Tapping in and out may remove material or open up the hole slightly, heating head expands the alloy more than the guide so it comes out easier. Chilling the guide and warming the head during installation does the same thing. Should ream valve guide and recut the seats afterwards, nothing worse than a valve sticking when it gets hot because there was not enough clearance it could trash whole engine. If you hammer out and in as you did and open up the hole slightly, valve guide might not have the correct interference fit meaning it can move when engine gets hot. If you got away with it and it runs under full power you got away with it. I know because I know what you should do I would not get away with it.😀
Thanks for the info! I was planning on heating the head, but when I took a couple taps I was surprised how easily it wanted to come out so I went with it..! And good to know about the material loss, but do you think the new guides having the lip that holds the guide up in place will be ok? They needed a good amount of convincing to go in, so I cant imagine them 'falling out'. And I did have to ream the guide opening a little and got a Neway valve cutter and recut the seats, and lapped the valves!
The machine shop will ream and hone the guide once it’s installed, ensuring a perfect seal on the seat. Or you can just hammer it in your living room 😂
@@moforockband you always cut/stone the seat after a valve guide install. If the guide needed to come out then it normally means the valve was sloppy and wore the seat uneven. If you put a now straight guide in the seat needs to match it.
Yeah I should have, just jumped the gun then was surprised how easy they went in haha. I will be doing that on a CRF450r head next, interested to see the difference!
You need to heat your heads. I did two 2014 KX 250F and one 2016 CRF 450R heads and all 3 needed oven heated to allow valve guides to hammer out! I have a press but all were at a angle.
You have to cut/stone the seat after a valve guide installation. Also no machine shop would charge you $500 for that job. We do 3.4l chevy pairs exchange for $475 Canadian. A little dirt bike head isnt going to be nearly as much.
I used some valve lapping compound but there ended up being a knick on one of the intake seats that was causing a backfire, so I got a Neway cutter and refaced it! And the $500 quote I got was for new guides, new seats and recutting them with new valves.. How much do you charge for 4 new seats?!
You’re welcome! If the valves bend from hitting the piston, when the return up the will bust the tips of the guides and get pretty stuck :/ I guess you’re lucky you haven’t had this happen yet haha
Buy a $1 5x60mm Allen bolt and use a drift to punch out the old guides. The drift will allow subtle off center hammer blows to protect the ID of the soft bronze guide. Often these turned down tips will bend and not insert fully especially if the fit is valve tight, probably not so much for a 5mm drift and a 5.5mm I'd guide. I used a 3lb mallet and they came out just fine. Heating head and chilling guides makes install much easier as stated. You still saved $495....:-)
@@tieNagle Mine came out perfect. I actually found the last valve job I got was so far off axis of the original #4 exhaust that the valve wasnt even closing. I showed the head guy after I installed all 4 intake guides and he said the new guides were perfect, it was the old #4 exhaust seat that was ground wrong. He cut the #4 exhaust to the old guide and it turned out fine.
I got one from Neway that has some adjustability on diameter so I can do smaller exhaust seats and larger intake seats! Then it has the different angles too
Thanks! It was so much easier than I thought. I would encourage to hit lightly once the guide seats out, to avoid the mushrooming. If you have a press you are golden! The bike is running too.
We cut the valve seats as minimally as possible (30, 45 and 60 degrees), but there was a small gap on one of the intakes we needed to cut deeper for full compression. It allowed it to backfire a little, but has been resolved. The gouges in the head/combustion chamber have not been a problem, but the Honda dealership warned me these could create 'hot spots' and cause its own detonation separately from the spark plug going off.
3 года назад
Hi. Thanks for your video. Can you help me with an 4 stroke engine, please?? It got 2 admition valves and 2 exaut valves. Has new valves and new retenair but I got lots of smoke with oil at the exhaust aut. So the problem only can be at the valve guide. But the can't identify witch guides are broken. The 2 admition valves are OK, clean. Tne 2 guides of exhaust aut are full of coal. Can you tell me please witch guides I must change?? Many thanks. And cart on with the channel.
I think a more common way for oil to get into the combustion chamber is through the rings. I would test compression, or if you can spin the kick starter by hand, its probably too low and means bad rings. You could have a loose/leaky exhaust valve guide, but all the air is flowing out of the combustion chamber so I wouldn't think that oil is getting in and burning.. Let me know if you figure it out!
3 года назад
@@tieNagle thanks for your reply. It was the valve guides (exhault). The bike has lots of compretion. It is a problem to star it. Again, many thanks. Take care.
We are referring to the surface of the valve seats and how well they mate up to the new valves. After I did valves I used a valve cutter to get a new face on the copper valve seats. Then you should use a valve lapping compound to spin the valve on the newly cut seat and mate them together. Does that all make sense?
@@tieNagle yes man I thought you guys were talking about the dang valve guide hahaha man thanks to you I was able to do it I broke the guide on my 660 saw muiltiple videos with presses and I tried it with a press I couldn’t so I just heated it up nicely put wd40 taped the old one out and it took a while but I was patient yours came out faster than mine and then with the new one I heated the area up very nicely put some high temp lubricant and tapped the new one in slowly and it went in with no issues thanks once again man be safe 🔥🔥
To machine shop or not, the guys in my area do great work and always pleased with end result but don't expect it to get done in any resonable time frame but like most things these days its who and how you know people sadly.
noooooo!!!!!! calienta la tapa en agua hirviendo y no golpee!!!!! con un extractor , luego calienta la tapa y enfria las guias . ESTA EN EL MANUAL DE TALLER LA EXPLICACION. Saludos