Thegreanest
Registered
Let me start by saying, I'm pretty darn mechanically inclined, I work on all my own stuff, but I've never built an engine before.
Soooooo, I was doing some top speed runs with my 99 busa with an rcc stage 1 kit, and after 2 back to back runs the motor gave up.
It just stopped accelerating at 10k rpm in 5th at about 178mph.
As I slowed down motor spewed 90% of it's coolant out of the overflow reservoir cap that must have been blown off and started knocking and died once it dropped down to idle.
I've since completely torn down the motor, and what I found hurt my soul deeply.
Attached is a picture of the piston from cylinder 4.
So some quick background on this bike, it was built in 2012, has.... Well had lol, a balanced gen 2 crank, carillo H-beam rods, je 81mm 8.7:1 turbo pistons, base spacer, web 70-751 cams with ape adjustable sprockets, valve springs, head studs and a few other things.
Along with an rcc stage 1 kit from 2012 when they were using comp turbos.
And was making 9-10psi of boost.
I bought this bike from the guy who had it built only a month ago, only rode it about 1000 miles, so I'm pretty bummed about it giving up so soon, but sometimes that's just the way life goes, right?
Anyway, back to the blown motor...
So as I tore this motor apart, I found that 3 of the 4 pistons had broke, and 1 of those three (the one pictured) had a hole melted in it.
Aluminum bits were everywhere, beaten badly into the head and embedded into the cylinder wall on cylinder 4, in the oil pan, sitting on the pistons.... It was bad.
I don't know much, but I think it was and intake temp and/or fuel issue causing detonation that caused this.
Anyway, from what I can tell (again, new to this) the crank and rods appear to have not taken any damage, and I will be taking them to a machine shop or something to verify that.
Everything else except for the head, pistons and cylinders seem fine.
The cylinders may be reusable but would probably need bored to 83mm.
But... Let's move on to some questions.
How "safe" is an 83mm bore for boost?
I know it'll reduce head gasket surface area by a bit, but is it doable for a street ridden bike?
Do y'all have any insight on what could have caused this?
How much power could I make on the parts listed if I did an intercooler and a secondary fuel system?
Any other advice on rebuilding this motor for a little more power?
Will add more pics soon
Soooooo, I was doing some top speed runs with my 99 busa with an rcc stage 1 kit, and after 2 back to back runs the motor gave up.
It just stopped accelerating at 10k rpm in 5th at about 178mph.
As I slowed down motor spewed 90% of it's coolant out of the overflow reservoir cap that must have been blown off and started knocking and died once it dropped down to idle.
I've since completely torn down the motor, and what I found hurt my soul deeply.
Attached is a picture of the piston from cylinder 4.
So some quick background on this bike, it was built in 2012, has.... Well had lol, a balanced gen 2 crank, carillo H-beam rods, je 81mm 8.7:1 turbo pistons, base spacer, web 70-751 cams with ape adjustable sprockets, valve springs, head studs and a few other things.
Along with an rcc stage 1 kit from 2012 when they were using comp turbos.
And was making 9-10psi of boost.
I bought this bike from the guy who had it built only a month ago, only rode it about 1000 miles, so I'm pretty bummed about it giving up so soon, but sometimes that's just the way life goes, right?
Anyway, back to the blown motor...
So as I tore this motor apart, I found that 3 of the 4 pistons had broke, and 1 of those three (the one pictured) had a hole melted in it.
Aluminum bits were everywhere, beaten badly into the head and embedded into the cylinder wall on cylinder 4, in the oil pan, sitting on the pistons.... It was bad.
I don't know much, but I think it was and intake temp and/or fuel issue causing detonation that caused this.
Anyway, from what I can tell (again, new to this) the crank and rods appear to have not taken any damage, and I will be taking them to a machine shop or something to verify that.
Everything else except for the head, pistons and cylinders seem fine.
The cylinders may be reusable but would probably need bored to 83mm.
But... Let's move on to some questions.
How "safe" is an 83mm bore for boost?
I know it'll reduce head gasket surface area by a bit, but is it doable for a street ridden bike?
Do y'all have any insight on what could have caused this?
How much power could I make on the parts listed if I did an intercooler and a secondary fuel system?
Any other advice on rebuilding this motor for a little more power?
Will add more pics soon
