top end

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brodie filipek

Member

Mar 28, 2008

5

0

• Mar 28, 2008

• #1

Need help fast! ( top end rebuild )

i have a ktm 125sx 2001 model. i just bought it last year in november fully rebuilt and i have road it around alot and i think it needs a top end rebuild. How do i tell if it needs one or not?

 

Last edited: Mar 28, 2008

X

xkevenx

Member

Dec 4, 2007

95

0

• Mar 28, 2008

• #2

feel your compression, if you feel it lacks then you should change it, and you could check your piston itself, for scratshes and stuff thats the only way, just open it up!

 

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Coop

Member

Jan 21, 2000

153

0

• Mar 28, 2008

• #3

A compression test is your best bet. Get a tester, screw it in the spark plug socket, hold the kill switch, open the throttle and kick until the gage stops moving. A 125 should have approx. between 150-190 psi.

 

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Clint3240

Member

Oct 21, 2007

61

0

• Mar 28, 2008

• #4

quick way is to puch the bike in gear or hold your thumb over the spark hole and if it blows off you could be ok.

 

IndyMX

Crash Test Dummy

~SPONSOR~

Jul 18, 2006

5,548

2

Amo, IN

• Mar 28, 2008

• #5

Clint3240 said:

quick way is to puch the bike in gear or hold your thumb over the spark hole and if it blows off you could be ok.

Click to expand...

Errr.. No it's not.

That will tell you absolutely nothing.

 

G

griffbones

Member

Sep 12, 2006

329

1

• Mar 28, 2008

• #6

The compression tester is the only way to really find out how much compression the engine has. Even a compression test will not tell you the story on the top end. There can be wear present, but that doesn't always mean that the compression will be low. Sometimes routine maintenance and a visual inspection is the only real way to tell what shape things are in. IMHO

 

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brodie filipek

Member

Mar 28, 2008

5

0

• Mar 28, 2008

• Thread starter
• #7

thanks guys for your help

cheers!!

 

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brodie filipek

Member

Mar 28, 2008

5

0

• Mar 28, 2008

• Thread starter
• #8

my mates always say after 30 hours your bike is due for a top end rebuild. Is that true?

 

R

RM85rider123

Member

Oct 28, 2007

681

0

• Mar 28, 2008

• #9

brodie filipek said:

my mates always say after 30 hours your bike is due for a top end rebuild. Is that true?

Click to expand...

it depends how you ride. if you race, maybe every 12-15 hours. for trail riding, it depends.