Stator - Grumble/bang thumping.?
 

Hiya I am a newbie to this bike world but I am a little mech minded.

My First bike just so happens to be this old bad boy from the hey days CBR1000FJ. Yes it now old but Its a dam beast when it works and I just love it so much I can't part with it.

However, I have an issue with what I think to be a Stator issue. When the bike runs by itself on tick over I get a bangin sound. I 1st looked into this CCT probs and the sound is defo not from the top of the engine. I have walked slowly around the bike engine from right to left and its defo the left hand side and at the bottom.

I started the bike up from cold and llisten to the engine more carefully with ear on the engine and then repeated this on the stator case. The sounds is more so louder on the stator case rather than the engine.
This does not mean that when i add power the sound is present/gone. I just cannot hear it over my old rusty exhaust sound with bunch of holes in it. Instead when i hit about 4k revs I can hear the sweet engine whine/whistle like a new bike would but its very feint cause of the freaking exhaust noise and just maybe the sounds from the stator casing.

The main real question is, Is their any problems with bearings or the tensioner in the stator region i should be concerned about.? Espec when bike is on tick over.

Yes the bike charges very well the bike runs like a champ, I have re adjusted the gaps on the rocker arms to .004 in and .006 ex. atleast i think that was the setting without rechecking via the online manual. The CCT seams to be strong, I have renewed all Coils and leads with plugs. Rep'd all seals on carbs and rebalanced and slightly increased the tick over to 1150/1200 not the 1050RPM. Cleaned all leads from scale build up. Main chain free and tight and no lock ups on free rotation.
and finally when I ride the bike I do not get a feedback of any banging or grumberling espec when on tick over.

Please anyone who has some knowledge of this problem please reply.

thank you.

Alternator bearings have been known to wear out. Check out this thread -

https://cbrforum.com/forum/cbr-1000f...-dealer-42812/

Welcome to the CBR Forum Gemini,

I agree with DRam, the alternator just pokes out of the engine just above your left ankle when sitting on your bike. I'd check alternator bearings, alternator chain and perhaps even the alternator tensioner.

Cheers, SB

Let this be the answer.
 

I really appreciate this quick reply, I even thought of this and did attempt to remove the housing however I failed. I removed the 3 very long bolts gave it a slight tap with a hammer, this allowed the housing to turn freely about 10' but I just could not pull it off.
Maybe im just to affraid of the bike falling on me without no centre stand on the bike. >.<;;;

I will re-attempt this tomorrow first thing if weather is permitting and if i follow the OEM guide to the bearing im guessing its the following item located here:

Honda Motorcycle Parts / Genuine Honda Parts | Honda Cars | Honda Motorcycles | Honda Power Products | Lings Honda

Part is listed either of the following bearings. No. 23 - 24 or 31..

Would be so kind to check those numbers to be one of the correct item/Bearing.?

It looks simple to remove but its not without fear kicking in.

One dumb question, why the hell did Honda put a tensioner in the engine without having the adjuster outside to adjust easily enough. Seems idiotic to remove and crack open your engine to rep a tensioner if it fails. When an external adjuster could prove to be a slightly better way of working this small issue if it turns out to be the tensioner. Maybe im asking for to much sense.

Besides my 1 gripe, I am pleased some people have had the time to answer my question and hope this might helps others out with this lovely bike.

Very best regards. N thank you for your kind welcome.

quick update.
 

just a quick update, I finally remove the stator casing and the best way to do this for me tha worked in 2 mins was to use a claw hammer and use those claws and lever it against a very thin block of wood and use those 3 bolt holes as my lever point. It slapped lightly one way then used a screw driver to pulled it in the other direction and wiggled off quickly.

Now its off, I have tried in vein to remove my first bearing and i am having no luck at all. Further more. The outter casing to the stator that gets left behind because of a (22 mm bolt I think) which is blocked by this bearing. The outter casing is flapping around badly, this is where the windings are. The windings seem to be attached to the outter casing and the whole thing moves violently.

Please refer to no. 13 Picture from this website OEM.
Honda Motorcycle Parts / Genuine Honda Parts | Honda Cars | Honda Motorcycles | Honda Power Products | Lings Honda

From this I suspect this maybe the cause of the thumping but I am being stopped by the picture number 23 bearing. Am I to use a small hub type puller to get this bugger off. If so I do not have one.......>.<;;;...

First, if bearing #23 rolls smoothly, has little or no side play and makes no noise when you spin it, it's most likely okay and something else is making noise.

As for removing the bearing a puller is the best way to take it off, if that is what you want to do.

Second, take the following with caution. I haven't disassembled the alternator on my bike, and am going by work on past parts. But from the illustration and that experience I think that . . .

Part #13 (labeled Stator Comp.) and part #17 (Fan Cover) are sandwiched between the generator housing and the generator cover. When the cover is off it is possible for the stator to move. When everything is bolted together the stator should be immobilized.

If it was me working on the bike at this point I'd replace the alternator cover and try pinpointing the noise a little more closely. The most effective way to pinpoint noise is to use long screwdriver. Put the end of your screwdriver on the engine, put the screwdriver handle against your ear, and listen.

If you want an even better way, pick up a mechanic's stethescope at your local automotive parts house.

Good luck. And a belated welcome to the site.

IMO - classic oil pump drive chain rumble - there's no tensioner & you just keep on
riding - or if a perfectionist - complete tear down and replacement

Gemini,
If you can, get everything back together correctly so she'll run.
Start her up, let her tick over and remove the headlight fuse (I'm assuming you are in the States and have no light switch).
By doing this you will remove most of the load from the alternator which in turn will remove the load from the alternator chain which runs directly off the crankshaft. If your chain or tensioner are worn out you'll hear a lot more noise coming from the alternator area. It's a good clue as to whether this is the real problem or if its related to something on the alternator shaft if the noise doesn't get much worse.

The alternator chain tensioner is almost impossible to get to without stripping the bottom end down. If you suspect that this is the problem you will have no choice I'm afraid.

How many miles has the bike covered. We don't often hear of this problem before 50-60K miles.
I had to do this soon after buying my last one a few years ago. It's a pain to do but most satisfying when you finish.

A word of warning- be very careful if you're thinking of taking the alternator shaft right out. If the chain tensioner still has much life in it and takes up the slack when you remove the shaft you may not be able to get it back in again without the patience of a saint and a gynaecologists tool kit.

Keep posting. Good luck.

reply to the latest queries
 

The bike has just covered 50K but the noise has been present for some time.
Being in the UK we have a switch on our lights and It does not make any difference in sound.

I have rotated the bearing no 23. It runs smooth and fine with no catching. So i will look into the other 2 bearing soon but I really need to get the dam 23 bearing off. Its a very resistant sob.

I wish I could ride it at the mo but the fuel stopcock is leaking like a sive and having to wait now for cash to buy one from Dsilver. Unless I can find a newer version with a 2 filter tube which i think is part on the update revision on the CBR post '88.

I had thought of using a screwdriver for the testing location however I would only hit one of 2 things, IE alternator or the lower casing where the tensioner would be.

Yes I have read up on the tensioner location and had seen its a real GIT if all goes wrong and I feel Id like to avoid this as much as poss. If all 3 bearing seem good then the only thing left would be the tensioner I guess.

However I will look into this oil pump idea tho.

Thank you for all your help. i hope to get this sorted soon.

Hang in there Gemini, we're here as a sounding board so keep asking questions as you need to and hopefully we can help pin point the problem.

If you do have to remover the alternator unit, it is fiddly but doable. I know because I've done it!

Cheers, SB