I blew it

[BlairGreen]

I was riding 2 weeks ago I went to shift to second I missed and hit neutral and boom. No compression. Cylinders scored pretty bad. My uncle wants to get it bored and ported by protec. Are they any good? He's been racing and building mx bikes and quads for 40 years.

 

[Blaaster]

Others may chime in about Protec, I have no experience with them, PM me for my favourite builder.

Leak test after you replace the top end, over revving seldom blows an engine, I fear the damage was done well before you missed a gear.

The gear miss could have been the final straw that broke the camels back.

 

[BlairGreen]

The rebuild when we first got it lasted 3 years and the rings they had on were terrible I think the over rev finally broke them . It was a good run on a bad rebuild. The quad was free too so it was a good run

 

[harley1-5]

not bad for a free blasty

 

[Blaaster]

Not trying to be a Dick, but I have heard the story many times that it was a bad build and inferior parts were used.

My guess is that you developed and air leak or ran a lesser than optimum AFR which over time has damaged the piston and rings.

When was the last time the engine was tested for air leaks, it should be tested at least once a season?

 

[BlairGreen]

I really never checked it. We did 2 times last year and once after we rebuilt it. It was a beater. I'm literally not lying about the bad parts. The owners before took the rings on and off because they didn't know how to rebuild it. I know people use that excuse, but the previous owners didn't even line the rings up with the mark on the piston

 

[Blaaster]

If the rings were not lined up with the locating pins on the piston, there is no way that the piston can be inserted into the cylinder.

The locating pins must have been removed and that is what could have caused the rings to break as they migrated and snagged a port.

 

[motoman159]

If the rings were not lined up with the locating pins on the piston, there is no way that the piston can be inserted into the cylinder.

The locating pins must have been removed and that is what could have caused the rings to break as they migrated and snagged a port.

listen to this man, he knows a little bit

 

[BlairGreen]

I don't remember how they were, but I remember them not being lined up, and we took them out again to fix them. And taking them in and out isn't too good for them

 

[joeak47]

Dude...your missing the point.
The rings can go in only one way. If they don't , the piston won't go in.
Perhaps the piston was put in backwards?

 

[BlairGreen]

No but I'm saying they were taken on and off a lot. We got the quad in pieces the engine was not together. The piston and rings were separate because the idiots before us couldn't figure it out. That's why they had wear from being taken on and off

 

[Blaaster]

Rings do not wear from being taken on and off, rings wear from abuse whilst reciprocating in a cylinder bore.

Holy crap I have to do a lot of reading to get to understand modern technology if ring specifications have changed that much.

I fitted a set of rings yesterday and they look the same as they did 10 years ago, what has changed to make them wear whilst handling.

I am off now to wipe the smile off my face.