Alright, what did I do here....

[rotaxrule1]

Hello,

I made a prior post thinking I toasted the top end of my XP's engine. I was riding it, it was not running at its best (but decent) and suddenly cut out. I Lifted the seat to hear a knocking sound at idle at which point I immediately shut it down. I thought for sure it was a broken ring, RAVE valve hitting, etc. But after getting around to troubleshooting it tonight, here is what I have found.

Compression test: 150, 150 (almost down to the exact psi)

Engine will turn over normally with starter, but makes a scraping / knocking especially with the plugs in.

Engine turns easily by free hand, but I vaguely feel an intermittant roughness and it almost feels like it is on the crank, or something fell into the crankcase and is rubbing.

I have torn off the raves, they are both fine. Took off the flame arrester, carbs seem to be intact and normal, though I have not taken them off yet.

I will attach pics of my plugs, the MAG cyl had a nice tan color, the PTO cylinder was similar color but wet like it was not firing.

Any ideas? I hate to tear it down if I am missing out on something simple. But I have a feeling that something is wrong with my crank at this point.

-Brandon

 

[LouDoo]

I honestly don't know either, but the first thing I would do is pull the pump, since it's a direct connection it could be a bad bearing in the pump.

The PTO spark plug looks like that cylinder was running rich, is this something new. Do you know what it usually looks like?

Lou

 

[tictoc]

Bottom end... sounds like you threw a bearing in the crank, have it rebuild... Mine made the same sound and thats what it was and my comp was the same 150/150. Good Luck

 

[Dr Honda]

I'm with Lou. Pull the driveshaft, and the pump... and then play with the engine. It's easier to get the pump off that to rip an engine apart.

 

[rotaxrule1]

I honestly don't know either, but the first thing I would do is pull the pump, since it's a direct connection it could be a bad bearing in the pump.

The PTO spark plug looks like that cylinder was running rich, is this something new. Do you know what it usually looks like?

Lou

Unfortunately I am not sure what is normal color for that machine since I had only a couple rides on it since I rebuilt the fuel system and carbs this winter, felt like it has been running rich though cause it had been loading up and sputtering.

Good idea and thanks for your input guys, I am afraid i am in for another crank replacement (not with this specific machine though) so I should be getting pretty good at rebuilding these things after this.

I will disconnect the pump and try again to be sure it's not as simple as a pump bearing, I would have to take the pump and driveshaft out anyway for a bottom end rebuild, so no harm done either way.

Thanks again,

-Brandon

 

[Dr Honda]

Here's the plugs out of my XP. (for normal color) Generally, you want to see the PTO plug darker.

 

[rotaxrule1]

Here's the plugs out of my XP. (for normal color) Generally, you want to see the PTO plug darker.

Thanks Doc, that is good to know.

Here is a vid of my troubleshooting tonight. I disconnected the driveshaft and pulled the pump. The engine still made the same noise unfortunately. This video can give you guys an idea of the noise it was making, I didnt dare let it start or crank it for much longer than I did, but it did fire to help express the noise a bit more. I can't think of anything else at this point besides a bad bearing or something with the crank.....

http://www.youtube.com/watch?v=hPIjAviBs6g

 

[rotaxrule1]

Well, the noise ended up being a CB shaft that completely snapped in half. How did this freaking happen?? Must have had a bearing trying to lock up on the opposite end of the gear.

Anyway, if anyone has a good core I can send to SBT, or a new OEM, let me know. Id rather not pay 300 through the dealer.

:cheers:

-Brandon

 

[Dr Honda]

Wow.

That doesn't normally happen. But... if the engine got water in it, the bearings could have given up.

Check eBay or PM minnitonka to see if he has one.

 

[rotaxrule1]

Yeah, it did have water in it when my father in law tried riding it once. He is a big boy and tried to switch me from the GSX in the middle of the lake and ended up tipping it sideways, getting water into the engine from the exhaust.

I ran through the routine of getting the water out immediately, and eventually got it started within the hour and ran it for a good 20 mins. But I can't account for what happened in its previous owner's life.

Since day 1, It has always had an unusually audable lower end noise when spinning it by hand (just sounded worn out). Too bad I didnt notice when I bought them, maybe I could have brought the price down even more.