Topic: clutchy subject "cb 400fss 1976"

[Redline it]

so the last times here i had 2 outside pipe temps like 100 or 200 degrees warmer than the 2 inside pipe temps (at the first bends,) on a recent 10k bike that i checked the camchain tensioner and removed the cam cover to glance at the tops and to check head bolts. got a bunch of suggestions but decided to wing it and after a 1k mileage flipping over, the problem stopped 1k before, soon as i stopped checking the temp. pretty sure nothing has changed, except worrying about it. runs great.

only the clutch is working smooth when cold and when it gets warm doesn't seem to be disengaging well from 1st to neutral, or even 2nd to neutral, until it cools to room temps.

when i picked it up from setting outside for maybe close to 20 yrs in the rain and leaking brake fluid res, landing on the #4 header, and other than rust, healthy rust, growing on various surfaces the one place that was showing the most weakness of that rust was the lower clutch cable spring inside the triangle cover. the water level was evident with a line that crossed the lower spring loop that was below that waterline, and gone from the rust, although the pushrod was above that water level, showed no signs of leaking, oil looked fine, other than resembling 90wt and only 2 quarts low. with a single written recorded oil change in the manual at
 mileage 2617 on 9-14-80 with 20-50w castrol oil change. written exactly like that. it's all that was in the notes part of the manual. i picked it up at 9,500, i ran a couple of quick oil and filter changes with hondalube 10w-40sj and stayed with that 1000 miles later it's running good. the cable was corroded seized and i worked it for a few days and it's been working ok from when i got it. freeplay is good only it's at the last of the cable adjustment, adjusting it tighter looses the freeplay. the shifter lever looks like it hit something, it has a weird twist to the factory weldjob, not the adjusters nor the shaft pinch lever-they look fine, it seems to the necessary travel up and down. hopefully this description will point to the narrowed down suspected problems = when warmed lower gears tough to find, first to neutral while running. engine stopped no problemo. thanks

[bryanj]

Most of the fours are more difficult to find neutral when stopped hot, get into the habit of finding neutral whilst rolling to a stop is what i do

[HondaMan]

Is the shifter bent upwards at the toe lever?

When this happens with the 750 it always bends the "L" shift fork if the bike is parked, fell over, and hit the lever. Then it has troubles like not shifting well into 2nd (or popping back out of 2nd under power).

Another thing that happens on bikes like these that sat for a long time with old oil inside: the steel clutch plates get rusty. Old oil always has water vapor in it, which finds those steel parts and rusts them. Then, when the engine is hot and the plates are all slightly thicker, they drag a bit. The greatest leverage (from your toe) needed to shift is in the #1 sand #2 gears' shifts. These 2 things together can make the 2 lower gears stiff-to-shift when hot. With additional oil changes and some ZDDP added to the oil (2 ounces is about right) it will eventually wear the rust off the steel plates in most cases.

I use ZDDP Plus from eBay.

[Redline it]

Is the shifter bent upwards at the toe lever?

When this happens with the 750 it always bends the "L" shift fork if the bike is parked, fell over, and hit the lever. Then it has troubles like not shifting well into 2nd (or popping back out of 2nd under power).

Another thing that happens on bikes like these that sat for a long time with old oil inside: the steel clutch plates get rusty. Old oil always has water vapor in it, which finds those steel parts and rusts them. Then, when the engine is hot and the plates are all slightly thicker, they drag a bit. The greatest leverage (from your toe) needed to shift is in the #1 sand #2 gears' shifts. These 2 things together can make the 2 lower gears stiff-to-shift when hot. With additional oil changes and some ZDDP added to the oil (2 ounces is about right) it will eventually wear the rust off the steel plates in most cases.

I use ZDDP Plus from eBay.

  i'll try the ZDDP Plus.  thanks for the replies, the splineless shaft looking square at it from the side is bent slightly forward and down. the foot lever c clipped to that shaft has even a strange bend to it that adds to those down and forward bends. so adjusted to have clearance in both up and down motions is short in supply, but clears. when downshifting the lever "rides" towards the case, and when upshifting it "rides" out to the c clip, there is alot of slide movement. i dare not try to retwist the lever, as we know that would probably end in a broken weld or lever itself, even a little bent without heat could be a problem and i don't want blue rings on the chrome even if it could stand the heat. i just got an idea to add a washer on the c clip side to the sliding motion. drill out a penny. translate the slide to the forward and rearward motion. i'll report back on that before addin the ZDDP. only the heat is still strange.

the bike came from san fransiscio, i don't know what they do up there, but it had some massive huge tires, like what normally goes on the rear was on the front and a rear tire big enough to run on a 750rear was worn on this rear rim. the rust on the plates sound more like it. as the oil was low a couple of quarts and most likely had enough water vapor to account for the 2 quart loss, lol. sat out in the rain for 20ys maybe.  this bike had 9500 miles on it. i've added 1000 to it. it drinks gasoline like no other 400f i've riden. this is the 3rd. 40,000 miles on the first before a comp ring broke. the other found in my backyard had less than a 1k miles on it. and runs sweet. this 10k motor runs solid, i only got it to 80mph, and slimbing b4 i backed off. both wheels have a wobble, that i cannot work out. until about 30mph then you can't feel it. no signatures of a high speed wobble attempt. only i get visions of picking myself up off the pavement dressed in slacks and a t shirt, is a regulating source of higher speeds.

 plus i'm finding out, just babying these and a xr650r 2000 cuts down on tire changes and hopes of a super long life of riding mellow.