1965 Honda 50cc Super Cub

[Ironside]

Anyone have an opinion on the 10w40 synthetic. The original specs were 20 weight in winter and 30 in summer.

Some of the guys in the c90 club have reported excessive clutch slip when using fully synthetic oils, others have no problem.

I don't want to start an oil thread, just reporting the facts. 10/40 is probably the best choice.

Ironside.

[jkv357]

Originally Posted by Ironside

Some of the guys in the c90 club have reported excessive clutch slip when using fully synthetic oils, others have no problem.

I don't want to start an oil thread, just reporting the facts. 10/40 is probably the best choice.

Ironside.

Full synthetics aren't any more "slippery" than regular oils - just designed to be stronger. They have a closed molecular structure that holds together much better in extreme heat, flow better in extreme cold, and don't oxidize like conventions oils do.

Most likely they (the people that had the slipping issues) used an auto oil that contains Friction Modifiers that can build-up on clutch plates and cause slipping. In general, auto oils are a terrible idea for a cycle (full synthetic or not).

The engine was designed for a 30-grade oil. A 40-grade builds more oil pressure and flows slower - not usually an advantage. Heat is moved away from critical areas by flow, not pressure.

I would say to use a safe 30-grade oil like Rotella T5 10W-30 synthetic-blend for the best lubrication for that particular engine type.

[sendler]

Mobil 1 4T is motorcycle specific and readily available in 10W40 at auto stores. If you want to order something fancy to eek out the ultimate fuel economy and protection, Motul 300V is among the best and available in 5w30.
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Motul 300V Ester Synthetic Oil - Motorcycle Superstore
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[user removed]

I wobble between Castrol and Mobil 1 on the bikes. Since the Cub is not a pressurized system and since the left over oil from a change on the GZ 250 is perfect for the Cub, I buy two quarts of synthetic 10-40 and that changes the oil in both bikes. What remains to be seen is if the Cub needs a change before the GZ250. I've put 3k of the GZ and less than 75 on the Cub but the GZ goes back to Dec 13. The Cub will not get many miles on it maybe a couple hundred a year. Might save the left over and spread it out between both bikes.

regards
Mech

[user removed]

First fuel log entry. Took me 3 weeks to get to 14 miles on 10.5 ounces of fuel. 170.73 MPG. It's probably not dead accurate since there is no tenths markings on the odometer. My fuel measuring quart bottle works like a charm. Top of the motorcycle list .

I wonder how much I lost to evaporation from sitting two weeks?

The tank capacity is 3 liters and I don't like filling it all the way because it will leak out of the cap if you fill it to the top.

regards
Mech

[sendler]

Top speed?

[user removed]

43 MPH from what I have read. The speedo is still a little wacky, I saw 50 indicated on a downhill stretch yesterday going to the car show 2.6 miles from my home, but traffic was still passing me in a 45 zone. I'm supposed to keep it below 35 MPH to run a scooter tag in Va. I think it would do 45 if I tucked maybe even 50, but I hate to take a 50 year old engine to that kind of RPM and risk blowing it up (splash feed oil system).

regards
Mech

[user removed]

Just changed the oil in the GZ250 and changed the Honda 50 with the left over .6 liter from the GZ"s 1300 ml (out of 2 quarts 10w 40 synthetic). I think it has gone 119 miles since purchased. I need to do some fuel log entries, if the weather holds up this week.

regards
mech