JonDunlap

Member
Dec 29, 2013
4
0
I recently bought a 1987 Suzuki RM 125 for my son, knowing that I had "A LITTLE" bit of work to do. After more investigating, that has become more work to do. Basically, I have to replace both sides of the engine case because there is damage to both sides. I have disassembled the entire motor. After looking online for used engine cases, I have found a person who has the bottom end, without the stator, for $300. Never having assembled a motorcycle engine before, it seems like this would be a much easier way to go, basically I just add my top end and go. The other option is buying the 2 new cases and new bearings and using all the guts out of mine. Not sure which way would be better. Maybe a little cheaper to go route number 2, but less work to do number 1. Any advice?
 

arnego2

Member
Mar 8, 2008
271
1
I think it be better to get new cases or find good ones at ebay then buying a bottom end. Not much guarantee that the bottom end is all OK. Dirt bike engines are not so complex and swapping gearboxes is pretty straight forward.
 

jason33

Member
Oct 21, 2006
655
0
splitting the cases isnt hard, i would say even if you get the used one for300 split it and get new seals, possibly some bearings, and fiber clutch plates, and if it has a center gasket kool, but if not, i suggest using 3m rubberized sealer, i think its a hondabond 30.00 for the tube,but it is better than yamabond or suzukibond
i would let the guy know this and see if you can get the motor for less, i bet- a local shop could do it for a hours worth of work ,i know i could and they have all the tools ect... if they say anything different they are full of crap, a tear down is fast, unless they break something ect...
 

sbest

Member
Mar 12, 2013
19
0
Buy the whole bottom end and a good manual. This gives you all the parts you need. Check out the crank for any rough spots. If it is smooth, use it, if it is rough swap it or get a rebuild or new for about $250. These engines are so easy to learn and work on you will not regret the time or money spent (if you do it right!).

I was doing this work when I was 16 and my son was doing it when he was 12.
Get a manual, use a torque wrench and locktite everything. You will soon be an expert too.

Steve
 
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