2-stroke transmission/wet clutch oil

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ccdhowell

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I'll be campaigning a 1990 Suzuki LT250R Quadracer in a local cross country racing series this year for the first time. I've wanted to do this for some time now and the planets have finally alligned properly to allow it to happen. The engine is esentially stock, only a bigger carb and headpipe. I will run Mobil Racing 2T until I exhaust my stash and local supply and then plan to run Bel Ray H1R, which I run in my Tecate with good results.

Anyway I haven't settled on a good transmission/wet clutch fluid. Lots of guys on various 2-stroke fourms have lots of different ideas. I am running Bel Ray Gear Saver 75w in my Tecate right now and it's just okay, not great, neutral is hard to find. The Quadracer has whatever was in it when I bought it 3 months ago and I've hesitated changing it just because I'm waffleing on what to put in it. I've run Royal Purple Syncromax and Silkolene Medium weight gear oil in the Tecate, but haven't found a winner yet. I shy away from Type F ATF because of lack of gear shock protection.

I'm looking at Castrol MTX synthetic. I've not run this, but it looks promising. Anyone run this oil?

The weight of the trans oil seems to affect shifting feel oposite of what I'd think. The Silkolene was the heaviest oil and felt the best, the Royal Purple was really light, theought it would be better, but was terrible. I think ATF would be just as bad as the Royal Purple cause viscosity is similar.

Anyway, any thoughts on the topic are appreciated...first race in 2 weeks.

Thanks,
Chris
 
I don't have any advice to offer on the trans fluid but if you aren't already doing so I would suggest some arm excercises. Your arms will be killing you if you're not prepared. Good luck and let us know how you do!
 
Warlord, I normally ride pretty hard, but lately I've ridden harder and for longer periods of time. Yesterday I went to one of my favorite ride places and pounded my Quadracer and myself for 4 hours straight. I was absolutely exhausted when I stopped, but I'm trying to build my endurance at the high speed of XC racing. I've even joined a gym and have been working cardio pretty hard along with shoulders, arms and legs. We'll see how it goes, I'm not exactly a young pup anymore. I'll let ya'll know how it turns out. Chris
 
Manual, a 1990 vintage, calls for 10w40 motor oil. I have to believe that a specific engineered transmission oil of today would be much better than a motor oil of yesteryear. What was the API spec in 1990? SG? Lots of additives in an SG oil that wouldn't be present in today's oil.
 
Just use a diesel oil, such as 15w40, its a tough oil and Ive never had any trouble with clutch slippage. Its cheap, is avaiable everywhere and its better than the motorcycle specialty oil that will cost 4 times as much. Ive used in my KLR650, KDXs, ITs, DTs and every bike in between with excellent results.
 
Panzerman, I use HDEO in my 4-stroke atvs. Haven't run it in the 2-stroke transmission yet, I know it will work, but I was looking for something with a bit more gear protection. My two machines in question are ridden hard and one will be raced this season in a cross country series. Don't want to replace bearings or gears half-way through the season.
 
Well ,I have never seen gears go out on a two stroke tranny and we badly abused them being drunk and having "Beer Gears", alot of the old RMs and YZs were wore out when we got them, and we beat them to death in our young carefree boozin days, the transmissions were last to go. Bearings such as rod bearings on a two stroke have nothing to do wih the gear oil. Now that Iam older and wiser,I did try ATF type F, in the one KDX and it did shift nice, but it made me nervous, because it was so thin. I think the 15w40 is overkill for any two stroke tranny.
 
I've used type f or dextron for many years in two strokes with good result. Most were open class bikes that only held 500cc of oil, never seen anything but good gears when split open.

Motor oils will work also, but are usually too thick in my experience. Clutch drag is usually noticable. The oil never really gets hot so even a thinner grade is still pretty thick.

Understand your shock load concern though, felt the same way when my 1 ton truck 5spd spec'd atf.
 
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I used to use regular 10W40 in my CR125, which is pretty much the same setup. The older 10W40 may have had less friction modifiers, but I don't know that for sure. Just make sure that you change it often.
 
Like most applications - it’s a trade off. It's really tempting to recommend a light medium gear oil such as Amsoil MTF (at 9.6 cSt, but GL-4 protection), which would be great for power to the ground and gear protection - but NOT great for the wet clutch. So mainly I was thinking Amsoil MCF 10W-40 would work, but I wanted to make sure with Amsoil Tech:

Quote:
Yes, Amsoil MCF 10W-40, will work very well in the application.


Amsoil MCF 10W-40

Not as thin as Type F, but not as viscous as dino 10W-40 at ambient - put with great gear protection and behaves really well with wet clutches. You could still mess with viscosities within this product type. On the thinner side would fully synthetic SAE 30/10W-30 ACD (or ASE), an HDEO and the viscous side synthetic 20W-50 MCV.
 
For what you would pay for Specialty oils, you could change oil every other ride with Walmart 15w40 oil. Try the ATF type F, it made my bikes shift Great, I didnt run it long enough to really give it a chance, but sounds like others have and had good luck with it. I would take the 15w40 HDEO over any automotive oil, synthetic or otherwise. The transmissions on two stroke motocross bikes are pretty much bulletproof and very forgiving of anything you dump in there. I think they would shift with Wesson cooking oil.
 
Originally Posted By: Panzerman
For what you would pay for Specialty oils, you could change oil every other ride with Walmart 15w40 oil. Try the ATF type F, it made my bikes shift Great, I didnt run it long enough to really give it a chance, but sounds like others have and had good luck with it. I would take the 15w40 HDEO over any automotive oil, synthetic or otherwise. The transmissions on two stroke motocross bikes are pretty much bulletproof and very forgiving of anything you dump in there. I think they would shift with Wesson cooking oil.

The only thing that is not always so forgiving is the clutch. They take a beating on a MX bike.
 
They can take a beating, in some woods and mx tracks, but you are also talking about something that was designed with taking a beating in mind. They are very easy to change. Nothing like a car clutch, one side cover, couple nuts, six or so disks and spacers,(heavier springs if you got em) your good to go. Can swap a clutch in less than a hour with parts in hand. Still, I never burnt a clutch out, got them hot where they faded, but unless you race every week hard, and if you do clutch plates are going to wear out, and no oil is going to stop it. Let me save you the trouble of ever trying gear oil like, 75w90, doesnt work, or it might but the clutch doesnt.
 
I ordered 6 liters of Castrol MTX synthetic oil special made for 2-stroke transmissions. I'm hoping to change it after every race weekend. Panzerman is correct about that, no matter what oil I have used, it always comes out greyish and nasty from clutch particles. I was hoping for a wet clutch friendly oil with the right viscosity to give the right cluch feel. I guess in the end I will experiment with various oils and choose the one I like best for my application. Might even try some GC 0w30 in it, seems to work great in every other thing I've ever put it in, including 4-poke atvs with wet clutches.

I'll keep ya'll posted on how the Castrol MTX works.

Chris
 
Well I ran my first race with Castrol MTX synthetic in the transmission this past weekend. I will say that clutch action was very good, not jerky nor a hint of slip. The gears shifted fairly well, maybe better than fairly well, I had trouble shifting. As funny as that sounds, the race was in 37 to 40 degree weather, with lots of water and mud. Dress for the cold and within a couple laps it is soaked through and weighs twice what it should. I noticed on lap 3 that I was having trouble moving my right leg to and from the brake pedal, the cold and wet taking it's toal on my reactions. The MTX shifted pretty good, but I remember numerous times in the race where I had trouble selecting the correct gear. Now that I think of it, it was probably more of a function of conditions than transmission fluid. Chris
 
Update on the Castrol MTX Synthetic. I've grown to really like the feel of the transmission with this oil; it seems to "cushion" the gears very well. The initial filling is still in the Quadracer with about 15 hours on it; will be changed before I ride it again, my goal for this race quad is a 10 hours OCI.

I drained Bel-Ray Gear Saver from the transmission on my very modded '85 Tecate and put in the MTX Synthetic and immediately noticed a difference in clutch feel for the better. On this trike I've always found it difficult to select neutral when sitting and idleing. Just couldn't find neutral until I shut the engine off, and the clutch is adjusted properly. Different fluids have made this better or worse to varying degrees. The MTX synthetic is quite good in this respect. Actually Silkolene Medium Gear Oil was the best for this, could select neutral without issue every time. I ran out of it and never bought any more.

Bottom line is I like the Italian-made MTX synthetic and will continue to use it in both my old 2-stroke atvs. Just thought I'd give a longer term update.

Chris
 
Thanks for the update, How does it pour ? thick, thin? as compared to other stuff you tried? If someone snuck in your garage and switched it out to another brand, do you think you'd notice?
 
Wiley, I'd notice pretty quick. It is golden color, like motor oil, pours about like a 5w30 motor oil and the biggie is...I can select neutral easily with the bike running, especially in my Tecate. Seems most oils I've tried in the Tecate are fine until I try to select neutral with it running, then no go. Neutral cannot be selected. It is between first and second gears and isn't really a detent in the selector in the trans, just sort of "between selector positions". Anyway this stuff and Silkolene Medium Gear Oil allowed me to select neutral while running, lot's of other oils were tried, these worked. The thinner stuff seemed worse to me, perhaps a bit thicker is better in that aspect, you tell me.
 
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