sanding cam bearings???

I have a 1980 kz 1000 ltd with a 1075 kit 10 to 1 comp. I had some problems with the orginal head. My brother had a j head that was in good shape that i got for little of nothing. I got it all prepped for my bike, ape idler clearenced and ready to install. My jug has been milled .017. So i hopefully will only lose little more than 1 point compression, if i figured correclty. The question i have is. My cam bearings got some scoring on them and i wondered how deep the grooves can be and still be sanded out. I really want to buy new ones but some medical issues took up all my kz stash cash. I had another buddy told me to buy used ones, but i dont think that would be to good idea? Any help would be greatly appreciated.

Plastigauge.

Do not sand or scrape the bearing shells it will make them scrap if they are not already.
Leaving them alone would be the lesser of two evils.

If they are very badly scored or worn through the white metal then replacing them with good used items is ok if getting new ones is a problem at the moment.

mine were scored due to lack of oil to the top end, u can sand the cam journals but not the bearings, get new ones period, used ones may been overheated unbeknownst to u and while not scored ,still could be suspect, this is something u dont want to cheap on

Two of the last three responses are completely incorrect. :dry: Sanding cam bearings is not uncommon, post pics or pm larryc he can tell you without doubt if the are worth saving.

Thanks for the help everyone ill try to get some picutures posted later. i wanted to get the bike back together before summer gets here if possible. My orginal head was junk, stripped threads and broken tach drive. and it seemed like when you drove it and it got warmed up the valves got really loud like they need shimed, but when you got it apart the clearences was in spec. so i got this other head. i sandblasted the jug and head and started polishing them. ill try to get some pictures posted later. I also got a set of psp-3x cams on the way. I am trying to decide if id be better off running my stock 28 carbs or if should try and put my set of rs 36s on there, that i have sittin on the shelf?

andy9802gt i think i might have saw you last summer. i go though fort wayne once or twice a week. Your bike looks really nice. How do you like your 8 over extended swingarm? Mine is 4 over, i thought about going longer but i went with the 4. The picture in my sig is what my bike looked like when i got it . I need to get new pictures up.

Powerstroke_fan wrote: Thanks for the help everyone ill try to get some picutures posted later. i wanted to get the bike back together before summer gets here if possible. My orginal head was junk, stripped threads and broken tach drive. and it seemed like when you drove it and it got warmed up the valves got really loud like they need shimed, but when you got it apart the clearences was in spec. so i got this other head. i sandblasted the jug and head and started polishing them. ill try to get some pictures posted later. I also got a set of psp-3x cams on the way. I am trying to decide if id be better off running my stock 28 carbs or if should try and put my set of rs 36s on there, that i have sittin on the shelf?

With a J head, KZ pistons & that particular grind of cam, the bottom end torque is going to be less than stellar. It will pull hard from about 5000RPM on up. May as well put the 36's on it and get the most from the upper mid range power. If you don't like the result, you can swap the boots off your KZ head and try the 28's.

Don't misread that as a "slam" against those cams. It's not. Building a motor is mostly about putting the components in it that will suit the way you realistically ride the bike.

If you want to really wake it up, a full on port job with GPz11 Intake Valves with the correct pistons to get the dynamic compression ratio up where it belongs would do the trick. You'll be grinning all day long.

If you and your brother want to take a go at the head, copy this shape. I'd give you dimensions but this if for a 1260cc motor with K435 cams & RS36's. This is just roughed out...not finished

Thanks Larry, I appreciate you sharing your knowledge with us. And i didnt take that as a "slam" i know your just speaking the truth. I want to just send you the head this summer if funds allow it.If i could sell my turbo stuff that would get me close to having it there this winter lol. do you think just being one point off on compression will make that big of diffrence? I almost always run 50/50 on the fuel (premimum/110 octane race fuel).

Larry, why didn't you address the question about sanding cam bearings?

Personally, I don't see the advantage to any process that leaves abrasives embedded in a bearing surface.

Powerstroke_fan wrote: Thanks Larry, I appreciate you sharing your knowledge with us. And i didnt take that as a "slam" i know your just speaking the truth. I want to just send you the head this summer if funds allow it.If i could sell my turbo stuff that would get me close to having it there this winter lol. do you think just being one point off on compression will make that big of diffrence? I almost always run 50/50 on the fuel (premimum/110 octane race fuel).

Long duration cams need compression to prop up the area under the torque peak. It's just that simple. Joe Hooper sells a specific set of pistons for use with those particular cams to help that situation. MTC can also make you a set for the J head chamber. Think combo, combo, combo!


Steel,

I don't get into a lot of those discussions anymore because it's a pissing contest. Had my fill of stupid shit on the Internet I'll say this much about it. I have prepped hundreds of cam bearings with 600 & 1000G paper. NEVER had an issue with it. It's very common to find that even new cams don't spin free when they're checked. I correct that.

In all the heads I've ported or done valve jobs on, I've only had one come back with a top end oiling problem. It wasn't from the cam bearings being prepped either. I had the guy pull his oil pan snap a photo of his oil pump... You be the judge :whistle:

I had him send me the head back. I took it all apart, went through it again, installed different bearings cause his were toast and sent it back....NO CHARGE....

FWIW.... the guy is above average in intelligence and intellect. He just didn't figure the pump should have been pulled when he went through the top end.... Another case of SHIT HAPPENS

While we're on this subject, consider this. Cams don't generally fail at the journal. They fail at the lobe. Everything you can do to assure less stress on the lobes by eliminating friction is a point in your favor