What's a safe RPM to run for an extended time?

I'm planning a trip to baja this fall and really want to ride with the 14/47 gearing for the low end but am concerned about running at 65 mph for extended miles.

I've never been on this trip before and understand there will be spells of 20 miles or so on paved highways where we will likely be riding at 60 to 65 mph. According to a gearing spreadsheet that I downloaded from these forums several months ago, that speed will have me riding at about 7,200 RPM's.

Is this too high of RPM's to run steady at?

Anyone else taken trips to baja with this gearing?

Any input is appreciated!

WFO !

:ride:

Nah, 7,200 rpm is nothing. I ride at or above that almost all the time. you'll be fine. High rev's are easier on the engine than low revs, less loading. Engine is making more power so it is less stressful.

I don't know the rpm but when I am in 5th gear at about 58-59 mph and then go up to 60-?? I notice a different sound and almost like an engine vibration. Its almost like the carb has a second barrel kicking in. Anyone else feel this?

Thanks,

db

I'm planning a trip to baja this fall and really want to ride with the 14/47 gearing for the low end but am concerned about running at 65 mph for extended miles.

I've never been on this trip before and understand there will be spells of 20 miles or so on paved highways where we will likely be riding at 60 to 65 mph. According to a gearing spreadsheet that I downloaded from these forums several months ago, that speed will have me riding at about 7,200 RPM's.

Is this too high of RPM's to run steady at?

Anyone else taken trips to baja with this gearing?

Any input is appreciated!

I have ran baja a couple of times in the last few years. My uncle goes every year. Like William sayed, your motor will be fine at that speed. I don't know what your ride will consist of, but we ride the entire peninsula, top to bottom, in two weeks (and I'm not talking about taking the highway). On our trip you would be hurting with 14/47 gearing. Your gonna have poor fuel economy and there will be a few times your gonna be revving that motor higher than you ever want to considering there isn't a local suzuki shop nearby. Baja is about survival. I personally would run 15/44 or 41 unless your gonna be on a sightseeing tour within 15 mi of civilization :thumbsup:

BTW, my uncle (15 year veteran of baja) swears by going with the biggest front sprocket you can get and 2.5x that in the rear. That is 16/40.

Hi Dave, you are experiencing harmonics. Be it the air box or the metal in the bike, at certain rpms, almost a tuning fork resonance can be heard and felt. A few RPM up or down and it goes away or a different one appears.

Stock well tuned motor.. No real limits.. let the vibs and monkey butt be your guide

Nah, 7,200 rpm is nothing. I ride at or above that almost all the time. you'll be fine. High rev's are easier on the engine than low revs, less loading. Engine is making more power so it is less stressful.

William1, Thanks for the response. So is there an RPM that is dangerous to keep it at for an extended period of time? It seems like there would be a point where it would be working too hard and risk damage to the engine.

Thanks again...

Stock well tuned motor.. No real limits.. let the vibs and monkey butt be your guide

LOL, Yup, the 'monkey butt' is truly the real limiting factor.

Fred, I assume you have a MCCT on there and will do an oil change just before you leave and right after you return, right? I also assume you have been keeping a log of valve clearances and they have been stable too.

William1, Thanks for the response. So is there an RPM that is dangerous to keep it at for an extended period of time? It seems like there would be a point where it would be working too hard and risk damage to the engine.

Thanks again...

Well, hard against the rev limiter on an E probably is not the wisest of moves, or even on an S. On the limiter does add a little more stress than you would get just off of the limiter. I would think 9K for a hour at a time would be ok. This is assuming you have an engine in good mechanical condition and your jetting is either perfect or a tad rich. You are planning to be running at about 1/5 less than max rpm, you should be fine.

Hi Dave, you are experiencing harmonics. Be it the air box or the metal in the bike, at certain rpms, almost a tuning fork resonance can be heard and felt. A few RPM up or down and it goes away or a different one appears.

William, Are the strange whistle noises I have heard on 2 occasions usually when the bike is fairly warmed up but only driven a mile or 2 also harmonics?? Yesterday we went out and a half a block down the road I could hear like a fairly loud howling or whistling that sounds like its coming from the radiator area at medium rpms as I am accelerating. I always turn my head to make sure its not wind noise in my helmet (and its not). I just keep riding and it seems to go away. Is it maybe coolant flow through a bypass or something? Or the airbox singing to me?

Thanks,

Dave

LOL, Yup, the 'monkey butt' is truly the real limiting factor.

Fred, I assume you have a MCCT on there and will do an oil change just before you leave and right after you return, right? I also assume you have been keeping a log of valve clearances and they have been stable too.

William, I don't have a MCCT nor have I been keeping a log of valve clearances but I do plan on changing the oil before and after the ride. Tell me more about the MCCT if you don't mind.

MCCT Manual Cam Chain Tensioner. A good insurance item to avoid a slim chance that the ACCT (Automatic Cam Chain Tensioner) fails. About $50 and less than an hour to install.

DB

The ACCT uses a spring to control cam chain tension. It is a weak spot on a DRZ. The spring can break, letting the cam chain get too lose, the chain then can jump a tooth or more and ause catastrophic engine failure. It can als overtighten the chain, creating exxcessive wear on the chain sliders and the chain, also resulting in a bad day. Do a search here on TT for either ACCT or MCCT. You will see many references to the failures and the methods for install. Very easy job, a novice can do it in under an hour.

The other major engine weak spot is the valves themselves. The stock ones are a two piece affiar, the head being 'spin welded' to the stem. They have been known to seperate, again causing major problems. Regular checking (every 500 to 1000 miles) of the valves and recording the clearances provides a 'view' to a valve that is 'tightening' a sign the stem is stretching and needs to be replaced.

You should take a good read of the threads in the "Look Here Before Asking" thread at the Top O' the forum. Great information and How To's in it.

Nah, 7,200 rpm is nothing. I ride at or above that almost all the time. you'll be fine. High rev's are easier on the engine than low revs, less loading. Engine is making more power so it is less stressful.

Higher piston speeds (RPMs) cause faster wear - period.

I can ride my DRZ at lower revs with out lugging the engine - runs cooler, and uses less gas.

Higher piston speeds (RPMs) cause faster wear - period.

I can ride my DRZ at lower revs with out lugging the engine - runs cooler, and uses less gas.

True, but I have not heard of any failures on a DRZ engine due to wear. Either a part simply fails or the rider was lugging, causing piston slap, transfering material to the barrel wall and then to the ring land, therby losing compression. As long as you are in the power band of the engine (between 5,500 and 7,500 RPM) your engine will be happy. And isn't that what it is all about, a happy engine as a happy engine makes for a happy rider. The only time rpm's are a problem is if a valve is bad, it can make it fail sooner.

Why wouldn't you want higher gearing if you were to be riding around the desert for days on end?

Is there a hidden supercross track out there somewhere?

:excuseme:

I did a trip to BAJA last year with 14/47 and still run it on the highway from time to time no problems at WFO except I keep looking for 6th gear

Thanks for all of your input.

William & Davebert - I will definately check into getting a MCCT.

Clutchsmoke - good point...Since I've never been to baja, although I realize it's desert, I didn't think about most of it being rather flat. Our riding terrain around here is quite mountainous, which is what I'm accustomed to.

I think I'll go ahead and leave the 14/44 on it and take the 15 with me which would be easy to switch if I want even a higher ratio.

Thanks again for everyone's input.:thumbsup:

fred - question for ya. About that gearing. I haven't really gotten the hang of the whole highway riding thing yet on my E, haven't gotten it above 45mph in fact. In the shop right now for a kickstart installation.

You mentioned switching out a 15 for a 14. How much would this change your speed at say, 7000 rpm? (like, if you're riding that rpm on one gear as opposed to the other)

I'm asking because I'd LOVE to be able to comfortably cruise down the highway... and I have been concerned about the rpm, so I'm quite interested in this topic.

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