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Holding high RPM for an extended time?


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I've got a question that might be stupid but... I was told not to hold the engine near the top of the RPM range for more than a second or two to avoid engine damage. Is this accurate information?

 

I was told not to just stand on it once it is revved up, and to blip the throttle open and close near the top of the RPM range.

 

I was racing with a friend who has a Raptor 660R and held the throttle wide open through 1-5 gears (letting off only to shift), but once in 6th and on the pipe and pulling, when it started to top out I began letting off and he started to catch up.

 

I searched and read the Banshee has no rev limiter, so is it possible to let it rev too high and tear it up?

 

It is a stock bore/stroke engine with VF3 reeds, Pro Circuit Platinum pipes, Pro Design K&N intake, #320 main and #27.5 pilot jetting, and it pulls nicely but I don't know what the stock crank and connecting rods and so on are capable of doing in there.

 

The Banshee ate the 660R up on acceleration, and on top end I think it is very close but I wasn't standing on it to find out once it stopped pulling hard in 6th.

Oh, I am about 40-45 lbs heavier than the 660R rider and it still accelerated like a scalded-ass ape. After that days ride, he found a Banshee on craigslist that evening and we went to look at it yesterday. It was shit, he passed on it.

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Sweet.... thanks, that's the info I was after.

Stock porting will limit how much air it can move anyway, so it won't allow it to rev itself to destruction.... awesome.
Next time, I'll hammer it and stand on it to see if that 660R will eventually close the gap up.

Just out of curiosity, what does a stock banshee rev to without a load, like out of gear?
How fast have people made them spin?
At what RPM do things start letting go?

I'm used to the Yamaha Warrior, so when this Banshee engine really gets up there it made me a bit paranoid about tearing things up but if I know they only rev to maybe 11K stock and people take them to 15K or something when modded and the engine holds up fine, I know I can not worry about over-revving this one by many thousand RPM, it would remove some worry from my mind.

Jetting seems good, maybe a little rich on the pilot and blubbery at times down low, but nice in the mid- and high-ends, with no leaks that I have noticed or found.

Thanks again for the info!

 

Brian

Edited by BrokeVW
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What is your final gearing?

I´m not a pro, so don´t put much weight on my words, but I´m saying this just to give you something to think of.

It is very important thing to jet your carb´s good. That is one safe way to keep piston temp down.

Another thing is to gear it up and load the motor enough.

Sorry my english lol!

When you are on 6th gear and getting RPM´s up, don´t let your motor "think" it was/is an easy thing to do. Let it work hard.

Avoid over reving it for a long time.

I don´t know how to say it better, but I can give you an example. My final gearing can give me a top speed up to 100mph or a little over, but in real life it can only pull 96mph on a long long asphalt strip. So my motor needs to fight against wind/air with my heavy ass on it.

Hope this makes sence, if it doesn´t, ignore it.

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If a bike is tuned right it should be absolutely fine revved out. After all, looks at many 2 stroke sleds. There is absolutely nothing wrong with reving a 2 stroke out. However, there is some longevity/reliability to be gained with gearing the bike so the motor only revs to where peak power is.

 

The real problem is guys who are afraid to keep the bike opened up while keeping it pegged at top speed. Think of it this way. Your motor gets it's lube from the gas/oil mix from the carbs. Now you rev it up and get it maxed out at say 70mph on a long dirt road. Your in 6th gear wide open, then you start feathering the throttle yet keep the bike going at that same pace. That means the motor is still free spinning at that RPM, if you keep letting the carbs close yet keep it spinning where is the lube for the motor coming from?

 

Keep it opened up if it's revved up!

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The real problem is guys who are afraid to keep the bike opened up while keeping it pegged at top speed. Think of it this way. Your motor gets it's lube from the gas/oil mix from the carbs. Now you rev it up and get it maxed out at say 70mph on a long dirt road. Your in 6th gear wide open, then you start feathering the throttle yet keep the bike going at that same pace. That means the motor is still free spinning at that RPM, if you keep letting the carbs close yet keep it spinning where is the lube for the motor coming from?

 

Keep it opened up if it's revved up!

 

Shiiiiit..... I never thought of that, nice one.

Well, I'll hammer the fuck out of it the next time, let it wind out and see what happens. :clap:

 

Thanks for the replies!

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I bet if you spin it high enough you will feel it fall on its face as it runs out of the power band. If you are going to ride fast and hard alot like riding dirt roads its not a bad idea to leave it a touch on the rich side.

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Our desert/play bike runs stock gearing (14/41). It's in 6th gear before the 1/8 mile mark & hits around 74 mph. At the 1/4 mile it hit 89 mph this past weekend. Talk about screaming into overrev for a long period of time. We have about 40 runs on it this way & not showing any damage yet. LOL!

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