Oil ratio for a 2001 RM80

[xrocket21]

Dad bought some toys for the grandkids and isn't sure on the mix for the RM 80

He doesn't have the manual and asked me to figure it out for him.

Thanks for the help, much appreciated.

Edit: RM80

[gregp]

RM-*90*? I would run 40:1, with good, name brand oil. Some folks might go 50:1, but the smaller bore, higher revving motors like more oil, IMO.

[csmutty]

I run 32:1 Amsoil Dominator in my KTM 125.

[xrocket21]

RM-*90*? I would run 40:1, with good, name brand oil. Some folks might go 50:1, but the smaller bore, higher revving motors like more oil, IMO.

yeah, and rm-90 dirtbike. Ill suggest 40:1, this thing wont be run that hard I don't think.

thanks

[typeone]

if the bike will just be used to putt around, i would run Amsoil Interceptor at 40:1 (or even 50:1)... Interceptor has a lower flash point than a lot of other oils so it will burn more efficiently at the slower speeds/RPMs. less buildup and drool. (assuming your jetting is correct, of course)

[gregp]

The small RM's were produced in 80cc, 85cc, and 100 sizes. I do not recall ever seeing an "RM-90"....

[xrocket21]

hmmm, I could be wrong. Like I said, Im asking for my dad. He wanted to get a small quad for the grandkids, and was looking at a Honda 80 or 90cc atv. He liked it, and the guy offered to throw in the RM 80 or 90 for a good price. Dad ended up buying both, and he says the RM is pretty fast. That's all I know. He said he was having trouble figuring out what oil ratio so I figured Id ask here. The RM is too fast for grandkids, so I assume after a little playing it will just get sold. If 40:1 will work good enough for now, that's all the info I need.

Thanks again guys! small 2 strokes couldn't be much further from my expertise!

[gregp]

FWIW - The little RM's are indeed little rockets! No matter the size. The RM 85 has what is usually referred to as the "Best Beginner/Novice" motor of the class - with, for a long time, the only power valved motor in the class - giving it much better low end and mid-range than the KX/YZ/CR 85's - all of which are more "top end" tuned. Suspension is where the little RM fell flat for a long time, being the last one of the 85's to make the switch to inverted forks.

[Rada]

Good oil 40:1 or 50:1

Smaller higher revving engines actually respond better to higher ratios.. I certainly would not go richer that 40:1 more is not always better. If you run a richer mix then your carb jetting will be off because of it.

Any of the name brand better oils will be fine. I like Yamalube R.

[Rambunctous]

Good oil 40:1 or 50:1

Smaller higher revving engines actually respond better to higher ratios.. I certainly would not go richer that 40:1 more is not always better. If you run a richer mix then your carb jetting will be off because of it.

Any of the name brand better oils will be fine. I like Yamalube R.

That is correct. The excess oil will displace the needed fuel and cause a lean condition which makes additional heat.

[breakdirt916]

(I learned this at stimilon) too much oil will make the bike not run...do 40:1

be careful of those small 2-smoke mx bikes, I even flipped a ds80 at visser's house by accident!

[TTD]

I'll never forget I was getting ready to ride with a group of people and someone was having a hard time starting a Honda XR100.

After several of us tried kicking it over and looking at different things, the owner says, "I'm running 32:1 ratio for the oil, is that OK?"




NOTE: The XR100 is a 4-stroke bike.

[breakdirt916]

could be worse...the kid I sold a '98 RM125 to (which I invested $3,500 to repair) ran straight gas in a 2-stroke...locked it up in 30 mins

[gixxer72]

could be worse...the kid I sold a '98 RM125 to (which I invested $3,500 to repair) ran straight gas in a 2-stroke...locked it up in 30 mins

$3500??? How the fuck did you manage that?

[breakdirt916]

$3500??? How the fuck did you manage that?

oh man...I couldn't even total it anymore...

roughly:
$700 - bought bike used
$1,200 - GMD computrack: front fork oil and seal change, front fork seals, oil, remove the stuck rear brake pin & heli coil, parts & labor to replace front/rear wheel bearings...steering head bearings...swing arm bearings...pivot linkage bearings...upper shock bearings...rear shock serviced (includes N2), rags/grease/oil/parts/washer/recycler fees

THEN an internal blind bearing shatters inside the cases and wrecks it.

~$1,600: I had zero tools to take it apart - so add flywheel puller, tusk crankcase splitter, tusk crank puller (well technically I split the cases and pulled the crank without it...then wrecked the threads on the crankshaft, and bought the tools later anyways), a gasket kit, yamabond to seal the new cases, chain cutter, tire irons, a dremel, dremel bits, drill bits, brake fluid, transmission oil, radiator fluid, motocross step-up stand. While you're in there, get a new top end, crankshaft bearings (after f'ing it up using the freeze method, paid a shop to install them), alllllllllllll of the internal transmission/engine bearings (total ~$180), reaplace the crankcases (which I needed to shave off metal inside it to provide piston skirt clearance for the 144 eric gorr top end - bought dremel and bits)...while doing that I knicked the cases just enough and needed a machine shop to put in a weld and re-finish the surface so that the cases to back together for a proper seal, trued the crankshaft, drilled out the shifter shaft (leaking) and burned in a new seal, re-tapped the drain plug bolt (stripped by previous owner), re-inforced the replacement crankcases with more machine work where the old crankcase shattered, replaced all the washers & spacers in the transmission, new hinson clutch basket (old clutch basket notched), replaced friction plates, steel plates, clutch cable, flushed brake lines, new front/rear brake pads, replacement rear tube (rear tire kept going flat & I still couldn't get the damn bead over the rim, so I paid a shop $45 to finish the job), paid a shop to take off the clutch basket nut (I didn't buy the clutch tool to hold it in place), water pump bearing replacement, water pump impeller gasket (& new impeller...previous one pretty grooved and start leaking coolant), then after I almost shot myself since the I still couldn't get the stupid mismatched cases to connect straight (the crankshaft was binding pretty bad), I paid Adam @ out of control racing to re-install the crankshaft bearings/crankshaft/transmission in a way that went together straight, and I put it all back into the bike with the top end.

so ya...pretty much everything...

and I sold it with an extra set of wheels, extra crankshaft, extra top end, gasket kit, extra FMF exhaust, extra clutch, 2 stroke oil, 2 stands, extra plastics, dirtbike ramps, spare frame, etc,

even after allllll that friggen work, would ya believe I had a hard time selling it??

because I did! turns out the general public doesn't understand much more than "does it have a new top end?"...they don't give 2 shits about a GMD serviced suspension (most $1,000 dirtbikes never had their suspension serviced), pivot linkage bearings, steering head bearings, water impeller bearings, etc. But you never get your money back in mods or repairs on a dirtbike...so buy it used, ride it while it still runs, then when it's about to pop, sell it!

lesson learned!

on the plus side, I know *every* single nut, bolt, washer, etc. inside the engine on a 1998 RM125!!

[Kurlon]

(I learned this at stimilon) too much oil will make the bike not run...do 40:1

be careful of those small 2-smoke mx bikes, I even flipped a ds80 at visser's house by accident!

The key is to jet for the amount of oil you plan to run. Small bikes that get wrung out tend to like more oil. If they're getting putt-putted go less. Either way jet for it.

[mrl1300r]

50:1 would be safe for that bike. I usually run 70:1 in both our KTM 200's.