Topic: Shift into neutral

[mycb750k6]

I know these are old bikes and I own a 71 and a 76 but occasionally I can't get them into neutral. With the 76 this is a problem. Is there a trick to this? Am I doing something wrong or is there some adjustment I can make? I found that a quick rev in second or first and then shifting sometimes works.

[Bill/BentON Racing]

Find neutral while bike still moving,or rock slightly if already stopped.

[Popwood]

Somebody tell me I'm wrong, but I swear it's the oil. Sure, there are tricks to get into neutral, but with the right oil it's no problem regardless of the situation-- totally hot engine or whatever.

I, for one, would like to get to the bottom of this question. Experts . . . how about weighing in. Yes, another oil thread, but this comes up rather frequently and the question has not yet been nailed.

[GammaFlat]

Grab a handful of front brake and rock the bike forward and backward while gently lifting up on the lever.  Compressing and de-compressing the front forks is enough to move the chain enough to move the sprocket enough (you know, the leg bone is connected to the...). 

My K6 is otherwise a pain in the ya ya to get in neutral. 

John

[vames]

In my experience, the older and/or thinner the oil the harder it is to get into neutral (while stopped and running with the clutch pulled). I have no idea if there is a rational mechanical explanation. On my 350 twin, in fact, I thought it was truly incapable of going into neutral till I put in a fresh batch of 10-40 and now it always clicks in.

[Popwood]

OK, I'm no oil expert and I don't want to start another oil thread but my hunch is many, not all, but many, "modern" oils are too slippery for our older bikes that have a wet clutch. Maybe it's  550 problem. I've only had my '75 750 a couple months but that clutch seems to be very forgiving by comparison. I'd still like to hear what some of our experts have to say about this, like TT or Hondaman. Can you guys weigh in here?

[fmctm1sw]

I let my clutch out a little when this happens.  Normally gets it to go..

[tatjunkie]

The PO of my 650 said he had a hard time getting it into neutral. When I changed the oil I used the regular SAE 30 and have never had a problem. But maybe he was exaggerating, he's an odd cookie.

[lordmoonpie]

I had this on my 350 twin - run with Castor oil (R40) and the only sure fire way to hit neutral was to select it just before the bike rolled to a stop. Worked every time that way. I fugure it couldn't have been the oil though as it was good old caster based oil. 

[mycb750k6]

I recently took a motorcycle safety coarse for the insurance advantage and was stuck with a Honda that wouldn't go into neutral either. The instructor showed me that if I revved the motor and tried it it would slip in and it worked fine. I tried that on mine when I got home and it works on both 750's. Hard to believe an oil change would do anything. Like I'm sure most of you do, I change the oil every 800-1000 miles and can't say I notice a difference in shifting. My bikes are low mileage though, 6K and 12K.

[Tower]

All of the suggestions that work have a common element:  The shift drum is slightly jostled while the shift lever is moved to neutral.  Revving engine, rocking, rubber mallet, multi-clutching, etc

There is rather a large amount of play in the shift drum and forks.  So, when they are moved they do not necessarily move to the "best" position, they move to the earliest position for the shift to happen - leaving a little bit of unused room.

Finding neutral requires the drum and forks to be in a more exact dog position - usually just a bit shy of where the shift movement actually places it.  Jostly the drum moves it that little bit thats needed and makes it easier to zero-in on neutral.

Slickness of oil has very little impact - if anything, the slicker the better.
Thickness of oil has a bigger impact - thicker oil dampens the movement and in the extreme may clog the dogs and prevent full movement

A badly adjusted clutch that is not fully disengaging places extra force on the gears and transmission shafts, which also makes shifting much more difficult - in all gears as well as neutral.

[Popwood]

All of the suggestions that work have a common element:  The shift drum is slightly jostled while the shift lever is moved to neutral.  Revving engine, rocking, rubber mallet, multi-clutching, etc

There is rather a large amount of play in the shift drum and forks.  So, when they are moved they do not necessarily move to the "best" position, they move to the earliest position for the shift to happen - leaving a little bit of unused room.

Finding neutral requires the drum and forks to be in a more exact dog position - usually just a bit shy of where the shift movement actually places it.  Jostly the drum moves it that little bit thats needed and makes it easier to zero-in on neutral.

Slickness of oil has very little impact - if anything, the slicker the better.
Thickness of oil has a bigger impact - thicker oil dampens the movement and in the extreme may clog the dogs and prevent full movement

A badly adjusted clutch that is not fully disengaging places extra force on the gears and transmission shafts, which also makes shifting much more difficult - in all gears as well as neutral.

Thanks for that, Tower. We're now moving toward an explanation and past the work-arounds. Progress on this topic.

I get the description of what's happening (or not) in the tranny, but still wonder about the clutch role in this. If the oil is not right for a wet clutch set up then it won't disengage sufficently to let the tranny do it's work properly. If it didn't make a difference, why are there motorcyle oils formulated for wet clutches (just marketing)? Why did my problem completely and immediately resolve with an oil change (and the oil I replaced had less than 500 miles of easy use)? I'd like to hear oil in the clutch discussed as rationally as Tower's description of transmission operation.

[Gordon]

I get the description of what's happening (or not) in the tranny, but still wonder about the clutch role in this. If the oil is not right for a wet clutch set up then it won't disengage sufficently to let the tranny do it's work properly. If it didn't make a difference, why are there motorcyle oils formulated for wet clutches (just marketing)?

The difference in oil made specifically for wet clutch engines is that it doesn't have all of the added friction reducers that most other oils today have, because this can cause the clutch to slip.  I don't think friction reducers would cause a wet clutch to not fully disengage. 

[Tower]

You're on the right track about oil additives.  However, its not the friction reducers that are the problem, but primarily the detergents cause trouble for wet clutches - they foam up - creating oil shortage and burned "dry" or glazed spots.  Its these glazed plates and corks that fail to stick.

Oil slickness is NOT a factor.  Synthetics are very slippery, yet work quite well as long as there are no detergents (I run full synthetic in my 750K3).  Synthetics stand up well to sheering - which happens a lot in clutches.  Picture what's going on as the plates spin against each other...the oil acts like a thin film of adhesive that binds them together when under pressure.  Have you ever tried to pry up a pane of glasss from a smooth counter-top when a bit of water was wetting the surface?  It becomes much harder to lift the plate.  Whether its water or oil, the same thing happens.

The hard neutral is a transmission design flaw on these old bikes.  No sychro and very loose shift drum don't help either.