Some people on the Portland Puddle Cutters text group where asking if Tomos Racing Transmission Fluid (TRTF) was as great as it appeared. I didn’t know honestly. I had seen the article before but it never occured to me to try it. Right about this time I had put Royal Purple ATF into my Tomos and was unhappy with it’s shifting compared to my usual type F oil. Seemed like a good time to try a new oil.
But first I must see if I’m eligible for such power. Let me see if I pass the checklist on the wiki:
So lets say you have a tomos. You enjoy how fast the tomos is. But it’s not fast enough.
Hmm… yes, I do feel that I am happy with it’s power while also not being happy with its power.
Lets say it’s fast when it finally gets onto the pipe, but it (1) doesn’t hit the pipe in first gear and (2) shifts way too early so it takes forever to hit the pipe in 2nd gear.
Yes, that is what happens. And I hate it.
Your tomos doesn’t shift like a ZA50.
Well yea, but the ZA is a better design, so be a big ask for the oil to fix that.
You can’t get on the pipe in first gear.
So per my own dyno runs on this bike I know my pipe starts to hit about 5500 rpms and my first gear shifts closer to 4200-4500 rpms. So…eerrrrr…. no I do not get into my pipe in first gear.
Your 1-2 shift leaves you in superbogville, and E50s out-accelerate you.
Superbogville, Population: my stupid transmission.
You can get up a hill in first, but then you shift into second, and get stuck.
“I refuse to downshift. I will die on this hill.” – My Tomos.
You get really irritated at all of it.
OMG every ride.
Tuned E50’s completely smoke you.
Of course, but I expect that.
Did I mention it’s annoying?
*checks notes* Yes
Now I know I am a candidate for the power, but I’m going to be semi-scientific about it. I needed a benchmark. My first step was to go on a test ride around some hills in my neighborhood and recording some base shifting stats. I wanted to know what rpm the engine starts to move from a stop, when it shifts into second gear on a flat under full accelleration, and at what rpm does it downshift back into first going up a hill. After a nice test ride I recorded the following: first gear stall rpm is 4200-4500 rpms before the bikes starts to move, shifts into second 4600-4800rpms, and I could blip downshift 3800-4000rpms going up a long hill.
The transmission in this Tomos is a Lucky 2 Strokes ZA50 adapted first gear with the stock spring from treats it shipped with (I don’t think these are available anymore), the second is the Treats slightly better clutch shoes with a 20lbs spring, a functional sprag spring, and final gearing of 26:22. I was running Royal Purple ATF filled to the regular fill line. When I drained the oil out I measured 285cc of oil so I’ll assume that’s roughly my normal fill volume. The motor is the same one from the Bazooka Mouth tests.
Now for the new hotness. I purchased the cheapest oils at the local autoparts store, totalling about $14. This should be enough for two full oil changes, costing $7 per change. The instructions are pretty simple, a 700cc 50/50 mix of the two oils, 350cc of 75-140w gear oil, and 350cc of Dex Merc atf. I will say I didn’t follow the directions perfectly because I did not have a container large enough to mix the two oils in so I just measured 350cc of each and poured directly into the motor. I don’t think that will skew my results. It’s interesting to note the new volume of 700cc of oil is more than twice the normal volume. I do run a sealed sprocket nut and while I always suggest running one, I think it’s probably required if you are going to run twice the oil volume.
With no other changes to the bike, and about an hour after the first test, I went out again. I went on a small test ride to give the oil time to mix and to help wash the clutches of the old oil then redid the test route. My new first gear stall rpm was 4800-5200 rpms, shifting to second happend around 5800-6200 rpms, and I could blip downshift at at much higher 5600-5800 rpms. So the first thing to notice is that those numbers are bigger. That’s great. My bike gets into the pipe at about 5500 rpms and climbs pretty quick from there so shifting into second later than that and being able to downshift into a better rpm range is just lovely. First gear stall is much better as well. I will say that’s it’s not as smooth of a shift as it was before and there seems to be a bit of clutch “bounce” when fully engaging into second, like it surges a bit instead of engaging and staying there. That’s a minor quibble. I did notice the bike seems a little bit more sluggish once the transmission is fully into second gear and maybe it’s from spinning in much more heavy oil. The transmission power loss is slightly noticable but the difference in accelleration makes up for it.
I need to put a lot more miles on this, with a couple group rides as well, but for such a cheap and simple change it’s hard to fault it. It did exacly what was advertised. The next day I installed the stock catalytic pipe back on the bike (for an unrelated test) and I will say do not use this oil unless you have at least a pipe. The super restrictive stock pipe doesn’t work well with it. I run a Treats black pipe on a stock a55 cylinder and with this oil it’s a pretty solid setup. Working as you dreamed it would.
How does the clutches handle it over time? Ehh, that’s gonna take some time to find out. I also wonder if I could get the same shifting by just running 700cc of type f, or just merc-dex, or maybe less of the 50/50 mix. If I could get let parasitic drag but with the same shifting points it would be perfect. But it’s hard to not recommend this as it is. It does what it advertised and in moped world, that’s a rare thing.