Topic: CB400F Shifting Trouble

[TRPLE]

My 400F has recently started having trouble shifting back into first gear when it gets hot.  It usually takes about 20min of riding before this issue occurs, and up until then it shifts great.

The issue is that when I am decelerating to a stop and shifting back down through the gears, I sometimes have to attempt the 2-1 downshift multiple times or it will hang in 2nd gear.  This is sometimes accompanied by a clicking (not grinding) noise.

The engine has what I believe are 28,000 original miles on it.  I'm not sure if the clutch is original or not, but there is no outside evidence to suggest a sloppy replacement.  I've had the bike for about 3 years.  I haven't had the clutch cover off of the engine yet, because I don't know what to even suspect is the problem.

 - Matt

[kghost]

What oil are you using?

Specifically brand and weight?

[number13]

Make sure your shifter linkage is snug, it
just may be slipping.

[WHALEMAN]

Since this happens when warmed up I have to think clutch adjustment. You might have too much play which is OK when cool but when the plates heat up and expand some the clutch drags making the shifting harder. FAQ has clutch adjustment method. Dan

[TRPLE]

I have tried different brands of oil, right now I think I'm using a Motul non-synthetic motorcycle oil.  I always at least use a wet-clutch-specific oil, and always 10W-40.

My clutch adjustment should be pretty good, I keep on top of that stuff.  I know I've adjusted it at the lever since this began, and I am biased towards the slip side without actually inducing slip.

From surfing some other posts, it seems like it might be time to replace the clutch.  I've heard that I'm better off with a Honda unit than aftermarket.  Does anyone have any experience with this issue being related to impending clutch replacement?

 - Matt

[WHALEMAN]

What does biased toward the slip side mean? Does that mean more than 3/4" movement at the clutch lever before it begins to push? dan

[marty]

I'm having a similar issue with my CB400F. It is very hard to shift into first gear when coming to a stop or while stopped. I bought this CB400 recently and it's had this problem from the moment I bought it, my mechanic friend thinks it's the clutch plates sticking and they should be replaced. I adjusted the clutch where the cable enters the right side of the engine, that helped a little but it still has the problem. Mine has about the same mileage as yours. Have you had any luck fixing it?

[malcolmgb]

martymattern - what you described sounds like adjusting the cable, you need to check adjustment of the clutch actuating mechanism too.

[marty]

I will try making more adjustments with the cable and see if that helps. So here's the full story...the first few times I rode this bike, it tried to jump forward when I put it in first gear (this is while the clutch is engaged). After it did that a few times it stopped doing it for some reason, the guy I bought it from had been storing it for the winter and maybe it just needed to move some oil through the clutch (at least that's what I figured) So then I rode it just a few blocks, when I came to a stop I downshifted to second then tried to go to first and it wouldn't go into first gear. I took the bike on the highway and it slipped out of gear a few times. Since then it has slipped out of gear a few times each ride. So if this is all just simple cable adjustment I will be relieved.

The Clymer guide I have threw me for a loop when I read up on the part about adjusting the clutch. There is a locking nut on the lever which engages the clutch, the Clymer's guide was confusing when it explained how to adjust both ends of the cable to get the 1/2" of play on the lever. What do you set the screw to?

[grcamna2]

I have had this problem before and found it to be the steel clutch plates.
When you remove the clutch cover and ultimately the clutch & All the drive &
driven plates;pay careful attention to the sequence of 1) fiber plate & 1) steel
clutch drive plate. I recommend getting an O.E. service manual and following the
instructions for replacing  All  the clutch plates;the fiber plates & the steel plates.

     I believe that your steel original Honda clutch drive plates are Warped, which
tends to keep them in contact w/ the fiber plates rather than fully releasing to
let your clutch completely unload it self before shifting. I recommend doing it
soon before you have trans. problems and have to split the cases.
    When you adjust your clutch: always leave just a bit of freeplay at the
Lever; you never want the adjustment tight w/ no freeplay.
     A good factory service manual is very valuable for the long haul.
I know that a good service manual explains what direction to install the fiber
Friction plates in your clutch pack; they are manufactured w/ directional swirls
to release the oil as they spin in your wet clutch - The Qaulity book is best.
I hope you enjoy your new clutch...traffic will be less of a pain w/ it.

[camelman]

Do you get false neutrals while shifting through gears or have jerky clutch engagement (especially noticeable when accelerating from a standstill)?

Camelman

[kajtek]

Do you get false neutrals while shifting through gears or have jerky clutch engagement (especially noticeable when accelerating from a standstill)?

Camelman

 i get that sometimes, assume its me being lame with my shifting, is there a reason for it?

ashley

[camelman]

Those are typical symptoms of worn clutch basket fingers, especially the rough clutch engagement from standstill. The fingers can be smoothed down with a file if they are worn, but there is no way of knowing without pulling the clutch out. If it is worn, then you'll see indents where the tabs of the clutch plates contact the clutch basket.

Camelman

[marty]

I spent an hour tonight trying to find the perfect cable adjustment, and I came to find that the best I can do still isn't quite good enough. So I'm definitely leaning in the direction of my friends original diagnosis which seems to be the same thing "grcamna2" is saying. I haven't taken apart a clutch before so this will be a first, but a good learning experience one way or another. I bet the Clymer doesn't go into much detail about changing the clutch plates so you're probably right about getting a real service manual. Do you know of a good place to buy one? I'm assuming ebay is a good place to start.

Yes, I have had false neutrals, I'm in 2nd gear and the neutral light will pop on. It happened tonight while I was testing different cable adjustments. Sometimes as I slow down from 3rd gear or 2nd gear it will actually just pop into neutral without me touching the shifter.

I don't know anything about the clutch basket and the fingers being rough, I guess I'll see it when I take the clutch apart.
So is there anything else I'll need besides the plates?

[MoMo]

You will need a new gasket.  If you need the fiber plates, I have a new set of Honda plates for your bike...Larry

[grcamna2]

Marty,
          That clutch basket is the large round "basket" that holds All the clutch plates
& the clutch fingers described are the large slots on the basket where the fiber
(friction) plates fit into to engage the primary drive; You'll see it when you dis-
assemble your clutch pack;make sure you keep everything in order & take pics &
label everything...take notes.
    The problem is, that the slots where the friction plates fit into develop "wear
notches" at the points where the friction plates ride on the clutch basket;the hard
shifts get those notches to become deeper over the miles.
      I recommend inspecting your clutch basket & if it has those notches in the places
described,take it to a person who understands how to carefully use emery cloth
to make the notches alot less pronounced...in other words- NO SHARP EDGES.
   the smoother - the better. They need to be carefully sanded w/o changing the
shape of the "fingers" and their original flat surfaces.
     I would almost say...go ahead & use a fine file VERY carefully; DON'T change
the shape of the original surfaces...just try to keep those fingers looking the
exact same as when they were original...with out the notches.
  I have seen some clutch baskets that needed to be replaced because they were
notched too severely; take that empty basket to a Good Japanese motorcycle
mechanic and he will make a good judgement call for you.

                                                                   Best regards,
                                                                                          Bill

[kajtek]

interesting stuff, great replies taht help me even though i didnt start this topic thanks.

read some stuff online and the notches in the basket all make sense now. time to pull the clutch and drive the car to work i think!

ashley 

[tommanos]

My 71 cb500. Had the same problem - shifted great when cold, but very poorly when hot. Here in the Phoenix, the engine is hot by the time you hit the end of the block. This week I re-did my clutch and I can't believe how well it shifts now regardless of temp.  I picked up some great pointers on this site that I will pass along:

   Don't assume that the previous owners put the pack back together correctly.  Go to
   a site like cmsnl and look at the fiche.

   Soak the new friction plates overnight in oil before assembly

   If there are locator pins in the clutch cover, keep track of them when you remove the the cover

  The metal plates in my pack are directional. You have to look closely, but the rounded side should face you.

 The is a good time to consider Allen head screws for the clutch cover. I like my Honda to be 100 percent original but the Phillips head screws are a pain.

I would order a seal for the kick starter while your at it.  They are cheap and you don't want to wait another week if yours is bad

David Silver offers a kit with new Honda springs, replica friction plates and a Honda
gasket.  The delivery time for me has been about the same as a domestic supplier and I have been happy with everything (lots) that I have ordered from him

I hope this helpful. - tom

[marty]

Thank you Bill, Larry and Tom you've all been very helpful. Larry, I'm assuming I might as well replace all the clutch plates while I'm in there, is that a fair assumption? I would think the plates all affect each other; if the steel plates are warped they probably affect the fiber plates. Do you have a full set or just the fiber plates?

Bill thanks for the explanation on the clutch basket, that will make more sense when I take it apart but looking at the service manual I can visualize what you're explaining. I will look closely for any notches and smooth them very carefully. I just rebuilt the top end last week, so I got a full engine rebuild gasket set. I think the gasket for the right crankcase cover should be in there, but I don't think the kick starter seal would be in the set. I guess I'll pick up one of those, I want to be prepared so I can try to do this without getting hung up.

Tom, those are some helpful tips. I wouldn't have known to soak the friction plates over night, I'd assume you need to coat them with oil, but I didn't know it would have to soak. I like your idea to replace the phillip head bolts with allen heads. The phillip head is so prone to stripping, it seems like a great idea to replace all the bolts with allen head bolts. If I was doing a full rebuild I'd definitely consider that. Then maybe an impact driver wouldn't be as necessary.

[MoMo]

I have the complete set of new fiber plates and if I dig deep enough I may have a full used clutch hub with all plates.  Let me know if you need anything...Larry