RPM / Speed / Gear Questions

Hello everyone,

I have come to the understanding that the XJs like to rev a bit higher, and I am trying to get that into my head when riding. I had been playing it 'safe', maxing out the gears at about 3-4k, reaching 5th gear at about 45mph but lately I have have been going closer to 5k and up...I'm definitely not used to such high RPMs so I guess I have a bit of fear in the back of my mind when riding.

My question is what speeds do you usually hit in which gears. I myself have an 81 XJ650 so hearing responses from members with similar rides would prove helpful.

Thanks

 

If you're shifting at 4K you haven't even tapped the "fun zone."

These motors don't begin making serious HP until 6K rpm. REV IT. (Assuming it's in a proper state of tune.)

 

Properly tuned, these bikes wake up north of 7K. If you're keeping it that low you're missing out.

Where you shift depends on how quick you want to get away from where you just were.

Just cruising around I'll shift whenever without paying much attention. Need to get up a ramp, twist it open and let it scream. Shift around 8 or 9k. But hang on the beast is awake at that RPM.

 

It all depends on my mood - mostly I'll change as low as you have been and pooter about, but on the odd occasions I get out of town I can use the revs much more. As has been said, the XJs come alive after 6K.

 

For me:

2nd - 20mph
3rd - 35-40mph
4th - 50-60mph
5th - I only use 5th at motorway speeds, or if I'm cruising down a back road for miles, to save fuel.

When I want to "get after it" I'll take 2nd up to 7,000rpm, then I have to back off because I'm going about 5mph over the limit.

Most places in the US you can't redline 2nd gear because you'd be speeding.
(although it is FUN to do :twisted: )

 

All this is very good to know. I just have to get over my little stigma of seeing the RPMs that high. What should the engine sound like at 6-7k?

Another question, how does putting the revs that high affect all of your mileage?

 

Revs vs mileage is a two-way street.

Will it use more fuel at 8,000rpm vs 5,000rpm? yes, of course it will.

BUT

If you shift at 3,000rpm all the time, you are actually making the motor work harder, and probably not burning all of the fuel the motor is taking in. So you could be using more fuel at 3,000rpm than at 5500rpm.

Also, keep in mind, your charging system doesn't kick in until around 2,000rpm, so if you are always shifting between 2K and 3K, you are actually hurting your battery a bit.

 

That is great info tskaz!

I have my shims in spec, and I definitely hear a slight "chatter" of the valves when running which I understand is normal. How normal is a "whirring" or higher pitched rev sound? I did a vacuum sync, which I want to do again just to be sure and to dial in the idle. I still need to do mixtures also, but I am waiting for my Colortune. Anything else I should do to make sure my engine is properly tuned for higher revs?

 

Check your plugs for color once in a while. Lunch bag brown is the goal.

I remember getting my bike on the road for the first time after I got it and each spring when it's been awhile since I've ridden it. Takes me a bit too to let the RPM up. I guess that comes from driving a jeep and a diesel pickup. Both would probably throw rods at 4 or 5k.

 

And clean plugs in-between checks to have a "blank canvas"?

 

I haven't found that necessary. They'll change colors on their own. If they are black black maybe make some adjustments and toss a new set in. About $8.

 

Thanks everyone. The more I work on this bike, the more I find it was the best investment I've probably ever made. The knowledge I'm getting working on it and from all the help on this site is well, well worth the price of admission. Not to mention, I love my bike!

 

3-4k is alright for pootling around, but not for acceleration. Go higher and you'll find a big hole at 6k. Work round this by spinning up to 8k in the lower gears if you want to get a move on. It does feel high for an older bike but it's the way Yamaha designed it.

 

Hi. I have XJ650J- my mileage on the last tank was 47 mpg, I have been tending to run at higher rpm's this year because it's fun and has begun to feel "normal". Last year I regularly saw 52-53mpg but I wasn't rpm'ing as highl.
You will probably feel a range where there is some noticeable vibration - around 4900-5000 rpms, I think. That is common on these bikes due to engine/drivetrain harmonics. It is less harsh if the valves/carbs are all set correctly. It goes away above 5200rpm and on mine, it's real smooth at 5500+. My bike is happier at 60mph in 4th than it is in 5th and can run all day like that! Same with 75mph at 6000 rpm in 5th gear- it feels smooth and like it could do it all day. all day. However, if I'm doing 55 for an extended time, 5th gear is great on gas at that speed/rpm and it's just below the 'vibration zone'.

 

Another consideration is oil movement. Your pump is more efficient at higher rpms and moves more oil at a faster pace. With the airheads this is important because the engine is basically relying on the air in the fins and oil moving to stay cool.

Having owned a Honda CB650 (hydraulic valves) and after riding many water cooled bikes, it took me a while to get used to the XJ 'sound'. These engines contain nothing 'extra' and as a result they seem noisy by comparison. You should hear your valves tapping at idle and while revving up you should hear a nice eager growl. And as said when in tune revving up is fine-from experience my 550 would rather run above the harmonic level (3.5k to 5k) most of the time. Going for gas mileage I will go to 6th around 55. Of course above 8k it positively sounds like it's a speed obsessed beast, and rides like one too! The Honda was more tame (soundwise) at the same rpms.

 

These motors absolutely scream. They are noisy at idle and should be. Valve tapping is normal. Load metallic knocking is not. When reved, it will raise the eyebrow of any modern sportbike owner. One not familiar with XJ's will swear the thing is about to fly apart, but it is a rock solid plant if well maintained. In the happy range of the rpm's, it had a sweet low mellow tone unlike sportbikes which are more high pitched.

 

Yea!!! These bikes are fun. Mine actually raises the hair on the back of my neck when I hit the 7K mark up. That and the back wheel acts like your hotrod car does when you step in it (Rear tires start drifting to the side) That is how mine feels at that RPM only with a single tire.... Gotta Love-Um

 

i've been out of town for 5 days now and won't be back to my bike for another 5. After reading through this thread, i've never missed my bike more. I can't wait to ride it and feel the thrill again!

question, though. i don't know if my tach is the original, and I don't have mine around right now, so i don't remember where the redline is, but what do you fellas feel about about putting it close to the redline? It really takes no time at all for my seca to go from 6000 all the way up. i get nervous about being too hard on it and back it off. do you guys keep it in the redline region much?

 

I run my 550s into the red all the time. (10K on the 550.)

Just be sure your valves are in spec and you aren't running lean, then let it run!

 

Redline? What redline? I can't find one anywhere on my Tach!

Ha! Seriously the only way I can tell if I'm near is the power drop, but even then the engine still sounds pretty happy. It seems to enjoy 10 grand as much as I do.

 

Really? My tach shows a solid line starting at 9500. So 10000 is completely ok?

 

The 550 motor makes peak HP at 10K. It falls off AFTER that.

 

1982 XJ650R redline is 9,500

 

Hi guys, I have a closely related question for you. I just got this bike a week ago and as it is my 1st bike I am not too knowledgable about motorcycle mechanics or this bike in particular.

I generally ride low in the rpm's as well... (i am a beginner). Today i really opened it up for the first time in 2nd gear and found myself yelling (this is scarrrrrryyyyyy FAST!) inside my helmet. I loved it. I absolutely tore away from traffic till i got to a stop light. Where my bike promptly DIED. and had major trouble starting up again (5min). .... why could this be?

Here is some info about the bike.
-It requires alot of choke to start up.
- Choke was still full on at this point.
- bike had been running nicely for about 10 minutes prior to zooming off
- bike probably needs the carbs cleaned
- I have had to fiddle with the idle screw and choke to get the bike to start and then later after 15 ish minutes of riding i have to turn them both down to so the bike doesn't idle at 3-4000 rpms with the clutch pulled in.

Any help would be hugely appreciated! I love this bike, it just needs to be fixed up a bit to run more smoothly and start more reliably...

is this symptomatic of a dirty carb problem?

Thanks!

 

Alright, I took her to 6k several times on my ride home from work today. I can tell that the bike absolutely loved getting in some extra RPMs! The harmonic, vibe totally smoothed out about 5500. Hit 55mph at 6k in 4th. I have another 2-3k in RPMs and then another whole gear?!?! Jeez, that is pretty intense! Love it!

 

Slomo85, sorry, the 550 Seca redline is set at 10K, that may be because of the cams.

I didn't realize the 550 Max was redlined at 9500. You won't hurt anything running it to 10, but if it redlines at 9500 that should do fine.

I've hit 12K by accident (hey, I was passing some cars) a couple times without any issue; the motor just keeps pulling. NOT something I'd recommend, but it won't cause any damage in a solid mill.

Thanks for pointing that out; it will keep me from sticking my foot in my mouth in the future.

**EDIT** You guys type too fast.

Shah try running it to 7K or 8K; in second and third it will snap right up the range above 6. Six is the beginning of the fun band. Be ready to shift.

 

I just noticed in your sig that you have only seca's! lol, lucky... Yeah, guess that's one more difference.

 

This is curious-the max550 tach does have a solid white line starting at 9500 and going to 12000, but it also has the same solid white line starting at 55mph and going to the limit 85mph.

I can verify that what BF says about his Seca550 is the same with the Max as far as it is still pulling very hard right past 9500-so the question then becomes is this really a 'red-line' or is it more like a white 'hey buddy don't overdo it' suggested line. Because I think in 81, if I have this ancient history right, the speed limit was 55mph (hence the white line starting there), but honestly who really expected everyone to just zoom up to 55 on one of these bikes and then say 'well guess I'm at my limit.'

Every other actual red-line on a tach that I've had 'felt' like a red-line when you reached it, i.e. no more power and engine sounds like it would like to self-destruct. I think the 'true' red-line on the 550's is closer to 10,500 maybe 11k, maybe higher? Of course I don't and wouldn't recommend riding up that high for an extended period (or go above 5k w/o the mill loaded) but it is fun to poke through the stratosphere occasionally.

Over-engineered? Under-speced? Both? Keeping the bean-counters happy like shipping them from the factory slightly lean?

pouncingmailbox you definitely have issues with your carbs, and you don't wan't to ride hard with the enrichment circuit (choke) on. You should only need it for a short time when it's warm (<1 min). Sounds like your idle screw is set too high, and you may be lean otherwise-start reading on here about carbs.

 

Alright! Took the 650 to 6k-7k on the ride in today. WOW! You guys aren't kidding, that is definitely the fun band. She really thanked me for stretching her legs out today! Talk about power. I could get used to this!

On a side note, not sure what it is...maybe the sound of a high revving engine...but I had two rednecks in their bick ol'e pick up trucks try to race me today. Now, I'm not the type that races. Just always seemed silly and wreckless...but I smoked 'em. Nice Silverado, jackass.

 

Those "solid white lines" on your tach and speedo used to be red; they've faded to white.

 

are these lines easily accessible to re-paint them? can this be done with the gauge cluster still mounted? I've read your guide on inspecting the speedometer gauge but that's for a whole different cluster (seca, iirc)

...sorry to hack this thread but I've asked before on another thread and got no response & I'm sure somebody has done this before or is wondering the same thing

 

The cover comes off on the 650's. You could paint them while on the bike. it'd probably be easier with them on a table.

 

The speedo too? How do you take the cover off these? Currently using my iPhone as a speedo, as the needle fell off mine. :lol:

 

Reply to your post "pouncingmailbox".

Your quote - "Today i really opened it up for the first time in 2nd gear and found myself yelling (this is scarrrrrryyyyyy FAST!) inside my helmet. I loved it. I absolutely tore away from traffic till i got to a stop light. Where my bike promptly DIED. and had major trouble starting up again (5min). .... why could this be?

Here is some info about the bike.
-It requires alot of choke to start up.
- Choke was still full on at this point.
- bike had been running nicely for about 10 minutes prior to zooming off"


You should NOT be running up to these revs on choke! The bike should NOT need choke at all after a 10 minute warm up!

Will it not idle without choke after it's warm? No wonder it died wouldn't start again if it was still choked when up to temp.

 

If I'm remembering mine right you remove the nuts on the back to remove the chrome cover then on the inside the guage screws to the cover plate. On my bike it's one cover for both round gauges and the lights in the middle.

 

damn right, i love me some 6-9k pulls. these bikes just never cease to amaze me!

i love being able to hit 60 in 2nd gear before even coming close to redline. effin badass!

 

Wow. I don't think I want to take her that far. LOL :lol:

 

I'll have to give that a try when I get home and test it out.

 

As far as "painting" the lines:

The numbers and the redline are actually done with a see-thru silk screen process, and the black is just that, black, and not see-thru.

Of course, I found this out the hard way.

The only good way to re-do a face gauge is to sand the old off, and apply a new decal to the face.

Problem is, no one makes them for the XJ.

What I did was found a set from an older Yam that wasn't weather-faded and replaced them.

I used XS gauges on my 650 Seca, but I don't know which models will easily interchange with the Maxim.

 

My wife works at a print shop, I could probably make one in PS and have her print some decals.

 

I cheaped out and simply used a sharpie:


Not fancy but looks way better than before! I'd like to comment on the whole power band thing. If you're not used to it these bikes can get away from you in a hurry when you get past 7K, especially in the lower gears. I hardly touch red unless I'm in at least 2nd gear, it can be hard on the transmission bashing her into second after spinning her into the danger zone...

 

original





$11 and an hour's worth of work later

 

my 81 650 regularly hits 10 000 RPM, sometimes when the traffics lite i like to get myself at the front of the que at the lights and open it up in 1st abit and give second 2nd a work out then im sitting all alone with a heap of cars behind me and heap in front, no cars to worry about for awhile, and a bonus is a sh#tload of fun, if i want something to putt around on i would get a moped

 

You know you want to

 

Thanks for your help NigeW

Thanks for the Info! This was very helpful! I wish the woman I bought it from told me not to drive it with the choke on. But instead she said i should just tap it over to the off position as the bike warmed up on my way home. The idle was set low too so it would tend to die in traffic if i took the choke off.

BUT NOW THIS IS FIXED, I now have the idle and choke set harmoniously enough to start the bike with choke warm up for about 2 minutes then bring the choke to off and keep the bike idling nicely. It might have helped that today was very warm... but anyway its progress.

Have I been doing any serious damage to the bike by running with the choke on for a couple of days? I really only took it above 6000 rpm once. I am guessing it died in traffic after being driven too hard because it running way too rich and or flooding...?

Any other info on the responsible operation of an old motorcycle would be greatly appreciated! The info i have been digging up on this forum has been very helpful so far!

 

One time I forgot to take the choke off, had it on the halfway mark on the way home. I couldn't get the bike above 6000 on the highway in 5th. Thought it was weird, bothered me.

Just after getting off the highway, realized the problem.

I can't imagine you've damaged anything, it would just indicate serious problems if that was really required... But who knows, maybe I'll learn something here in a minute.

 

Sounds like you've got it sorted now. Your plugs might want a clean after running that rich for a while but I can't think there'll be any damage to anything. - apart from your mpg!

 

As Nige said, you might have sooted up the inside of the engine and the plugs a bit, but that will burn off when you open her up a little bit. If you did create a lot of soot, you might get a little smoke for a hundred yards of so, but if you're looking forwards you won't notice.

 

The motorcycling equivalent of turning up the radio to drown out the knocking...

I love it! "As long as you're looking forward you won't notice the smoke."

Seriously though; you didn't hurt anything but you need to learn a bit more about your bike and get the recommended maintenance caught up on and soon.

 

Wanted to revive this thread for a 1yr< rider question. I did a 30 mile ride today taking the rev advice here. Like the others, I had been shifting conservatively (too quickly). Today on my ride, I let 2nd rev to 5k and 3rd to 5-6k. Hit a highway and never got into 5th, but loved cruising in 4th at 5500-6k.

My question is shifting technique. How do you shift 3rd-4th gear with 3rd gear at 6k without getting some lurch? It didn't seem to be a problem going from 2nd to 3rd at high rpm, but 3rd to 4th gave me a little uncomforting lurch.

I picked up a 125cc Kymco scooter for my commute into work 13 miles one way through mostly urban streets - 40mph max roads, and the Kymco keeps up with traffic no problem. Comparing my XJ750 to the Kymco commute, I felt the Kymco was just safer not having to constantly downshift and stop. But higher rev riding might work just as well, perhaps not ever getting out of 3rd gear.