rebuilting a 1997 cr 125

[dansdr125]

what all....do i need to rebuilt my motor i think the rings are bad...the bikes smokes really bad and has no power... i changer the tranny oil air filter gas mix and even repacked the muffler....so do i just buy a piston kit and top end gasket kit..?

 

[mandark1967]

Smoking is not necessarily an indication that you need a top end rebuild.

What color is the smoke? Is it blueish? That's normal if you have a 2stroke. If so...

1 Is your jetting correct?
2 Is your air filter clean?
3 Is your float level set correctly?

Before you go tearing down your motorcycle engine, it's best to correct any jetting issues, clean your filter and adjust your float level.

If the smoke is a different color, then you "may" need to rebuilt your top end.

"If" you need a top end, you'll need the following (at a minimum)

Service Manual for your particular bike
Top-end gasket kit
Piston
Ring(s)
Wristpin
Wristpin circlips
Wristpin bearings
Radiator coolant (50/50 with distilled water in general)
Circlip pliers
Ring Compressor
Moly Grease (if applicable)
Small File (may be needed to file ring edges, if applicable)
New Spark Plug

If you do a top end without making sure your jetting is okay, you may very well be doing another top end 1 hour after your first one...

 

[dansdr125]

its a really white smoke with some oil...coming out the pipe and header

 

[dansdr125]

and whats good pistion and rings...?

 

[mandark1967]

Wiseco makes good pistons and rings.

Oil coming out the pipe and header is normal for a 2 stroke.

The white smoke would seem to indicate you are leaking some coolant.

Sounds like it's time to get that service manual and use it

 

[whenfoxforks-ruled]

When you pull the head off,look for signs of a leak.

 

[dansdr125]

yea..i dont have a manual....lol..ill have buy one on e-bay....but it smokes white and sprays oil...out really crazy...its not normal...all over the ground and my tire...

 

[dansdr125]

so how would it smoke white...if coolant... wuz leaking like on the piston..? or what...that would not mean a blown ring or whatever u call it with all the oil and smoke

 

[IndyMX]

so how would it smoke white...if coolant... wuz leaking like on the piston..? or what...that would not mean a blown ring or whatever u call it with all the oil and smoke

That would be a gasket leak... Head Gasket or Cylinder gasket.

Water doesn't smoke, so much as it creates steam, which will appear as White Smoke.

I might also suggest some english language classes. It will make your posts appear more intelligent and easier to read. :whoa:

 

[dansdr125]

ok...but i should do the piston...and rings anyways...right..?and thats the problem why im lacking power to

 

[IndyMX]

You should tear it down and measure the cylinder & piston, to see if they are out of spec. A service manual for your bike will give you all of the correct specs.

If all that is good, then you shouldn't needs to replace parts just yet.

But I would definitely put a new gasket set in there.

 

[dansdr125]

ok...i think im going to just put new piston and rings and gasket how hard is it to tear it down and remove the piston and rings and is there any special...tools u need and whats the tq spec..?thanks

 

[IndyMX]

ok...i think im going to just put new piston and rings and gasket how hard is it to tear it down and remove the piston and rings and is there any special...tools u need and whats the tq spec..?thanks

you will find all of that info in your service manual.

 

[dansdr125]

so buy one of them 30 dollar how to work on cr125 92-00 books...? is that what u mean

 

[91kx125]

what are signs of a blown top end

 

[84cr125]

no compression, you cant kick the bike over, metal grinding, melted aluminum on the spark plug, there are lots of signs.

 

[TheLadiesMan]

Just happened to notice this thread.

Im running into a problem with my 97 CR125 also. Just got the thing this past weekend, first time riding, and when I get back he asked me if I checked the coolant level.. I said no cause I expect the owner to do that before they lend the bike out. Anyway..

Rode the thing for a good few hours with no coolant in it apparently. I topped off the coolant level and when I start it, coolant gushes out of the over flow. I ran the bike for a min to see if it would get some of the air out with the rad cap off and then topped off the coolant again. Ran it again for about a minute. Checked the coolant and it was like black and oily and lots of white soapyness to it.. dur.. and there was plenty of whitish smoke coming from the exhaust while it was running. I can be just about certain that its a headgasket or something right? I did a general compression test on it (not a leak down) and it got up to about 150..

So I guess im lookin at replacing the headgasket and, if warped, the cylinder head..

Am I right in assuming this is whats wrong? Ive obviously got the manual unlike this other fellow and read through the stuff a few times already.

 

[TheLadiesMan]

Update: Lol.. just tore the motor down a bit.. took the cylinder head off and what not.. piston is scored to hell.. cylinder head is pretty messed up.. oil in all the water jackets..

Got a question that I cant seem to find the answer to in the manual.. Can I install the piston from the bottom of the cylinder head? With a car you go out the top and in the top. And, will a regular car ring compressor fit enough or do I need a special small engine ring compressor? All my real tools are at my friends place.

When you buy a new cylinder head, is it bare bones and all the little internals need to be swapped over or is it fully assembled ready to bolt in?