Trouble up shifting at 4,000 RPM?

[DrDarkMatter]

hi guys, I recently changed to a full syth motor oil and the bike was going fine.

then all of a sudden I am having a very hard time upshifting at or above 4 grand.

it seems its exactly at 4 grand it started too, below that shifting is fine.

Its a 1998 BMW F650ST with only 30,000k on it.

I am using 10/40 motorcycle oil fully synthetic oil. I dont know if that has anything to do with my problem shifting up but the timing is the same.

I tried adjusting the clutch cable to no avail.

Any help would be greatly appreciated

[haydes55]

Is the oil what is recommended to be used in your bike? Is the oil filled to the correct levels? Have you not done the drain plug up right and leaked half the oil out? Was the old oil full of metal flakes?

[DrDarkMatter]

hi, yup I checked all that and its all fine

[AllanB]

Motorcycle specific won't cause any issues in your bike. Been running full synth in mine since running it in.

Check the shifter linkage is all nice and tight - maybe it is a bit sloppy and you are running thru a quicker shift as revs rise and missing a clean change.

[DrDarkMatter]

thanks good thinking I will check it :yes:

[BuzzardNZ]

I had a problem which sounds kinda similar to yours.

If you are experiencing 'clutch slip' ( like I did after an oil change and only at high rev gear changes ), well it went away after a while ( 500 km ), I suspect it was the oil getting dirtier and less slippery ( just my theory anyway ).

[Akzle]

rev match and clutchless shift like a fuken boss.

[F5 Dave]

Your description is a bit crap at best. What do you mean? The lever gets hard?, doesn't shift despite moving? Revs like crazy?

[DrDarkMatter]

Your description is a bit crap at best. What do you mean? The lever gets hard?, doesn't shift despite moving? Revs like crazy?


I pull in the clutch I lift up with my left foot it does not change gear but stay in the same gear............better?

[DrDarkMatter]

Motorcycle specific won't cause any issues in your bike. Been running full synth in mine since running it in.

Check the shifter linkage is all nice and tight - maybe it is a bit sloppy and you are running thru a quicker shift as revs rise and missing a clean change.

Hi I had a look and its all tight and proper, I am playing some more with clutch lever settings to see if it helps.

thanks

[F5 Dave]

I pull in the clutch I lift up with my left foot it does not change gear but stay in the same gear............better?
A little. So the lever moves the normal amount but it doesn't make the change? I'd be pulling the cover and inspecting the shift pawl. Sometimes there is adjustment with an offset bolt. Or you could be looking at damage there or in the box itself.

[DrDarkMatter]

A little. So the lever moves the normal amount but it doesn't make the change? I'd be pulling the cover and inspecting the shift pawl. Sometimes there is adjustment with an offset bolt. Or you could be looking at damage there or in the box itself.


exactly, it moves as normal but doesnt shift. One thing Dave, I found today (on a 300K ride) that if I am more deliberate ( like pause, shift slowly and all the way off the gas, in my shifting that it helps a lot, sorry to vague, but again if I am below 4 grand it shifts fine.

thanks Dave

[F5 Dave]

Ok so it's borderline not moving the shift drum far enough, the extra vibration may be enough to make it not far enough. First, is ther a linkage to the shift lever? They need to be working in a parrellogram. Sorry spelling escaping me today. But imagine if one was at 90* and the lever it's pushing at 0*, clearly it would not rotate the shaft at all.

if all good and not heaps of slop! then find online manual and see if there is adjustment inside case like I suggested above. I'm not familiar with Rotax common practise for shifting.

[Jjgres]

There is a ratchet-type thing that rotates the shift drum. The ratchet grabs pins on the drum, kind of an escapement device. Maybe the oil is a bit stickier causing the rachet to not release fast enough.

Change back to dino oil for a cheap try.

[Jjgres]

One other option that would be a real stretch- on some bikes there is a bolt that looks like the drain plug but is actually the shift detent plunger. (A sping loaded pin that locates the shift drum via a cam on the drum.

Maybe the wrong bolt was removed and the plunger reassembled wrong?

[F5 Dave]

That was a suzuki thing in their 70s trail bikes, can't imagine Rotax adopted it. If it doesn't shift on any oil there is a problem, best find it.

[DrDarkMatter]

thanks for the input I will check things out some more...