Henkie's yamaha xs360c A quick hello and trouble in motorcycle paradise

[henkie22222]

Hello everybody from xs400.com,
I am Henkie from Holland. I bought an xs 360c a couple of weeks ago because im turning 18 soon and I really like motorcycles and would lover to ride a proper bike. I have some experience riding on and tinkering with my Yamaha fs1 from 1978. But a 360cc four-stroke beats a 50cc two-stroke any day of the month ofcourse. Even if the 2 stroke has been modified like mine (top speed is just below 90km/h wich is double the speed the law allows me to go )

However I bought the xs 360 in non-working condition hoping i would just clean the carbs, set the valves corectly maybe do a bit of carb jetting and set the ignition. So far these things haven't worked out quite the way I wanted them to.

I cleaned the carbs with some household vinegar (very strong) and then used some brake cleaner to get rid of the real nasty bits (works like a charm)
I never did any valve adjustments before because i have only owned 2 stroke, so i did exactly what the workshop manual told me to do. Same with the ignition.

In the end this all resulted in a bike that is very hard to start, it will only start once then shut off and wont start again untill a couple of mins. later (fuel flow to carb?)
It doesnt idle, it will emediatly shut itself down when below 2000rpm.
And every once in a while you hear a loud poof from the carburateurs.

Help in the form of advice on what to do would be appreciated.

 

[XS400D]

welcome! I think I have finally started to gather this from reading enough and doing it a few times myself... if you think the carbs are clean and you have only tried once... the probably need another cleaning. =( You may need to adjust the idle adjust screws, and if you took the carbs apart thoroughly you will probably need to re sync

KEEP US UPDATED!

 

[drewpy]

hello Henkie, there is a fellow dutchman on here called Hornix, check him out!

sounds like you still need to clean the carbs, I suggest you do a search on here for carb cleaning as there are plenty of threads on it!

make sure your battery can hold its amps too!

 

[henkie22222]

I guess i will clean them again then, but this time by the book
And then sync them if that is what you advice me.
About the battery, i might have killed it. I think it is dead because I used the electrical start a couple of times without actually driving it (oops) and now it has been empty for a week. Maybe my dad can get it filled with juice tomorow at his work, we will see if i will have to buy a new one :s

 

[OliverB]

Congrats on the find and welcome to the forum. Yeah, as Drewpy indicated, these bikes won't run if the battery is very low or dead.

 

[henkie22222]

I made a short clip while the engine was "running"
Can anybody hear what the problem could be.
BTW, i allready set the valves, Checked contact breaker points, cleaned the gasfilter, set the sparkplugs at 0.7-0.8 and some other basic stuff.

 

[drewpy]

can you not rev it up to 4k?

are you using the choke as the engine is not getting warm.

I'd set the tickover screw higher so you have a chance to do some thing

 

[henkie22222]

I can easily rev to 4k, I just cant go below 1600/1700 rpm.
Using the choke after reving a while wil keep it steadier.

Just found out my sparkplugs both give a strong but white spark :s what does this say?

 

[drewpy]

lean lean lean.......

 

[henkie22222]

Im not that experienced with how CV- carbs work. So I have a couple of questions... What jet has to be readjusted now? The idle jet right?

 

[drewpy]

http://yamahaclub.com/forums/topic/16081-xs400-links/

 

[henkie22222]

Got it idling ok now (just tuned it with the idle screws), however i tried to tap oil from the engine. And I let my dad put in some muscle grease, and now the metal piece that sticks out at the bottom of the engine holding the oil tapping bolt is begining to crack. im sure it will break off if i use force again. It is now leaking and i have no clue on what i have to do now.

 

[drewpy]

you talking about the oil pressure switch?
that is tapered!

 

[henkie22222]

I mean the bolt that you take out to leak all of the oil out

 

[drewpy]

the xs400 have 2 oil plugs, 1 under the sump and 1 near to the oil pressure switch, facing out left! just don't use one of them

if its leaking bad, try some plumbers goo that can resist oil/petrol and nip it up as tight as you dare to!

 

[lhaolpa]

Do you have a manual on your bike? There is a downloadable manual on the site in English,French and German,maybe that will help. You may need to adjust your idle screws out a bit[1/4 turn at a time] until it idles better. Read the manual and you'll know more about how to adjust everything.Good luck....lha

 

[henkie22222]

I was planning on keeping this thread updated frequently, however hardly anything positive has happened since my last post. Basicly I had a crack around the bolt that you tap the oil from underneath your bike. What happened was that my dad wanted to surprise me with a loose bolt when i got home from work. However he just broke the thing off. Result: an oil drained engine with a big hole in it.
Luckily I could find the lower half of the engine for sale on german ebay, it is probably coming this week.

 

[Shaun Chandler]

I pritty sure those are a match machined part. Do you mean you bought both the top and bottom of the crankcase?

Some stuff on the engine is magnesium but I'm rather certain that the crankcase is aluminum so it would be a cheap weld repair although you would have to pull the engine right apart to do it. Just bolt the top and bottom back together so warpage is less likely then weld. I wouldn't charge more then 50 or 60 bucks myself for a repair like that if someone else did the cleaning.

Shaun

 

[henkie22222]

You mean two 1u4's crankases (top and bottom) dont just bolt right on? That would be crappy. Took me about a month to get that part and cost me 60 euro's :s (actually not hat much but if it doesnt fit)

I know someone who knows someone that can weld aluminium so that will not be a big problem I was just worried that if i get it welded it might break again. Because i was told that cast aluminium does not give great welds

 

[Shaun Chandler]

I have a special rod that I use for cast and it works great. That being said every piece is different and some just sucks to weld.

With aluminum clean is king so it needs to be cleaned then the weld area has to be cleaned with acetone and mabey abit of heat put on to get the oil out from the cracks ,but your welder should know all that. As long as it is welded right to the end of the crack (so the end of the crack should be drilled, this will end further cracking) it shouldn't crack again.

As far as I know they take the two halves and bolt them in their fixture then line bore for the crank then bearings would be custom fit according to the amount that had to be removed from the rough casting to get a good machined surface.

You could replace the entire crankcase but not one half. Otherwise you will likely end up with an egg shaped bearing surface. You could always bolt them up and have a machine shop rebore but that to me sounds cost prohibitive.

I don't see why your cylinders wouldn't bolt right on to a whole new crankcase though.