Just to add to the "My Bike Doesn't Run" threads...

Well, it "kinda" runs. Problems arose just as it ran out of gas one time. I'm not sure if this is actually correlated with the problems but I figured it was worth mentioning. The bike was running, then it ran out of gas. After filling up the tank and trying to restart the problems began. I can only describe its behavior as "excessively boggy" to the point where it will not idle. If I get going quick enough and open up to about 1/2 throttle, it will run, and be able to take me along, however it has next to no power, and it will putz out if you slow down.

Here are the things I have tried thus far:

1) I figured the carb jet might have been clogged. It was pretty caked up with grime I figured it was worth cleaning up anyways. I took it completely apart, and cleaned it up. It looks like new, inside and out. Sadly, it made no difference.

2) I figured the spark plug could have been fouled. I replaced it with another plug to no avail. I even tried a BRAND NEW one, and it made no difference.

3) Perhaps the Spark Plug boot was making a poor connection? I replaced the boot with a brand new one. Still no difference.

4) I unscrewed the little screw on the side of the carb that the gas flows in through, to make sure gas was actually flowing. Maybe my fuel filter was clogged or something along those lines? No, fuel flowed through it just fine.

5) Popped the magneto cover off, and there was a tad of oil inside there, but nothing seemed out of the ordinary.


I notice the engine seems to get much hotter than it usually does if you force it to run this way. Not sure if that is related? (Probably is)

I don't think a head gasket could have blown, I retorqued the headbolts only one day prior to this. However since I am officially out of ideas, i'm willing to pop them off tomorrow and take a look inside.

So to all you experts on here, what would you try next? I find it odd my engine after running flawlessly for a full year and 2000 km would just die on the spot......

Thanks in advance!

Matt

Wouldn't an air leak cause the engine to behave in a "fuel starvation" way, as in high reving, and high heat? I do have the high heat symptom, but the way the engine feels, (boggy) really seems to indicate an over-fuel scenario. I don't think there is an air leak anyways, there was one tiny drop of some fluid that happened to be black behind the magneto cover, but the hole the wires come through is open to the air, and it did rain the other day. I think it was just a drop of water.

How likely would it be that a clogged muffler would cause this?

I'm leaning towards trying to move the carb C-clip one notch up (to lean it out) but given the heat situation I'm hesitant to do so.

Will try popping the head cap off when it cools down a bit. That's like, the one place I haven't looked for a problem.

I notice the carb kind of leaks a little bit around the seal. (Between the bowl and the top assembly with the jet) I wonder if the mechanism that controls fuel intake into the bowl might be broken?

2door, I'm not trying to completely discount your suggestion. I'd just like to hold off on the more drastic fixes for the moment. I'll keep what you said in mind though!

Any ideas on the additional information, especially the leaky carb.

If a picture is worth 1000 words, here's 7000 words to describe my situation. I have taken off the engine head, and taken pictures of the guts. I also took some pictures of the magneto and spark plug.

Please take a look at the magneto images and let me know if you still think there's a leak there.

Without further delay, here are some images.


Piston head in up position.





Piston head in down position. I see an injury here, is this cause for alarm?





Same thing from the other side. A similar injury on this side too.





Magneto




My crappy attempt to show below the magneto.



Seems there's a 5 image per reply limit. 2 more images in my next post.

Piston head cover. Nothing strange here.





The spark plug. Is this a good color for a healthy fuel mixture, or is this getting fouled? Note this spark plug was brand new yesterday and has been run no more than 5 mins. I notice its more brown on one side than the other.....



Let me know what you guys think of these. I'm still pointing fingers at the exhaust pipe or carb. Perhaps I can take some pictures of the carb also tomorrow.

Thanks again!

Well I hope I don't have a broken piston ring... I rolled the bike along a little bit without the carb on, and it feels good for compression. It sounds OK, and puts up about the same amount of resistance it did before. I'm no expert, but I'd like think this damage isn't the direct cause of the current problems. I guess it depends on how much of a difference damage like this can make..... What I do like about this theory however is that it supports the sudden appearance of the problems.


I do find it odd that similar damage occurs on opposite sides.... Makes me wonder if a piston ring might have hopped up at an angle or something scraping opposing sides.... Perhaps if this did happen the added friction (metal on metal) could be the cause of the extra heat I am seeing. I was able to easily move the piston with my finger however, and it felt smooth. I'm not so sure.

Sounds like it may be time to take the whole engine apart.

Before I pop that off, do I need any special tools to reinstall the piston? Something like.... a ring compressor? I don't have any special tools. I don't want to pop it off unless I know I will be able to get it back on.

How do you actually separate the piston from the crank... I have the little retainers on either side of the piston pin out, but the piston pin itself seems wedged pretty good.

I was hoping to get it off without taking apart the crank case....... I get the sense putting the entire bottom section in the oven would be a bad plan XD

Well that thing is seriously stuck on there. All my might and I could not move that pin!!! I can push it so that its flush with the side of the piston, but will not slide any further than that. How should I proceed?