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Old 04-19-2009, 08:59 PM
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Question 86 cr125 Engine Questions

I just purchased a 1986 cr125 and am new to two stroke engines. Somehow there has been water getting in the oil,and the water pump impeller shaft seal and bearing have been replaced.....still leaking. Motor still ran strong before it was parked due to the water leak. Also i noticed the power valve is missing its cover....can anyone give me a quick breakdown of how these work? How do i check if it is working properly since it has had the cover off for ?? amount of time. Also the shifter and kickstart, drive sprocket shaft all have a reasonable amount of play (in and out of case), i know some is normal but how much? I was looking at maybe getting another motor for the bike if i find out its beyond repair.....what years 125 will fit? any 250s? Any info would be greatly appreciated.....Compression checked out at about 140ish psi, has recently new top end.....he claims it didnt smoke excessively when it was running just milky oil. Where could i find another engine for this bike?? Any rough ideas how much it will run me to replace all case seals, bearings and gaskets? Manual will be coming when i get some more cash...
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Old 04-27-2009, 09:31 AM
ThePipe's Avatar
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Only an 85 CR125 will directly bolt in. Although 1985s didn't have head stays (No biggie)
That water pump cover is prolly pitted since it's magnesium.
Once it has holes from pitting... it's done for.
1984-86 CR125 covers interchange. Try and find a good one on FeeBay
No other years fit.

Missing ATAC chamber? No Sweat
That system worked better when it didn't work.
Make a block off cover out of a piece of Aluminum and run it that way.
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Old 05-25-2009, 12:19 PM
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i have an 86 too and i blocked off the atac, but my bike will not idle. mayb getting too much gas at idle?
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Old 05-25-2009, 05:25 PM
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Quote:
Somehow there has been water getting in the oil
This indicates either a bad oil seal at the waterpump impeller or
some kind of defect of the right crankcase cover where the water
pump is housed. If the water seal was defective, water would be
dripping out of the inspection hole beneath the pump housing.

I recommend you first get a complete gasket kit from Honda then
remove the right crankcase cover and inspect the area around both
the water seal (right or outside of the cover) and the oil seal (left
or inside of the cover). If the casting looks sound then replace both
seals again being very careful installing the water seal.

Quote:
can anyone give me a quick breakdown of how these work
It doesn't. The ATAC system was a bust and ended up being more
of a maintenance nuisance than a performance enhancer. As others
have said, block it off and run without it.

Quote:
Also the shifter and kickstart, drive sprocket shaft all have a reasonable amount of play
You're talking about a 20+ year old tiddler. I can't think of any other bike
that takes more abuse. The kickstart lever will be loose because after
a zillion rotations back and forth, the pin holes will be elongated and the
detents will be rounded off. Same goes for most of the other parts.
If you want a nice tight motor, you are going to need to do some work
and spend some money. Most of the fixes are inexpensive (depending on
your wrenching skills) but require a good working knowledge, tools and the
confidence to split it open and replace/repair all that needs attention.

Quote:
Any rough ideas how much it will run me to replace all case seals, bearings and gaskets?
Less than $200. I'm glad to see the first thing you ordered was a manual.
Check out this site for all the original Honda manuals available for your
model: [Only registered and activated users can see links. ]
I strongly recommend you stick with American or Japanese bearings (can't
go wrong using OE Honda) and Honda seals. I always use Honda gaskets
but there are several good aftermarket alternatives for this.

Quote:
Where could i find another engine for this bike??
Let's call that plan B. If you can find one, it will more than likely be in
similar condition to what you have.

Good luck with it.

dogger
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