Safe cruising rpm

Is there a reasonable upper rpm limit for various builds. I got a digital rpm meter and put it on my 2011 tomos with the uni/biturbo/ upjet kit and i find it cruises at 9600 rpm when warm at about 37 mph. Is this a good idea for longevity ? Are the main bearing built for hours or minutes or moments. I typically ride for ten miles full throttle.

What about rpm with a pa 50 with original crank and bearings but a dellorto 42 cast iron upgrade or my Vespa bravo when I figure out how to make it go fast?

Is it just bearing temp that somehow we infer from another temp measurement? Or are these internals so nukeproof that rpm at the 10,000 level is inconsequential?

Re: Safe cruising rpm

Overpriced Parts /

Change sprockets and get a few more mph

Re: Safe cruising rpm

I have them but I'm asking not a top speed but a longevity question.

Re: Safe cruising rpm

Overpriced Parts /

Lower rpm lower temps, more mph, more mpg

So if a engine has a certain life and you slow it down it could last longer.

I just gear a bike to whatever the engine can pull .

Takeoff is important but that's but for a moment .

I don't need to wheelie and then go slow .

I try to balance good take off with good top speed .

It seems like you have enough rpm and power to up gear a little

Re: Safe cruising rpm

Adrenaline junkie speaking, go fast safety last. and its not really the RPM's its the heat thats the killer. like when i start to press it, I hit temps around 390.... Kinda waiting for something to boom excuse to spend more money and upgrade upgrade upgrade. Though when i see a cop, or an asshole pedestrian who i know is going to do the slow the fuck down wave. I will drop down to about 27 mph at 280 degrees. Since i dont know my RPMs i go off the heat. Granted this speaks nothing for the crank bearings but what ever i take my chances. i'd say when you're at speed and holding a little on the gas (around 32 for me) would be safe. and i can't speak for all mopeds but no the internals are NOT nuke proof. Then again i ride like an absolute asshole and give mopeders everywhere a bad name and have never seized or broke a drank or gear. GRanted i'm not ported polished tuned like a race car and pressing every degree out of that engine i can. Also this is just my CRAZY theroy but i believe (you can all talk the shit you want but i'll spill it) it is not safe to put put around, with the lowest temp you can. Engines and pistons rings etc... are designed to expand at temp without that expansion shit dont work right. So anywhere around mid range is probly safest for temp and longevity. The again i'm just a rookie tossing some pennies into the wishing well followed by my insanity and bullshit. Enjoy.

Re: Safe cruising rpm

Well stated, a veritable bard!

Re: Safe cruising rpm

Marc,

I think you are asking a reasonable question. Obviously not getting an answer from anyone but I would also like to know the "safe" upper rpm range for an average moped motor.

I'm sure it depends on the brand, and a million other factors but maybe it would be cool to see a poll on what rpms most people cruise at.

I would like to run a fairly large gear on the rear of my garelli since where I live has a lot of big hills so I think it's a valid concern.

Re: Safe cruising rpm

Some mopeds create heat at lower RPM, some at higher. There is not definite answer is depends on your timing jetting and many other things. For example if your timing is more advanced you will create a lot more heat at lower RPM but make more power. a person who will retard their timing will run cooler, and create less bottom end. its the HEAT that will kill you. NOT the RPM. it all depends on your set up. If you run your fuel lean it creates more heat at the SAME rpm as someone with rich mixture. so at the SAME RPM someone will go BOOM and the other can run all day. There is no SAFE rpm range only a SAFE heat zone. if you whine it out more often it causes more ware and tear. Use your brain and watch your heat.

Re: Safe cruising rpm

Realized how all over the place i was the first time. I reviewed my first mistakes in an attempt to Give a more specific answer. Beat your shit up it will die. Use your brain and take care of it can last a lifetime.

Re: Safe cruising rpm

Ok let's assume for a minute its all about heat. What is the best heat monitoring method and the cost

Re: Safe cruising rpm

https://www.treatland.tv/SearchResults.asp?Search=temp

Some are for case some are for the head. From what i understand anything over 400 is the danger zone. So i use the head temp. $40 is enough to make sure i dont go BOOM with my $100's i've invested into it. like i can tell you this my buddy holds his wide open all day everyday while we ride. while we ride i'm only about 1/4 throttle. i mean obvioulsly the wear and tear from him holding it wide open is greater than mine at half throttle. but is he doing any real damage? no... i can't say he is. They are designed for this ya know. (edited)

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