Gear problem

[Moto3wannabe]

Hi, I'm having difficulty in engaging gear during WOT . I'm not able to upshift when my rpm is above 9k. Anyone experienced this issue before? I thought it might be the engine oil (Motorex about 2k km) and i just changed it to Motul 300V 15W50 but the problem is still there. Thanks.

 

[Moto3wannabe]

Something I should know before stripping my gearbox? What to look up for? Anyone?

 

[isaac_]

Stupid question - have you played with your shift lever and shift rod? Sometimes when I don’t put the shift lever back at the right angle, it’s hard to shift into gear.

 

[Moto3wannabe]

Thanks Isaac for reminding me that. I have aftermarket rearset and has not touch it since adding quickshifter 8 months ago. Will check out the shift lever and shift rod adjustment for any loose movement before going for the big job of stripping the gearbox. The problem I,m not able to engage upshift is both with quickshifter and with clutch. Thanks again.

 

[Formula390]

Thanks Isaac for reminding me that. I have aftermarket rearset and has not touch it since adding quickshifter 8 months ago. Will check out the shift lever and shift rod adjustment for any loose movement before going for the big job of stripping the gearbox. The problem I,m not able to engage upshift is both with quickshifter and with clutch. Thanks again.

Yeah that sounds like you need to verify your connection is tight and at the correct angle between your gear shift shaft link arm and the gear shift shaft. Man, say THAT 3 times fast!!! Anyway, if the bike isn't upshifting that's most likely going to be your issue. There is also a spring / detent arm that MAY be the source of the problem. That might be what's causing the issue with the RPM based lack of shifting... maybe. I still suspect it's the gear shift shaft link arm tho. If that's good, and it still isn't shifting, you may need to replace your detent arm. Chad over at Commonwealth Moto has one on their website at:
KTM Store :: KTM Street Powerparts :: 390 DUKE :: Engine Performance :: KTM 390 SHIFT DETENT ARM BY FACTORY PRO
and most racers running it, swear by it. I haven't put one on the test mule here, but the second I think about pulling the clutch, you can bet I'll be putting one on myself.

 

[vulgr]

I would suggest disconnecting the quickshifter before diving in to the gearbox. Easier, quicker and cheaper to diagnose if it’s an issue with the quickshifter, if it still has the same problem then it’s time to open the cases

 

[Moto3wannabe]

Rechecked and realigned all the gear shift link and shaft link arm but the problem is still there eventhough i tried to upshift using clutch. 4th gear is the worst as can't upshift anything above 6k rpm. I believe this is caused by my 2 idiots friend. First one took my bike for a spin while I was loading my other bike on my truck after dyno (2 rc390 dyno at the same time. Yup I uesd to own 2 but sold the other just months ago so now left with this one). Thie first guy came back and asked me later that does he need to clutch during downshift since I have quickshifter? Since then I was able to upshift but sometimes the geat will disengage and goes back to the lower gear (4 to 5 and suddenly will jump back to 4) but not often. 2 weeks back, 2 nd guy took my bike for a spin without informing me and did a launch and this is where my nightmare begins! Looks like no choice but to strip my gearbox now.

 

[Moto3wannabe]

Lesson learned, never leave my key in the ignition anymore!

 

[isaac_]

Rechecked and realigned all the gear shift link and shaft link arm but the problem is still there eventhough i tried to upshift using clutch. 4th gear is the worst as can't upshift anything above 6k rpm. I believe this is caused by my 2 idiots friend. First one took my bike for a spin while I was loading my other bike on my truck after dyno (2 rc390 dyno at the same time. Yup I uesd to own 2 but sold the other just months ago so now left with this one). Thie first guy came back and asked me later that does he need to clutch during downshift since I have quickshifter? Since then I was able to upshift but sometimes the geat will disengage and goes back to the lower gear (4 to 5 and suddenly will jump back to 4) but not often. 2 weeks back, 2 nd guy took my bike for a spin without informing me and did a launch and this is where my nightmare begins! Looks like no choice but to strip my gearbox now.

So did you figure it out?

 

[Fangfactor]

Rechecked and realigned all the gear shift link and shaft link arm but the problem is still there eventhough i tried to upshift using clutch. 4th gear is the worst as can't upshift anything above 6k rpm. I believe this is caused by my 2 idiots friend. First one took my bike for a spin while I was loading my other bike on my truck after dyno (2 rc390 dyno at the same time. Yup I uesd to own 2 but sold the other just months ago so now left with this one). Thie first guy came back and asked me later that does he need to clutch during downshift since I have quickshifter? Since then I was able to upshift but sometimes the geat will disengage and goes back to the lower gear (4 to 5 and suddenly will jump back to 4) but not often. 2 weeks back, 2 nd guy took my bike for a spin without informing me and did a launch and this is where my nightmare begins! Looks like no choice but to strip my gearbox now.

I had the exact same issues, jumping out of gear between 3rd and forth WOT under load and sometimes not able to upshift to 6th with WOT. Factory pro detent arm sorted it.

 

[Formula390]

Or could be his "friend" bent a shift fork.

 

[Moto3wannabe]

Managed to open up the clutch side and this is what I found. It seem the shift shaft CPL 90234005033 has worn out at where it suppose to shift the shift drum location (detent star) 90134015000. Looks like upshift is on the tight side to create this wear n tear or a material defect. Ordered the part and will be getting it the coming Saturday. Will reinstall and test it out and if the wear n tear is the same after 2,000 to 3,000km (will open up to verify during next oil change, extra cost of gasket only), then will have to open the gearbox further to inspect the shifting drum side to inspect whether the shift forks are causing this tightness. Hopefully is the quality of part here that is the culprit. Will be putting in Pro detent arm then as the existing detent arm is in good condition. Will give the detent star and arm bearing a good mirrior polish for smother shifting and maybe deepen some groves here and there on the detent star to get a better fit with the detent arm bearing diameter. Sorry for replying late as only got it open up yesterday. Work commitment!

 

[Moto3wannabe]

View attachment 4763View attachment 4764
Managed to open up the clutch side and this is what I found. It seem the shift shaft CPL 90234005033 has worn out at where it suppose to shift the shift drum location (detent star) 90134015000. Looks like upshift is on the tight side to create this wear n tear or a material defect. Ordered the part and will be getting it the coming Saturday. Will reinstall and test it out and if the wear n tear is the same after 2,000 to 3,000km (will open up to verify during next oil change, extra cost of gasket only), then will have to open the gearbox further to inspect the shifting drum side to inspect whether the shift forks are causing this tightness. Hopefully is the quality of part here that is the culprit. Will be putting in Pro detent arm then as the existing detent arm is in good condition. Will give the detent star and arm bearing a good mirrior polish for smother shifting and maybe deepen some groves here and there on the detent star to get a better fit with the detent arm bearing diameter. Sorry for replying late as only got it open up yesterday. Work commitment!

 

[Moto3wannabe]

Will be putting back the parts tomorrow. It just occured to me whether the mod I did earlier with the detern spring that causes the wear n tear. About 2000 km ago, I changed the metal roller of the detent arm to micro bearing and changed the 2.8mm spring to 3.0mm. The design is the same as original except 3 coils compare to 4 coils. 3.0 mm 4 coils will make it too thick compare to original. Could it be the 3.0mm spring that causes the wear n tear? Should I use back the original 2.8 mm spring?

I have also polished the detent star and arm bearing to make it less friction compare to before. Any advice?

Will be putting in the factory pro detent arm n spring when I do my next oil change as I planned to open up to inspect the wear n tear and if my current detent is not up to mark.

 

[Formula390]

Could it be the 3.0mm spring that causes the wear n tear? Should I use back the original 2.8 mm spring?

Interesting. Possibly! I don't think I saw an earlier message about you having done this... Chad or Paxton may have a better recommendation than me in this department as they've had their fingers inside the cases of these things more than I have, but that sounds like a reasonable possiblity. {hrmmm}

 

[Moto3wannabe]

Sorry Matt for not making it clear earlier about my detent arm. I thought mentioning about polishing the detent bearing might have given you a clue as the original detent arm only comes with only a roller. IÂ’m ridding with MT09 group and their bike comes with detent arm with bearing and that got me exited and did the mod. Then it got me thinking of throwing in a stronger spring to get the detent Star to click faster. Hence the 3.0 mm spring mod. It just cost me less than USD14.00 for this mod. Then later I got to know Factory Pro detent arm and I believe my mod might not match what Factory pro has developed especially with their fine tuned correct tension spring for our bike without causing any damages. So I might need to get one for replacement when I do my next oil change as I cannot get it on time this round. IÂ’m 12 hrs time difference from you. LOL.

Anyway got everything put in place and the gearshift is extremely smooth since I smoothen and polished the detent star and detent bearing to reduce as much friction as possible. And I used back my 3.0 mm spring in anticipating less friction and I need a more solid feel when I upshift or down shift. Finger cross and see what happens in 2000 to 3000 km time. Or sooner?