Author Topic: CB400F help: What is this rubber plug next to my sprocket? (Read 9135 times)

dave500 · « **Reply #25 on:** January 16, 2012, 10:23:51 PM »

id get that out easy,and not damage the case.

Toxic · « **Reply #26 on:** January 17, 2012, 04:47:23 AM »

How specifically would you get it out with those little tabs built into it?

Not doubting you, I just want to learn a new skill.

Bodi · « **Reply #27 on:** January 17, 2012, 07:33:57 AM »

I think this is a steel cap with a rubber coating. I'd like to hear how to get it out without splitting cases as well.

ttr400 · « **Reply #28 on:** January 17, 2012, 08:13:45 AM »

Bodi is correct. not too hard to get out, just punch a hole in the end and lever it. But you most certainly will not get a new one in without splitting the cases.

Kevin

strynboen · « **Reply #29 on:** January 17, 2012, 10:58:51 AM »

make a nev of brass..with a o ring in a groove..vho not lines up vith the hole......or just make one of nylon and slam in
i made one to plug my rpm counter hole vhen it broke..the drive

dave500 · « **Reply #30 on:** January 17, 2012, 12:21:14 PM »

toxic it only has one little nub located at the top,punch hole,slide puller or pry bar with some care and finesse,have you read the whole thread ttr400?you must have missed the brass freeze plug bit?i see it as being no more difficult than a spigot bush in the end of a crankshft,or a bearing cup in the end of an axle housing or a gearbox extention housing bush,or a suspension arm bush/kingpin bush,regular freeze plug in an auto engine,youd have a harder time removing the brass plug once fitted because youd lose most of the back space,i used a chair leg plastic end plug in a tacho drive once strynboen.

Bodi · « **Reply #31 on:** January 17, 2012, 01:25:16 PM »

OK, if the "nub" is just rubber you can pull out the old one. You could put something new in or just add some permatex or something to seal it onto the old one and push it back in. There's some oil pressure behind it, I don't know how much. As has been mentioned, the oil pump has 2 independent trochoidal pumps - one that feeds the main oil gallery and a smaller one that feeds the transmission only, it pumps oil to the area behind this plug. I wouldn't much want that plug to get pushed out by oil pressure.

dave500 · « **Reply #32 on:** January 17, 2012, 01:34:55 PM »

bodi,the old one gets destroyed in the removal,the new one wont get pushed out by any oil pressure.

stickfigure · « **Reply #33 on:** January 18, 2012, 07:15:28 PM »

Ernest - thanks for posting those pics from your bike!

So, while prepping for the sealant I noticed a small knick in the casing where the oil was weeping the othe day. My guess is a previous owner did a little damage while tinkering.

It's been cold here so I'm going to give the sealant another day to cure and then we'll see if it did the trick.

stickfigure · « **Reply #34 on:** January 19, 2012, 06:56:50 PM »

So, the sealant seemed to do the trick after running my bike. That's the good news. Bad news is that I noticed the bearing that holds the shifter rod (name?) is leaking. Don't think there's anyway to patch that one.

In this picture you can see my sealant patch and the oil that started to pool under that shifter.

dave500 · « **Reply #35 on:** January 19, 2012, 08:19:05 PM »

well done,that can be replaced easy,clean the entire length of the shifter rod,then use a self tapping screw and screw it into the old seal,you should be able to grab it with decent pliers and pull it out,lay the bike over slightly to the other side and clean the recess out well,apply a smear of sealant on the new seal and squarely and gently tap the new seal into place,youll need a nice drift to go evenly around the seal in steps or you might find a tube that goes over the shaft but will contact the seal on its extreme outer edge only,make sure the shaft is clean and oiled for the new seal to go on undamaged.

stickfigure · « **Reply #36 on:** January 19, 2012, 08:37:08 PM »

Dave, that's good news and sounds like an easy fix. Thanks for all of your help.

dave500 · « **Reply #37 on:** January 19, 2012, 08:41:56 PM »

you need seal part # 91206-286-013,,wire brush the shafts splines clean and blow all the crud out of the shift lever female splines,feel along the shaft for any burrs and file them of so they dont nick your new seal.

bollingball · « **Reply #38 on:** January 19, 2012, 08:46:46 PM »

Dave that brass freeze plug seems like a no brainer.My teenage son could do that. Don't know why anyone would fight that idea?

Ken

dave500 · « **Reply #39 on:** January 19, 2012, 09:10:59 PM »

yeah no worries bollingball, i think its pretty obvious aswell,some people talk themselves out of doing something they havent done before?

The Mayor · « **Reply #40 on:** September 06, 2013, 01:39:00 PM »

Old thread - but I just ran into this issue on a finished 350F build... low mile engine without any known issues... as you can imagine the last thing I want to do now is pull the whole damned thing apart again. Has anyone had any luck with the freeze plug method or otherwise? was going to try and seal it temporarily from the outside. Mine just started pushing out a bit when the bikes running, enough for it to leak a good bit. Is there anything else that could be causing this or just old and 'shrunk'??

dave500 · « **Reply #41 on:** September 06, 2013, 10:51:37 PM »

40 year old seals can leak.

lucky · « **Reply #42 on:** September 07, 2013, 02:12:55 PM »

Quote from: bryanj on January 16, 2012, 10:09:30 PM

OK heres by 2 penorth,

Have rebuilt too many hondas to think about, unless there is physical damage to the outer of the rubber or inner of the bore (this could ONLY happen with the engine in bits!!) the clamping fit should be too tight to allow leakage

SO

EITHER
(1) It's been apart and bodged

OR
(2) It's leaking from somewhere else and is just pooling around there.

Dave,

If yoou can get one of those plugs out of a 400 without damaging the case you deserve a medal mate due to the tight fit and depth, never mind the peg

OR the breather separator is clogged and this is the only place the gases can escape.

Bodi · « **Reply #43 on:** September 07, 2013, 02:42:50 PM »

There shouldn't be much oil pressure behind it: the transmission oil pump is pretty feeble and there are lots of places for the oil to trickle out on the shafts/gears, so pressure is very low I think. I would look at the breather (very top of head) and make sure the outlet isn't plugged somehow. If blowby gas is pressurizing the engine then that has to be fixed. You could try running it a while then removing the oil filler cap... if oily stinky air whooshes out then there's no breather outlet working.

crazypj · « **Reply #44 on:** September 08, 2013, 05:01:54 PM »

If the breather is trapped between swing arm and crankcase or otherwise plugged, oil WILL come out of every seal and not just one
If your certain it's that seal, good chance case is already damaged from a bodge repair?
Sell it to someone who will do it right and put the cash towards a bike that's running
400 doesn't gave separate oil pump for transmission like 550
Oil is fed direct from main gallery, it goes behind that seal before being distributed to the shafts and gears so pressure could well be over 40psi or more at high rpm

mickvain · « **Reply #45 on:** May 14, 2020, 05:42:04 PM »

Old thread- went to replace the gearshift seal as I saw oil leaking from that side near the chain. Opened it up and saw someone had used gasket material to stop a leak on the transmission seal and it had failed. Removing the gasket material now. Will attempt using a 34mm freeze plug with O-Ring after extracting the old seal.unfortunately it looks like the old seal is just thing plastic/ or rubber and is breaking completely apart. Would prefer not to split the cases, but if it has to be done, it has to be done.

Any more input would be appreciated. Cheers!
Sam

mickvain · « **Reply #46 on:** May 28, 2020, 02:11:03 PM »

Took the old plug out with no problems. I can find a steel expansion plug locally that will fit. Would I be more likely to damage the casing with a steel plug? Should I order a brass plug?

Bodi · « **Reply #47 on:** May 28, 2020, 05:01:53 PM »

"400 doesn't have separate oil pump for transmission like 550"

Well, yes it does. In the chart the main pressure pump goes to the #1 line, the transmission pump goes to #2.
You can see the transmission pump cover on the pic of the top side of the pump body - the much larger pressure pump is in that main body.
On the gear side, there's a pointy bit around 11:00: this is a nozzle that oil from the transmission pump squirts out of. Not too sure where it lands, the hole is about 2mm and there's no restrictor orifice... this pump has no relief valve so excess pressure just shoots more oil out the nozzle. This pump also connects to the two small ports at 5:00, an inlet from the pickup and an outlet connecting to the transmission shafts and clutch. The capped bearing bore is fed from the outlet to send oil into the centre of that shaft (counter shaft or primary shaft, not sure which). Since that nozzle is wide open the pressure can't get super high, I have no guess on actual running pressure.
The last pic shows how small this trochoidal pump is, the rotors are only about 4mm thick. Sorry it isn't metric but I had an inch ruler right at hand... the outer rotor is likely 25mm diameter.

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Author Topic: CB400F help: What is this rubber plug next to my sprocket? (Read 9135 times)

bollingball