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Hey guys i've decited to do a "How To" Write up on rebuild the top end on a Honda Rancher

The Gas Tank And Front Plastic and air fliter housing, carburetor and Exhaust Must Be Removed For This.

1. Remove the following upper hanger bolts and nut hanger bracket and mounting rubbers

Now You Can remove the following four head bolts and head cover

Next Remove the following Timing Hole Cap (by foot brake pedal right side) Now Rotate the crankshaft clockwise using the recoil starter knob to align the T mark on the flywheel with the index mark on the rear crankcase cover.
Make sure the piston is TDC (Top Dead Center) on the compression stroke.
This position can be obtained by confirming that there is slack in the rocker arm. If there is no slack, it is because the piston is moving through the exhaust stroke to TDC. Rotate the crankshaft one full turn andmatch up the Tmark again.


Now Remove the following spark plug cap,sparkplug , rocker arm bolt the four cap nuts and washers(Loosen in a crisscross patter in 2 or 3 steps) and the two 6mm bolts. then remove the rocker arm.


next you need to remove the two push rods(they just pull out)


Now its Time To remove the cylinder head start by gently taping the cylinder head with a hammer to loosen the seal( Do not strike the cylinder head too hard) once it is loosened it will come right off(straight up).Now it will look like this. next you need to remove the two dowel pins and gasket(just pulls off) .
[/IMG]


Now You ready to remove the cylinder start by gently taping the cylinder head with a hammer to loosen the seal( Do not strike the cylinder hard) now it will come straight off. now it looks like this. Next remove the gasket and two dowel pins.


Now remove the gasket and two dowel pins.
Next Place a clean shop towel over the crankcase to prevent the clip from falling into the crankcase. Remove the piston pin clips(one on each side) with the pliers. Push the piston pin out of the piston and connecting rod, and remove the piston.
I will get the rest later today.
 

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Discussion Starter #4
No there is no need to remove the timing chain for a "topend rebuild"
i am still working on the rest of the how to probley have it up tomorrow.
 

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Discussion Starter #5
WARNING! IF YOU HAVE DIRT OR DEBREE IN YOUR MOTOR YOU WILL NEED TO COMPLETLY DISASSEMBLE THE CASE AND CLEAN EVERYTHING


Now That You've Got everything apart it's time to put it all back together:happy

Fist you need to do some work on the cylinder head (optional but recommended)
start by Remove the valve spring cotters using the valve
spring compressor.



Now Remove the Following:
spring retainer
inner and outer valve springs
valve
stem seal
valve spring seat


Check that the valve moves smoothly in the guide.
Check the valve for bending, burning or abnormal wear.

replace the valve's if necessary.

Now Blow through the oil passage (stud bolt hole) in the cylinder head with compressed air. Install the valve spring seats. Install new stem seals. Lubricate the valve stem sliding surface with molybdenum oil solution. Insert the valve into the guide while turning it slowly to avoid damage to the stem seal.



Install the inner and outer valve springs with the tightly wound coils facing the combustion chamber. Install the spring retainer.



Now Install the valve spring cotters using the valve spring compressor.



Next Support the cylinder head so that the valve heads will not contact anything that cause damage. Tap the valve stems gently with two plastic hammers as shown to seat the cotters firmly. Install the spark plug.




Now You can install the rings on the piston


Now Place a clean shop towel over the crankcase to prevent the clip fromfalling into the crankcase. Apply molybdenum oil solution to the piston pin
outer surface. Apply engine oil to the piston pin hole and connecting rod inner surface. Install the piston with the ‘‘IN’’ mark toward the intake side and insert the piston pin through the piston and connecting rod. Install new piston pin clips into the grooves in the piston pin hole. Make sure that the piston pin clips are seated securely. Do not align the piston pin clip end gap with the
piston cutout.



Clean the gasket surfaces of the cylinder and crankcase thoroughly, being careful not to damage it, and being careful not to allow gasket material
into the crankcase. Blow through the oil passage (stud bolt hole) in the cylinder with compressed air. Apply liquid sealant to the crankcase mating areas as shown. Install the dowel pins and a new gasket.





Now Apply engine oil to the cylinder wall, piston and piston ring outer surfaces. Install the cylinder over the piston while compressing the piston rings with your fingers. Make sure that the cylinder touches the crankcase
evenly.



Now its time to install the cylinder Head
Clean the mating surface of the cylinder and head Install the following:
two dowel pins new gasket



Now install the cylinder head, push rods and two dowel pins




Now Rotate the crankshaft clockwise using the recoil starter knob to align the T mark on the flywheel with the index mark on the rear crankcase cover. Make sure the piston is TDC (Top Dead Center) on the compression stroke. If not, rotate the crankshaft one full turn and match up the T mark again.



Next Apply engine oil to rocker arm followers and adjusting screw tips. Install the rocker arm holder onto the cylinder head. Install the following and tighten them in a crisscross pattern in 2 or 3 steps (our cap nuts with new sealing washers (apply engine oil) rocker arm holder bolt (apply engine oil) two cylinder head bolts.
TORQUE
(Cap Nuts 29 lbf-ft)
(Holder Bolt 22 lbf-ft)
(Rocker arm holder point 5.1 lbf-ft)
(Spark Plug 13 lbf-ft)




Next Install the following and tighten the bolts and nut:
engine hanger bracket
mounting rubbers (large I.D. side toward inside)
10 mm bolt (from front side) and nut
8mm bolt
TORQUE
Upper engine hanger nut (frame side 40 lbf-ft)
Upper engine hanger bolt (engine side 24 lbf-ft)




Next Coat a new O-ring with engine oil and install it into
the groove in the carburetor insulator.
Install the insulator onto the cylinder head and
tighten the two bolts.




Install the following:
exhaust
carburetor assembly

Next you'll need to adjust the valve's



now you can reinstall the head cover



NOW YOU DONE :happy
 

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Discussion Starter #6
This was My first how to write up. maybe it will help somebody out.
 

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It should, thanks. I will add if doing the valves (cylinder head) it's the easiest to install the cotters with a touch of grease to hold them in place. Also lapping the valves to check and make sure they are seated properly.
 

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Discussion Starter #8
Thanks Toodeep. if anyone else has anything to add post it on here or pm me and ill add it.
 

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when installing the piston rings the rounded ring goes on top and the squared up ring goes next then the oil rings

when i was installing the rings on the 400 i searched this forum over for this answer and its nowhere to be found lol
 

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Good post. I have a question. How do you know when you need a top end rebuild. Is it the compression test? If so what should good compression be?
 

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I would like to add,
that the cylinder should be honed if within Spec's (if not it need's to be bored) to get the chris cross pattern in order for the rings to seat properly.



The Chris cross pattern can be seen at the Right side of this photo




Now this being said,
I have a question: what grit hone would be best suited for our Honda's?

BTW: this is a Great thread, Thanks for posting it FloatingForeman & Welcome to the Crew!
 

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For those who have never used a honing tool I found a Great video showing how easy it is to use and the before cylinder wall before and after!

 

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How do I make sure that I am on the compression stroke on the rebuild? I can't check the valve slack like on the tear down.
 

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HELP!! So is there some trick to getting the piston in the cylinder??? I got the rings compressed and the piston is started in....I don't want to force it and mess up the rings. All the rings are good and in place. Anyone got any tips??
 

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Usually some engine oil down the cylinders walls works good for me, I've even seen piston rings compressed with a cut open can and jubilee clips before : )


Sent from my iPhone using Tapatalk
 

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I set my top center as instructed in the beginning of the tear down. If I don't move the crank, do I just put it back together where it's at?
 
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