Broken Shift Lever

The shift lever on an ATV takes a lot of abuse.  They are constantly being kicked and pushed around with your foot.  The most common problem with them is that they work loose and the small splines that connect them to the shift shaft wear out.  That did not happen to this machine, instead the lever simply broke off.

This photos shows me holding the lever in place where it is supposed to be.

This close up tells a little more of the story.  To remove the lever you take out the pinch bolt by the green arrow and the lever slides off the shaft.  It is important that the bolt is removed all the way, there is a groove in the shaft that the bolt passes through.   A few years ago someone was working on this machine and wanted to get the shift lever off for some reason.  They loosened the bolt, but did not remove it all the way, leaving the lever loose but still stuck.  They then got a large crow bar and preyed on the back side of the lever.  Eventually the small C clip that holds the shift shaft into the transmission failed and the whole shaft came loose.

After this happened they called me up to ask if I could fix the shift shaft that was now falling out of the transmission.  To fix it properly would require removing the engine from the machine and splitting the entire engine and transmission open to replace the C clip on the end of the shaft.  This would be a very long and expensive job. 

In order to save myself some time (and the customer a lot of money), I found an easier way.  The shaft was still able to shift the gears inside, but would simple fall out because there was no longer anything to hold it in place.  The red arrow points to my quick and easy solution.  I simply welded an "ear" unto the frame that keeps the shaft from sliding out.  It has worked fine for several years, and this new problem appears to  be unrelated.  This time the lever actually broke off at an original factory weld.

Fixing the lever this time is a rather simple welding job.  The only complication is the limited access to the welding area.  This photo shows one of my welding tricks.  Sometimes you can bend your welding rod to reach around obstructions.  In this case I used a "U" bend in the rod to allow me to weld on the back side of the lever where there is only a couple of inches of space.

Here is the completed job, ready for a few more years of being kicked around.

Honda Foremen

I had Honda Foreman in the shop recently with an oil leak.  The leak was at a faulty seal on the output shaft coming out of the front of the engine.  The red arrow points to the spot where the lip of the seal is distorted.

To replace this seal the front drive shaft needs to be removed.  The drive shaft has splines on each end and "floats" between the engine and front differential.  The mounting bolts for the front differential are removed and this allows the diff to move forward about 2 inches.  Once the differential is moved forward the drive shaft will slide right out. 

Once the drive shaft is out of the way I used a pick to pry the old seal out.  On small seals like this one it is normally easy to pry them out.  Larger seals may be stuck tighter and require a little more work to get out.  I have a couple of examples of this here and here.

Once the old seal is out it is a simple matter to clean the parts up and press the new seal in.  A small seal like this can almost be pressed into place by hand.  It only required a few light taps with a small hammer to seat it.  When driving it in you must make sure that is not bent or distorted. 

Honda Foreman

I have a newer Honda Foreman in the shop today with a shifting problem.  It was hard to change gears, and impossible to get into neutral.  The transmission on this machine, like almost every ATV, is part of the engine.  In order to do any transmission work you need to remove the engine from the frame.  That takes 2 to 3 hours on this machine.

Once I had the engine on the workbench I pulled the side cover off and removed the clutches to expose the shift mechanism. 

 Part of the escapement mechanism that that turns the shift drum was broken.  This machine was sunk under water last winter.  I suspect that this piece broke when someone tried to shift the machine with the crankcase full of ice.  This second photo show the broken part and another used part that I had left over from a Honda 420 rebuild project.  It appears that Honda uses the same shift linkage on the 500 and 420.

This last photo shows the shift mechanism put back together. There are a lot of springs, spacers, and little parts to keep track of.  Now I need a few more hours to put the engine back in the frame and try it out.

C.O.

Honda Foreman

I have a Honda Foreman in the shop.  This is the standard everyday machine here in rural Alaska.

The owner said that it was hard to start and they thought it was not running correctly.  I started it up and noticed right away that the engine was making a terrible rattling sound.

I pulled it in the shop and checked the compression.  As I suspected, the compression was very low. 

As soon as soon as I pulled the valve cover off I could smell the burnt oil.  These engines are air and oil cooled, if they get over heated the oil gets cooked .  This photo shows the "fins" where the oil flows over the top of the head.  The baked on brown crud is a sure sign of overheating.

When I pulled the cylinder off, the piston was scored.  This photo shows my setup for jacking the piston pin out.  The paper towels are there to prevent pieces from dropping into the engine.  Like most of these small engines, the connecting rod is one piece and cannot be removed from the crankshaft. The pin is held in the piston by two circlips, normally when you take the clips out you can push the pin out by hand.  Sometimes it gets stuck and you have to use more force.

It is impossible to swing a hammer in the small area and using a hammer would risk bending the connecting rod.  I have found that a piece of all thread with the appropriate size spacers and washers can be used to "jack" the pin out.  In this case the pin was stuck in the connecting rod because the rod was overheated/ ran without oil.

This last photo shows the cause of all these problems.  This is the oil filter being removed from it's housing.  The filter was put in upside down.  When this happens it blocks off the oil flow to the engine.  I have seen engines damaged this way several times.  Honda did a poor job designing this system and some owners do not pay enough attention when working on their machines.

This engine is going to need a new piston, cylinder, crankshaft/connecting rod, and all the various gaskets.  The parts are around $900 and there is about 12 hours of labor in the job.  Pay attention when you change that oil!

Frozen Honda Foreman

Today I have a newer Honda Foreman in the shop.  It went through the ice and spent a bit of time upside down and submerged in salt water.    The driver was cold and wet, but she is ok.

The top of the engine was full of water.  I pulled the spark plug and the water ran out of the cylinder.  I had to remove the exhaust to get the water out of the lower bends in the pipe and the muffler.  The throttle, choke and brake cables were also frozen.  The rear drum brake (that never works anyway on these things anyway) was filled up. The gas tank and the carb also needed to be cleaned out.  Somehow the oil in the crankcase and the front and rear differentials did not have any water. 

For most of the mechanical system being submerged is not a problem.  The real problem is the electrical system.  The machine was sunk in salt water, which is very corrosive.  Once that salt gets into the connectors there is no way to get it out.  It does not cause immediate problems, but I am expecting that this machine is going to have a lot of faulty corroded electrical connections in the years to come.  The salt can also be a problem in carburetors.  The salt deposits block up the jets and small passages and they cannot be dissolved, they must be scrapped or picked out.  Sometimes it is impossible to get rid of it all and the jets must be replaced.

Honda Foreman

The basic Honda Foreman is the most popular ATV in rural Alaska.  They are cheap and reliable.  They may not be the best machine for serious work or off road travel, but they are great for around town.  That is where most ATVs spend the majority of their time, going to the store, picking up mail at the post office, etc.  They get used the way most people use a car.

With all those short trips the electric starters get a workout.  The machine that I had in the shop today was about 2 years old and had 4500 miles on it.  The brushes in the starter where wearing out.  They were not completely gone, but every once in a while the starter would not go. 

This is an easy problem to diagnose.  When you push the starter button you can hear the solenoid click, but the motor does not turn.  If you hold the starter button down and tap on the side of the starter the brushes make contact and it runs.  If you tap on the starter and it still does not run, you should check for battery voltage at the positive terminal on the starter.  If there is full voltage the problem is definitely the brushes.

It is a quick and easy job to replace the brushes, about 1/2 hour of work if all goes well.  The only important thing is to make sure you get the rubber and fiber insulating washer on the positive stud assembled correctly.  Beginners sometimes misplace these washers and end up with the stud shorted to the motor case.

Honda Foreman

I'm continuing work on the Honda Foreman from last week.  I got the engine reassembled today.  Tomorrow I'll put the all the other stuff back on (seat, fenders, etc.)

This photo is a shot looking straight down at the head under the valve cover.  The rocker arms come off with the cover.  The interesting thing to see here is the back and forth ridges on top of the head.  These engines are air/oil cooled and this is where most of it happens.  The oil that lubes the rocker arms and valves drains down on top of the head and flows around those ridges.  It then drains down past the pushrods and lubes the cam before heading to the oil sump.  Along the way it cools the top end off.  If you overheat one of these motors it shows up here first.  The oil gets cooked on to those ridges and makes a stinky mess.

Update:
I put the rest of the machine together today.  I had to drill out the oil drain plug threads and re tap it to a bigger size.  This is a common problem on machines here.  People seem to have a habit of stripping the threads on the drain plugs.  After finishing that I filled it up with oil and started it up.  The engine ran great.  There is a little bit of a rattle noise.  I suspect it is from a slightly loose piston to cylinder fit.  I did not replace the old scuffed up piston, I just cleaned it up with emery paper and honed the cylinder.  It makes a little noise but will run fine.

Total time on the project, 8 hours.

Honda Foreman

The new parts finally came in for the Honda Foreman that I took apart a few weeks ago.

Today I started putting the head back together.  I used my new valve spring compressor.  It is much easier than my old homemade "push real hard" tool.  Having the right tool for the job is great.

Honda Foreman

2008 Honda Foreman TRX 500 FM

This machine is a great example of Honda engineering.  It is nothing fancy or high performance, but well thought out and durable.  The engine is a basic single cylinder four stroke motor with push rod actuated overhead valves.  It is air/oil cooled with an electric fan.

This is a standard ATV here in the village. These machines will last forever if you keep oil in them.  Unfortunately people seem to have a habit of running them out of oil.  The normal engine disaster starts just after someone changes the oil.  They either strip the threads on the drain plug and it falls out a few days later or they put the oil filter in backwards.

The stripped threads are definitely operator error, but the upside down oil filter is an engineering mistake by Honda.  The filter is a cartridge type with a hole on one end and a spring that pushes on the other end.  If it is installed backwards the hole for the oil to flow through is blocked off and the engine does not get any oil.   I have seen these problems many times.

The lack of oil typically leads to an overheated piston and cylinder.  If you run it long enough like this the piston breaks.  The rod and crank have roller bearings, so they normally survive fine.  Being a push rod motor, the cam is low in the block and it normally has enough oil to survive.

I'm not sure what is wrong with this particular one yet, it smokes pretty bad out the exhaust, uses a lot of oil, and sounds a little "rattly", but it still runs ok.   I'll pull the top off tomorrow and see what it looks like inside.

C.O.