My '76 XS360C Restoration

Moving on to the front forks. I get a lot of sag when I sit on the bike. The spec on the springs is 19.1". Mine measure 18.875". None of my manuals state a service limit for the springs.

I read a few articles about the Minton Mods recommended for XS650s, including the original from Motorcyclist magazine in 1981 and decided to do some of the fork mods.

Minton suggests drilling two more 1/4" holes in the dampers for a total of 4. My dampers already had 4 holes in them so I drilled them out to 1/4". They were just under 1/4" to begin with.


Then I cleaned up the holes with a file.


Minton says to drill the top hole all the way through to the other side for a total of 2 holes. My dampers already had 2 holes, albeit side by side, so I opened them up a bit and then polished the dampers by wet sanding with 400 grit paper. To finish I blew them out with the compressor to get all the gunk out.


He suggests changing the seals as well but the dimensions of the ones he lists may be too big for my 33mm forks so I ordered stock seals from Yamaha. They need to come from Japan but are still available.

I will fill the forks to 6" below the top (when compressed) and stick with the stock 20W fork oil for now.

The last outstanding issue is the springs themselves. Although I realize new Progressive Suspension #11-1109 are the best solution for my weight, I want to try a spacer before ordering new springs.

I have some Honda dampers lying around and thought of using the damper springs as spacers. They measure 22mm wide (the Yamaha fork springs are 23mm) and .77" long.


My fork springs are ~.2" short. The suggested Progressive springs are .65" longer than mine are supposed to be at 19.1". So maybe a spring spacer of this length would be OK. Unless someone here says why I shouldn't try it, I think I will. I can just barely squeeze them under the fork caps and still get the caps on.

I have to wait another week or so for the seals and then I can get them back together. In the meantime I'm open to suggestions.
I installed the Z-8 needle jets and new o-rings today. They fit like a glove. It will still be a couple months until I see how they work- the wife hates it when I start the bike up in the house.

I also installed the butterfly shaft seals. My Yamaha Parts List doesn't even show any seals for my carbs so I went with the ones XSChris mentioned using in a thread somewhere.


They're listed as being for the XS650 BS38 carbs, amongst many others, I found. I ordered a set from but then I found they had them in stock at the Yamaha dealer so I picked up some official ones, too. I kept the cheap ones as spares.

They appeared to be the exact same as the ones I removed from my BS34 carbs.

That's the carbs all buttoned up and complete now. I think I'll move on to changing the front brake hose. I got it cut too short by mistake last year and it barely fits. Maybe I'll change the brake pads while I'm at it.
I got the master cyclinder and caliper removed and drained so I can reposition the brake hose. I think I'll trim the MC like jthiessen did so I can point the banjo down where it is supposed to go instead of routing it horizontally like I had it.

Also got both front forks re-assembled with new damper seals, fresh 20W oil 6" below the top and the spring spacer as described in a previous post. I ordered the seals from the Yamaha dealer. They have changed from the original type I had, on the left, to these on the right.


The top diameter of the fork boots are a bit big for my fork tubes so I wrapped the tubes with strips of inner tube below the lower triple and then zip-tied the tops of the boots for a good seal. I punched a small hole in the back of each boot so they can breath.
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My brake line would have been fine for my flat bars the way I had it, coming across from the left and straight in to the MC but I had the brake line cut too short for it to have any slack. Rather than order a new brake line I decided to make this one work and look a little cleaner in the process.

I took a tab off my Master Cylinder so I could re-route the brake line to come up to the MC from the bottom. Being aluminum it cut real easy with a hack saw. I had a bolt in the hole to keep cuttings from getting inside the MC.


I smoothed it off with a file then dabbed on some primer and flat black paint. I know it's not perfect but it will do.


I'm waiting for an adapter for the brake line so I can put it all back together.
When I drained my oil a while ago I found that I'd either a) left my petcock on Prime sometime or b) my petcock was leaking. Either way gas overflowed the float bowls into the cylinders. I'd originally put around 2.6L of oil in the engine but I drained out nearly 4L and it smelled real strongly of gas.

So today I drained the last of the oil I could by removing the oil filter screen. Got another bit of gassy oil from there. I then made a new gasket for the cover. It's back on now and ready for oil.

Got my carbs back on.


Finally took the bike off the axle stands so it's back on 2 wheels and nearly ready to go.



This evening I went and saw a painter who gave me a Yamaha fairing to bring home and try. Too bad it's not suitable for my flat bars.
When the gas leaked out of my carbs and into the cylinders it also sat in the H-pipes for a while. Apparently my ingenious Liquid Electrical Tape mod doesn't stand up to gas too well. I didn't really expect it to be a long term fix but it worked for the whole season last year and may well have lasted longer if it hadn't been for the overflowed gas.

This is how it looks now:

I picked up two NOS carb breather tubes on eBay. Both were less costly than when I was looking last year and they're so nice I have to show them to you.



Anyway, I got them on the bike and they are pretty there too.

Great progress! looking good, I have some front brake work to do this spring as well.

Chris will those butterfly seals work on a 78E?
my parts list shows 2A2-14997-00-00 not 256-14997-00-00

just curious since the 256 ones are half as costly on ebay.
Great progress! looking good, I have some front brake work to do this spring as well.

Chris will those butterfly seals work on a 78E?
my parts list shows 2A2-14997-00-00 not 256-14997-00-00

just curious since the 256 ones are half as costly on ebay.

Thanks Sesty

The butterfly seals I got from XS650direct (mikesxs in Canada) cost less than the Yamaha brand ones but are made in Taiwan.

The same seals have been used in many other Yamahas, so much so that my local Yamaha dealer had a bunch of them in stock which is unheard of for anything I've been after. He didn't have them listed for our bikes but I took them anyway. They cost more but I don't remember how much more. I chose to use the branded ones and keep the Taiwanese ones as spares. There may be no difference in the seals but the extra cost is minimal in the big picture.
As I've mentioned earlier, I had gas leak into my crankcase at some point before I brought the bike into the basment in the winter. I figure that I'd either left the petcock on Prime when I tried to start it for a friend in the late fall or my petcock had leaked. Either way, I tore it down.

The rubber gaskets and o-ring were dried out and gritty


The diaphram looked a little worse for wear after only one season and about 1000 miles


There was a grenish residue inside all the ports...

16734842847_9e353c87fc_z.jpg I washed it all up with carb cleaner


I used this rebuild kit from Parts 'n More


Then put it all back together along with 2 filters on the inside and the vaccum tube


I also have a filter in the gas line. It looks clean but given the grit inside the petcock I'll change it too.

Now I think I only need to add fluid and bleed the front brake then I'll be ready to get it outside again.
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So I just finished reading through your thread and man, have you done a lot of work! But it has paid off and your bike looks really good.

What model is yours... C?

Hopefully today I get my XS360. It looks identical to yours but not as clean.
Thanks, man. Appreciate the comment.

Really though, I was lucky to get a bike that was in awesome shape to begin with- just dusty. I've documented every little thing, too, so that makes it seem like a lot, but I want a permanent record.

Correct- XS360C 1976

Good luck with your bike today.
The weather is looking like it will cooperate for a while now so I got my 2 nephews over yesterday and we dragged the bike out of the basement. I'll finish up the last few things and get the bike on the road.

It was so nice working outside yesterday. The temp. got up to around 12ºC.

The front discs were just doing their job. I knew they were all dried out and shiny so I replaced them. I used these ones from Parts 'n More


Here they are installed


I had this much Rotella T leftover from last year. I will need a new jug anyway so I'll add more if I need it, which I probably will because I installed a new filter too.


My last oil change (my first on this bike actually) was at 6467 miles and last year at this time. Almost exactly 1000 miles ago. At this rate the bike should last me forever.


Although the bike was running 5 months ago, I wanted to make sure the valves were well lubed when I started it up. I checked and it looked like there was still some oil up around the valves


I added a few cc's of engine oil to the top of each valve stem anyway.


It's a good thing I took that photo because I hadn't noticed the cracks in the vacuum tube plug- circled in red. I'll have to check if that is causing an air leak or not. The very top looks OK. We'll see.

Last thing I started yesterday was adding brake fluid but I ran out of time. I'll finsih that up today. I'm getting excited. I like having a bike ready to ride on April 1st. That is the start of a good year.
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Right on schedule, I fired up the bike on April 1. I expected it to run properly right from the get go just as it had last year but no such luck.

It started alright but as soon as it started the revs quickly crept up to 6000 RPM and stayed there. The first time it started revving I shut it down right away. I looked at the throttle cable and made sure it wasn't under tension or caught up on a ferrule or something. It seemed nice and free moving so I tried again and the same thing happened.

I noticed the revs didn't keep getting higher so I waited this time to see where they settled out and they were steady at 6000, then I shut 'er down.

I ran out of time that day. Then the weather turned cold again so I haven't worked on it for a couple days.

Any ideas on why it revs like that upon starting?

I will try re-routing the throttle cable and I'll check inside the handle bar throttle housing to see if the cable is hooked onto the grip properly. Also, I wonder if I didn't set something in the carbs back to where they should be when I re-assembled them after cleaning. I doubt I could be so lucky that the idle screw is just turned too high. Hmmmm.
I would start with the idle screw then make sure they are synced with a manometer.
I found the source of my revving problem, I think: a plastic sleeve inside the throttle handlebar control had become dislodged and was scrunched up around the throttle cable, not allowing the throttle to close fully.

I also re-routed the throttle cable so it snaps closed when I release the throttle.

I didn't get a chance to try starting it because I had the tank off but will try again in a day or two when it warms up again.
When I went out to the bike a couple days ago there was a puddle under it. Bad news. It was sitting on the patio and the puddled liquid felt sticky so I thought it was oil. It turns out it was gas leaking from the freshly re-built petcock. It had run down the engine and down the centre stand and dissolved the finish on the patio. That's why it felt sticky. I checked and luckily it hadn't overflowed the carbs and gotten into the crankcase again. That may have been what happened last time.

I was going to a buddies shop yesterday anyway so I took the tank and we dissasembled the petcock. We determined the only place it could have been leaking was the o-ring on the diaphragm shaft. It must not have been sealing properly.

Below is a new, larger o-ring on the shaft, an example of one of the new ones in the centre and the original o-ring from the rebuild kit I used. The new, slightly larger o-ring did the trick and stopped the leak.


I used an F-02 o-ring from a metric o-ring kit with an ID of 4.4mm and an Section of 2mm.



When I went out today there had been no gas leaked. I had a few minutes and I started the bike up and took it for a quick spin up and down the block. It idles fine with no choke when cold but has trouble idling when it warms up a bit. I'll have to balance the carbs and set the idle properly.