Valve bucket emergency

kb22
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Knoxville, TN US
6/28/2021 9:06am Edited Date/Time 10/8/2021 2:16pm
I need some serious help here, so I needed my head rebuilt on my 2015 yz250F so I did a bunch of research and found a guy out here that was local and figured I’d give him a go. Well that turned out into a 3 month run around. Anyways I ended up getting my rebuilt head back and everything looks great. unfortunately it was late so I was in the middle of moving from Tennessee to Michigan, which is where the shop was. So 3 weeks later here I am putting it all back together.

On the last valve bucket I got some major resistance ( exhaust valve kick starter side), it got stuck, so I massaged it out and tried that exact same bucket in the other exhaust valve and it got amazingly. Obviously I didn’t leave it in there but while I was at it I tried the bucket from said valve and it also did not fit. So it seems to be an issue with this valve site not the bucket. Does anyone know what to do? I’m pretty tired of taking this thing apart and putting it back together and it’s been apart since the whole head extravaganza began so it’s pretty useless at this point.

Thanks in advance for the help and allowing a guy to blow off some steam in a rant.

Keith
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kb228
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Mansfield, OH US
6/28/2021 9:14am
Have you tried swapping exhaust valves and springs to the other side? Maybe its the spring he used
kb22
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Knoxville, TN US
6/28/2021 9:26am
I had him use stock springs and valves throughout, would the spring be color coordinated for exhaust valves?
btroxler
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Saltillo, MS US
6/28/2021 9:46am
Make sure the bucket is clean and also the cylinder it rides in is also clean. Spray them out with some non chlorinated brake parts cleaner. They may have bead blasted the head and could be some blast bead media that is causing it to be tight.
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kb22
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Knoxville, TN US
6/28/2021 11:02am
Like this?

The Shop

kb22
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Knoxville, TN US
6/28/2021 11:05am
Sorry here we go, didn’t say chlorine but wanted to make sure

Paul_Pitzonka
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Grand Terrace, CA US
6/28/2021 11:13am
Is the bucket getting stuck in the head or is the valve sticking in the guide? Were the guides replaced??
kb22
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Knoxville, TN US
6/28/2021 11:32am
Everything was replaced guides and all. The bucket is getting stuck in the head, I tried swapping the exhaust buckets and they both worked in the other exhaust valve but neither worked in the problematic valve hole.
Paul_Pitzonka
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Grand Terrace, CA US
6/28/2021 11:34am
kb22 wrote:
Everything was replaced guides and all. The bucket is getting stuck in the head, I tried swapping the exhaust buckets and they both worked in the...
Everything was replaced guides and all. The bucket is getting stuck in the head, I tried swapping the exhaust buckets and they both worked in the other exhaust valve but neither worked in the problematic valve hole.
Is there any scoring on the bore that the bucket rides in? I’d pull the spring and make sure the valve isn’t too tight in the guide as well...
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kb22
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Knoxville, TN US
6/28/2021 4:00pm
So after spending a 1060 on this head it looks like he may of done something to alter the bore because I have a stuck intake and the exhaust one still won’t fit even after I took the head apart. So that was awesome, won’t be riding this year. Thanks for all the help anyways all, wish it would of turned out better.
PNWRider
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Stanwood, WA US
6/28/2021 7:37pm
Guessing he didn’t get the guides in or reamed straight. With the valve out of alignment it would push the bucket off-center, making it not fit the bore. It also likely means the valve wouldn’t seal against the seat as the valve head would be out of alignment.
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kb22
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Knoxville, TN US
6/29/2021 9:25am
It shouldn’t be warped, the seats and valves look great but now that it’s mentioned above that makes sense. It looks like the bucket bore was nicked on one and idk about the other bore because the bucket went in smooth but is not coming out. I reached out obviously because he’s local and wanted to give him the chance but was told I didn’t pay for a clean up of the bucket bores. Even though I test fitted everything prior to shipping to him. I’m taking the easy way out and whenever I have money again, I’ll send it to millennium. Hopefully it just needs a couple buckets and clean up. It was just one of those situations that went to hell after the head was shipped, oh well.
garagedog
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Tulare, CA US
Fantasy
802nd
6/29/2021 12:50pm
Use a strong magnet or maybe put a heat gun on the head to get it out.

Maybe there is a little burr. Sand paper might do the trick.
1
kb22
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Knoxville, TN US
6/29/2021 1:05pm
I’ll try and get it out that way thank you, not sure this is one of those I can that to though. What do you think? Might be hard to see
kb22
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Knoxville, TN US
6/29/2021 1:06pm

DynoDan22
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Location
Victorville, CA US
6/29/2021 3:01pm
Looking at the tappet bore, it looks like the engine guy either smacked the tappet wall while replacing the valve guide or hit it accidentally with the valve spring compressor causing a nick. I've seen this happen a lot with sketchy builders. I always cut up some thin plastic tubing and insert it into the tappet bores to prevent this. Hope you get things sorted and back riding soon!
1
kb22
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Knoxville, TN US
6/29/2021 6:39pm
Thanks for the input! I hope so as well, I found a local guy recommended by moldstar to install moldstar 90 intake valve seats and unfortunately he was a jack off. Well see if PayPal is all that they’re chocked up to be.
RyanLester761
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El Dorado Hills, CA US
7/1/2021 9:02am
garagedog wrote:
Use a strong magnet or maybe put a heat gun on the head to get it out. Maybe there is a little burr. Sand paper might...
Use a strong magnet or maybe put a heat gun on the head to get it out.

Maybe there is a little burr. Sand paper might do the trick.
Agree 1000%! I've seen this a few times. You just need to deburr/sand down any high spots and get on with life. It shouldn't be that big of a deal.
kb22
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Knoxville, TN US
10/7/2021 3:13pm
Update: found out that the guy here in Michigan that did my head absolutely butchered it and my seats were well past nominal. Huge thanks and shout out to millennium tech who cleaned it up and delivered an absolutely amazing head! Bike is up and running again and it feels great to be back on it.
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Sandusky26
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Eastern, NC US
10/8/2021 2:16am
kb22 wrote:
Update: found out that the guy here in Michigan that did my head absolutely butchered it and my seats were well past nominal. Huge thanks and...
Update: found out that the guy here in Michigan that did my head absolutely butchered it and my seats were well past nominal. Huge thanks and shout out to millennium tech who cleaned it up and delivered an absolutely amazing head! Bike is up and running again and it feels great to be back on it.
I read this thread before I sent my head off for new valves, it definitely scared me. Glad you got back running.
kb22
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Knoxville, TN US
10/8/2021 4:50am
Yeah if I would of been able to run that head it would of been catastrophic, learned to always go with a well known shop instead of a local guy. Hope yours turned out well!
Sandusky26
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Eastern, NC US
10/8/2021 7:00am
kb22 wrote:
Yeah if I would of been able to run that head it would of been catastrophic, learned to always go with a well known shop instead...
Yeah if I would of been able to run that head it would of been catastrophic, learned to always go with a well known shop instead of a local guy. Hope yours turned out well!
It went good, Bundy Built is in NC so I went with them, bike runs great. I’m just glad to be done shimming valves.
Timo
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Wichita, KS US
10/8/2021 2:16pm Edited Date/Time 10/8/2021 2:16pm
On an old 98 WR400F I used a brake piston hone on one bucket bore that was sticking, worked great after that.
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