KX'er

Member
Oct 12, 2000
140
0
First off, I have a '00 kx250 that has been bored to a 310 and replated by US Chrome. I'm doing a topend after a few seasons of running. I've read all the posts about honing, and it seems many prefer just using a scotch bright pad. I don't have a hone, and am afraid that a machine shop may use the wrong type of hone, or screw it up somehow. Will a scotch brite pad work good enough? the bore has a smooth finish, I cant really see any crosshatch marks. Do auto parts stores usually carry aluminum oxide hones in approximately 74mm?

Also, the KIPS valve seems to have a slight catch in it, even after a good cleaning. Should I worry about that?

Thanks,
Matt

ETA: how does this hone look?
Nylon soft hone brush:
63-76mm 2.48”-2.99” W6077 4” 14” $54.51 (D0094)
http://www.wiseco.com/PDFs/Catalogs/CB07/Comp-ComprsrSleevesHoneBrushes.pdf
 
Last edited:

acesnkush

Member
Apr 29, 2006
86
0
I just helped my friennd with his top end end. I dont know if ide use scotch pad on the cylinder. We used emery clothe on the head and gasket areas to clean off the grime and carbon. But im pretty sure that when u hone the cylinder it almost needs a croshatched pattern (so i hear). We just brought the cylinder into honda to hone. Only cost 22 bucks and they did an emaculate job. To get a proper honer i can cost like 55 bucks, and u may only do tha job a few times.
 

KX'er

Member
Oct 12, 2000
140
0
Update- I called US chrome and they said to just rough up the surface with 320-400 grit sandpaper by hand is fine. A cross-hatch pattern is not needed in a plated cylinder.
 

KXtrailrider

Member
Sep 12, 2004
96
0
KX'er did you get your piston from Maxpower, and when, if not where and when? I hear they don't have any more. I have two 310 cylinders one with a maxpower piston, both are setup for that piston, the other with a modified LASleeve piston. That piston is working good but I had to move the ring gaps and cut a little ofr of the skirts. My home made ring gap pins make me nervous but I have put 10 hours on it and all is well. After another ride or two I am going to take it apart and inspect it. Thanks. Ed
 

matego

Member
Feb 17, 2007
27
0
US Chrome told you what? Did you talk to the receptionist there? A cross hatch is needed to seal the rings properly. The angled scratches hold oil for lubrication. If there are any vertical scratches, compression will be greatly affected. It is also very important to get the angle of the cross hatch correct. I am one for saving cash, but that is one of those things that needs to be done correctly.
 

KX'er

Member
Oct 12, 2000
140
0
KXtrailrider said:
KX'er did you get your piston from Maxpower, and when, if not where and when? I hear they don't have any more. I have two 310 cylinders one with a maxpower piston, both are setup for that piston, the other with a modified LASleeve piston. That piston is working good but I had to move the ring gaps and cut a little ofr of the skirts. My home made ring gap pins make me nervous but I have put 10 hours on it and all is well. After another ride or two I am going to take it apart and inspect it. Thanks. Ed


I got my piston from Max Power, where did you hear they don't have any more?
 

KX'er

Member
Oct 12, 2000
140
0
matego said:
US Chrome told you what? Did you talk to the receptionist there? A cross hatch is needed to seal the rings properly. The angled scratches hold oil for lubrication. If there are any vertical scratches, compression will be greatly affected. It is also very important to get the angle of the cross hatch correct. I am one for saving cash, but that is one of those things that needs to be done correctly.


No, I talked to one of the plating guys in the shop. I brought up that point, he said the cylinders only need to be deglazed. I was able to accomplish that with a scotchbrite pad. He said that the nickel carbide in the plating retains the lubrication, no need for crosshatching a plated cyl as in steel bores. They should know more about thier plating material that I would, so I'll trust them. Besides, Wiseco says the same thing..
 

matego

Member
Feb 17, 2007
27
0
You can make a emery paper hone in a pinch. Take a long 1/4 inch bolt and cut a slit down the middle. Put a long piece in the slot and wrap the emery paper around it so the grit is out. Then chuck the bolt in a drill and go to town. It will get you by, but it is not the preferred method. Did you check the piston to bore clearance? Usually if there is no cross hatch left, the cylinder is near the limit to its clearance. A bunch of piston companies make pistons that are a hair bigger than stock to take up the wear. Just do your best to get all the vertical scratches out and it might seal. Check real good around the ports for flaking.
 

KXtrailrider

Member
Sep 12, 2004
96
0
KX'er said:
I got my piston from Max Power, where did you hear they don't have any more?

I Thought Eric said that on one of the forums here. I already had the LASleeve piston so I was going to try it anyway. The LA piston has a window cut in it and the top cut for the stock head. The motor is real strong, may be stronger than my other one. Anyway it is good to hear they are avalible, thanks. Ed
 

KX'er

Member
Oct 12, 2000
140
0
KXtrailrider said:
I Thought Eric said that on one of the forums here. I already had the LASleeve piston so I was going to try it anyway. The LA piston has a window cut in it and the top cut for the stock head. The motor is real strong, may be stronger than my other one. Anyway it is good to hear they are avalible, thanks. Ed


They told me they had both regular pistons and teflon coated pistons. The one they sent me has a port on the intake side, my old one didn't. I assume this is for lubricating the wristpin and con-rod bearing? My old wrist pin had some definate wear. Is this from poor lubrication?
 

KX'er

Member
Oct 12, 2000
140
0
breezeair said:
I used scotch brite and easy off oven cleaner on my 00 yz250. It worked like a charm.


Did you take a compression reading after the rebuild? I'm going to check mine, I'll post my results from the scotch-brite/soapy water combo. Should have it together this weekend, waiting on a couple of gaskets.
 

KXtrailrider

Member
Sep 12, 2004
96
0
The window on the intake side lets fuel-air go up the rear boost port. On honing I have had good luck taking sand paper and rolling it and putting it in the cylinder then taking a 3 stone auto glaze braker and putting it in the sand paper and using a drill turn it and moving it up and down to make the cross hatch, the sand paper keeps the hone from catching the ports. I have done this many times. Ed
 

KX'er

Member
Oct 12, 2000
140
0
KXtrailrider said:
The window on the intake side lets fuel-air go up the rear boost port.

Ok, makes sense. What does that accomplish though, is it a lubrication thing or a performance thing?

Thanks!
 

breezeair

Member
Feb 8, 2006
89
0
KX'er said:
Did you take a compression reading after the rebuild? I'm going to check mine, I'll post my results from the scotch-brite/soapy water combo. Should have it together this weekend, waiting on a couple of gaskets.
My compression before the top end was 190 psi and two rides after was 235 psi.
 

KXtrailrider

Member
Sep 12, 2004
96
0
KX'er said:
Ok, makes sense. What does that accomplish though, is it a lubrication thing or a performance thing?

Performance, but you have a good point about more lub to the upper rod bearing. I have not noted any upper bearing trouble with my old MaxPower piston with no hole. On your new piston with the window in it, is the top (dome) of the piston just like your first piston? Thanks. Ed
 

KX'er

Member
Oct 12, 2000
140
0
KXtrailrider said:
KX'er said:
Ok, makes sense. What does that accomplish though, is it a lubrication thing or a performance thing?

Performance, but you have a good point about more lub to the upper rod bearing. I have not noted any upper bearing trouble with my old MaxPower piston with no hole. On your new piston with the window in it, is the top (dome) of the piston just like your first piston? Thanks. Ed


The pistons are identical except for the window and a four small holes drilled in the back of it.
 

KX'er

Member
Oct 12, 2000
140
0
Forgot about this post.... I'm getting about 185 psi after a few heat cycles. I have about 4 hours on the engine so far and will be taking another compression reading at about 10hrs. Seems like the scotchbrite worked ok.

Also, for reference, the piston wasn't the same. The skirts were slightly longer and needed turned down. It wouldn't clear the cases.
 

Top Bottom