Failure upshifting from 2nd gear

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VINCENT75
Cucciolo - the Lil Pup
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Failure upshifting from 2nd gear

Post by VINCENT75 »

Recently I had my 75 860GT out on a ride and could not shift from 2nd to 3rd after a few miles.
Downshifts ok.
When first starting out for a miles, all shifts up and down thru the gears is fine but after a while.....no upshift.
This has started only recently.
I was thinking it has something to do with the heating of the clutch after a few miles.
Also very difficult to shift into neutral.
I am going to replace the clutch cable and check the throw adjustment of the linkage rod/balls/rollers.
Any other ideas?

Thanks for any comments
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abmartin
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Re: Failure upshifting from 2nd gear

Post by abmartin »

Replace the gearchange return spring and see if that makes a difference. They are prone to weakness and breakage at regular intervals.

Bruce
1979 900SS
Fredericton, NB
Canada
VINCENT75
Cucciolo - the Lil Pup
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Location: Concord CA

Re: Failure upshifting from 2nd gear

Post by VINCENT75 »

thanks Bruce
I'll look into the spring condition.
Would it allow normal operation at first then cause the problem after engine/clutch
gets warmer after a few (5) miles?
ducadini
860 GT / GTS
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Re: Failure upshifting from 2nd gear

Post by ducadini »

I don't think the separate gearselector will get THAT warm so that shifting becomes difficult.
The rods-n-balls set could cause the clutch to act strange.

cu
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wdietz186
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Re: Failure upshifting from 2nd gear

Post by wdietz186 »

If the shifter spring is broken the lever won't return to the center position,it will feel loose. Possibilities are the spring or the ratchet mechanism in the shifter box is binding from dried out/nonexistent lube or maybe the eccentric adjuster for the lever travel is out of adjustment[not too likely]. Other than those things, what's left is internal,shift drum,forks,worn out dogs that will require the cases come apart.
VINCENT75
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Re: Failure upshifting from 2nd gear

Post by VINCENT75 »

Thanks all!
I will check the gear selector assy for proper operation/lube.
Anything specific to look for?
I believe I can investigate the proper operation of the shifter drum and forks by removing the gear
selector assy and rotating the shifter drum manually and run thru the gears. At least that will stop me worrying about
the internal bits.
Pardon my ignorance but what is the purpose for the little M6 eccentric screw (0400.13.160) in the
gear selector assy?
wdietz186
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Re: Failure upshifting from 2nd gear

Post by wdietz186 »

That is the eccentric I mentioned. It is used to adjust the lever pawl position so you have equal travel in each direction of the lever swing. It makes some difference but it probably isn't causing your problem.
radecal
Parallel Twin
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Re: Failure upshifting from 2nd gear

Post by radecal »

Hi Vincet75,
Have been having similar issues with my MHR Mille. Been off road for a while and took her for a run the other day and it would only change 1 through 3 gears and no more. Same as you, up and down to 3 only. I pulled the covers but can't find any issues with the shifter mechanism so now face an internal look. Used an inspection camera but couldn't see anything out of the ordinary so will change the shift springs and reset the adjustment and if that fails, split cases here we come. Will let you know how I get on.
Regards,
RAD
ducadini
860 GT / GTS
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Re: Failure upshifting from 2nd gear

Post by ducadini »

You could unscrew the bolt at the rear of the cases, lefthandside.
That's the positioning bolt-spring-ball that holds the gear-drum into position.
Could be that this combination is a bit rusty.
If the engine has been standing for a long time, the forks can bind on the pins, preventing further movement.
Always remember that going through the gears with a dead engine isn't easy : keep spinning the shafts.

cu
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radecal
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Re: Failure upshifting from 2nd gear

Post by radecal »

Haven't checked the positioning bolt-spring-ball setup yet. Intend having another close look at the output shaft as I had changed the rear sprocket prior to the parkup but don't remember giving it any undue whack. Currently away from home so have to wait until the weekend to have a look.
Trying everything I can to avoid splitting the cases. Will keep everyone informed of outcome.
Regards,
RAD
ducadini
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Re: Failure upshifting from 2nd gear

Post by ducadini »

The most common mistake after working on chain related things, is the wrong positioning of the gear selector.
The flat on the outshaft of the gear-drum should be horizontal and gearbox should be in neutral.
Be sure the gear selector is also in neutral position and fit it.
Put one or the other in the wrong position and You can only use 3d, a false neutral and 4th.

Since Your's is a crossover engine, be sure to check thecoupling between the shaft and gear selector.
They should be aiming straight at eachother for best performance.
Check for wear.

cu
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Re: Failure upshifting from 2nd gear

Post by BevHevSteve »

"The flat on the outshaft of the gear-drum should be horizontal and gearbox should be in neutral.
Be sure the gear selector is also in neutral position and fit it."

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ducadini
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Re: Failure upshifting from 2nd gear

Post by ducadini »

You're right Steve, I shouldn't have mentioned it.
I've fitted it the wrong way a few times and I'm sure better mechanics have done it also.
I was wrong in assuming that people make those mistakes ( and doing so giving me the chance to buy cheap Ducatis and Laverdas) and wrong in assuming I was able to explain what could be wrong.
Next time I can try goegel translater :-)

Now : three more night-shifts and then off to WDW, a bit of wine, a lot of sunshine and a couple of days in the Alps.
Sure beats hammering the keyboard about bevels :-)

cu
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Ducman71
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Re: Failure upshifting from 2nd gear

Post by Ducman71 »

I know I'm digging up this post from the wayback machine, but to clarify @ducadini's post above, if the stub from the shift drum is off by 180 degrees from true neutral when the gear selector box is installed, the only gears you'll get are 4th, a false neutral, and 5th. Ask me how I know... You learn something new every day, and this was today's lesson for me. Always best to manually shift through the gears turning the drum by hand to confirm the correct neutral position before installing the gear selector box if the trans has been opened, or if you are not the last person that touched the engine while the gear selector box has been off.
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