Thanks guys, I have been considering trying the GRO and at least have an actual usage information on it now.

Guess I need to see if I can find a supplier in the US now to try some.

Have used ATF in monts for probably 15 years with good results. An automatic gearbox clutch pack is very similar to a trials clutch. I even made my own gasgas clutch plates using automatic gearbox friction material several years ago.

Have not tried any of the recent oils but when I did try some alternatives the ATF was best option.

Do you recall witch brand and type of ATF? I know Gas Gas for a time in years past (not sure on how long ago) had a reaction to one brand or type of ATF and would swell the plates but a different type was fine.

Jonathon,

 

I have been using Dexron 6 ATF in my 4RT for a couple years now.  No problems at all.  Also I can now start the bike in gear most of the time.  Significantly reduced drag when in gear with the clutch in.  I think it is Castrol but I am 1/2 a world away from home at the moment so can't check.

I've been using ATF for a few years in mine. Currently Havoline dexron 6 with no problems. No slip or drag issues. Smooth clutch. Plates haven't swollen or fallen apart. No Mitani plates, changing masters, or removing springs. I haven't had any of the clutch problems I read on various forums.

This is great info, nice to hear the stock plates are good with the Dexron 6, sounds like it runs more like the Elf HTX 740.  I would guess its in part because it is so thin like the Elf.  

 

Will keep Dexron 6 on the list for when I run out of my current supply of Elf.  

Havoline Dexron VI (6) is a slightly more advance oil than Elf HT 740 but designed with very similar aims. Dexron is a General Motors auto transmission oil specification. Dexron IV seems to have been designed with a very wide vehicle compatibility range so it should avid the problems (like dissolving motorcycle clutch lining bonding) that you can get with other synthetics and ATFs.

bel ray gear saver 75w work good used it in all my bikes for the past  30 years never had clutch problems gears or bearings

Ive used atf in mine for ages it rides fine 

Do you think there would be any problem using castrol gtx 10/40 in the engine

I assume GTX appeals because it is not overpriced to the same degree as motorcycle oils?

May well be OK but the 4RT, I feel, runs a lot hotter than a car and with not much oil in the sump so I prefer bike oil.  On the other hand, at recommended change intervals, it's not in there for long.  No doubt more technically qualified contributors will be on soon.

Tesco can be a source of Castrol bike oil at a drastic reduction.  

Edited April 18, 20179 yr by 2stroke4stroke

8 hours ago, nelly1 said:

Ive used atf in mine for ages it rides fine 

Do you think there would be any problem using castrol gtx 10/40 in the engine

Briefly you can put engine oils into 3 groups, Mineral, Semi synthetic and fully synthetic. GTX is an "old fashioned" mineral oil. At any given viscosity synthetic oil has a higher film strength than mineral oil. Considering the small volume (600cc I think) in a 4rt engine its probably worth paying a little extra for something like  Petronas Syntium 7000 0W-40 (Fully synthetic) rather than 10w 40 GTX (mineral). If you ride the bike hard try https://www.smithandallan.com/products/transport-engine/3989-valvoline-racing-vr1-5w-50-motor-oil/

If you are looking for something cheaper try Smith and allans own brand. I have used them for near on 40 years and never had a problem. I presently use their 10w 40 semi synthetic in some of my cars and all my motorcycles. 

Honda manual just states 10w 40 so GTX should be OK but if you used something like the above synthetics or Mobil 1 you engine would have better protection.