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Monday, January 30, 2012

Splitting RG500 Crankcases

It's never good when oil is on the OUTside

Never wrap exhaust pipes with high heat cloth.  Then your pipes will never rust through and have an exhaust leak.  Exhaust leaks can make a perfectly healthy engine seize.  The paste around the bent rod used to be a piston.  As can be seen by the fine condition of the other piston this engine could have gone a lot more miles if it weren't for the cloth tape caused exhaust leak.

Before RG500 cases can be split the inner disc covers have to be removed.  This is difficult as they become one with the strange gasket Suzuki puts behind them.  The gasket also becomes one with the cases, so it is stuck on both sides.  Removing the inner disc cover basically means delaminating the gasket.  First I sprayed some penetrating oil (stronger than WD-40) around the openings in the covers.  I figured to make the gasket soft.  It worked a bit.  

I used vice grips to lever the cover off.  Vice grips are made by riviting a piece of folded sheet metal to the top jaw.  I put the shoulder of the folded-to-jaw meeting point to the case while hooking the tip of the jaw on the edge of the inner cover's opening.  I slid a piece of newspaper back and forth behind the vice grips to assure myself the force was going into the top case, rather than just the other side of the inner cover.  I pushed on the end of the vice grips with one hand to push the jaw into the work.  While doing that I did an isometric exercise on the side of the vice grip handle to lever the cover off.  I pushed towards the engine, which pivoted the force so it was prying the cover out from its inside edge.  After about ten seconds of steady presure the cover began to move.

As a result of this posting I have received a comment that a heat gun can be used to soften the gasket so the cover can be removed.  I haven't tried it.  It seems-ta-me that it would take longer to put heat into the cover than the ten seconds of gently prying it took with vice grips.  Even with a soft gasket the cover still has to be pried off, which leads right back to the vice grips.

After the gasket delaminated the cover moved out.  It could only be pulled so far before the angle was wrong.  Then I used a prydriver (large screwdriver with rounded off tip used only for prying things since the rounded tip can't catch in a screw's groove) to coax the inner cover the rest of the way off.

A little more coaxing and the cover came completely off

Then it was on to the next inner cover.  All four have to be removed before the cases can be split
A bit of levering, a bit of coaxing, and another inner cover is removed.
Go to the other side of the engine and remove final the two inner covers .  No pictures as they are the same as already depicted above.
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After removing all the inner covers it is time to remove all the bolts holding the cases together.  Remove them in reverse order from the torque down sequence. That is, start at the outer bolts and work towards the center, criss-crossing the engine.  Normal torque stuff.  The trick with Gammas is to make sure to get ALL the bolts out.  There are a lot of them.

Just for grins, there are two little ones with black heads which help them hide in the shadows.  Even better, they are placed in the shadows underneath the rear cylinder's base gasket.  The cases will NOT separate until those little 8mm head bolts are removed.  Look under the cylinder base gasket (if it stayed on the case like mine always do) to find them.

Also, the case bolts are different lengths.  Lay the bolts out on the bench in a spacially correct manner as they are removed so you can tell which bolt goes where.  A n empty cereal box can laid down on the bench then stick the bolts in the big flat side as they are removed from the engine.  You wind up with a cereal box lying on its side with all the bolts in their relative positions.

After removing all the bolts the next step is actual separation of the cases.  Suzuki shows a fancy splitter tool in the factory manual.  There are two pry places built into the cases.  I didn't want to get the factory splitter tool, so I came up with an alternative.  I used a tap to hand thread the hole, then put a bolt into it.  I applied force to the same pry place as the factory tool for a lot less ca$h.  Got a little clearance at the back pry point as shown below:

The reason there was only a little clearance and only near the pry point is because I had failed to remove those pesky little bolts hiding under the base gasket.  All I was doing was warping the case.

Flush with success I moved to the front pry point, which I had also tapped by hand.  Inserted a bolt and turned it to apply a bit of pry pressure on the designed-in pry point.  It broke :-(


Faced with total disaster, unable to imagine how to go any farther given I had just broken the factory designed pry points, I was a bit upset.  There is nothing the factory can do about a mechanic who fails to remove all the fasteners before attempting to force things apart.

At this point I called the Gamma Guru, Rick Lance.  He soothingly said the top case would be off in less than a minute.

First thing Rick asked me to do was look under the very back of the cylinder base gasket.  I had left the base gasket on as it looked like all the bolts were out and I wanted to split the cases.  I figured to scrape all the base gasket bits off later.  Turns out there are two little bolts with black 8mm heads which are "hidden" under the back of the base gasket.  The cases cannot come apart until these little bolts are removed.  Once those little bolts were removed the rest of the job went lickety-split.

Rick then told me to put a half inch breaker bar through the top case opening and lever on the crankshaft.  I lifted up on the bar, which pushed the end down onto the crank which held it in place.  The bar lifted the top case up and all was well with my world once more.

It took less time to lever the case off than it did to retrieve the set of taps, let alone all the time tapping the two holes.  Next time I'm going to call Rick before I start taking anything apart.

Mission accomplished.  Top case removed.  Next step is sending the cranks to Lance Gamma for refurbishment.