Huge Problem...Engine died. Take a look at these pics
#41
06-29-2011, 02:21 AM
Join Date: Jun 2011
Posts: 592
From bad to worse. Good luck man..
And I doubt it was the cam mod that did it. If it was running fine for a while, then grenaded, it was something else. If the cam mod allowed piston to valve contact, it would have grenaded the first time you fired it up - if it even fired. It would probably just throw the valve before that happened.
Something let loose at a high RPM.
Where are you located?
And I doubt it was the cam mod that did it. If it was running fine for a while, then grenaded, it was something else. If the cam mod allowed piston to valve contact, it would have grenaded the first time you fired it up - if it even fired. It would probably just throw the valve before that happened.
Something let loose at a high RPM.
Where are you located?
#42
06-29-2011, 02:21 AM
Join Date: Jan 2011
Location: North Shore of Lake Superior
Posts: 419
Another potential variable that could be a contributor is head and base gasket compressed thicknesses as compared to stock.
It is very good practice to ALWAYS verify valve to piston clearance when assembling a new engine combination such as this one. New piston, new valve timing, new gaskets, potentially shorter cylinder deck height - lots of variable that could reduce clearances and allow the piston and valves to kiss.
As they say, you live and learn. Good luck!
It is very good practice to ALWAYS verify valve to piston clearance when assembling a new engine combination such as this one. New piston, new valve timing, new gaskets, potentially shorter cylinder deck height - lots of variable that could reduce clearances and allow the piston and valves to kiss.
As they say, you live and learn. Good luck!
#45
06-29-2011, 02:24 AM
Join Date: Jun 2011
Posts: 592
Another potential variable that could be a contributor is head and base gasket compressed thicknesses as compared to stock.
It is very good practice to ALWAYS verify valve to piston clearance when assembling a new engine combination such as this one. New piston, new valve timing, new gaskets, potentially shorter cylinder deck height - lots of variable that could reduce clearances and allow the piston and valves to kiss.
As they say, you live and learn. Good luck!
It is very good practice to ALWAYS verify valve to piston clearance when assembling a new engine combination such as this one. New piston, new valve timing, new gaskets, potentially shorter cylinder deck height - lots of variable that could reduce clearances and allow the piston and valves to kiss.
As they say, you live and learn. Good luck!
#47
06-29-2011, 02:25 AM
I've been lurking and following the jhoffy saga from the very start. Being a 15 year auto mechanic. This bike motor is beyond simple to me. I have destroyed a couple of 4 cylinder and 6 cylinder engines of my own, when I was his age. I know that sick feeling hes talking about. But with many years of fixing cars under my belt. I now am old enough to sit back and laugh, not only at jhoffy, but at myself. I paid a thousand bucks to have a vw cylinder head machined and the head gasket shaved to gain compression. The car hauled *** for 10 minutes until I overheated it and warped the head so bad it wouldnt even start. I forgot to change the thermostat, which caused the car to overheat originally. Which led me to decide to get some more power out of the engine while fixing the warped head.
Luckily Jhoffy is working on a bike and the parts are way cheaper. My suggestion is start from scratch-----Get a new big bore kit. Get a used head. The importance of the piston rings sealing to the cylinder walls cannot be stressed enough, when breaking in a new cylinder and piston. Jhoffy's is all ready broke in. Not 100 percent broke in, but by now there is microscopic divots that will never be sealed due to whatever murdered this engine.
Which is why I would get a new big bore kit.
I would do the work myself jhoffy. How else will you learn? Just verify the timing chain is set correctly and the cams are set correctly. The bike will start and run I promise. And last of all, take your time.
Luckily Jhoffy is working on a bike and the parts are way cheaper. My suggestion is start from scratch-----Get a new big bore kit. Get a used head. The importance of the piston rings sealing to the cylinder walls cannot be stressed enough, when breaking in a new cylinder and piston. Jhoffy's is all ready broke in. Not 100 percent broke in, but by now there is microscopic divots that will never be sealed due to whatever murdered this engine.
Which is why I would get a new big bore kit.
I would do the work myself jhoffy. How else will you learn? Just verify the timing chain is set correctly and the cams are set correctly. The bike will start and run I promise. And last of all, take your time.
Last edited by clgdswr; 06-29-2011 at 02:27 AM.
#48
06-29-2011, 02:29 AM
Join Date: Jun 2011
Posts: 592
I've been lurking and following the jhoffy saga from the very start. Being a 15 year auto mechanic. This bike motor is beyond simple to me. I have destroyed a couple of 4 cylinder and 6 cylinder engines of my own, when I was his age. I know that sick feeling hes talking about. But with many years of fixing cars under my belt. I now am old enough to sit back and laugh, not only at jhoffy, but at myself. I paid a thousand bucks to have a vw cylinder head machined and the head gasket shaved to gain compression. The car hauled *** for 10 minutes until I overheated it and warped the head so bad it wouldnt even start. I forgot to change the thermostat, which caused the car to overheat originally. Which led me to decide to get some more power out of the engine while fixing the warped head.
Luckily Jhoffy is working on a bike and the parts are way cheaper. My suggestion is start from scratch-----Get a new big bore kit. Get a used head. The importance of the piston rings sealing to the cylinder walls cannot be stressed enough, when breaking in a new cylinder and piston. Jhoffy's is all ready broke in. Not 100 percent broke in, but by now there is microscopic divots that will never be sealed due to whatever murdered this engine.
Which is why I would get a new big bore kit.
I would do the work myself jhoffy. How else will you learn? Just verify the timing chain is set correctly and the cams are set correctly. The bike will start and run I promise.
Luckily Jhoffy is working on a bike and the parts are way cheaper. My suggestion is start from scratch-----Get a new big bore kit. Get a used head. The importance of the piston rings sealing to the cylinder walls cannot be stressed enough, when breaking in a new cylinder and piston. Jhoffy's is all ready broke in. Not 100 percent broke in, but by now there is microscopic divots that will never be sealed due to whatever murdered this engine.
Which is why I would get a new big bore kit.
I would do the work myself jhoffy. How else will you learn? Just verify the timing chain is set correctly and the cams are set correctly. The bike will start and run I promise.
Live and learn I guess. It's just that hopeless feeling of what if I go through with getting all these parts again and then the same thing happens? Unless I can identify what caused this, I cannot make a careless decision like that. I made sure that the timing chain was perfect, and turned the engine over repeatedly by hand before putting it all back together. I'll take this project on again, but damn is it going to be a hard road if the same thing happens again.
#49
06-29-2011, 02:30 AM
Join Date: Jun 2011
Posts: 592
I made sure that the arrow was facing forward. The piston was most certainly in the correct position, and you can tell from the picture I posted.
#50
06-29-2011, 02:32 AM
Join Date: Jun 2011
Posts: 592
This might be really dumb, but could shifting without letting off the throttle cause this to happen? I have a bad habit of sometimes just racing through the gears without ever letting off the throttle - all clutch.