Horizontal Engine Oil Filtration _ Tech Reference

[66Sprint]

It has come to my attention that many of you may not be aware that the Chinese copies of the Honda horizontal engines actually DO have two provisions for filtering the oil, a screen, and a permanent, cleanable, centrifugal "filter"....
BOTH should be checked and cleaned after the initial "break-in" period of 180 to 200 miles, (at the same time as the initial oil change, head bolt/nut torque check and valve adjustment...) This procedure SHOULD be re-done at least every following 3000 miles, although I personally recommend it be done every other oil change...I change oil by every 1000 miles, (as it's cheap insurance), so my maintenance schedule would indicate at least every 2000 miles....
Most of you are aware that there is a screen to remove large particulates located at/on the oil pump's pick-up, (accessible by removing the kicker lever, right-side main case cover, and whatever else {depending on your specific bike} is in the way....Often this includes the exhaust and/or foot peg bar.....
Once you drain the oil and have this cover off, the filter screen is found in the lower front "corner" of the engine, usually right above the drain plug, and it can simply be pulled out and flushed clean.





When re-installing, the screen, insert the narrower tapered end first with the removal "lip" down....
Next, remove the clutch outer cover (also called the bearing plate) by removing the screws and gently lifting it off...(in the pics, the four screws have already been removed, but, SOME smaller engine versions use only two screws)....



Any fine particulate debris that manages to get past the screen will accumulate in the "pockets" (any recesses outside the round center) formed beneath this cover and should be scraped/flushed out....



The center is "ramped" so the spinning clutch acts as a centrifuge and deposits the particles outwards, away from the central hole which is the oil passage to the engines internals (primarily the crankshaft and rod's big end)......



Care must be taken so the plunger components held by the bearing are placed correctly during re-install so the clutch works properly and the crankshaft receives oil.....
This procedure CAN require new gaskets on both the bearing plate and the outer case cover, but often, if the covers were removed gently, they can be reused....At worst, it's about $5 worth of gaskets.....
Clean oil is the life-blood of your engine....Performing this maintenance at the appropriate intervals will help insure it lasts.......
Questions or requests for clarification can be sent to Sixtysixsprint@aol.com, or you may phone me direct at 540-525-5199 .....Steve

[MICRider]

Excellent info! I've never had the cover off of my 125 yet (Lol, because I haven't finished putting the bike together yet!), but are the semi auto's set up the same?

Thank you kindly for posting this 8)

[66Sprint]

Yes, but with one major exception...(IF they are the Honda pattern)....The shifting pressure/engine speed manipulates a "ball and ramps" set-up to actually release the clutch just AS the shift is being made....
They have essentially the same friction parts in the clutch, it just releases "automatically" as you shift.....They ALSO have the centrifugal filter built into the clutch housing like the one I pictured.....
SOME of the larger Honda engines had an extension to the shift shaft with an "arm" that "worked" the ball and ramps assembly, some had a centrifugally activated spiral worm inside the clutch center that put pressure on to release the clutch.....Never having been inside an "automatic" Chinese engine, I can't tell you which scenario you'll find, but either is pretty much self explainatory if you think about how/when the parts move....

[Weldangrind]

Steve, you've provided a great service to us!

I'm familiar with the centrifugal device on an old XR200 and a similar removeable screen on the XL250S, but I've never popped the right side cover off of a horizontal motor. I can't make out what's under the bearing plate; will it accept the same clutch tool as an XR200?

[66Sprint]

I believe the Honda takes the same size tool, (Don't want to disassemble the new engine that far yet, and I've already reassembled it) ....The one on my Lifan 125cc Horizontal measured .939" (23.85mm) inside of cuts along the diameter, and 1.90 (27.68mm) on outside diameter, so I'm guessing the "standard" Honda 24mm prong socket would work, but I didn't actually try it out...BUT, you don't need to remove that to clean it...simply tilt the bike to the right and spray it out with Brakekleen or carb spray after removing the bearing plate...Wipe it out and/or blow it dry and reassemble the parts.....

I'm hoping a member with a "semi-automatic" clutch engine will post some disassembly pics as they take it apart to do this, so I can comment on how close to (or far off from) the Hondas those assemblys are.....

[SpudRider]

Thank you for taking the time to post this valuable information, and documenting your thread with such excellent photos, Steve!

Spud

[66Sprint]

Spud, I'm Not sure about the "quality" of the pix, but it's enough reference to guide the members as they look at the engine in front of them.....LOL....

The important part is we get them to perform the maintenance to protect their engines.....

I'm sure the "vertical" clones also need this service, as, in about 90% of the Honda engines that were brought to the shop, the centrifugal filters were full of captured metal particulates and needed cleaning....Trust me, you don't want this stuff to get to the big end rod bearings.....

[humanbeing]

The universal chinese tool looks like this : http://item.taobao.com/item.htm?id=6927819662

[Weldangrind]

Thanks, HB. That's what I figured.