New to this, bike cut off and now wont start.

[MFJustin]

Ahhhh where to begin. Gentlemen I come to you as a complete noob to the XS650 world. I'm a transplant from the 4x4/off-road/Jeep community. Many months ago while making my usual forum rounds, I saw a thread on Pirate 4x4 created by none other than Punkskalar detailing a bike he was building and ever since then I have been hooked on owning a Yamaha. After a year of searching I finally found the right one, a '79 that had the majority of the work already completed by the current owner at the time. Unfortunately I'm a huge do-it-yourselfer and wanted to build one of my own but I couldnt pass it up for the price.

Fast forward to the present, I've ridden the bike for the past 3 months that I've owned it and thus far it had been problem free for the most part. Until now....

Here's a quick synopsis of my current debacle, and bear with me and my noobiness....I know how forums work and I've read read read as much tech as I could and searched my butt off so please no "search noob" responses. Several weeks ago I took the bike on a multi hour trip away from home. Usually I would just ride around town and plug it into a battery maintainer at night just because. While out on this extended trip my bike started bogging down in the middle of the highway and eventually just died as I coasted to the shoulder. Went to turn it back on and there was absolutely no juice in the battery so I figured it was a bad charging system. Got it towed home and a new battery later I was on my way again vowing to ride it until winter when I could fix the charging system.

Unfortunately I didnt make it that far....

While riding home the other day the bike again started having the same bogging problems. I figured it was once again the charging system not charging the battery so upon stalling out and pulling to the shoulder I looked and the headlight was still as bright as could be and the electric starter was still working. I almost always kick start it and could get it up and running for a few seconds before it would die out again. I noticed while doing this that there was a bit of white smoke coming out of the air filter. I got the bike back home and read as much as I possibly could on here but still didnt really know where to start in diagnosing this problem. Here is what I have done thus far to try and figure it out but unfortunately I know that I am jumping around because I dont really know where to start and evening reading the "Bike Running Rough?" tech thread still had me jumping around because I wasn't satisfied with what I was finding.

- First thing I did was run a compression test, both spark plugs removed, throttle rolled all the way out. One cylinder came back with 90 while the other cylinder read 150. I dont know for sure if I did this test correctly but I kicked it over for the test and did not use the electric start. Those results would indicate a problem based on what I've read but once again I didnt know if I did the test correctly to get accurate results.

- Second thing I did on a hunch was check for spark. Pulled a blug and while it still connected I grounded it against the engine block and turned the ignition. No spark was to be seen so I figured I had found my not running problem. Instead of trying to mess with the points ignition because the previous owner had stripped the crap out of the adjustment screws I simply opted to get the Pamco kit from MikesXS. I ordered a kit that came with a new high performance coil, wires, the works. I checked and double checked all of my connections to make sure that it was wired up properly and also so I wouldnt fry the system as I read about how it easy it was to do so if you didnt put it in correctly. The moment of truth came and I went to fire it up hoping it would work and still nothing.

At this point in time I am sort of lost on where to go next, it will crank and crank and crank but not fire. I'm not sure if it could be the fuel system, something internal on the motor given what my compression test results were or what. Also if this helps serve as any sort of clue, over the 3 months that it was running there was almost always a constant popping from the exhaust on deceleration or when not on the throttle. Also occasionally it would idle really high when the clutch was in or while sitting idle at a stoplight, I just shrugged it off and eventually it went away.

Sorry for the write a book guys, sometimes I spend way too much time typing out a full explanation of my problems. Any guidance would be awesome, I was really hoping to get it running so I could at least finish out the season but at this point in time I'm convinced its going to have to sit for awhile. I'm excited as all hell to be a member of this forum though, I've been a member of many great forums in the 4x4 world and from what Ive seen of this place so far there are a lot of helpful people. Glad to be aboard.

 

[jd750ace]

Did you ever change the plugs? Check your grounds? 90 should support combustion, but 150 is obviously better.

 

[MFJustin]

When I ordered the Pamco kit it came with new plugs so everything ignition wise is new.

Even before I ordered the kit I had a few new NGK plugs still in the box so I gapped them properly and put them in just to see if they worked, they were a no go as far as creating a spark was concerned.

I guess my question would be, just to make absolutely sure I now have spark with the Pamco kit, can I pull a plug and as long as I make sure its absolutely grounded against the engine block try to crank it over to see if there is spark or do I still run the risk of frying it?

I was hoping that the fact that it just died while running and then wouldnt restart would be indicative of something and help me narrow my search down a bit. Tomorrow I suppose I will double check all of the wiring and make sure everything is grounded, etc. but so far from what I've seen everything looks to be hooked up ok.

 

[jd750ace]

You sure you have good gas? You said it sat a few weeks. It could have originally fell on it's face due to the coils building resistance with heat, and it may be that your fuel has gone bad after sitting for a few weeks. It goes to crap as quick as 3 weeks in Texas summers with no stabilizer in it. Just a thought.
Can't answer your spark check question. Risking blowing out a pool payment checking fire sounds too fragile for me to mess around with!

 

[MFJustin]

Gas has to be good, I was riding it pretty much every day it didn't sit for any time at all really. I'm reading up on this carb guide right now, first time messing with carbs so I'm sure it'll be an experience but I guess I can always pull them apart tomorrow and check them out.

Biggest thing for me in the Troubleshooting thread was that a comment was made that said dont necessarily jump straight to blaming the carbs when it could be a much easier solution than that. Just trying to go with what I know so far and whats happened and try to narrow things down without jumping around too much.

 

[MFJustin]

So just an update, started reading through some stuff I could potentially look at.

I did Pamco Pete's test for spark without having to turn the motor over and there is spark on both sides. Can this eliminate ignition as the primary cause or is there other stuff that I should look at. Once again it has a brand new dual outlet coil, plugs, wires and caps as well as the Pamco so most of the ignition components were replaced and it still wont turn over.

 

[XSLeo]

Pete's test proved that the spark is happening. If you installed it right the spark will occur at the right time to get it running well enough to set the timing with a light.
If it srtill won't fire up I might suggest using an oil can with a trigger lever, fill it with gas, pull the plugs, put a squirt or three in each plug hole. Replace the plugs, Try starting. It should fire and run a few seconds. If it does then the ignition isn't the problem.
Time to put the reading of the carb guide to use.
Leo

 

[MFJustin]

Sounds good, I will attempt that now and report back.

 

[MFJustin]

So I think I found my problem and wouldn't you know it was one of the simplest things possible.

Pamco Pete's test for spark calls for removing the little itty bitty centering "pin" on the advance rod in order to let the rotor spin freely without turning the motor over. Well while trying to reinstall the little pin, I pulled the advance rod all of the way out and noticed that the little pin on the other side was not actually engaged on the slotted disk that holds the weights in place. Rather that disk was sitting at an odd angle not even touching the pin. I had to tap it off with a hammer, put it back on making sure that it engaged the pin and put everything back together. The bike fired right up on the first kick.

Now all I need to do now is properly time the bike now that I have it running. I have a mechanic friend that has a timing light and is willing to help me but he's never timed a bike before. Unfortunately I learn better by seeing than reading so does anybody know of a good instructional video or is it just that easy I should be able to figure it out?

 

[Dennis]

glad you figured it out
Always remember to make sure battery is fully charged when ever trying to diagnose a problem.
Wouldnt hurt to check to see how well it charges when you get it running

 

[MFJustin]

So another update, good news and bad.

Took it to my mechanic friends shop and we got it timed perfectly. I took it for a spin up the road and it feels to be a lot more responsive than it was before. I'm satisfied that now it seems to at least be running better than it was before.

The bad news though is that the right cylinder exhaust was smoking pretty bad. We did a compression test again and sure enough the right cylinder is a lot lower than the left one. Pulled the right cylinder plug and it was definitely coated in oil, keep in mind these are brand new plugs so they hadn't fouled out yet. These were probably all pre-existing problems that finally showed themselves in a rather obvious fashion compared to when I was looking for these signs before.

While the bike was running he showed me that if you put a rag in front of the left cylinder pipe it would just blow but when he put the rag in front of the right cylinder exhaust pipe it would blow the rag and then kind of suck it back in. We did a cylinder leak down test next and air was coming out of the right cylinder exhaust pipe a little bit. At this point in time I'm assuming that it most likely means a bad/burnt exhaust valve and maybe more. Like I said I'm new to this but based on everything that I've read on this forum so far I have a general idea of what could be wrong and at least a starting point of what I need to be fixing now that we got the bike running.

I'm going to do another search on these issues and read read read as much as I can but does anybody have any insight into what else I need to look for. Is replacing a burnt valve a pretty simple fix and what else should I replace while I'm in there? I'm mechanically inclined so I'm sure I could do it all myself, its just a matter of getting the proper guidance to let me feel comfortable tearing into new territory.

 

[ippytattoo]

Forgive me if you have already checked this and set them but usually some of the first maintenance items to check off the list are cam chain adjustment, valve lash adjustment and carb sync. If your valve lash is to tight it could keep that exhaust valve partially open which would account for the low compression on that side but not the oil on the plug. There are great vids in the tech section on setting cam chain adjustment and valve lash adjustment.

 

[MFJustin]

Forgive me if you have already checked this and set them but usually some of the first maintenance items to check off the list are cam chain adjustment, valve lash adjustment and carb sync. If your valve lash is to tight it could keep that exhaust valve partially open which would account for the low compression on that side but not the oil on the plug. There are great vids in the tech section on setting cam chain adjustment and valve lash adjustment.

I actually have not done this yet but am aware of how to do it based on the wonderful videos posted in the tech section. I skipped over this step because my problem was ignition related and now that I've solved that I have the bike running well enough to go from there.

I can still do the valve adjustment and cam chain adjustment but considering the smoke coming from the right cylinder exhaust pipe and the fact that the plug is covered in oil its probably time for me to tear it down and rebuild some stuff anyways. With the symptoms I described, is that indicative of bad piston rings or a multitude of things?

 

[peanut]

sounds like the exhaust valve not seating or burnt.

Have you checked the exhaust valve gap on the duff cylinder ? remove the plugs and turn it over slowly on the kick start and check the gap is as specced.

I doubt there is anything wrong with your piston and rings if its holding 90psi and the other cylinder has 150psi.

90 psi would suggest to me that your exhaust valve has been incorrectly set and the escaping gases have burnt the valve allowing loss of some compression.

 

[MFJustin]

Peanut I'll definitely do that check later but what would be causing the oil on the plug? I wouldn't think an incorrectly set or burnt exhaust valve would cause that but then again what do I know, thats why I'm the one here asking questions lol.

 

[peanut]

well there is only two places that the oil can be coming from and thats either past the piston oil ring or past the valve stem oil seal !

You have clearly got a serious problem which will need immediate attention before you can run the engine again so why not rip the head off and assess the extent of work required.

you can test and guess all you like but at the end of the day you are still going to need to get that head off at some stage.
Testing the valve gap as I suggested may identify the source of the problem . Its better to know what caused this sooner rather than when you've rebuilt the engine and find you have the same problem further down the line

 

[MFJustin]

well there is only two places that the oil can be coming from and thats either past the piston oil ring or past the valve stem oil seal !

You have clearly got a serious problem which will need immediate attention before you can run the engine again so why not rip the head off and assess the extent of work required.

you can test and guess all you like but at the end of the day you are still going to need to get that head off at some stage.
Testing the valve gap as I suggested may identify the source of the problem . Its better to know what caused this sooner rather than when you've rebuilt the engine and find you have the same problem further down the line

I'm going to do the valve gap adjustment as well as the cam chain just so I know that I've done it and where I'm at before I tear into this thing. I know the head needs to come off and I've read a lot of good info on this site so far and am actually looking forward to tearing into it and replacing/upgrading what I can. I've made so many boneheaded mistakes it the past from just diving into projects without knowing too much about them and making mistakes so I wanted to make sure it was done right this time around.

I'll definitely update this thread once everything is apart to get some better info of what I'm looking at it. Thanks again for the help!

 

[5twins]

There is another possible source for the oil. Hows your head gasket? Is it leaking? Oil can get in from the cam chain tunnel down the center of the motor, between the 2 cylinders. If your head bolts have loosened up (which is quite common), the head gasket can start leaking and if loose enough, start sucking oil from that cam chain tunnel. I would re-torque your head bolts, you never know, just might fix it.

The reason the head bolts come loose all the time is because of those rubber/metal washers Yamaha used under the 4 outside acorn nuts. You should replace them with brass or copper washers (Mike's sells them). The other problem is Yamaha speced too little torque for those large acorn nuts (about 26 ft/lbs). They don't need to back off much to start things leaking. Here's a tightening sequence chart with upgraded torque specs .....

 

[MFJustin]

5twins thanks for the info, I'm going to head out to the garage and get started on pulling the engine and I'll check the head torque specs while its out.

 

[5twins]

What I'm saying is you may not need to tear it apart. Re-torque the head and set the valves, then try it out. Maybe it will be fixed.