I'm a numpty
 

My bike has had a little rattle ever since I bought it, but have never done anything about it as it hasn't hindered the performance.
About 3 weeks ago I thought that I would check the camchain adjusters as I'd heard that they can be a little lazy. I took the front valve cover off & had a tug at the camchain, it didn't seem too bad, but I'd bought a couple of manual adjusters, so thought I'd fit them. I removed the OE adjuster & heard a twang but thought nothing of it & fitted the manual adjuster, tightened it up, put everything back together & tried to start the bike.
There was a large bang & flames out of the carb. When I took the head off this is what I found, 2 bent valves [emoji17].
Moral of the story is, do everything by the book & don't assume that nothing has moved. I've now fitted a second hand head, checked the shims.... To the book & took her for a short ride this morning.
The old SV feels like a new bike, she revs really well, no stuttering & most of all, no ticking noise anymore. I was that impressed I even gave her a wash! https://uploads.tapatalk-cdn.com/201...da35534833.jpghttps://uploads.tapatalk-cdn.com/201...6c3032acce.jpg

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Re: I'm a numpty
 

Wow lucky nothing major was damaged Col

Re: I'm a numpty
 

I've been very lucky Mav. I won't assume again, that's for sure.
It did show up another problem. The previous owner couldn't be bothered to re tap the heads when the exhaust studs had rusted away, so he welded the clamp onto the knackered studs.
https://scontent-lhr3-1.xx.fbcdn.net...6c&oe=5DCAF3EC


I had a full standard exhaust under my bench & the new heads had studs fitted.
https://scontent-lhr3-1.xx.fbcdn.net...40&oe=5E0367E6

Re: I'm a numpty
 

Well the old exhaust and head weren't going to part company, were they :-)

Re: I'm a numpty
 

This is true. The old system was solid even after cutting the welds, I had to take a hammer to it to get it to come off

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Re: I'm a numpty
 

Oops! Lucky not to have done the piston in there Col!

We all do stuff like that from time to time though. :-(

Re: I'm a numpty
 

Luckily one bang was enough to make me check it. Looks like the piston metal is harder than the valves [emoji23]

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Re: I'm a numpty
 

Also the valves are at an angle so the stems bend (luckily theyre very slim on modern engines) when hitting the pistons which takes a lot of the force out of the impact. I imagine there must have been some sort of mark on the piston top?

Re: I'm a numpty
 

Not much of one to be honest. Very lucky indeed

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Re: I'm a numpty
 

Your right about the angle but its just enough that the piston hits the edge of the valve rather than the centre so Ive heard of quite a few cars doing it through cambelt failures and the pistons usually escape....