Here is some pics of the Engine Mudbogger sent me from this project http://www.pilotodyssey.com/PO/viewtopic.php?f=34&t=10462

Engine out of the box


WTF is this red stuff for? Take a look at the bolt/washer used to hold the junk sprocket on.




Where this muck come from?



I sealed up the Engine then put it in my shop sink and spent about a hour scrubbing it down removing all the external grease and dirt Mudbogger's pressure washer could not remove.

Pulled the head surprise surprise the guy who pulled the Engine out of the frame failed to drain the coolant now we have a coolant mess all over my shop wonderful.

Someone NEEDS to remove their Engine removal procedures and coolant draining procedures yanking off the coolant hoses is NOT all that is required.

If this was just a simple top end rebuild how do we get the coolant out of the bottom end?

don't know what the manual says I have not read it in years but here is what I do FIRST I remove the water pump drain bolt, I got a little out this one just setting on the bench be ready to catch alot of coolant if still in the frame and the cooling system is hooked up.

Then I remove the COOLANT SYSTEM DRAIN BOLT IN THE SIDE OF THE CYLINDER.

Out pours MORE COOLANT be ready to catch it, with the Engine on the bench now I have coolant not only INSIDE the Engine but OUTSIDE the Engine on my bench and about 1/2 dozen shop towels.

If THIS Engine was still in the bike now is when I would pour tap water in the radiator to flush out all the anti freeze then when it ran clear out the two drains I would remove the radiator hoses then rinse the Engine/frame/ shop floor off .

After taking a break from cleaning up the coolant mess I pulled the cylinder off, found one of them self locking flange nuts installed the type that digs into the cylinder so you can never maintain proper torque because the cheap ass WRONG nut you used destroyed the surface.

Mudbogger said the former owner said NACS Racing rebuilt this Engine, I am not impressed.

While were on the subject of the wrong nuts or bad nuts I would like to point out the 2 wrong nuts that was used on the cylinder head, is this some of the NACS Racing work too?

Cylinder removed shows this is a updated port design notice the intake port is more like on a Honda Pilot cylinder yet still retains the bridged exhaust like the FL350 and the older ATC/TRX cylinders.

Note will post more detail pics of the cylinder later.

Cylinder off looking into the bottom end everything looks normal the big end of the rod is IMO on the lose side if we end up splitting these cases and go into the bottom end I would replace the rod no use spending a gasket set and new crank bearings (required if cases are split) seals and not rebuilding the crank.

All kinds of crankshaft options are available for this Engine here are a few found on evilbay I have no idea of the quality of these kits and cranks that are NOT Honda. http://www.ebay.com/sch/i.html?_nkw=87+TRX250R+crankshaft&_armrs=1&_from=&_ipg=

Looks like Honda no longer offers a replacement? they still offer the key better add this to the parts list, fact is order 3 keep a few for stock. 13331-360-000 KEY, WOODRUFF SPECIAL (25X1)

Time to remove the flywheel and ignition looks like its been years since NACS Racing rebuilt this Engine looking at the amount of rust.

Seems no matter how well you seal up these ignition cases moisture still gets in, I suspect its from the heat cycles each time you use the Engine it heats up then cools as it cools it draws in air and moisture from some place.

SHAME on who ever the last mechanic to install this flywheel look at the rust.

I always brush this area with Engine oil and a acid brush before installing.

Under the flywheel it looks pretty good other than the last mechanic here must have lost the OEM screws to hold the CDI (Capacitor Discharge Ignition) trigger on so just substituted what ever they had laying around the shop, this more of the quality work of NACS Racing?

When I pull the flywheel I put ALL the hardware in it the magnets hold them until your ready to reinstall then you don't end up losing one and installing the wrong shit in its place..

Here is the wrong bolt remove from the CDI (Capacitor Discharge Ignition) trigger look at the lock washer they over tighten the bolt so much it destroyed the lock washer, tighter is better? I simply use a drop of loctite on the threads of these bolts.

The correct bolt part number is 93301-05012-0A BOLT, HEX. (5X12) $0.23 each add these to the list might as well get 6 of these.

Once I remove all the ignition system I put everything including all the cover bolts into the cover then into a zip loc bag.

With the ignition system removed this exposes the mag side crank shaft seal, its been a while since I installed one of these seals but do they install this deep into the cases?

I don't see any of the normal signs of the seal leaking.

Following the trail of stupid or skillbilly on the outside of the cases I run into this makeshift nut on a stud no idea where this nut came from but its made from aluminum

Only tool I have to remove this POS is a visegrips glad it was not tight.

I have no way to remove the stud other than to weld a nut on the stud then let it completely cool then crank it out, with 100% of the ignition system removed no chances of it being damaged by welding.

Stud removed not sure what they were trying to accomplish will investigate more when the cases are split something is not right the bolt should be a 6mm it appears to be a 7mm but not long enough to thread through the cases to clamp the cases together.

If I am looking at the parts pics right it should be a bolt 70mm long 96001-06070-07
BOLT, FLANGE (6X70) $0.94 and extend into the right side crank case.

.94 each looks a little over priced I did a search for BOLT, FLANGE (6X70) and found 90016-KYJ-900 BOLT, FLANGE (6X70) they are .26 each still a Honda part number used on a Honda Engine I say order 3 of them for that price

I removed the right side case cover and that is about how far I got I didnt see anything nasty but just gave it a quick look, the clutch basket don't look too worn will know more once the clutch plates are removed might even have a after market clutch basket installed kinda looks billet black not the factory cast.

Removed the clutch sub assembly for inspection.

It has the updated shifting mech.


Steel plates look ok


Fibers look ok will measure them later see the KAB 57 part number? KAB is for the TRX ?

Too remove this nut you need a holding tool you put the trans in gear the holding tool on the final shaft where the sprocket goes.


The holding tool