I thought it was a submarine

Hi,

So, I have been through some deep water plenty of times with my X, but I got deep enough this time that she cut out on me. It took about 5 tries to get it to crank back up, and after that I rode the rest of the day. I noticed that sometimes the rpms would stay up even after letting off the throttle, but I could make it stop by revving it and letting off again. On my way home, it would cut out every time I let off the throttle, but would crank back up again. I never noticed it throwing any codes. The next day it wouldn't fire up.

The engine is turning when I try to crank.

I took the spark plug out, cranked it and I am getting spark.

I tested the coil over, and the primary is a little out of range (~3.5 ohm when normal is 1.5-1.9). Not sure if that would cause the problem. Secondary is in range.

I checked the error codes in the diag under #61, and all the history shows is a 30 (lean angle) and a 70 (Idle too long, auto shut off).

I emptied the tank, put in fresh gas and some HEET, and cranked until I was sure all the old gas was out of the lines. nothing.

The fuel pump is priming.



I bought a new spark plug even though I am getting spark. I am gong to try that, but I doubt it will solve my problem. Any ideas? Thanks

Check air filter? If the element got saturated with water, it could be a problem.

I forgot to say that I did check the air filter and it was dry, I had it removed while trying to crank it.

outlaw230 wrote:

I forgot to say that I did check the air filter and it was dry, I had it removed while trying to crank it.

I know myne won't start unless the air filter is in and the door is closed. you can poop the door open once it is running though

did you do a compression test?

I replaced the spark plug and its still a no go. I will try a compression test next. The only fuse I can find is the one for the main battery Pos. lead. Are there any other fuses I can check? Thanks again

yeah there are more fuses located under the left shroud cover.. just behind the shroud above the rad overflow tank..

good luck

Possibly water in a wiring connector?

xy500 wrote:

I know myne won't start unless the air filter is in and the door is closed. you can poop the door open once it is running though

Airbox door?

Yours won't start without the airbox door closed?





I've been running without an airbox door for years. Best performance upgrade going.

We don't have O2 sensor in pipe here in the USofA, so perhaps that's part of the difference?

Compression Test:

I bought a Compression tester with the 10mm attachment.

Cranked the engine over about 15 times to ensure lubrication.

Took the spark plug out, and screwed the gauge in to the spark plug hole.

Held the throttle wide open and cranked it over 4 or 5 times.



I am only getting about 6-10 psi of compression. I am pretty sure the spec is over 100 psi. I did the test many times out of denial, and even did the test on my 400cc atv to make sure the gauge is working which it is. I have found other threads stating that this test is useless, but this is the only troubleshooting I have done so far that has told me anything might be wrong. I have never done a "leakdown test", but I guess that is my next step.

Hmm. Might have a tweaked valve. If you got water in the cylinder, it could have hydro-locked, but you said it kept running (not well) after the event. If the compression is gone, then it sounds like a valve is sticking open.

To distinguish between rings or valves squirt a little oil in the cylinder through the spark plug hole and retest the compression. If its rings the compression will come up, its its valves there should be no change. Also if you put the piston and top dead center on the compression stroke, lock it there firmly and pressurize the cylinder you can here where the air is going. One unknown is the compression release on the exhaust valve cam, you may possibly have to go a little past TDC into the power stroke to make sure the release is not engaged.

Did you look at the oil in the crankcase for signs of water?

if you do an wet compression test(squirting oil in the cylinder) and you still have low compression, you can do a leakdown test, what you do is use a threaded compression tester fitted to an air line fitting and inject air when the motor is at top dead center your valves are all closed, if you get a stabilized air pressure reading, your valves are good. If you can't hold the air pressure constant for a little while, your motor has bent valves...

Good luck

Thanks for the tips. Next I will try to isolate whether its rings or valves, and check the oil to see what it looks like.

I'll post what I find.

Leakdown Test

Made sure the piston was TDC by sticking a screwdriver in the spark plug hole, and turning the crank by hand until the piston was at its highest point.

I don't have an actual leakdown tester, so I just used the attachment from the compression tester and attached it to my air compressor hose and screwed it in to the spark plug hole.

Held the piston in place at the crank and set the pressure to about 25psi.



I am always getting air out of either the intake, the exhaust, or both. At first I thought that I might have been at TDC on the wrong stroke, so with pressure still applied I kept turning the engine by hand to see if it would change. By doing this, I can get the air to stop coming out of the intake or exhaust separately, but never at the same time. I never get any air out of the crankcase.

If either the intake or exhaust valves were messed up, should I be able to stop the air from coming out at any point? It seems like if a valve was bent/ stuck it would let air out no matter where the piston is.

If the valves are working properly, shouldn't there be a point at which they would not let any air out?

It seems like the valves are closing and opening, but not at the correct times, and they are never closed at the same time so that the cylinder can get compression. Maybe the timing chain or cam? Any thoughts? Thanks

If something did lock up in the head, I guess it is possible the cam chain jumped some teeth or something on one of the cams. It sounds like you have some serious timing issues. Any way you look at it, it sounds like you need to open the valve cover and see what it looks like in there.

So it has been a looong time since I have had time to revisit this issue. I ended up knocking up my girlfriend and the bike lost its spot in my to-do list. We finally had our baby boy a month ago and I am just starting to get back in to my projects.

Picking up where I left off, I popped the valve cover off and here is what I found:

I put the engine at TDC on the compression stroke by aligning the mark on the crankcase with the SINGLE mark on the crank. When these marks are aligned, the marks on the camshafts are not aligned. I guess this means that, at the very least, one of the cams jumped a tooth or two. Maybe I will get lucky and this will be the extent of the problem.

I guess the next thing to do will be to loosen the timing chain, align the cams, put it back together and test compression again. Anything I should be sure to check, be careful for, etc? Thanks

I'd strongly recommend to replace the chain tensioner as well, as to jump any teeth would mean that the tensioner would have been "forced" against itself & overly stressed / loaded.

Cheers.

Got the tensioner off, corrected the Cams, put the tensioner back on (PITA), tested compression.

The compression actually looks a little better, maybe 10psi over what I got before, however it still isn't where it needs to be. After pouring a little gear oil in the cylinder and re-testing, I get almost 110PSI (I was getting no improvement before correcting the cams).

I had to take the exhaust off to remove the starter and tensioner, and when I watch the exhaust valves from there I cant see gear oil squeeze through one of the valves on the compression stroke. The other valve does not allow oil through it. Wish I would have done this a long time ago.

Taking a step forward, it looks like one of the exhaust valves is not closing all the way. I will be taking the head off this weekend now that I am sure it's a valve.

Congrats on the new family member.   

Keep us posted with what you find when you get the head opened up...

Can also check valve clearances, if you have a 0 clearance then the valve isn't closing all the way. Might be as simple as changing shims, but if you suspect a jumped tooth then there could be valve damage if it contacted the piston.

I got the head off, and valves out. No bent valves, but a ton of carbon caked both on the valves and on top of the piston.

Removed valves and reseated them using lapping compound. After that I verified the seal by pouring some water in the intake and exhaust ports and watching for a leak. None observed.

The cylinder has a little scoring at the very top, but I can still see the factory cross hatches so the wear seems pretty minimal. I went ahead and ordered some new piston rings and will deglaze the cylinder before installation.

I will be putting it all back together for another compression test as soon as I get the rings.

Well, it's back to life!!

What I ended up doing:

1. Removed engine from bike: this was not as hard as I thought it would be, and made working on everything so much easier. Highly recommended.

2. Disassembled and removed the head.

3. Lapped and re-seated the valves.

4. Adjusted valve clearance. Clearance was at Zero, and very well could have been the problem. Shims are stupid IMHO.

5. Re-assembled the head.

6. Removed the Cylinder.

7. Replaced piston rings. The old rings were collapsed/ had zero end gap clearance. Definitely part of the problem.

8. Honed/ deglazed the Cylinder, and cut the lip at the top of the cylinder. Cylinder had some vertical scarring at the very top, but after honing was back to normal.

9. Re-assembled the engine using new head gasket, but re-used the old bottom end gasket and valve cover gasket.

10. Re-installed on to the bike. I did this without a manual and was easily able to match up all hoses and electrical connections.


Cost:

piston rings- $36
shims- ~$10
head gasket- $35
valve lapping kit- $10
assembly lube- $7
oil, anti-freeze, etc.- $20

Total: approx. $118



I am now getting well over 100 PSI compression. Actually, when I bench tested it before re-installation I was getting over 200PSI with a little oil in the cylinder.

She popped off on the first attempt using two year old un-treated gas (same gas that was in the tank when it broke down). I know that isn't smart, but it's good to know that gas will last that long in my tank.

Things I learned:

*if you have lost compression, just rebuild the engine. Trouble shooting each part (rings, valves, etc) wastes time, and if your going to replace one you might as well rebuild the whole engine while its apart.

*if you need to take the head off, or anything more, just remove the engine from the frame. It's easy to re-install and makes working on the internal parts so much easier.

*you must hone/ deglaze the cylinder when replacing piston rings.



Thanks for all the help.

Congrats on getting it all back together!
How was working on the head, did you have any problems getting the valves in or out?

The head was pretty easy. Each valve has two little keepers at the top that hold the valve stem to the spring. I made a tool out of a magnetic screw driver and a spark plug socket to get them out, and gravity does the work for you when putting them back in (without a magnetic screw driver). Lapping the valves is super simple and straight forward.

When it comes to adjusting the clearance it's a guessing game. To adjust clearance you have to replace the shims. Those are located underneath the buckets that the cams push on. The shims have numbers on them that measure the thickness (in millimeters I think). The numbers had worn off my shims, but I knew they were too big because I had zero clearance. I actually ended up ordering 6 shims: 2 each in 3 different sizes. They were only 1.99 each at Rocky Mountain ATV. Luckily the sizes I got were perfect to get me within range on the clearance.

I only have 10k miles on my bike and valve clearance was at zero. Maybe because I was so hard on it? Anyway, I will definitely check clearance again in 5k miles despite the supposed 20k mile service interval according to the manual. I guess they are assuming these bikes stay on the street and are driven by old ladies when they came up with that.