maxim x max rpm

I've read online that the max rpm is 12k but my numbers on the tach get red at 10k. When riding hard I normally shift at 9500. is it safe to run it up to 11 or 12k? is there "more juice" up there or am I pretty much out of the power band at that point?

i know its not an r1 just curious how high o can ring up on occasion without issues.

thanks in advance guys.

 

The red WARNING from 10-12K is just that, a warning that you are over revving. The bike may possibly spin up that high but there is nothing left in the motor except possible damage. IIRCC the bikes have a built in rev limiter at 11500, but I wouldn't bet my motor on it.
At 9500 does it still feel like it's pulling or does it drop off or just go flat? Been a while since I've "Wrung" mine out.

 

I doubt that the acceleration from 9500 to 11500 rpms will be as impressive as from 5000 to 9500 rpms.

 

I rarely get to go wot but every now and then I like to get on it. At around 9500 its climbing but nothing crazy. I normally shift by 9k to be safe. What I've read says it'll do 69mph in 2nd at max power which is right at 9k. so I guess I'll still think of 10k as" max".

 

Once, I hit 175 km per hour when shifting from 3th to 4th, the counter was around 10 000 rpms, can't tell for sure, my main concern was to find my way back in the right lane after passing the last car...

 

"Worldsfastestxj550" claimed 14,000 from a modified Seca 550
but he had trimmed the crank, lightened components, AND he blew the engine eventually.

 

Kinda follows the old saying..."The candle that burns twice as bright, burns half as long".

 

These bikes were CRAZY fast when you consider the type of bike they were sold as, "Boulevarde Cruiser". They are pretty much an FZ with just a few degrees difference in the engine slant.

 

I have also read the CDI has a built in rev limiter set at 12K. Not that you want to test the limits, but I had the unfortunate mishap of a 2-3 missed shift that nearly pegged the tach one day. That incident didn't trigger the limiter, so I'm not sure if the engine over-revved high enough to test it?

Putting things into perspective on peak power, my current X is still pulling at 10.5K, possibly higher but I'm not interested in pushing beyond that. Keep in mind that's with a K&N, Custom 4 into 1 exhaust, Dyna coils, and carb tuning to match the powerband.

With the high tech "5 valve" technology, it enables the valve and spring package to be lighter, therefore helping to prevent high RPM valve float. One limiting factor on the X is that it also has a milder cam profile compared to it's FZ and FZR brothers. This keeps the power peak on a "stock" bike at, or around 9500 RPM's, so you won't get much more power going beyond that. I've settled on a good compromise as I chose to set my shift light to trigger at 9800 RPM's. That lets me explore some of what these engines are capable of in the upper RPM range, while giving a margin of error. With the ultimate goal being to keep from over revving it and avoiding potential damage.

Another factor that should be considered is the reciprocating weight of the rod and pistons. Most of the later (FZ1 and R1) "5 Valve" engines use a lighter and stronger piston/rod package (plus the cam profiles are different), enabling higher engine speeds than our's are capable of.

Tony

 

One other thing to consider is the "F" models had a chain drive so you had a few more options with the gearing as compared to the "fixed" gearing on the shafties.

 

Right. And having 6 gears (instead of 5) also meant less RPM drop between shifts, keeping the engine in the powerband.

And speaking of FZ's, another interesting Genesis Screamer Yamaha made back in the day. The 86/87 FZX700 and 750 "Fazer". Tuned for a power peak at 9500 RPM's.

http://www.motorcyclespecs.co.za/model/ ... 0%2086.htm

Tony

 

So generally speaking there is "more" but you start to mess with reliability at that point.

I did a mis shift a few months ago Tony and noticed the same thing. But I don't normally "abuse" my bike so I was curious.

While we are on the topic of shifting. I am pretty quick at shifting seamlessly through the gears even under high rpm. Sport bike guys all talk about clutch less up shifts. Is that an option on our bikes? How is it done?

Btw I bet your 750x is a blast.

 

2 schools of thought on clutchless shifting, personally I can't see why anyone would want to on these bikes & not sure with shafties if the extra weight in the trans. would affect things.

It's done by applying slight pressure to the shifter, then quickly blipping the throttle off then on again to allow the box to shift when the load comes off. If done precisely & with a skilled hand & foot can't see it causing any issues with any bike, clumsy people round off their dogs & bend selector forks.

FWIW I wouldn't bother on an XJ

 

These bikes are still reliable with reasonable mods. The main three things to watch out for are: Gas in the crankcase, a lean condition from gunked up carbs or tuning issues, and intermittent misfires from bad coils.

I don't think I would recommend clutch-less up shifts, as it creates the potential of too high a shock load on the gears. You could do it in a pinch if you have a broken clutch cable though.

Guys that have newer bikes, with fuel injection, can add an electronic shift assist that does allow full throttle clutch-less up shifts. Some new bikes even come equipped with that feature stock or it can be had as a factory upgrade.

And yes, the 750X is a blast. But I too try not to "abuse" it. These bikes are unique and I just like to have some fun on occasion.

Tony

 

Good point, forgot I had to do that on the CX for about 50 miles with no ill effects. Was "fun" stopping and starting in traffic or at lights though, had to hold the clutch lever in to fool the cut out, abuse the starter and paddle off with people behind getting impatient

 

Thanks guys I love learning more about these bikes. I wouldn't trade my X for anything. Is there a huge difference between the 700 and 750?

 

Yeah, you had to start out your CX like you were Fred Flinstone. The biggest challenge is finding neutral before you stall it coming to a stop.

@ Ryan: In my opinion there's only a slight difference when comparing stock bikes. It seems that the shorter stroke 700 actually revs a bit quicker, but the 750 provides a smidge more HP / torque.

I only got the 750 from Canada because it was a trade-in at a dealer in Toronto. They were well versed in setting up a transaction through customs/ shipping and the EPA. After all is said and done, they helped tremendously in the transaction, and it was well worth the added expense and hassle.

Tony

 

Here you go Ryan, a little comparison info...
http://www.maxim-x.com/specifications.html

 

Yabba dabba doo :lol: yeah wasn't fun. and I didn't bother hunting the neutral, just hit the kill switch & left it in gear. Guess I coulda started with engine running in neutral by paddling along then kicking it into first but I figured of the two I'd rather rebuild the starter than the gearbox if I did break anything.

Overall though, the clutch is there for good reason, you really miss it when its gone & it's not to be recommended if you can push or get recovered

Also, to the o/p, isn't the 700 water cooled & 750 air? apart from that not sure of chassis differences etc.

 

My 700 is water cooled. Not sure on the 750.


Maxim X thanks for that link that's what I was looking for.

Honda Hack: What all have you done to yours?

 

Bloke,

The 85 and 86 Maxim X was produced with either the 700cc or a 750cc 20 valve "5 Valve" Genesis engine. Both were water cooled. The bikes sold in the US had the 700cc engine in order to comply with Tariff restrictions. The 750cc model was sold in Canada and I believe in some other markets scattered across the globe. One of Yamaha's unique offerings being that it married the high tech engine of the FZ model to a cruiser style chassis.

Ryan,

It's a long list. I actually created a video a while back outlining a lot of the stuff I did. Check it out:
http://www.youtube.com/watch?v=b7zLHbDrux0

Hope you like it.

Tony

 

Thanks for clearing that up, I thought the water pumpers were all 700. US have some strange/crappy ideas on restricting people to what suits the big dogs best huh?

 

Ryan, the basic rule for running any motor "hard" (the way it was designed to be run, in our case) is that there's no sense going beyond where the mill makes peak HP. In the case of most high-performance motors, the power drops off significantly past the peak.

In the case of MOST bikes, that is a grand, maybe 1500, below redline. For instance, my Norton is redlined at 7K, but it makes peak HP at 6200rpm, so there's no point running past that.

A rare exception (and the only vehicle, 2 or 4 wheels I've ever owned like this) is the XJ550R which is redlined at 10K and makes peak HP at 10K. Whooo baby!

Do a little research on the Max-X. Find out what RPM it makes peak HP, and what RPM is peak torque. For stoplight-to-stoplight riding, there's really no sense pulling past your peak torque (which generally is a bit lower than the peak HP rpm.) But if you're really jumping on it, like getting on the freeway or that little thing I like to call "rocketing into the distance" when passing a car, you want to shift at peak HP, not redline (unless they happen to be the same.) Running past peak means you're not accelerating like you were (bummer.)

I don't think you're going to hurt your X-motor running it to redline; but it may be possible to go even faster if you shift at the peak HP rpm.

 

Yeah, gotta love govt. control. They put the Tariff's in place to protect Harley-Davidson. Thankfully it only lasted for a couple of years.

Fitz, you bring up some great points on not revving your engine past the HP peak. Gives you no real benefit to go beyond it. And like you said, the best thing is to experiment while you have it under a load and find out where the power drops off.

The factory rating on the X is 9500 RPM for peak HP, and 8000 RPM for peak Torque. Your results may vary due to many factors, including altitude.

Tony

 

Adding to Fitz and Hack, if you have the cash take it to a dyno shop. They will run the bike and give you a print out of HP, Torque, Speed, etc. may even have a gas analysis. The results however will be directly related to the state of tune at the time.

 

There you go. Hard on it, shift at 9500. Squirting about, shift at 8K.

 

I was racing a guy and was busy watching the road and not the tach and noticed the power go flat as I went around him. After passing I noticed I was in the red. I figure it was a rev limiter but could have been valves floating. The important thing is I won. Mine is an 86 should it make a difference.

 

Being an 85 or 86 won't make a difference. Sounds like you were having some fun and just got past the power peak.

I suppose it depends on how high you were actually revving it, and the sound the engine was making when spinning that fast. Valve float creates the potential for the valves to hit the pistons, and is not something you want to occur. My guess is that you hit the rev limiter and that helped "save" your engine.

Tony

 

Yep more likely, as the limiter "should" stop the revs from reaching the point where the valves start to float (although it's possible on an older high mileage engine the springs could conceivably be weaker & allow float at lower revs, unlikely IMO). The only time you could "defeat" the limiter in normal use would be shifting down way too early

What bike did you beat by the way?

 

Here's a YT of a fazer 700, whippin it through the R's.

https://www.youtube.com/watch?v=OpiUX2hilcc

Not me, just one I found yesterday. He really wrings that thing out.

 

Yeah, I've seen that video, he does wring it out.

It emphasizes the sound of the engine hitting the power peak. Then you hear the revs stop climbing indicating the need to shift.

I also like his video of his FJR1300.
https://www.youtube.com/watch?v=okt3P44Z7v0

Nuts!

 

I was curious as well as to what you raced?

 

I don't know if I can really call it a race. It was a co-worker and we were coming back from lunch. He is a Harley rider and is always trashing non Harleys. We were on a four lane riding side by side doing 45 and in about an eighth of a mile it becomes two lane. He dropped back a few lengths, downshifted, and nailed it flying by me in order to be in front of me on the two lane. I didn't see it coming. Once he past me I opened it up and got in front. I don't know what gear I was in but I was doing about 100 going around him. His bike is an Ultra Clasic with a stage two kit.

 

Then no, it wasn't a race! lol

 

intermittent misfires from bad coils>>???

I'm struggling with an intermittent misfire right now. Or should i say AGAIN. I replaced the spark plugs and am rebuilding my carbs AGAIN right now.
I stuck my meter to the wires and I'm getting the proper resistance from my ignition coils..... Could it STILL be the ignition coils giving me hell?

 

Could be, but I would check the plug caps first (after you unscrew them from the wires) to see if the resistors inside are all corroded. Do a search on the site to see if anyone's done a tech article on that. Also, snip a 1/4 inch or so off the ends of the wires to give it a good connection when screwing them back on.