FatBoy Racing
08-30-2004, 06:21 PM
Well, on a ride last week my piston stopped moving, which is usually a bad thing. Motor locked up while on a ride, and kicker would not move. This discovery came at the 10 minute mark of the ride from my property. I also discovered a 10 minute ride out is equivalent to a 90 minute walk back home. Fortunately it was only 90 deg out that day, a bit cooler than temps have been lately around here.
Anyways, got the motor opened up saturday morning and got good news and bad news.
Good News! The piston and cylinder are fine, no problems, no need to remove/rebore/blahblahblah.
Bad News -- The bolts that hold the cam sprocket to the cam had come loose. Looks like for a while, the cam rubbed against the right side of the valve cover, throwing a pile of thin aluminum shavings all over the place. But wait! There's more! After distributing aluminum confetti throughout my motor, the bolts finally came out all the way, and the cam went for a ride - - - straight down. The cam lodged itself within the cavity alongside the cylinder and the extra slack in the chain bunched up and locked up -- but that didnt stop our mighty little engine! Our hero expressed that a runaway sprocket and a wimpy little chain was not enough to delay progress any longer, and promptly snapped the chain and took out no less than 3 teeth from the lower sprocket (the crank, I believe?). At some point, a part of the case casting which acts as a stopper or guide for the front plastic cam chain guide got itself in the way since progress again is more important, that part of the casing was quickly snapped off and cast aside like a stepchild. As every motor has its limits, this is where our motor had enough, locked up and quit.
As best I can tell, the problem lies with my installation of the HRC cam. I clearly recall using loc-tite on the bolts, and if anything, I used too much, or I used the wrong type. I'm pretty sure I used the removable loc-tite -- so probably my bad there. I'm flushing the motor with diesel and sifting out the wreckage with panty hose to make sure I get all the pieces out -- hopefully I won't have to split the cases, but I'll know for sure when I have all the pieces accounted for. At this point I would have almost rather a ring cut loose and seized it, but I'll take the punches as they come.
Anyhow -- I 'spose lesson learned here -- use permanent loctite on the cam sprocket bolts when changing that cam!
Have fun and wish me luck!
Anyways, got the motor opened up saturday morning and got good news and bad news.
Good News! The piston and cylinder are fine, no problems, no need to remove/rebore/blahblahblah.
Bad News -- The bolts that hold the cam sprocket to the cam had come loose. Looks like for a while, the cam rubbed against the right side of the valve cover, throwing a pile of thin aluminum shavings all over the place. But wait! There's more! After distributing aluminum confetti throughout my motor, the bolts finally came out all the way, and the cam went for a ride - - - straight down. The cam lodged itself within the cavity alongside the cylinder and the extra slack in the chain bunched up and locked up -- but that didnt stop our mighty little engine! Our hero expressed that a runaway sprocket and a wimpy little chain was not enough to delay progress any longer, and promptly snapped the chain and took out no less than 3 teeth from the lower sprocket (the crank, I believe?). At some point, a part of the case casting which acts as a stopper or guide for the front plastic cam chain guide got itself in the way since progress again is more important, that part of the casing was quickly snapped off and cast aside like a stepchild. As every motor has its limits, this is where our motor had enough, locked up and quit.
As best I can tell, the problem lies with my installation of the HRC cam. I clearly recall using loc-tite on the bolts, and if anything, I used too much, or I used the wrong type. I'm pretty sure I used the removable loc-tite -- so probably my bad there. I'm flushing the motor with diesel and sifting out the wreckage with panty hose to make sure I get all the pieces out -- hopefully I won't have to split the cases, but I'll know for sure when I have all the pieces accounted for. At this point I would have almost rather a ring cut loose and seized it, but I'll take the punches as they come.
Anyhow -- I 'spose lesson learned here -- use permanent loctite on the cam sprocket bolts when changing that cam!
Have fun and wish me luck!