So when pondering the most recent of my 200X topend rebuilds, and having completed a fair share of XR motors, I remain stumped as to why Honda would have designed such a miserable method of camshaft mounting....the steel bushing in the rear of the cam heats up, seizes, and can destroy the cam should the flow of oil be restricted or the viscosity break down over time.
Same holds true for the forward cam journal in the head and rocker cover....I`ve seen a fair amount of those journals scored and smeared making the "journal", and thus, the whole head useless unless you want to drop $350 on a Megacycle full needle cam bearing kit...After spending alot of time smoothing intake and exhaust runners, it occured to me how precarious the oiling situation can be and that I may very well accidently cook the bearings and journals thus wasting not only my good head but all the time I had working on it as well.
the full bearing Megacycle kit would only be an option for me should I have built a stroker 200....I would rather spend that kind of money on a more powerful machine with a little better resale value like a 250 2 stroke. Megacycle kit or not, I would be running an oil cooler for this flat-track setup to ensure I`m not killing the top and bottom end both with overheated oil from running high rpms.
There are some other threads in here I think from Howdy about this job but I couldn`t get a good link to them from the search so I decided to shoot a query to Mickey Dunlap on another thread (like the shameless thread hijacker I am) to make sure I was tapping into the best possible place to brach off the feed lines for the cooler.
First, I placed the clutch cover in the Mill and located the center of the little plug in the front of the clutch cover that is installed on every 200X and XR where the factory drilled out the oil plumbing system....this can be carefully achieved w/o a mill but since i had one at my disposal, I used a mill.....I found center of the plug (looks like an "O" 1/8" in diameter on the flat in the front of the cover, center-drilled it, then drilled thru with an "R" drill (can also use an 11/32) checking every .050 or so deep to make sure I drilled down only far enough to just pass the bottom of the oil galley where it shoots off to the right toward the motor. This ensures that you have as free a flow as possible as any added restriction will boost the pressure but on the other hand, lower the volume....higher the pressure, the slower the oil moves thru the motor making it heat up more....a higher volume of cooler, cleaner oil is preferred.
after this step, I shifted along that flat pad on the cover over about 1.250 (1 1/4") and drilled another hole making sure to stay inline with the first hole which would be a perpendicular line to the gasket surface on the cover....Again, I stopped drilling every so often to check the hole depth as you want a clean break-thru into that galley (feed) while being VERY careful not to drill too far or thru the cover completely.
Next, I backed up to the area between my two holes to the center of the distance between the two which would be .625 (5/8) from either hole on each side and drilled a new hole with a 27/64....this will be for the socket-head set screw I will use to block the passage between the two other holes thus forcing the oil to leave the pump, enter the cover, go to the cooler via the first fitting, and return to the cover from the cooler via the second fitting with the set screw keeping the two seperate.....This hole, I opted to drill all the way thru the cover. I did so because it would have been very difficult not to break thru the inside while trying to get the bit deep enough to tap for the set screw to be able to COMPLETEY block off all chances of oil getting by...all it takes is a pinhole for oil to pass thru and your cooler will not be 100% effective.
the two outer holes were then tapped 1/8-27 NPTF (tapered for pipe...fine thread) in order to facilitate installing the two brass elbow fittings I picked up from the hardware store. I used elbows (or 90s) as i didn`t want a long fitting jutting out of the fron of the cover making it much easier to snap off should something get by your frontend and hit the front of the clutch cover. I am making a guard to mount to the RH motor mount front plate for further protection.....more on that later....when taping for pipe thread fittings, you have to tap a little and then maock install the fitting to make sure you tap deep enouigh to get a good seat for the fittings...most NPT taps I have, I run down to about 3/4 of the cutting edges of the tap in the hole before I start checking as it`s a good starting point. When using elbow fittings, you have to be more attentive as the fittings will need to "clock" correctly to where you want to run the line out to the cooler. In other words, you don`t want the fittings facing down or to the outside of the machine when tightened so you have more of a straight shot to the cooler....the shorter the cooler line , the better IMO.
The center hole was then tapped all the way thru for 1/2-13 standard thread. I installed the set screw to the correct depth where the screw (or plug) would completely cover the entire galley passage. I used 1/2-13 since you want the widest plug you can get as the galley passage is not right in the middle of the pad. Mine was shifted about .100 to one side of the holes I drilled. Since you can`t see the passage until you drilled a hole, it`s critical to use a big set screw or plug in order to get the full effect of blockage should the hole be a little off center of the passage.
I installed the 1/2-13 set screw using hi-strength Red Loctite allowing it to set a week before moving forward. NOTE: Take care with the Loctite as you need to keep any excess from running into the oil passage and gumming up the works or sealing off the passage elsewhere....I sprayed out either side of the passage with carb cleaner and used pipe cleaners (q-tips leave fibers in the holes too easy) to clean EVERY last bit of thread locker out of where it wasn`t supposed to be. I then mixed up some JB FastWeld epoxy and filled the leftover holes on either side of the set screw with the stuff making sure to work it down into the socket head and threads to ensure a good grip for the epoxy...on the inside of the cover, I hit around the hole with some 80 grit to rough it up for better grip as well. You don`t want it coming loose inside the engine at some point. I used a set screw that when placed, would give me about 1/4 inch on the inside and outside of the cover to fill with epoxy again, to ensure a solid grip on the cover.
Again....this project isn`t complete as of yet, so the thread will be added to as I get more done to show y`all what the rest of the project entailed. Stay tuned for more.
Disclaimer: this is only how I did my install and my methods. There may be better ways/methods out there to achieve the same thing. This is only intended as a "how I did it" thread.
Enjoy
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Originally Posted by Crash5291
