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Crf250r transmission oil

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Is yamalube 4 stroke engine oil SAE 20w-40/API SJ, non friction modified safe to put in the transmission of a CRF 250r ?

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There are some very good gear/wet clutch oils that will work better than an engine oil in the tranny. Depending on which oil you select you can fine tune clutch action. ATF oils are gear/wet clutch oils designed for automobiles but there are others out there.

Thicker oils cause more clutch drag, thinner oils quicker engagement (the oil must be wiped off the disc before the clutch can engage). Some oils like Dextron have static and dynamic coefficients of friction that are very close so that clutch lockup is smoother, the "F" oils are grabbier. The first might be better for limited traction situations, the latter for hard surfaces.

Trannies run cooler than engines so oil viscosity at 100F is more important than viscosity at 212F. Syn vs dyno doesn't matter except for viscosity at operating temps, what is important is not use an oil that has friction modifiers like Hypoid Gear oil or some of the newer "Energy" engine oils.

Montesa (owned by Honda) recommends a very thin synthetic gear oil for the clutches in the competition Trials bikes, the clutch is the same as the CR125/250 clutch but with a different combination of friction plates. Here is a table of some gear oil viscosity:

Gear Oils............................... @40C........ @100C

Elf HTX740............................. 21.4............. 7

Valvoline Dextron VI ATF syn.. 29.5........... 6.0

Mobile 1 Syn ATF.................. 36.3............. 7.4

Royal Purple Max ATF............ 35.0............. 7.5

Mobile Dextron VI ATF........... 38.8

Valvoline +4.34..................... 13............... 7.55

Allison Transynd ATF ........... 53.9............ 9.75

Elf HTX735.............................114............17.8

Silkolene Medium 85W-90... 150-340..... 15

Silkolene Light 75W-80......... 100-180..... 15

Silkolene Comp 80W-90........ 100-145.... 15

Silkolene Pro SRG 75............ 100-180..... 11

Elf HTX755........................... 197.24......... 2

I replaced the Elf HTX740 with Valvoline Dextron VI syn and while a bit thicker clutch engagement is much smoother. You can get the viscosity values for other oils by checking the on-line Data Sheets for an oil.

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don`t cheap out on oil its cheap insurance for getting the most life out of your engine. I use honda 80w oil in my tranny its really smooth feeling and really good oil in my opinion but you pay for wat you get its all up to you.

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I too use the Honda 80W but have run out...........I have a case of Redline Syn 75-90 any idea if this oil is OK to use? I also have a case of Valvoline 60W left over from my Dragboat days. is this oil Ok to use? I mostly trail ride my '04 250R.

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I use the Honda HP Trans. Its the stuff intended for the CR125/250 but works in the 250R as well. It works great. Not sure its available everywhere though.

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I run Rotella synthetic in ours, it has a dyna ring in it. Do mostly woods riding, very little moto.

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I took my newly acquired bike for a ride today and shot some vid. Can you guys check it out and give me your opinion on the tranny whine? I haven't had the bike long, but the little I've read, it sounds like they tend to whine.

Bike runs great, clutch seems to feel "grabby" to me when it first engages. It feel no slippage when ripping on it in any gear.

Opinions please. Thank you

Edited by Yokomo

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I stopped by a car parts store and MC store to check out my options. The price on tranny oil is cheaper at the car store (surprise, surprise). No Honda 80w in town.

Can I use any of the car tranny oil? If so, which one is a good one? Could you please give me a specific brand and weight?

I'd like to be able to slowly let out the clutch and it would smoothly grab.....

Thanks

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I just switched her over to Type F ATF based on others recommendations. Put in 690ml. Took'r for a very short ride and I'm pretty sure the clutch didn't feel as "grabby" and "ratchety".

Remembering back, I'm pretty sure Type F is what I ran in my 2 strokes.

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