Rev limiters

[FJTillDeath]

Just a question as I couldnt find it in my manual. Does the FJ hav a rev limiter? I know its old and so far people have told me due to that it wont have one. its an 85 1100.


The reason I ask is cos I know without a rev limiter the pistons can bounce excessively causing damage. A few months ago I participated in a "loudest pipes" competition. I didint excessivley rev the bike but it was revved just under red line. For maybe 30 seconds. For those who know the problems I have mentioned with my bike, would this maybe be another contribution to it?

Otherwise what kind of damage would I be looking at(if I were stupid enough to over rev it) and how would such things be repaired?

Thanks
Jesse

[andyb]

Overrevving won't hurt the pistons, as they usually win the fight with the valves.  The valves do poorly if you spin the motor hard.

More importantly, the crank has a nasty tendancy of breaking, literally tearing the motor in half. 


Don't do that.

[rktmanfj]

Just a question as I couldnt find it in my manual. Does the FJ hav a rev limiter? I know its old and so far people have told me due to that it wont have one. its an 85 1100.


The reason I ask is cos I know without a rev limiter the pistons can bounce excessively causing damage. A few months ago I participated in a "loudest pipes" competition. I didint excessivley rev the bike but it was revved just under red line. For maybe 30 seconds. For those who know the problems I have mentioned with my bike, would this maybe be another contribution to it?

Otherwise what kind of damage would I be looking at(if I were stupid enough to over rev it) and how would such things be repaired?

Thanks
Jesse

Over the red line, or just under... if you really love your FJ, why would you want to subject it to this kind of abuse for 30 seconds??

Besides the obvious, there's also the fact that during this time, there was no air flowing to cool the engine at all.

Didn't you mention that you had a problem with diluted oil in another thread?  Hope it wasn't in there during this stunt...

[FJTillDeath]

I am really not sure when the oil problem I had started although the bike had been knocked over before I went to the rally...

I do know that things started getting worse with the bike a little after the rally but not close enough after it for me to think anything of it , say 2 weeks after..

I only found out recently that the bike didnt have the limiter and never thought that simply opening the throttle would damage her, though I did what I did conservatively...well I didnt rev the shit out of the motor atleast. There was a bit of smoke coming from the exhaust during the rev competition which I thought was just a bit of oil burning from the very toasty engine...

Atleast I am glad I didnt tear through the motor with the crank..

Thanks for the info on the matter. So it would best not to ride the bike hard enough for it to redline, well atleast not its max speed? It might explain why there are times the bike feels like its scraping forward under heavy throttle, sometimes its smooth so I couldnt say.

To be honest. So far the hardest thing about jumping from a little 125 to an 1100cc bike hasnt been learning to ride it, its been learning how to maintain it and treat it

[SlowOldGuy]

WARNING ---- FUN POLICE AHEAD!

Jesse,
In the last 26 years, I have never had the need to rev my FJ to redline.  Why would you EVER want or need to do this, unless you were being stupid.  It's got 5 gears so you can avoid redline at any SANE speed.  Redline in any of the upper gears should be reserved for the racetrack only.

Over revving a motor in neutral, with no load on it, is probably the worst thing you can do to it.  As Andy says, valve float is not a good thing and FJ valve springs are not the best.  Also, early model FJs were known to have bad valve seats that warp even without that kind of abuse, so that's a possibility.  I know I had 2 warped seats on my '85 and I've never subjected it to such abuse.  

I'm not sure exactly what's wrong with your bike.  It seems like every other day, you've got some long rambling post about some obscure problem or a new plan to rebuild it and, frankly, I've stopped trying to keep up.  

All I can say is you're riding a bike that's older than you are.  Treat it with some respect, it's earned it.  And, yes, the '85 has a rev limiter.

DavidR.

[racerrad8]

The stock Yamaha CDI has a rev limited at approximately 10,500 rpms. If someone has modified it or changed to a different ignition system then it might not have limiter.

I can say we run are race cars up to the limiter on a regular basis. This past weekend there was one portion of the track where I would have to breathe the engine as it would be on the limiter a couple hundred yards before the lift point of the corner.

We will maintain 10,000+ rpms but not allow the limiter to activate as it starts cutting cylinders and creates a ton of heat in the engine.

Randy - RPM

[fj11.5]

WARNING ---- FUN POLICE AHEAD!

Jesse,
In the last 26 years, I have never had the need to rev my FJ to redline.  Why would you EVER want or need to do this, unless you were being stupid.  It's got 5 gears so you can avoid redline at any SANE speed.  Redline in any of the upper gears should be reserved for the racetrack only.

Over revving a motor in neutral, with no load on it, is probably the worst thing you can do to it.  As Andy says, valve float is not a good thing and FJ valve springs are not the best.  Also, early model FJs were known to have bad valve seats that warp even without that kind of abuse, so that's a possibility.  I know I had 2 warped seats on my '85 and I've never subjected it to such abuse.  

I'm not sure exactly what's wrong with your bike.  It seems like every other day, you've got some long rambling post about some obscure problem or a new plan to rebuild it and, frankly, I've stopped trying to keep up.  

All I can say is you're riding a bike that's older than you are.  Treat it with some respect, it's earned it.  And, yes, the '85 has a rev limiter.

DavidR.

hi david r , as i recently found out i may have a burnt valve, just wondering if they are the same symptoms as a warped  valve seat, i know its the exhaust valve

[SlowOldGuy]

A warped valve seat will cause either a burned or badly pitted exhaust valve.  The cure is to have the seats re-cut and replace any bad valves. 

I had the head off my '85 at about 16Kmiles for this "service" and only had one slightly warped seat that required valve replacement.  I had all the seats re-cut at that time and haven't had any problems since.

DavidR.

[fj11.5]

thanks david , looks like she,s due for some headwork , asap

[Travis398]

It sounds like everyone has set you straight here.

But I will add anyways..................... I take my bike to red line nearly every time I ride it, call it a drug, an illegal one.

After the discussion of rev limiters earlier, I was curious when the rev limiter kicked in.

I have gone to 10,500 (indicated) many times and never noticed it kicking in.

So I decided to find out 11,400 (indicated) and the bike just shuts off, no spit sputter or anything just quiet ,

till the rpm's come back down. 

I will add that after 10,000 or so the bike stops pulling, so going to 11,500 is really pointless.

[FJTillDeath]

Thanks to everybody, I really appreciate the advice.

I really do want to take care of the FJ and thats why I dont rev it that high anymore, I dont even shift in that high of an rpm range.

This incident happened basically a month and a half after I got the bike still knowing absolute piss about it. I had never known that such actions would torture the machine and had I known I would never have done it.

Thank you to DavidR. I admit I do ramble on in most of my posts which is annoying to people who want to help or try to help. I know the only real way to know exactly what is wrong with my FJ is to let one of the guys here with a great condition one to ride it, that or find one where I am to compare it to. Other than that I would probably need to go into the bike myself, tear it apart and rebuild it from the ground up replacing basically everything. Which is something I plan to do when I have the time and money and most of all the skill.

As I said, thank your for all the help I get, becuase it seems everybody else around me who I ask for advice says the exact opposite of this group which means they too have no understanding of it, like this rev limiter issue. I will treat the FJ better, reserve hard riding for the track and only when I know she'll be capable of it. Other than over revving it is there anything else I should know to treat the FJ better. State the obvious because as obvious as it may be to everyone here, it wont be to me

[fj11.5]

Valve shims, make sure they have clearance. Either yourself or by a mechanic, don't let them get fish arse tight like I did mine 

[FJTillDeath]

Can I ask what exactly it means to shim the valves becuase when I asked somebody about shimming they explained it as cutting, sanding, scraping a little bit off. This sounds weird to me as why would you want to cut away from sometihing?

Then DavidR mentioned in another post that I could shim my needle a bit by putting a flat thin washer under it. Now it sounds like shimming adds a little extra onto the motor while still adding opening/ clearance. From the shim kit Randy sells it also looks like a bunch of small washes.

So I take it I know very little about bikes and what I do know is probably 50% wrong due to being ill informed.

[oldktmdude]

Your workshop manual explains everything you need to know about valve shims. How about doing some reading?

[Arnie]

SHIM - A thin piece of material used to adjust thickness of a main item.  In the case of the FJ you have shims that sit between the cams and the valve buckets to adjust lash, you have shims in the transmission to adjust clearance between various gears, and you can have shims that adjust the height of the carb needle. 
There are probably others, but these are the 3 most common uses of shims in the FJ.

If you had a 4 leg stool and wanted it shorter you'd cut all the legs a certain amount.  Knowing how deft you are with tools, its likely that you'd cut at least one shorter than the others.  You could use a shim to take up that gap.  :-)

Oldtmdude had a great suggestion for you.  More time reading, much less time typing.

Arnie