1983 cr 125

[newfiebullet]

just picked up a 83 cr 125r that needs a little tlc. Anybody know how much and what kind of gear oil this thing needs? I know i need to mix the gas-oil 32:1, other then this is gear oil the only oil i need to add. The bike never ran in years and has a head gasket blown. When i took out the drain plug it looked like pure water was coming out??? it half filled an ice cream tub then some thick milky oil dripped out at the end. any input to this? all info\input for anything to do with this bike would be great thanks

[MXtras]

The milky crap is likely coolant and oil mixed. Likely source? -> water pump seal/shaft.

Before you run this thing, I would strongly suggest that you closely evaluate the entire bike. Sometimes a few hours or work can save you a lot of headaches.

Scott

[newfiebullet]

Originally Posted by MXtras

The milky crap is likely coolant and oil mixed. Likely source? -> water pump seal/shaft.

Before you run this thing, I would strongly suggest that you closely evaluate the entire bike. Sometimes a few hours or work can save you a lot of headaches.

Scott

Thanks alot, ive got her stripped down and waiting for some parts....cleaned out carb,airbox,changed gas lines,cleaned tank,blew out petcock,any way to check this seal or should i change it now before i start adding fluids?

[OLDMXRACER 393]

I'm not a Honda guy, but is that one of the years with the magnesium housing? Hopefully Dogger or The pipe will see this and steer you through a fix.....

[MXtras]

Well - too many variables to really say.

I am a maintenance nut. I have been competing nearly my entire life and I have had exactly 6 DNFs from mechanical issues - 4 of which were from sucking spark plugs, one from a flat rear tire and one from an over-due piston.

Some folks prefer to ride until the bike quits, then look for solutions and repairs. These people usually end up spending more money on parts than I, even though I spend a LOT more time with the bikes torn apart. I prefer to eliminate any problems before they become problems.

With that said, I suggest popping off the clutch cover and taking a close look at the guts. If it has sat with moisture in the case, there are likely going to be a few future problems hibernating inside.

The H2o bearings and seal would be a great start. The housings on those things were (I believe) magnesium and didn't get along with the coolant, so you might be investing in some epoxy.

I would also look at your suspension pivots, wheel bearings and steering stem.

Take a peak at this thread - this guy bought a bike, rode it three times and now is looking into replacing some pretty critical, expensive things. It is likely that his fix will cost more than he paid for the bike!

2000 yz 250

***edit**** - check out this thread:
just purchased 87 cr 125 need help please


Scott

[newfiebullet]

thanks guys i will wait untill my manuel shows up then i will strip her down and check everything. I know this bike was running great a few years ago then blew a head gasket and sat for maybe 3-4 years. My buddy gave it to me for a case of beer so if i have to sink some $$$ into her no prob. Im already in about 200 ordering new chain and sprockets, air filter, clutch and throttle cables, top end gasket kit. This is more of a project then anything else, my 9 year old son will be on this in a few years. Thanks for everything, great site ,anybody with any input of info on this bike feel free to chime in...

[dogger315]

Before you run this thing, I would strongly suggest that you closely evaluate the entire bike. Sometimes a few hours or work can save you a lot of headaches

This is very good advice and I am glad you are following it.

When you drain a bunch of coolant out of your crankcase (especially coolant
that has been sitting in there a couple of years), you should split the cases
and evaluate the situation with regard to rust and corrosion on your tranny.
If rust and corrosion is present, simply remove everything and soak it in a ph
neutral rust remover [Only registered and activated users can see links. ] then clean with a solvent based
cleaner. All the parts are hard coated so the rust remover will not harm them
if used according to direction. While you have the cases apart, I recommend
you replace all the thrust washers and circlips along with the bearings and seals.
Also, clean and flush the cases with an aluminum friendly cleaner. These parts
don't cost much but their replacement will allow your bottom end to perform like
new again and eliminate many potential air leaks which are the nemesis of these
old engines.

The second problem you will have to deal with is the water pump. As has been
stated earlier, the only way that coolant could have gotten in your crankcase is
from the water pump coolant seal or, in your case, from a perforated water pump
housing. Honda used magnesium water pump housings on the CR125s from 1981
to 1987. Magnesium is a real weight saver but the chemistry of magnesium is
incompatible with water and anti-freeze. There is a good chance your water
pump housing is corroded to the point it contains many pin holes (like having
a colander for a seal). Since these housing were problematic, the spare supply
dried up years ago. If this is the case with your housing, hopefully the holes
are not in the water seal boss and can be filled by using a product like JB Weld.
Once the housing is repaired and new oil and water seals are installed, you will
have to run a magnesium compatible coolant to prevent the problem from reocurring.
That coolant can be purchased from these folks.
[Only registered and activated users can see links. ]

This sounds like a lot of work, and you're right - it is. But these are necessary
steps to bring this bike back into the stout running and reliable category which is
the goal, right?


Keep us posted on your progress.


dogger