres fuses? to keep a fully charged system from ruining your electronics? Thats kinda a silly question cause duh, thats exactly what they do, i think.

PS. My points came with grease, I greased everything but the actual point surfaces, surely no grease would go there right? I have some more grease at home awaiting application if this is the case. I just put it on the lobe wick and the nut washer assembly much like the grease you would put on car battery terminals.
So i'll be doing a total rewire, there are no fuses in the current setup and no thanks that's not right. Super duper excited and if i can fit it into the budget i'll freshen/consolidate some of the older electronics. Found some schematics on here and will be obtaining the wire and space to do it well and right. fingers crossed.
When you have no fuses, id think a circuit overload would go to the path of least reaistance. In our case, it would be a very thin wire melting/burning, or a light bulb burning out. Which could cause a fire. You can find used wire harnesses on ebay and probably here too. Id go that route probably.

Ive thought about making a mil-spec harness to make things super clean or also making one out of the classic braided wire. Now that my bike has been running for a couple months i may do this. I need to make a new seat and i want to relocate electronics over the winter.

Ii also picked recently picked up a 1980 CB650 and i still have my 1981 VW Jetta that have been put on the backburner.. the CB can wait. Im still focused on my XS and ill be able to stock up on VW parts till spring time
So i'll be doing a total rewire, there are no fuses in the current setup and no thanks that's not right. Super duper excited and if i can fit it into the budget i'll freshen/consolidate some of the older electronics. Found some schematics on here and will be obtaining the wire and space to do it well and right. fingers crossed.

Not sure how much you want to spend but motogadget makes some sweet stuff ;) I used a version 2 and re wired one and it works great. No fuses its all enclosed in a little plastic box the size of an I phone.
It never ends does it?
Been awhile and thought i would check in.
Since my last update I had a scenerio where i rode the bike all day parked it, pulled plugs looked at the color and buttoned it all up. Had to be at work and could not get the bike to start. I was done!
Done i say, i drained the bike rolled it into the yard and there it sat for a couple months. I was out and i thought it was finally over. Attributed it to the lack of fuses and rode my pedal bike like the good ol' days, soooo much quieter! But i wrench for a living, maybe not motorcycles but my mind is always in fixit mode. So i returned, made a list of trues and false's and systematically checked every length of wire. This was true, this is true and kick, bike runs on one cylinder only the left. Route everything correctly to use the opposite coil, kick and the bike runs again on the left. Never the right. Tried every combination and none of it made sense, multi meter put everything at spec and the list said all the communication between point, condenser, coil and plug was good. WTF! Decide its my timing. Left cylinder, good. Right cylinder nothing... the point was grounding against the head of one of the bolts i had replaced on the point contact breaker. tweak the ribbon spring ever so slightly to the left and voila! the point was finally entering dwell state again and getting a charge ready! 6 hours of testing and 30 seconds of moving a metal piece away from another metal piece and the bike kicks over for the 1st time in 2 months. I'm back in! Fresh plugs and oil and im riding around. New throttle and clutch cable and a deep clean of all external parts and its looking good. Im driving! then i notice a crack at the h pipe connection of the NOS mufflers i had ebayed. Closer inspection puts these mufflers in "i get the idea but you did it wrong" bin. Looking at lots of pictures and i notice my mufflers had a bunch of holes drilled in them at the end i suppose to promote airflow? idk. So i ebayed some good looking header and slipped the slip ons from the previous owner back on. Up-sized mains to what i had received the bike with - 147.5's since from what i could tell at some points someone jetted the bike right and leave in the stock pilots from the last attempt at tuning before it pooped, mostly because yes i have uni pods but i also procured a carburtor h pipe which i suspect is greatly reducing the tendency towards less the half throttle lean-ness. Bike pulls harder then i ever remember, ripped uphill at +7k to redline after a good long mild mannered 50 mile warm up. Feels good. so i leave it. Lower needle 1 groove to help keep things cool with fuel and midrange roars to life but my low end richness is pretty..well.. rich. Downsize pilots to 40 and raise fuel floats about 2 mm, a little less, im thinking closer to 1.7mm to promote readily accepting full throttle from all positions after observing a slight bog. Coffee brown mildly rich plug on the right, slightly lean on the left. Run idle mixture screw out to 4.5 on the left and getting ready to test again. Upsizing left pilot back to 42.5 this weekend which will put me at.

Left Carb
Pilot - 40 soon to be 42.5 to what i suspect will bring me back down to the 3.5ish sweet spot on mixture screw
Float measured from gasket - 27mm ish
Needle groove - Up one from middle. Counted from the bottom? Position 2
Main - 147.5
Turns out from lightly seated - 4.5

Right carb
Pilot - 40
Float measured from gasket - 27mm ish
Needle groove - 2
Main 147.5
Fuel regulation screw - 3.35 ish

Ordered stock replacement contact breaker screw and i don't get the grounding at the point, but i did notice at some point something has been damaged or my points cover gasket has been flattened farther then intended. If i don't push down towards the ground when putting the cover back on i'll ground the point against the points cover from the inside. Removed some material but maybe not enough as i have to continue to do it this way to have a reliable machine.

It never ends does it?
Bought all the goodys to redo the harness and have been replacing redundant sections and cleaning it all up overall. Inline fuse holders will be installed very soon, but unfortunately i don't want to get stranded trying to make the harness right. Oddly enough the bike has been driving the streets for many years without a single fuse, it seems to be reliably fuse less. I did notice a monster of a ground cable and maybe that bad boy is becoming rather hot but not enough to melt it, its easily 6-9 14 gauge wire's bundled together in wire width.

Im one of those straightish pipe hipsters now though "sad face" but i don't get to down on it. My bike is tuned and it sounds like it, they might all look and mutter stuff under there breath as i come up, but as i pass...i let the bike decelerate hard and it sounds soooooooo goooooood.

Back to wearing ear plugs though, bike is uncomfortably loud for long rides.
Last edited:
Could use some sage advice. Tested the bike again last night and nothing really jumped out untill about 17 miles in, what i consider is about the time the bike got warm. Was running around the hilly side off town to listen to deceleration and sustained acceleration. Deceleration sounds great maybe the slightest puh puh sounds but by no means any back fire. But i think im confused, i thought leaning the floats would help but i think i induced a dry flat spot 3-4k and once the bike is fully warm if i play my cards wrong i can stall the bike coming off of a red light. Looking at plug color when i get home and still going to upsize the left carb pilot but on throttle blip i suppose it hangs as opposed to dips in rpms. The hang is very very small if not just normal operation. When i say pods, carb hpipe and free flowing exhaust at 2.2k elevation what do yall think? Should i suspect more towards stall from lean or stall from too much fuel? Will update on overall plug color when i get home.
I religiously sync a warm engine after each change. I might remake my manometer and find mines wildly inaccurate after a bit of use.
Both cylinders are lean, upping pilots to 42.5. I dont have 45s but i do have 47.5s if needed. Carb sync tomorrow after a "spirited" 10-15 min ride in this +70F weather.
Blah still lean after 30 miles and im around 4 turns on both. Ive hit the rich part of the fuel screw but i think one size up on both is called for. I might install the 47.5s and use a lower fuel screw out position for the time being. Utilizing lower fuel screws out is totally cool right? I suspect ill have to run them in to 1-2.5 turns out after install.
The way you word your posts is overwhelming me... I cant explain why.

You must have an air leak somewhere. Get factory air filters. A 147.5 main seems wayyyy too big and I think you might be compensating another problem by thinking you need more fuel. I opened up my exhaust and I need to go down a jet size before it ran nicely. Going up isnt an absolute..

You shouldnt be altering multiple settings when you are tuning, especially if you dont know what youre doing and youre rushing and getting frustrated too easily.

When tuning, get the bike in top mechanical shape and make sure you have no air leaks, they can be tricky. Youre still working with points ignition and that makes things harder for you since points are terrible when they arent perfect. You start with the main jets and work your way down.

I tuned the main jets by looking at the plugs and just riding around for up to a month on a jet size before changing. The plugs gave me little answers as I really only saw results on the really rich, and really lean side. They did give me small clues though.

With the fuel mix screws, the bike should stall when you screw one in all the way. If it doesnt, your pilot jet is too big.

Also, getting the timing right is VERY important. it HAS to be PERFECT.
Going to hunt for an air leak. My manual puts 142.5 main and 42.5 pilots at stock. Im just trying to be as descriptive as possible and im really only fallowing the factory pro high rpm guide basically to the letter. Using feel as the majority of my post 4k rpm decision making and using plug color as my low end identifier. Elevation is the difference between our mains.
Last edited: