Jump to content

First bottom end rebuild help/advice needed

Recommended Posts

Im currently doing my first bottom end rebuild on a 2007 rm 125 and I have a few concerns. The first is that the idiot that was helping me at first wound up getting dirt into my brand new left hand side crank bearing. I would hate to have to take the seal out, most likely ruining it, and having to throw away the brand new bearing, but it doesnt feel 100% smooth and has some discoloration on the outside. What is your guys opinion on what I should do? Also, is flushing the cases and hitting the surfaces where the o.d. of the bearing meets the case with a scotch brite pad necessary? Ill post some picks of my engine below, im just really worried im going to make a small couple hundred dollar mistake because this is my first rebuild and I have no knowledgeable person to work on it with, just the internet. The last picture is of a brand new wiseco crank but it got surface rust in one day in a different and apparently much more humid garage. Is that something I should be really worried about? Should I clean it and if so with what?.1495925648570.thumb.jpeg.3d723d9e65e8b9fce4cbc0c92fd9730e.jpeg>1495925720961.thumb.jpeg.4104efd99afbfb26a429684ec604cb7a.jpeg1495925754597.thumb.jpeg.ee3c1ec565c9140f4b85f0d4f8a15b36.jpeg1495925798949.thumb.jpeg.02c08d49a12fa5d48b81bf13bfd57395.jpeg


Share this post


Link to post
Share on other sites

Good on you to ask for advice at this stage rather than continue the rebuild.

First thing I'll say is put that hammer back in the tool box! Even though engine casings and components are made of metal they can be easily damaged if struck by a hammer. You've got a rubber mallet which is far less likely to cause damage for the odd occasion when a light tap is required.

I would just sacrifice the crank seal to allow the bearing to be removed and properly flushed clean in a solvent. Cheaper to replace a seal than risk having debris in a rebuilt engine.

The crank corrosion is not good. The crank seal will be running on an area of the crankshaft that looks to have rust which is far from ideal.

Think it would be best to source another crank if you can. Whilst organising that you will have time to remove the main bearing and get all components cleaned and checked over and prepared for the rebuild.

Try to keep everything extremely clean and protected from humidty and dust. Store components in a box in the house if needs be. One gust of wind through the garage door could easily blow dirt all over those open casings and gears.

Share this post


Link to post
Share on other sites

How big of a deal is the rust? K font race or do anything extreme but I can see how the few thousands of an inch worn off the crank in areas could have some very adverse affects at high speeds and forces. Would you suggest removing all bearings and other seals before cleaning the case halves? Will I cause damage to my new bearings when I remove them or damage to the seals when cleaning, and what should I use to clean the halves, gears, etc? Man this sucks though what a waste, guess ill just it take all this as a lesson. I can buy a whole new bottom end kit from wiseco for about 170 and get brand new crank bearings and seals, ill just have an extra set of gaskets I suppose. How can I prevent things from rusting in the future? Also I have re allocated my bottom end components to my basement, does that sound like a better environment? Lastly I used a socket and hammer to get the crank bearings out last time is that a good/safe method?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Share this post


Link to post
Share on other sites

How long has this bike been apart? Next time I'd recommend taking it apart and not stopping til it's done. You're gonna have a hell of a time with remembering where those transmission parts go. You're not working on the spaceshuttle, so just good common sense and cleanliness, and it'll be fine.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:


×