Yamaha blaster engine noise after rebuild

[05crf450r]

Okay so I have a 1993 Yamaha blaster I got from a buddy. He put a new wiseco crank in and I just put a wiseco top end in it and honed the cylinder I also put new reeds in as well as a cylinder head. I started it up for the first time after the rebuild and immediately has to shut it off as I heard a grinding/squeaking noise when I revved it a little bit. It did not make the noise when idling but when I revved it up. I took the cylinder off and the piston looked like it has scraped somewhere. What could cause this?

 

[Awk08]

sounds like the cylinder needed bored to a new oversize piston, not just honed and replaced with the same size piston

what is the piston to cylinder clearence ?

 

[05crf450r]

I had bought a new cylinder and put it on at first and it had the noise then I took my stock cylinder and the noise got worse. I will look at the clearance and let you know

 

[99blasterzach]

I had bought a new cylinder and put it on at first and it had the noise then I took my stock cylinder and the noise got worse. I will look at the clearance and let you know

ebay special cylinder? ie a "brand new " fake yamaha clyinder or a real one?

 

[05crf450r]

ebay special cylinder? ie a "brand new " fake yamaha clyinder or a real one? View attachment 29445

I had bought one that you could say eBay special. I don't have the 400 for a new Yamaha oem cylinder. I had blown a top end bearing and it went through the top of my piston and banged around the top until it locked up. This makes me think the crankshaft is shot.

 

[speedyslyder]

looks like vitos super stock piston with the pied shaped exhaust side.
also that thing is toast no way bottom end is okay unless it all flew out the exhaust.
the cheap cylinder kits don't work.. kinda like shopping at a dollar store lmao

http://www.blasterforum.com/threads/anyone-ever-use-this-cylinder-kit.59677/

http://www.blasterforum.com/threads/niche-industries-top-end-kit.61580/page-2

 

[05crf450r]

Yes I had a feeling I'm going to try to use my stock cylinder and put a new crank in even though it has a fresh crank in it before this happened

 

[joeak47]

I would take the time and start fresh from the beginning by disassembling the lower end and inspecting the main bearings and crank.

 

[05crf450r]

Yes I had a feeling I'm going to try to use my stock cylinder and put a new crank in even though it has a fresh crank in it before this happened

I have done this before the cases into the transmission blew and sucked all the oil into the crankshaft then repaired the cases and I thought I blew the top end one night as I was riding and it lost all power but it ended up being a jet in the carb fell out. I put a different cylinder on and now it doesn't knock but more of a squeal or grinding at higher rpms

 

[Larry's Shee]

What all did you do/replace when pieces of a bearing tore up the piston ?
Could possible be damage to the lower end/ remaining shrapnel floating around.

IMHO a new piston should ONLY go in a fresh bore.

Time to tear it down and check it out closely !!

 

[05crf450r]

What all did you do/replace when pieces of a bearing tore up the piston ?
Could possible be damage to the lower end/ remaining shrapnel floating around.

IMHO a new piston should ONLY go in a fresh bore.

Time to tear it down and check it out closely !!

When it blew the bearing I had to tear the bottom end apart to repair the hole in cases so I cleaned everything out and inspected the crankshaft. There was no additional play in the bearing I just think the bore is out of round