Transmission issues

APEmike · August 20th, 2015, 03:50 PM

Alright, apparently it isint just me... I would be getting the occasional jump from 6th to 5th and 2nd gear slip outs. Not fun. Just had a customer drop off a 300 trans to figure out a solution. Its a race bike that is having the same issues.

The cause: there is NO factory undercut on the dogs. At all... Normally there is at least a few degrees to help lock the gears in to place when shifting. The 300 has none whatsoever.

To those that dont know what under cut is, think of how the transmission engages the next gear. Its a pin, known as a dog, that fits into a slot. Now, transmissions are not ridged, un-flexing things. When the two contact points come together there is some flex. If the dogs have no undercut like this > ll
the transmission will flex enough to change the angle they contact at when power is applied, and without undercut, it changes in a way that encourages the gears to spread apart. Undercutting cuts the dogs at an angle that when power is applied, it pulls the gears together harder, rather than letting them slip away. It would look more like this and the point of contact > //

I am VERY excited to see what happens when this transmission is done and back in the customer's bike. Typically we see with other bikes much more positive shifts, and eliminated slip outs. Cant wait! Im also excited that I'm not the only one having this issue and its not because of my NooBness

micoulisninja · August 20th, 2015, 07:00 PM

I thought that they had only changed the ratio for 1st and 6th, not that there is a major issue...
Good to know, keep us posted !!

rojoracing53 · August 20th, 2015, 08:37 PM

I've always assumed these cheap bikes didn't have undercut gears and I always wondered what the cost to undercut my trans would be. It would be so nice to get this thing to change gears like a proper sport bike.

alex.s · August 20th, 2015, 09:15 PM

OR... you could do a better job shifting.

Linkin · August 22nd, 2015, 11:42 PM

The solution is to hold the shifter up with your foot until you release the clutch. This ensures the gear is fully engaged and can't drop into a lower gear or false neutral.

rojoracing53 · August 23rd, 2015, 05:34 AM

I've never had a problem with the bike popping out of gear when I perform a complete prolonged shift. I've only had it pop out of gear when on track and I'm shifting without the clutch because your trying to get it done quickly. I've experimented with it and the time needed for the trans to drop completely into it's next gear is just too damn long for a quick snap of the throttle like a proper racing bike. I can get the shift done quicker and moth smoothly if I combine the clutch-less method with a little bit of clutch fed in. My understanding is with a proper undercut trans you can shift faster because the gears literally get sucked into place as so as you try to shift so the shift time is greatly reduced. This also make the bike more stable while shift up under acceleration in big sweeping corners.

GregS · August 23rd, 2015, 07:58 PM

My issues went away after installing the Factory Pro shift kit.
I'd recommend you try that before spending a lot of money splitting the cases and undercutting the gears.

APEmike · September 3rd, 2015, 11:45 AM

A stronger detent spring and higher quality bearing. That will indeed help, and aid feel, but it doesn't fix the cause of the issue. We are getting close to finishing up the trans, I am expecting it in the next week or so. I will post before and after pictures and try to get a review from my customer when its installed.

dcj13 · September 3rd, 2015, 01:02 PM

Quote:

Originally Posted by Linkin

The solution is to hold the shifter up with your foot until you release the clutch. This ensures the gear is fully engaged and can't drop into a lower gear or false neutral.

If you ride an older bike with a Getrag transmission, you’ll always preload the shift lever. Preloading works well on bikes with slick shifting transmissions, too!

APEmike · September 29th, 2015, 01:08 PM

Alright, we finally finished the trans. Pictures coming soon. Customer will be here today to pick it up. Hopefully we will get feedback from him, however I am SURE that this will have fixed the issue.

GregS · September 30th, 2015, 05:53 PM

Quote:

Originally Posted by APEmike

Alright, we finally finished the trans. Pictures coming soon. Customer will be here today to pick it up. Hopefully we will get feedback from him, however I am SURE that this will have fixed the issue.

What was the cost?

APEmike · October 6th, 2015, 12:02 PM

$413

mgentz · October 12th, 2015, 07:16 PM

pictures? reports?

APEmike · January 15th, 2016, 01:49 PM

OEM 250/300 transmission. Take a close look. The dogs engage at 90*. You would think this is OK however when forces are applied they flex a little allowing them to slip

Undercut 250/300 trans. See how the dogs are cut at an angle that locks them together when power is applied? These will not slip out. OEM 600s and up have this from the factory, though it can be taken even farther. VERY common modification for drag racing, and road racers will typically get up/down cuts which is undercutting on both sides. Its a required mod for all bike powered cars due to the added stresses.

Sorry for the delay in getting the pics out to you guys. I have not yet heard any feedback from the customer, however I am positive that this fixes any issues with jumping out of gear.

mgentz · January 15th, 2016, 02:35 PM

I had mine go through the ISF process and it made it smooth. Thus would have been a welcome addition but I did not do it at the time. If I take it apart again, I will do this.

dino74 · April 4th, 2016, 10:46 AM

APEmike,

Any update from the customer? My 300 has this problem and its driving me nutz!

APEmike · April 25th, 2016, 12:50 PM

Quote:

Originally Posted by dino74

APEmike,

Any update from the customer? My 300 has this problem and its driving me nutz!

I wish! Some times they just never call you back.

Maybe you will be the first to give forum feedback?

JohnnyBravo · April 25th, 2016, 01:19 PM

That ought to get the job done

RacinNinja · April 25th, 2016, 01:22 PM

Quote:

Originally Posted by APEmike

I wish! Some times they just never call you back.

Maybe you will be the first to give forum feedback?

You only hear from them when things go badly or don't work right or break.

I'm a service tech....no news is good news!

APEmike · April 27th, 2016, 04:52 PM

Quote:

Originally Posted by RacinNinja

You only hear from them when things go badly or don't work right or break.

I'm a service tech....no news is good news!

Yeah thats usually how it goes. We do get the rare guy that calls back very happy though... Those are nice. Like the guy who called to compliment our machinists "who came up with that wicked CNC port job" that flowed within 0.5% across all 4 cylinders, when we port by hand

mgentz · April 27th, 2016, 06:45 PM

I called a lot

August 20th, 2015, 03:50 PM	#1
APEmike ninjette.org member Name: Michael Location: Tehachapi, CA Join Date: Oct 2014 Motorcycle(s): 2014 Ninja 300 Posts: 160	Transmission issues Alright, apparently it isint just me... I would be getting the occasional jump from 6th to 5th and 2nd gear slip outs. Not fun. Just had a customer drop off a 300 trans to figure out a solution. Its a race bike that is having the same issues. The cause: there is NO factory undercut on the dogs. At all... Normally there is at least a few degrees to help lock the gears in to place when shifting. The 300 has none whatsoever. To those that dont know what under cut is, think of how the transmission engages the next gear. Its a pin, known as a dog, that fits into a slot. Now, transmissions are not ridged, un-flexing things. When the two contact points come together there is some flex. If the dogs have no undercut like this > ll the transmission will flex enough to change the angle they contact at when power is applied, and without undercut, it changes in a way that encourages the gears to spread apart. Undercutting cuts the dogs at an angle that when power is applied, it pulls the gears together harder, rather than letting them slip away. It would look more like this and the point of contact > // I am VERY excited to see what happens when this transmission is done and back in the customer's bike. Typically we see with other bikes much more positive shifts, and eliminated slip outs. Cant wait! Im also excited that I'm not the only one having this issue and its not because of my NooBness
	4 out of 4 members found this post helpful.

August 20th, 2015, 07:00 PM	#2
micoulisninja modaholic junkie Name: Nick Location: Athens, Greece Join Date: Sep 2012 Motorcycle(s): 2001 ZX-12R, 2009 ninja 345cc and plenty of others in the past... Posts: 438 Blog Entries: 2	I thought that they had only changed the ratio for 1st and 6th, not that there is a major issue... Good to know, keep us posted !! __________________________________________________ If noone has tried it before, I will !!! Last futzed with by micoulisninja; August 21st, 2015 at 10:18 AM.

August 20th, 2015, 09:15 PM	#4
alex.s wat Name: wat Location: tustin/long beach Join Date: Sep 2009 Motorcycle(s): wat Posts: Too much. Blog Entries: 5 MOTM - Oct '12, Feb '14	OR... you could do a better job shifting. __________________________________________________
	2 out of 2 members found this post helpful.

September 3rd, 2015, 11:45 AM	#8
APEmike ninjette.org member Name: Michael Location: Tehachapi, CA Join Date: Oct 2014 Motorcycle(s): 2014 Ninja 300 Posts: 160	A stronger detent spring and higher quality bearing. That will indeed help, and aid feel, but it doesn't fix the cause of the issue. We are getting close to finishing up the trans, I am expecting it in the next week or so. I will post before and after pictures and try to get a review from my customer when its installed.
	1 out of 1 members found this post helpful.

October 12th, 2015, 07:16 PM	#13
mgentz Board Member Name: ... Location: WI Join Date: Dec 2011 Motorcycle(s): 250R (street), 250R (dirt) Posts: A lot.	pictures? reports?
	1 out of 1 members found this post helpful.

August 20th, 2015, 08:37 PM	#3
rojoracing53 Fast-Guy wannabe Name: Jason Location: Brentwood, Ca Join Date: Oct 2011 Motorcycle(s): 2009 Ninja250, 2011 RM-Z250, 2004 NSR50, Posts: A lot. MOTM - Jan '13	I've always assumed these cheap bikes didn't have undercut gears and I always wondered what the cost to undercut my trans would be. It would be so nice to get this thing to change gears like a proper sport bike.

August 22nd, 2015, 11:42 PM	#5
Linkin Down Under Name: Linkin Location: Sydney, Australia Join Date: Jun 2014 Motorcycle(s): Kawasaki ZXR250C Ninja Posts: 296	The solution is to hold the shifter up with your foot until you release the clutch. This ensures the gear is fully engaged and can't drop into a lower gear or false neutral.

August 23rd, 2015, 05:34 AM	#6
rojoracing53 Fast-Guy wannabe Name: Jason Location: Brentwood, Ca Join Date: Oct 2011 Motorcycle(s): 2009 Ninja250, 2011 RM-Z250, 2004 NSR50, Posts: A lot. MOTM - Jan '13	I've never had a problem with the bike popping out of gear when I perform a complete prolonged shift. I've only had it pop out of gear when on track and I'm shifting without the clutch because your trying to get it done quickly. I've experimented with it and the time needed for the trans to drop completely into it's next gear is just too damn long for a quick snap of the throttle like a proper racing bike. I can get the shift done quicker and moth smoothly if I combine the clutch-less method with a little bit of clutch fed in. My understanding is with a proper undercut trans you can shift faster because the gears literally get sucked into place as so as you try to shift so the shift time is greatly reduced. This also make the bike more stable while shift up under acceleration in big sweeping corners.

August 23rd, 2015, 07:58 PM	#7
GregS ninjette.org member Name: Greg Location: San Antonio Join Date: Dec 2014 Motorcycle(s): Ninja 300, GSXR-750, Ducati M1100 Posts: 185	My issues went away after installing the Factory Pro shift kit. I'd recommend you try that before spending a lot of money splitting the cases and undercutting the gears.

September 29th, 2015, 01:08 PM	#10
APEmike ninjette.org member Name: Michael Location: Tehachapi, CA Join Date: Oct 2014 Motorcycle(s): 2014 Ninja 300 Posts: 160	Alright, we finally finished the trans. Pictures coming soon. Customer will be here today to pick it up. Hopefully we will get feedback from him, however I am SURE that this will have fixed the issue.

October 6th, 2015, 12:02 PM	#12
APEmike ninjette.org member Name: Michael Location: Tehachapi, CA Join Date: Oct 2014 Motorcycle(s): 2014 Ninja 300 Posts: 160	$413

January 15th, 2016, 01:49 PM	#14
APEmike ninjette.org member Name: Michael Location: Tehachapi, CA Join Date: Oct 2014 Motorcycle(s): 2014 Ninja 300 Posts: 160	OEM 250/300 transmission. Take a close look. The dogs engage at 90*. You would think this is OK however when forces are applied they flex a little allowing them to slip Undercut 250/300 trans. See how the dogs are cut at an angle that locks them together when power is applied? These will not slip out. OEM 600s and up have this from the factory, though it can be taken even farther. VERY common modification for drag racing, and road racers will typically get up/down cuts which is undercutting on both sides. Its a required mod for all bike powered cars due to the added stresses. Sorry for the delay in getting the pics out to you guys. I have not yet heard any feedback from the customer, however I am positive that this fixes any issues with jumping out of gear. __________________________________________________ I ride because therapy is too expensive, and less fun.

January 15th, 2016, 02:35 PM	#15
mgentz Board Member Name: ... Location: WI Join Date: Dec 2011 Motorcycle(s): 250R (street), 250R (dirt) Posts: A lot.	I had mine go through the ISF process and it made it smooth. Thus would have been a welcome addition but I did not do it at the time. If I take it apart again, I will do this.

April 4th, 2016, 10:46 AM	#16
dino74 ninjette.org certified postwhore Name: dino Location: Oceanside, Ca Join Date: Nov 2010 Motorcycle(s): '09 250 Street, '09 250 Race, '13 300 Race Posts: A lot.	APEmike, Any update from the customer? My 300 has this problem and its driving me nutz! __________________________________________________ CVMA #55

April 25th, 2016, 01:19 PM	#18
JohnnyBravo Certifiable nontundrum Name: Harper Location: NC Milkshake stand Join Date: Mar 2013 Motorcycle(s): 2013 SE NINJA 300 Posts: Too much. MOTM - Sep '13, Sep '16	That ought to get the job done __________________________________________________

April 27th, 2016, 06:45 PM	#21
mgentz Board Member Name: ... Location: WI Join Date: Dec 2011 Motorcycle(s): 250R (street), 250R (dirt) Posts: A lot.	I called a lot

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