Ryan's XS360 Build

Hello everyone!

My name is Ryan Meyer and I am a Canadian who has moved to the Netherlands last year for school. Along with a couple major lifestyle changes, such as mountains at my backdoor being subtracted for the flattest country EVER, I as well do not speak Dutch. I am still learning the language basics, so this makes the process of finding parts (as well as daily life) pretty difficult over here, so I hope I can get a bit of help from you guys. Maybe this is a good time to mention that I am not building a true cafe racer, either. My intentions are to create more of a hybrid (brat style mixed with tracker and lots of cafe influence), so I apologize if that is offensive to anyone. I do however possess great taste , which means you can save your knickers from getting in a knot.

I have wanted to build a motorbike for ages, but due to many circumstances in life I have yet to get around to this. I was obsessed with dirt bikes and motorcycles in general when I was under 10-years-old, and the itch has not gone away.

I have purchasing a 1977 XS360 (basically the same bike as XS250 and XS400) last month for €200 and finally borrowed a friends van to move it back to my apartment last week. I convinced a few peers of mine to let me use their shed as a work shop (it's perfect IMO) so I then pushed it over there, purchased the minimal tools that I could afford and started attempting to figure out why it wasn't running.

This is the bike before I loaded it up to take home. (History: Bought it off a gentleman in his late 60s who raced motorbikes his whole life and wanted to fix this one up. He never got around to it so it stayed in his shop the exact same as how he bought it in 2002, for €200 as well. He said that it was running before but it just wouldn't run when I came around.)


I took off the seat first thing and found this…  






(this one shows the wiring going to the battery)


As far as I could make out, this was some kind of switch or security for a second battery shut off. I really have NO clue, this is just a guess. Random and useless… I took it out.


So the bike wasn't running and it still isn't running! 
- I had a charged battery(new from previous owner) so I could test with the electric start
- The bike would crank but wouldn't fire
- Gas in tank and petcock set to run
- All electrical works perfectly
- I took out the spark plugs and they were dry
- I tested to see if I had spark and I had spark on both cylinders
- I then took the carbs off to open up and check out
- I cleaned and rebuilt both carbs (were not that dirty)



I put the tank and carbs back on and tried to start it up every way I knew.




To conclude:

The carbs get fuel, but the fuel doesn't get to the cylinders because the spark plugs are still dry and firing. I'm assuming a problem with the carbs, however I have just rebuilt the carbs and everything is in order and clean as far as I can tell. The battery is discharged to the point that it doesn't have enough power to crank but still can run the electrical, so I'm using kick start until I can find someone to lend me a trickle charger.

ANY help would be really appreciated to get this biking firing!

Thanks in advance for the warm welcome!

Hi Ryan and welcome, that's a very straight bike for that kind of money.

TBH diagnosis from afar is never easy, but have you tried any Yamaha forums? http://yamahaclub.com/ It might be a quirk of that particular model and they are the boys who would know.

Other thoughts, you have stripped and rebuilt the carbs but are they actually getting fuel? Try pulling the petrol feed off and see if there's a decent flow (don't do this without lots of rags or a container under it)

Also did you actually drain the old fuel and put fresh fuel in, or did you add to what was already there?

Good luck with the getting it running and keep posting on the build.

pauliexjr wrote:

Hi Ryan and welcome, that's a very straight bike for that kind of money.

TBH diagnosis from afar is never easy, but have you tried any Yamaha forums?  It might be a quirk of that particular model and they are the boys who would know.

Other thoughts, you have stripped and rebuilt the carbs but are they actually getting fuel? Try pulling the petrol feed off and see if there's a decent flow (don't do this without lots of rags or a container under it)

Also did you actually drain the old fuel and put fresh fuel in, or did you add to what was already there?

Good luck with the getting it running and keep posting on the build.

Hey Pauliexjr thanks for the direction. I am on a forum called xs400.com and have posted it up there and still don't have much luck. Just working through the issues right now when I have time.

(I'm going to make a post right after this to explain where I'm at with the diagnosis)

Maybe you could help me out with some aftermarket parts shops? All the stuff I can find is in America, so I need something a lot closer. The usual stuff: Clip on bars, levers, pegs, switches, tail lights and small blinkers, etc. Do you guys have a certain shop that is on the top of your list?

I tried a few different things when I finally got the time to go work on the bike tonight. I took the carbs off to rebuild them again and make sure that I haven't overseen something (photos below). When I did this, I as well put some gas into a spray bottle and sprayed it into the open cylinder ports and simultaneously cranked the bike over with the electric start. I had no reaction from this at all which was odd because usually I would assume to have a little ignition. I took the spark plugs out and they were still bone dry. This makes me think that they are really too short and I am somehow not able to get gas to them.

Here are the photos like I promised:



The bowls were full of fuel, so there is for sure fuel join to the carbs





















Main Jet





















And that's it for the carburetor disassembly (except for the choke valve on the side… I just didn't take a photo of that). Both of the carburetors look like this, so if you guys see anything that you can tell to not be OK with the condition, please let me know.




Now to the spark plugs: I will check these to see if they are the wrong size (Champion N9YC is printed on them)



and the ignition system











I also looked into the weird homemade electronic shut off and I could not figure out where he would have connected it, if it was ever connected to begin with. I could assume it was a project that was never finished.

Oh, and this was something I noticed when I just got the bike and took off the tank. Bummer, but I could think of many more serious places for a crack.

The upper engine mount that connects with the head/valve cover. I looked on ebay and can get a valve cover for €30, so that isn't too bad.

check your fuel tap's not been messed with ! mine had & they'd forgotten to put the spring back that pushes on the diaphram, so i wasn't getting a proper flow of fuel, also clean out pilot screw & passages in carbs these holes are usually small & easily block, replace "O" rings if thre re any. try and use a car batterie to jump start your bike while you're trying to get it started, the bike batterie on its own might not have enough left in it to give a good spark

Mike probably has a point there, if the battery is low it might just not be giving enough oomph to give a healthy spark. Mind you, you say the plugs are dry, that still points to fuel starvation, were the float bowls full when you took them off again?

As for bits, I used Unity Equipe in Todmordon http://www.unityequipe.com/ when I built my Bonnie, but they are damned expensive and geared primarily toward the British Classics. For shiny bits take a look at places like Highway Hawk, geared up for Harley and Jap cruisers but some of the lights are very retro and cool.

Other than that I fine Ebay is your friend, lots of second hand bits and a few stockists who keep retro cafe style bits.

Good luck with the build and sorting out your gremlins.

Thanks Mike and Paul,

The battery is fully charged and I don't have access to a car battery, so I will have to make due with this. The spark is very clear however so it should do just fine IMO.

Yes, the fuel bowls were full when I took them off again, so I am not worried that they are being starved from the tank/petcock.

My next option is to
- order a set of spark plugs and see exactly the difference
- get some starter fluid and try it out
- then check timing / compression and everything else

I have a question about the diaphragm in the carburetors, though. When do the (are they supposed to) diaphragms and needle move up and down?

The diaphragm is drawn upwards by a vacuum created when you open the throttle which opens the butterfly and allows air into the intake, the induction stroke of the engine pulls the diaphragm upwards and the needle with it so the amount of fuel being vapourised increases and the engine goes faster (creating more vacuum and drawing the needle further from the jet)

If you are concerned the diaphragms might be not working it's worth removing them and checking for pin holes or perishing. They looked OK in your photos, but a small pin hole would be enough to stop them holding vacuum.

pauliexjr wrote:

The diaphragm is drawn upwards by a vacuum created when you open the throttle which opens the butterfly and allows air into the intake, the induction stroke of the engine pulls the diaphragm upwards and the needle with it so the amount of fuel being vapourised increases and the engine goes faster (creating more vacuum and drawing the needle further from the jet)

If you are concerned the diaphragms might be not working it's worth removing them and checking for pin holes or perishing. They looked OK in your photos, but a small pin hole would be enough to stop them holding vacuum.

Are they supposed to move up and down when cranking? If so, this is not happening. They really are in good condition and when I slid them up and down manually, you can feel good suction.

ryMY wrote:

Are they supposed to move up and down when cranking? If so, this is not happening. They really are in good condition and when I slid them up and down manually, you can feel good suction.

I would say yes, because if the sliders aren't going up and down the needles are staying in the jets and you are trying to start the bike with just enough fuel to provide tickover. Might be worth checking the vacuum by putting your hand over the carb mouths when you turn the bike over. No vacuum would prevent the carb sliders from lifting. Am I right in thinking it'd an OHC? If so might be worth whipping the cam cover off and taking a look to ensure the cam chain is present and turning the cam over. Edit, scrap that, I've just gone back and seen your picture of the points set-up and they obviously run off the end of the cam, doh!

Really does sound like you have a compression issue I'm afraid.

morning Ryan,

just read through this and not surprised your having problems.

have recently picked up an xs250 for nought that i'm looking at putting an over bored 400 in and have been doing some digging myself on them.

appears they were known for starting problems when they were new and only got worse with age.

that said, a lot of people cafe them to good effect and i've seen carb swaps on some.

good luck and will follow with interest.

shaun.