old head, new valves. what needs to be done?

**kilabeez0** · 05-23-2008, 03:00 PM

i removed the old valves and ordered new ones through honda. this is for an 85 110 head. when the new valves get here what do i need to do to the head to make sure they seat properly? i've heard of lapping but i'm not sure how to do it. any instructions would be great. thanks.

**Erics350x** · 05-23-2008, 06:29 PM

buy a lapping tool from autozone and some valve grinding compound. put the compound on the outer edge of the valve seat area, insert the valves in there holes, and use the tool to spin the valves (like trying to start a fire with sticks) to seat them. Then clean em off good and install your seals,springs, and clips

**atctim** · 05-23-2008, 07:41 PM

once the stem is up through the head - a cordless drill works well to spin them - chuck the valve in the drill - just go slow and don't grind to much. Watch for the grinds to be "lapped" about maybe 3/32" or so.

**tbirdscott** · 05-24-2008, 01:18 AM

Do what atctim said, the drill makes things so much easier, it doesnt need to be cranked down tight on the valve, just snug it up by hand and spin, I usually switch directions back and forth a few times.

Scott

**SWIGIN** · 05-24-2008, 02:44 AM

this is how iv always done it

**Erics350x** · 05-24-2008, 09:02 AM

you can't get a drill in some heads

**SWIGIN** · 05-24-2008, 12:58 PM

you can in a 90 or 110.....i have a little tiny old 7volt cordless that fits great

**MTS** · 05-24-2008, 08:14 PM

You Seats on the head could probably use a cut,...takes bout 5 mins, you just need the right tools.

**lndy650** · 05-24-2008, 08:25 PM

lapping works but a 3 angle valve job is the best. if you do lap it, once it looks good push the valve in fast and all the compound should squirt out evenly if its a good seal. if that makes sense, its kinda hard to explain...

**kilabeez0** · 05-24-2008, 09:23 PM

so spinning the new valve in the head with the compound is what creates a good seal? the old valve looked pretty worn

**kilabeez0** · 05-26-2008, 10:02 AM

after seeing these pics, do you guys think i should cut the valve seat and then lap it? and is cutting the valve seat something i could do myself?

**lndy650** · 05-26-2008, 10:07 AM

its hard to find a person that can cut the valve seat you have to have certian tools to do it.
was it running with the valve like that? if not theres probably no damage to the head and just lapping it would work

**DIGGER DOG** · 05-26-2008, 10:28 AM

What was it that made contact with the valves? piston to valve ?valve to piston?
The tools for cutting valve seats are really $$$$$$ and you have to make 3 cuts
I would take the head to a machine shop to have the seats cut. if they need it
can you get us a pic of the head ?
I just hand lap and either use the suction cup tool or a fuel hose on the tip of valve
spin it back and forth a few times lift spin seat and spin back and forth a few times
and I always use fine lapping compund.And after looking at the pics again Id say yea re cut the seats

**kilabeez0** · 05-27-2008, 07:53 PM

what a money pit this is turning into. when i bought it, the motor had like no compression. i bored it out and have a new piston, the only reason i bought new valves is because I damaged one of them removing them from the head. I will take pics of the head tomorrow.

**kilabeez0** · 05-27-2008, 07:54 PM

these heads are really small, the machine shop couldn't believe how small the cylinder was when i brought it to them. i hope i can find someone that can cut them correctly.

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old head, new valves. what needs to be done?