"Healthy" cruising RPM...?

So I used to ride dirt bikes and I got my first street bike a month or two ago. It is a 1983 XJ400K, it has only 10,000 miles and runs beautifully...

Here is the question:

What is a healthy(for the bike) RPM: a) to cruise at on the freeway
b) To peak at when accelerating fast.

I don't want to push it too hard because I want it to last a while. It redlines at 10,000.

Thanks for your replies ahead of time.

 

Ya know, this is a topic that I would love to see some feedback on as well. C'mon folks, we're waiting here.
FWIW, my Maxim 700 '85 that I'v e had for all of two months just doesn't seem to have the top end that I wuould've thoght. NOt that I've gotten to the top end but it definitely feels less than "purring" at 55mph.

 

I think it's an "XJ" thang. My 82 Maxim 550 cruises at just about 5800rpm at 65mph but listening to the engine, it seems high to me but from other conversations on here, I think that is just the XJ purrrrrrrrrrrrrr

 

My XJ650 Maxim turns 6K RPM at 70 MPH in 5th gear - so that is the default cruising RPM.

If I'm in a situation where I think I may want to pour on the power I run at 4K RPM (The power really starts to come on there).

Now there is an interchange I ride through on my way home from work. Tight cloverleaf and I need to get left 3 lanes pretty darn quick to avoid a mandatory right lane exit and all the merging trafic after that. As that ramp straightens out I'm in 4th gear (55mph or so) and really roll it on. Don't hit 5th gear until I'm getting into that 3rd lane. Not sure what the tach says though because the grin this causes pushes my cheeks up to where I can't see the gauges Of course then it's 5th gear and 6K RPM until my exit.

 

I ain't happy unless I'm above 4-Grand.
I came back from Loudin Bike Weekend at above 6-Grand
I routinely show it the whip and hit 7-Grand
When I put the Rev-limiter in it ... I'm setting it at 7,850 !!!

 

5500 RPM's is were I get the best gas mileage on my 700S. I haven't hit the topend RPM on the bike yet, bet I can tell you the bike really gets a second breath above 7000 RPM's and wants to fly.

 

I love to feel that top end burst... I only do it getting up to speed limit and love every second of it, as few of them as there are. Cruising at 55 i guess is near 5k. I have red lined it, and I believe that red lining an engine is good every now and then.

 

Mine turns at about 4k at 55, 5k at 65. Personally, I'd like to see the thing rev lower, but that's just me. Being an '82, the speedo says I shouldn't be going any faster than 55, Sammy Hagar be damned.

I think I caught a whiff of that upper powerband when I first got the carbs balanced. I hopped on the freeway onramp and opened the throttle, and got a bit of a surprise past 6000... eek!

 

This is one of those topics that is totally subjective depending on the rider, bike, tuning, etc. I'd define healthy as being 30-50% of RPM redline for most engines, including bikes and cars. Some guys like to cruise at a certain "sound" of the exhaust and some go for maximum gas mileage. Myself, i usually settle for whatever speed i want to travel in a given circumstance and go for it. If i remember correctly my XJ750 settles in at 5500 RPM @ 75 MPH. Sure is nice to feel the bike hit that sweet spot between 6000-9000 RPM, i just hold it open until the tach swings past 10,000 RPM and grab some more gears.

 

Actually went for a ride today, found out my estimate was wrong... 55 at 4k.

Anyone know why the engine feels like it wants to vibrate itself apart at 5k rpm? I think it smooths out around 6k but it make is hard to ride at 65-75mph. Any ideas of smoothing this out would be great.

 

I notice a certain vibrational _resonance_ of he engine at about 56 MPH in 5th gear. I guess that translates to somewhere between 42-4500 RPM (I have to make a more accurate note of the RPM) but it does happen in 4th also (never stay at any rpm long enough in lower gears to notice).

Its not bad but noticeable from the smoothness at other speeds (RPMs).

 

I have the same vibration at those rpms also. 4.5k or so around 60 and it vibrates, kinda freaked me a little when I first felt it but everything seems fine, and it's not shaking uncontrolably, just a small vibration.

 

Worst of all: These things, like most all older Yamahas Have Too steep a 6th gear .. as ij at passable rpms (less than 5500/6000) the damned things labour in 6th so you have to shift down to fifth with even higher revs just to slowly pass a truck.
Seriously suggest dropping at least 1 possibly 2 teeth on the Countershaft sprocket.. IF.. you actually want to use yr Bike... and Gawd forbid, use it on the HiWay for more than a couple of miles.

 

watcha mean by a 6th gear?

 

"watcha mean by a 6th gear?"


I think he has a Seca. Us Maxim guys don't neeed no stiiinking 6th gears hehe

 

check if you have stock size sprockets now, then maybe go up one on the countershaft and have a usable 1st and forget 6th

 

6K RPM @ 77 mph.

From 7k to 10k it feels like a rocket is strapped to it

 

Oh man, rocket indeed. If you're looking for speed with the old xj (I have an '85), just get past 6k. And don't worry about blowing through to the redline, just hope you can switch gears fast enough. You'll hit 100mph in no time.

As far as freeway goes, I agree with a couple things some others said. There's definitely a resonance somewhere, probably around 5k like some others said. I like to stay above that, but I took a trip where I drove 80 or so the whole way (this is in 75mph speed limit land) and didn't get such great gas mileage. I think the best thing to do is settle in at a reasonable rpm, if you care about gas mileage. You'd probably be going 70 or so, maybe 75.

 

where I live, you have to get on the freeway to get most anywhere... 65-70MPH, 75 on the turnpike... 5.5 to 6.5K... now, getting on the ramp is a different story. that happens around 7.5 to 8.5K... gotta keep up with da yuppie folks in their SUV's :-D

 

I take my 82' XJ650 over 10K all the time when I'm looking to have an ear to ear grin on my face. Under normal road conditions going the speed limit here in the great garden state i usually keep it around 4500 to 5000 rpms when i'm cruisin'.

I ran it last august down the 1/8 mile track at englishtown and she did about 73 mph. I only had a couple month experiance under my belt then. This winter after I get some work done on my beast I'm going down the track again. Anybody been down the 1/8 or 1/4 mile track? What did you run time/mph?

 

I can't sit here anymore reading about this %^&*!

I have to get out and RIDE!

 

I have had my xj650 for three years, and it does the same vibration around 4.5 to 4.7 (In every gear). I always wondered if that was ok. I see it seem common at least

 

I was out today to go to the airport and back and confirmed that the RPM vibration "resonance" I can feel... is around 4.5K.

I didn't notice it for several months until I had driven the bike enough to start being sensitive to its every little nuance. Its probably a design phenomenon. There are certain aircraft engine-prop combinations that produce resonances that are to be avoided for prolonged periods (as per the manufacturer).

Any excess vibrations in an engine should be avoided whenever possible is always recommended in my opinion. Now that I'm sensitive to it I just try to avoid continuous running that that RPM. Less stress on the parts....

 

A few weeks ago I posted about breaking my header bolts. One broke by itself and the other I over tightened. I had just got back from making around a 400 mile trip. I also had the vibration around 5000rpm's. That is what made me aware that a bolt broke. I was going down the rode and was at the annoying rpm when suddenly the vibration quit. It made me wonder if the vibration at 5000 rpm's that so many have is do to the binding of the headers to the engine ? It was the bolts on the far right pipe if you are sitting on the bike. It would be interesting if someone else loosened those bolts off and tried the same thing to see if their 5000rpm vibration also quits as mine did.