Does anyone's tranny do this...

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Yellow_Cad

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The tranny on my 73 will hangup in 4th once an outing but not on every outing. It usually happens in the early part of the outing and doesn't seem to do it again that day. When I am approaching a stop early in the outing, I attempt to shift down to no avail. It won't leave 4th. If I reach down and do it by hand, it will shift down back to 1st. I seems like this started after and friend and I went in and replaced the layshaft bearing. Other than this the tranny runs fine. I use Redline MTL in it. Thanks for any thoughts on this. Jim
 
If it shifts by hand and not by foot, then maybe you need to put gloves on your feet ??

Obviously, your foot has a different action to hand shifting it.
Try consciously lifting your foot up fully to lift the lever all the way, rather than stabbing upwards.
Altering the gear lever higher or lower may make a difference ?

I'm sure someone will chime in here about the pawl spring...

P.S. AMC boxes were famous for changing gear without needing the clutch.
You tried it clutchless, and just blipping the throttle to match ?

PPS Your primary chain not too tight, nor the clutch dragging ?
Either can make for less positive shifting.
 
1. double check primary tension hot
2. suspect pawl spring
3. suspect dog lever faces.
 
Yellow_Cad said:
It usually happens in the early part of the outing and doesn't seem to do it again that day. When I am approaching a stop early in the outing, I attempt to shift down to no avail.
Click to expand...

Gearbox oil migration maybe. Sticky plates worst when cold.

Clean the clutch plates and try again. If you don't have the DynoDave clutch seal, invest in one.

Cheers

Norti
 
pierodn said:
Nortiboy said:
Yellow_Cad said:
If you don't have the DynoDave clutch seal, invest in one.

Norti
Click to expand...
Click to expand...

Hi Sir,
What is Dyno Dave clutch seal?.
Regards.
Ciao.
Piero
Click to expand...

Hi Piero,

Your English is better than my Italian.

See this link

http://atlanticgreen.com/store.htm

There is plenty on this site you can search regarding the DynoDave seal and gearbox oil migration.

It is an upgrade that eliminates a design problem where oil from the gearbox travels along the clutch push rod to the clutch centre. The gearbox oil is not good for the clutch and can make it sticky and hard to select gears.

One of the first things I do to any Commando.

There are many helpful installation diagrams if you choose to install this seal.

Cheers

Mark
 
Hi Mark,
But the DinoDave seal means COMMANDO clutch rod seal on the link you wrote?.

Sorry, but how is posible to buy it, i cannot find on web home page.

Thanks.

Ciao..
Piero
 
I am curious re the gearbox oil migration thing. I do not have the seal but have have never had any issue of oil migration via the clutch pushrod. I run ATF in the chaincase and there is no sign that gear oil ever gets into the chaincase. Frankly, I'm trying to figure out why my bike doesn't do it. Yes, I do occasionally check the gearbox to be sure there is oil in there! :)

I was wondering if perhaps later trannys were slightly different regarding the push rod "tunnel" in which it operates that could account for a difference in oil migration? Was there ever some sort of seal incorporated internally by the factory?
 
mike996 said:
I was wondering if perhaps later trannys were slightly different regarding the push rod "tunnel" in which it operates that could account for a difference in oil migration? Was there ever some sort of seal incorporated internally by the factory?
Click to expand...

No.
 
I see Norvil has a gearbox side clutch rod seal. Is this available in the US and does it involve any modifications? I wasn't real happy with the DinoDave one (clutch side), I had to remove all the washers under the nut to get the rod to stick out enough to work. Yes, I did measure everything and it's all to spec.

Other issue is now my clutch grabs since I installed it and cleaned the grease/oil off the plates. Haven't messed with it yet this winter. I was thinking about buying new fiber plates to see if that helps, I still have the original postage stamp style fiber plates. All the plates measure within spec.

Dave
69S
 
There are two AMC gb oil paths into primary, one the clutch rod and two the open seam of the last sleeve/main shaft bush. I believe from observation that the open seam of sleeve bush exit can get away w/o a seal because the opening is way below resting oil level and their turning slings any oil inside out and also prevents any oil re entering until in top gear turning. Besides DD rod seal in past some have cut rod to put a ball in the gap to catch oil so it drips off before reaching the clutch or some have put a narrowed waist near rod end to make oil drip off more than flow off rod end, others pack with heavy grease and a few also stuff on an o-ring or make a groove to fit 0-ring. I try to limit time and power in lower gears as wears the sleeve bushes faster which allows main shaft to tip which allow clutch basket to wobble. With ATF in primary and tranny so what if some leaks though clutch plates it just helps flush em cleaner instead of turning to plate binding greasy thick paste.
 
Nortiboy said:
Yellow_Cad said:
It usually happens in the early part of the outing and doesn't seem to do it again that day. When I am approaching a stop early in the outing, I attempt to shift down to no avail.
Click to expand...

Gearbox oil migration maybe. Sticky plates worst when cold.

Clean the clutch plates and try again. If you don't have the DynoDave clutch seal, invest in one.

Cheers

Norti
Click to expand...

Please,
I don't understand one thing.

If I mount the Dyno Dave prevent to oil from gearbox: theme but the clutch disks are not so wet from this oil in the primary
chaincase?.

Ciao.

Piero
 
Clutch spinning keeps primary oil from entering from the outside, mostly, but tranny leaks enter clutch from the inside along main shaft to leave by sling out the plates. AFT in tranny and primary make clutch happy whether wet or not. I think ATF helps better lube the hard to reach sleeve bushes which lie above oil level and sling oil out while spinning so only get a good splashing when in top gear.
 
[quote="
Please,
I don't understand one thing.

If I mount the Dyno Dave prevent to oil from gearbox: theme but the clutch disks are not so wet from this oil in the primary
chaincase?.

Ciao.

Piero[/quote]

Piero,

Gearbox oil is bad for clutch plates.

The oil in the primary is not bad for clutch plates.

cheers
 
Many have switched from the published 20-50 oil in the primary to ATF (myself included) with good results. My clutch was dragging badly, a DynoDave seal, Barnett fibre plates (they have aluminum host plates to reduce wear on the clutch hub) and ATF filled high above the level plug have resulted in a smooth, linear consistant clutch, no drag, no slip.
 
concours, when you say, "ATF filled high above the level plug," what caused you to try this and what is the idea behind it? I'm not saying that it wouldn't work, I'm just curious about it. Jim
 
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