Clutch slippage and oil question?

Just wondering if anyone has had a similar experience with xr? I purchased a 02 xr 400 from my brother in law a year ago. He kept it in really good shape always changed the oil religiously using Hondas semi synthetic oil. Before my last desert trip I wanted to do an oil change and bought some Honda gn4 standard oil, the same oil I've always used in all my older xrs. Right after I changed the oil my brother in law saw the container and told me he's always used Honda semi synthetic. I talked to a couple people who said I should be okay. Now a half hour into the first ride I notice some clutch slippage that wouldn't go away. The bike does have a few thousand desert miles on it, but it seems like to big of a coincidence that the clutch starts slipping after the oil change. But maybe I just didn't notice because it slowly got to this point. Hard to tell. Can going from semi synthetic to standard gn4 cause this, or was it time for new clutch plates and springs? Also, if it was the oil, did I do unreversable damage or can simply changing back oils do the trick. Probably 1 hour of trail riding after it started slipping slightly at high rpms.

The easiest thing at this point would be to change the oil to be sure. Beyond that it may need plates. Oem are recommended for longevity.

I have never liked any of the Honda oils, other brands always seemed to work better with the clutch and shifting.

Also major oil brands publish spec on their oils, Honda doesn't. I suspect Honda buys from a bottler (common for off brands) and they don't have much control over quality.

Oil base stock and additives are the key, the majors have this locked up for their house brands. Also the 15W-40 and thicker oils have very much better SAE minimum high temp specs than thinner oils, however some syn do well at high temp; gotta check the specs.

I've run a variety of oils in my XRs, including Mobil 1, and my favorite to date is Shell Rotella T6, although if in a high temp environment I'd probably go back to Torco 20W-50 (check the specs for 100C viscosity and HTHS).

I have been running 20W-50 Castrol 4T Motorcycle Oil which is a conventional oil with the JASO-MA motorcycle rating. The JASO-MA is rated for wet clutches so that's what you want. If you are above freezing you could try the 20W-50. 10W-40 if it's colder. Don't rev the 20W-50 until it's warmed up.

If you replace the plates, make sure to soak them for a few hours before installation.

Yeah I'm probably going to pull the clutch apart to see what the plates and springs look like. It's around $230 to replace everything so hopefully everything measures out okay. Either way I'm going to switch oils, I just have a little less confidence in Honda oils now. I live and ride in Southern California deserts where the winter temps usually don't go below freezing at night and generally stay between 40 and 90 degrees during riding hours. What do you guys recommend?

Did quite a lot of research and decided I'm going to try amsoil mcf 20w - 50 synthetic oil.

Pretty coincidental, but I can't imagine its the oil's fault. +1 for Rotella syn

I've had and raced a LOT of bikes, several XR250s

I always used Walmart car oil 10w40(or whatever the manual listed for vis)

Never had an oil related problem

Used the same oil in every two stroke trans too, never a problem

to each his own

Okay I finally got around to pulling the clutch out of the 400. To my surprise everything including the springs looked good and measured well within the service limits. No warped plates. I'm still going to replace everything since I have it out, but I'm leaning towards an oil related problem being the slippage culprit. The friction plate nearest the clutch boss had dry sections where oil was light or almost gone. It's just to suspicious that after years of perfect clutch service that right after an oil change it starts slipping. Definitely no more Honda brand oil for me.

Doesn't make sense, just saying...

Doesn't make sense, just saying...

Yeah it doesn't make sense to me either. I don't know what I could be missing.

Yeah it doesn't make sense to me either. I don't know what I could be missing.

Is there slack in the clutch cable?

How honest is the brother-in-law? 'Dry sections and slipping' could point to a plate that was replaced without being soaked.

Did some kind of additive get into the engine like Slick50 or STP?

Maybe some stray fluid got into the Honda oil bottle during manufacture or at the dealer. It could have been returned. Was the bottle factory sealed?

Did someone put something in your oil when you weren't looking? Graphite?

I would still try a different oil before I replace the plates. I don't know how you would clean clutch plates, but you could try a plastic bristle brush with some motor oil.


You said you used GN4 oil which should be OK but Honda has a mix of engines; some with separate crankcase/transmision and some with shared crankcase/transmission, and an assortment of oils specific to each. Can you check the label on the oil container to verify it is JASO-MA or MA2 rated? Don't use JASO-MB oils with a wet clutch, it has friction modifiers in it.

I've shimmed clutch springs in XR clutches to increase spring pre load which reduces slippage and provide quicker lock up. If you shim too much the springs will coil bind preventing full clutch dis-engagement, but a 0.060" thick washer under each spring is a good starting point and won't bind the springs. Finding washers with appropriate ID and OD to suit the springs is a challenge; some small valve spring shims would work but I found Moroso Spark Plug Clocking washers easier to find and the package has washers of three different thickness, available at automotive speed shops.

You can clean clutch plates using Brake Klean or similar, it remove oil and brake fluid from brake shoes so they are usable so it should be able to clean clutch frictions.

Edited by chuck4788

Okay, so I put the old clutch back in the 400 with some amsoil mcf 20-50. Rode it around for an hour pushing it way harder than normal and not a bit of slippage. Made no adjustments to any cables or anything else. So it seems oil may have been the culprit. So strange that 5 minutes after changing the oil from the old hp4 to gn4 the clutch starts slipping. Why? Did I get bad oil. Semi synthetic to standard oil? At least I don't have to replace the clutch now and I know it still has a decent amount of life left. Wrecked my last desert though.

+1 on the amsoil. been using that in all my bikes for a long time. Even my 100,000 mile 1983 CB1100F.

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