XS Broke down tonite!! Thoughts???

xscessivecompulsive

xscessivecompulsive

Live 2 Ride, Ride 2 Live
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Ok guys check this out! My bike has been running like a top after a fresh top end rebuild and broke down on me tonite! So a little history, The reason why I re built the top end was I had burnt exhaust valve on, (if I remember correctly the right side)! I took the head in to a very good machine shop and had them go over it! I replaced both exhaust valves with stainless ones from Mikes and the machine shop told me keep the same stock intakes as they appeared to be in good shape! After I got the head back, I purchased Mikes 650 stock cylinder kit with pistons,jugs, rings and installed! I had a brand new cam chain, a really good used cam and rockers and put it together to spec! So tonite Im taking a ride and while riding, I all of sudden heard a noise like something came loose and was rattling around in the engine! Right after that the bike acted like it was running on one clylinder and starting popping out of the right side exhaust! Just like before when I had a burnt valve! Now if that is the case again, what the hell would cause it to keep burning up a valve! Im running great scott pipes and pods, and after I did my first oil change I took a look at both plugs and they were the light gray tan color! So Im really scratchin my head on this one and to be honest dont know what the hell to think?? You guys have any suggestions on what might be going on?? Thanks in advance guys!

XsC
 
Did you take the valve adjustment covers off for a look yet? In my experience a burnt valve wouldn't rattle; the eroded piece would just go out the exhaust. If a keeper wasn't in right and the valve fell in it would make a lot of noise.
 
No, I havent done that yet, as it was getting late and I had to have a buddy come get me and trailer it back to my work! Im going in early tomm to take the covers off and take a look! I just dont know what could be going on, it ran so solid and I put a good amount of miles on it since the re build and now this again??

XsC
 
Might not be the same reason as last time. I feel bad about your bad breaks!
 
Thank guys, really appreciate it in this time of misfortune! And Xjwmx, if that was the case that a keeper came loose and a valve was rattling around do you think my whole top end is fubar?? That was my first thought that something came loose and I only rode about a couple blocks before I could find a safe place to pull over!:banghead::mad:

XsC
 
I don't know that that happened. It was just a wild guess at a valve problem that would make a loud racket. I would not be able to go to bed until I looked though.
 
I know Xj, and Im feeling the same way! Reason why I never took a look was I left my shop keys at home thinking theres no way I need all this extra stuff in my pockets while I go out for my evening ride so I left em at home! Then I realized I dont have my keys and my tools are inside! Needless to say it will be a sleepless night and I will be at work at 3:30 am to try and figure this out........

XsC
 
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Hey Guys, So I went today and took off the valve covers to see if anything looked strange! My right side exhaust valve was way off and you could easily move it up and down and there was tons of play up and down! I then checked compression and had around 125 on left side and got a zero reading on the right! The head just came back from the machine shop where I had two brand new stainless valves from Mikes installed. That is all I can think of at this point, is that something went wrong with my valves again, and dont know why it would keep happening! You fellas have any other suggestions??

Thanks,

XsC
 
Yes Im getting oil to the top end, I think its something going on with the exhaust valve on the right side! Guess im gonna have to pull the engine tomm and dis assemble!! Again..........

XsC
 
If you need to remove the head again, I would go for "standard" exhaust valves instead of the stainless ones that you have. I heard a couple of stories of other guys having problems with them.
 
Ya guys, everything looked fine in and around the valves! And more than likely the head will have to be pulled, and Ive also read about guys having problems with the SS valves! The reason why I ordered them the first time was because everywhere was sold out of the standard valves and I think that is still case!! So now Im tryin to figure out where in the hell I can get a set? I guess time will tell when I tear it apart! Just have a sneakin suspicion the exhaust valve is bad on the right side!

XsC
 
Which year is your XS? Try with this website, I look at a couple of years and the exhaust valve seems to be the same. They have 32 in stock. They are not cheap, around 80 bucks each, but I think they are NOS parts. I already order parts there and everything was ok. I give you the link just in case you don't find them anywhere and you want to replace your valves anyway ... Did you look at 650central ?

http://216.168.60.165/speedandsportinc/CatalogresultsIndex.tpl

I also find it on eBay ...

http://cgi.ebay.com/ebaymotors/1975...rcycles_Parts_Accessories&hash=item3a64aa1423

http://cgi.ebay.com/ebaymotors/Yama...rcycles_Parts_Accessories&hash=item2562634744
 
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xscessivecompulsive said:
Thanks 72XS2, My bike is an 81. And I will take a look at the link you shared!

Thanks again,

XsC
Click to expand...

I looked on the first website and the exhaust valve are the same for all years, Yamaha part number #341-12121-01-00. So, if you find a good used set from another year, il will fit perfectly.

Wish it will help you, good luck !
 

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