Bent exhaust valves!

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Bendo600

Bendo600

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Hi all, have a atomik fuse 150cc. Brought bike secondhand, bike worked fine. Was riding bike - just stalled. Then no compression. Took it to bike shop and it had a bent exhaust valve. $180 later. Got about one hour of riding then the same thing again. Took it back to bike shop replaced valve again, checked cam chain, said chain looks good they shaved the head to give a bit more clearance, got about 40mins and same thing again. Rang bike shop again and he is stumped and to busy to look at til after Xmas. Does anyone have any ideas? Cheers
 
did you check the valve clearances?

shaving the head will give the valves less clearance, and if the valves arent adjusted correctly they'll hit the piston
 
my67xr said:
did you check the valve clearances?

shaving the head will give the valves less clearance, and if the valves arent adjusted correctly they'll hit the piston
Click to expand...

Like My67xr just said might pay to check em yourself (or get someone else too) cause if you shave the head it'll give you less clearance not more??? Something doesn't sound right there...
 
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Shaving gives you less clearance and more compression, if they think that is giving you more clearance you're probably going to bend every valve that enters that engine, and if they didn't shave it dead flat it will probably leak a **** load of compression. Best to learn your self mate, it will make you learn allot and make it easier for you to understand future issues.


There is tonnes of tutorials on here so your best bet is to dive into them and have a crack at something new.
 
A chain will always look good, but without removing it and measuring it up to a new one its hard to tell. Id replace the chain with the next rebuild, and not knowing how much was shaved it maybe time for a replacement head.
 
They may of shaved down your cam chain adjuster block to allow the cam chain adjuster to tighten more.
Check the make sure the fly wheel is located on the key properly.
Replace the cam chain to rule that out.
See where the valve is hitting the piston and take a bit out of the piston to stop it from touching.
 
Thanks guys, sorry he shaved the top of the piston not the head. Will have a go myself. Where is the best place to get valves and cam chain? What about gaskets, is there ones made to fit or just go to supercheap auto and get gasket paper ect? Thank for the insight.
 
where are you up the sunny coast mate? there is a fella on this site who is a mechanic and knows his stuff. sean01 is his tag on here mate....and if you want gaskets depending on how far you wanna drive.. but i could buy you a set and send em to ya.. you could just reimburse me for em...
 
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Thanks Tim, I live in caloundra. I have herd of small wheel deals. Is that where you go or is there somewhere else that is better?
 
fella i go to is on the south side.... near old cleveland road.... so thats a mission and a half for you... he does have an ebay store.. and might have some gaskets on there... i think the store name is motox nuts.... or something like that..
 
Is it better to buy a new head with valves or just try new valve kit, as a newbie. I don't want to spend money on valve kit, gaskets and doesn't fix the problem as already spent $200 and bent 3 valves and just piss the mechanic off, don't want to spend $400 in total and still not working. When I could just get at new motor for $450? What do you guys think?
 
I think you are running the older style yx 150(looks like a yx140 but is a 150) honestly if the problem persists your right, you are just wasting money, if you want to go the repair i have a old style yx 150 in pieces and the head is in good condition with straight valves and good cam and can help out if you want to. Can you post pics of your engine mate.
 
Yeah that's the old style yx 150, let me know if ya need a 2ND hand in good condition head mate
 
Its all over at my bosses place , so ill duck over there today and grab it, but im thinkn $25 for the head and $15 for postage and handling fees, so i reckon $40 should cover it fine. Ill PM you before purchase just so i can grab it and do a quick seal test on the valves and AOK it. Is $40 reasonable for you mate?
 
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