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 420 - Complete

The Honda 420 that I have been working on for quite a while now is finished.  I used the parts and pieces from two wrecked engines to make one good one.  One engine had a cracked piston and a faulty transmission, the other one had a good transmission and a bad everything else.  Both engines failed from a lack of oil.

You can see the older posts about it here and here.

The whole project took about 25 hours of labor and $1000 in parts.  It runs great now, like these basic Hondas always do.  Most of the Honda models are not very high performance, but they all run great.

Honda 420

As part of the rebuild on this 420 I am going through the transmission.  The person that I bought the donor engine from mentioned that it slipped out of gear occasionally.  When I inspected the gears I found a few dogs that had the corners wore down.

When you grind the "gears" in a transmission you are not really grinding gears.  The gears are always meshed together, the grinding comes from the shift dogs.  The red arrow in the above photo points to the rounded off corner of one of these dogs.  As you shift the gears slides on the shaft and the dogs engage on matching bumps on the second gear.  You cannot see them, but the yellow arrow points too them.  Rough use can cause the corners to wear down and eventually they will not stay together.

There are a lot of pieces to keep track of inside the transmission.  I put these stands together to help me keep all the gears, spacers, and what not in order as I took them off the shafts.  You can see in this photo that some of the gears have a light coating of rust on them.  Those are the gears that I took from another machine to replace the ones with worn shift dogs.

Like most ATVs and motorcycles the engine and transmission are all one unit.  This photo shows the case just before I put it back together. 

To the left of the green line is the engine stuff, crankshaft and balancer/camshaft.  To the right is the transmission, forward gears, reverse gear, and shift drum.  It all uses the same oil for lubrication and cooling.

Honda 420 Rancher - Update

This is an update on a project that has been in the works for a while.  You can see the start of it here and here.

Basically I am taking two broken machines and making one good one out of the pair.  Back in December I took all the old stuff apart and figured out what new parts I had to order.  I needed a new piston, seals and gaskets, and a few other small items.  My work shop is very small so I only have room for one project at a time.  While I was waiting for the new parts to arrive (normally a couple weeks from one of the places in the lower 48), I put all the old stuff in tubs and put them in my storage shed.

These two tubs have all the parts needed to put together a complete engine. 

It is a little off topic, but I would like to mention how great Rubber Maid brand tubs are.  I use a lot of tubs for storage and transporting things.  They make it easy to store a lot of small parts on shelves, they are relatively waterproof, and they work great for shipping awkward or heavy things through the mail.  Over the years I have used other brands, but they all seem to end up cracking eventually.  Rubber Maid makes  the toughest of the inexpensive consumer type containers. 

Here is everything all spread out.  I hope I can remember how it all goes together.

Honda 420 Rancher - Update

Here is a shot of the engine all apart.  I found a cracked piston and the cylinder was a little scratched up.  I'll have to replace the piston of coarse, but the cylinder can be honed out.  I also found a few wore out shift dawgs in the transmission.  The gears and sliders are rather expensive to replace, but I can salvage those out of the other wrecked engine.  The oil drain plug threads were also stripped out.  I will have to tap them out to a bigger size. 

Honda 420 Rancher

My latest big project in the shop involves these two broke down Honda 420 Ranchers.  The engine in the green machine was another victim of a stripped out oil drain plug.  Normally when they get run without oil the piston fails and the cylinder gets a little scratched up.  This one wrecked everything, the piston, cylinder, crankshaft, and I think the case was even damaged when the broken rod flew around.  The red machine is a donor that I bought for parts.  It has some kind of  transmission problem.  I am hoping to to make one good machine out of the two.

The first step is too pull the engines out and take them apart.  I had some help in the shop today.  He needs a lot of supervision, but he works for cheap.

Here is the engine sitting on the work bench.  The Honda 420 is the same basic layout that Honda has had for years, single cylinder, overhead pushrod actuated valves.  It has now been upgraded with liquid cooling and a basic fuel injection system.  It also has lots of cost saving features like no recoil starter.  Like most ATVs, the engine and transmission share one common case and oil supply.