Jump to content
Sign in to follow this  

Do I NEED to replate my cylinder?

Recommended Posts

Whats up guys? I own a 2001 Cr125 and I am in the proccess of doing my first top end (not the first time the bike has had one). I purchased a new piston, rings and gaskets. What I need to know is would replating my cylinder be my only option without causing serious problems or my new piston failing after like 3 rides....the top part of the jug is smooth as ever but the bottom has some wear.... no dings in the ports just on the walls.... there is no metal sticking out that will scratch the piston, its just one or 2 spots where there are some kinda deep scratches. i was wondering could i get away with using a scott pad and smoothing it out a bit and use it like that? I know the best thing to do is replate but im trying to save money.... what would be the result in using a scratched cylinder? also would a hone do any good?

Here are some pics after i cleaned it up a bit:

This is the worst part by far... and what is the black lines?

2hs2bnm.jpg

sl6ul2.jpg

4tsuom.jpg

ALL PICS WERE TAKING FROM THE BOTTOM AND OTHER THEN THOSE 2 SPOTS, THE REST IS SMOOTH AND CLEAN

Share this post


Link to post
Share on other sites

If you can feel the scrathes and stick your finger nail and it catches, need a replate. send to powerseal or millinium. around 200 to replate + shipping. your ports dont look all that dirty. Looks like you were running it lean. What mix ratio were you running? stock jetting?

Share this post


Link to post
Share on other sites

i def wasnt running lean... i ran 32:1... i just cleaned the jug before the photos lol.... and i forget what jetting i have in there i think i changed the needle position and the main jet... as far as replating goes, what would happen if i didnt relplate it this time and just smooth it out to the best of my abilities? also what about honing.... im a little confused of what honing actually is

Share this post


Link to post
Share on other sites

honing deglazes the old oil glae off the cylinder for the ring could seat. You could just get a scotch pad and soap and scrub it for a couple mins and rinse with hot water and let it dry. If those marks are smooth you can re- use it but if thers infact gouges, then def. replate. What needle position is it? What elevation?

Share this post


Link to post
Share on other sites
by elavation do you mean which groove?

no jetting has some what a lot to do whith jetting. You can google your town for elevation

Share this post


Link to post
Share on other sites

o elavation for where i live... i was confused for a bit lol.... it says that im at 125 feet

Share this post


Link to post
Share on other sites

o ok.... so what do do you recomend for jetting? i will be ridiing anywhere from 70-150 feet for the elevation....i have another problem as well lol... is it normal for the power valve assembly be very hard to pull out? im trying to clean my vavles but the arm wont slip out and im pulling hard as heck!! i tried spraying over cleaner all on them too but still nothing... any tips?

Share this post


Link to post
Share on other sites

depends on you for jetting/ what type of riding. Its probably hard to pull out casue its gummy with lots of carbon etc.

Share this post


Link to post
Share on other sites

yea but dude im going to town on this thing! anyways.... i cleaned the inside with a scotch pad like u sed and it smoothed the scratches out a little... still there but helped some.... u think i can get away with not replating untill i do my next top end?

  • Like 1

Share this post


Link to post
Share on other sites

might as well throw the old piston... Theres not going to be as much compression, the rings could stick, only going to get worse so.... you can do it but no gurantees. I woulnt waist a new piston like that

Share this post


Link to post
Share on other sites

yea the old piston is burnt and all scratched up... so if i replate it how often will i have to? if i get new pistons ever 20-40 hours u think that it wont get messed up anymore? and whats the websites to do this?

Share this post


Link to post
Share on other sites

way way longer than that, its like a new cylinder after. Depends if you maintain your bike well. powerseal or millinium

Share this post


Link to post
Share on other sites

ok i think im gonna go with millinium (they seem more legit and a bit cheaper).... i havent rode in over a year cause it wouldnt start and i never really had the money to fix everything and now that i have the new piston, i just wanna ride lol... bikes are so expensive to maintain its nuts! o yea, do i have to take everything out of the head including the screws?

Share this post


Link to post
Share on other sites

yes, including powervalve, or it will cost you extra etc. Read the instructions, they will tell you. Thought about sending it to gorr? Check his site also

Share this post


Link to post
Share on other sites

ok i did... about the same prices.... shoot if i knew that i would have needed to get a replate, i would of just got a big bore kit... cause i would only be paying about 50 bucks more... just my luck

Share this post


Link to post
Share on other sites

na, just get it replated with a port and polish, enless you like all top end, should get it ported to, imo

Share this post


Link to post
Share on other sites

ok... but what is porting exactly? is that to the head or jug? and can millenium do that too?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...