Taller 6th gear?

Gaijin · 07-06-2019, 01:41 AM

Is there any reasonable prospect of installing a taller sixth gear?

I'm currently planning a long trip with plenty of off-road, and it really seems the RX3 would benefit greatly from lower gearing in the hills and off-road. I already installed a 46t rear, and picked up a 13t front).

That will make the bike torquier and more responsive, but probably be fairly awful for the highway.

I could use the 14t on the highway, and change to the 13t before setting out on the off-road portion, then change back to the 14t before heading home on the highway again, but... That seems absurd.

I am thinking that the whole situation could be resolved with a taller sixth. If I could run all the time with the 13/46 combo, and had a tall sixth that compensates for the new sprocket ratio to deliver usable highway speeds, well, that would seem to be the proverbial cat's meow.

Is it possible/practical/reasonable to do?

pyoungbl · 07-06-2019, 01:49 PM

Is it possible? Yes, if you have a machine shop and the skill to machine a new gear set. You will also have to tear the engine apart just to get to the transmission bits. Bottom line, it's not a simple part swap like changing sprockets. As far as I know Zongshen does not offer different transmission ratios for different markets. Tako might be able to source something out of the China aftermarket.

Gaijin · 07-06-2019, 02:51 PM

That's what I expected to be the case, but I figured I would ask since this forum is full of inventive/adaptive guys who have had this bike for a few years, and thought maybe they had figured something out...

pete · 07-06-2019, 06:28 PM

Gas Gas used the Zongshen motor in there 6 day enduro bike
after Yamaha's carbed WR motors run out and Yamaha would not sell
them there new injected reverse cylinder motor..

So it is very possible Gas Gas used different ratios in the gear box...
They may also have used different valve timing "cam" for more power..
As I can't imagine the motor as Zongshen use it would have been
suitable for a competition enduro bike with out a few mods....
Gas Gas may have used a lower first gear... that would let you up the final
drive ratio but still retain a low first gear....

..

NzBrakelathes · 07-06-2019, 10:24 PM

No gearbox mods that I know of. There was a 5 speed in older engines that just didn't have a 6th gear fitted, I sold a 6 spd box upgrade to a Kiwi guy in Christchurch recently and I bet Pete prob knows the go kart guys lol.

Maybe Gas Gad did make some of its own gears or parts in the Zong engine and I believe they assembled their own engines to manage quality in the early days.

willy dog · 07-08-2019, 08:00 AM

The mighty Zong is not really made for off road. It is not a true dual sport You are gearing it way down with a 46 rear sprocket and 13 front. perhaps that is what you need. I have found that the 13 front and the stock 44 in the rear gives me a longer power band pulling the hills nice range in 3rd gear on the dirt roads with plenty of speed on the highway but that's what suits me

Gaijin · 07-08-2019, 12:21 PM

My experience with the RX3 in Colorado was that there were many highway hills that the RX3 just couldn't pull at all. I am headed back that way soon and wanted to address that issue. SpudRider here had praised the 13/46 combo, so I thought I would try it; sprockets are cheap. I figured I would leave the 46 on all the time, it should perk the bike up without impairing the top speed much if at all. Then I would swap in the 13t when entering the hilly off-road portion of the trip, where top speed isn't really an issue.

But changing sprockets on the side of the road and bringing along the associated tools and all just seems like a silly excess. A true overdrive 6th (when using the 13/46) seemed like an all-inclusive solution.

My ultimate solution will be the 300cc kit, which should add enough torque to eliminate the need of the 13t (and maybe the 46t). But I would need to do extensive testing before I would trust that mod, and this trip is happening before the 300cc kit even shows up, so it's not an option for this trip.

Would be nice if there was a simple and cheap 6th gear swap possible, but it isn't. I appreciate the responses!

NzBrakelathes · 07-08-2019, 12:44 PM

Quote:

Originally Posted by Gaijin

My experience with the RX3 in Colorado was that there were many highway hills that the RX3 just couldn't pull at all. I am headed back that way soon and wanted to address that issue. SpudRider here had praised the 13/46 combo, so I thought I would try it; sprockets are cheap. I figured I would leave the 46 on all the time, it should perk the bike up without impairing the top speed much if at all. Then I would swap in the 13t when entering the hilly off-road portion of the trip, where top speed isn't really an issue.

But changing sprockets on the side of the road and bringing along the associated tools and all just seems like a silly excess. A true overdrive 6th (when using the 13/46) seemed like an all-inclusive solution.

My ultimate solution will be the 300cc kit, which should add enough torque to eliminate the need of the 13t (and maybe the 46t). But I would need to do extensive testing before I would trust that mod, and this trip is happening before the 300cc kit even shows up, so it's not an option for this trip.

Would be nice if there was a simple and cheap 6th gear swap possible, but it isn't. I appreciate the responses!

Just run the 13T as many did in the past
Once you upgrade you’ll prob find 14T to be fine

NzBrakelathes · 01-16-2020, 06:57 AM

Quote:

Originally Posted by pete

Gas Gas used the Zongshen motor in there 6 day enduro bike
after Yamaha's carbed WR motors run out and Yamaha would not sell
them there new injected reverse cylinder motor..

So it is very possible Gas Gas used different ratios in the gear box...
They may also have used different valve timing "cam" for more power..
As I can't imagine the motor as Zongshen use it would have been
suitable for a competition enduro bike with out a few mods....
Gas Gas may have used a lower first gear... that would let you up the final
drive ratio but still retain a low first gear....

..

1st is input shaft has the gear machines into it, then a spinning gear opposite
From what I can work out anyways

Jackrides · 03-20-2020, 12:47 PM

Looked at a taller top myself. The only way I could figure is to buy the stock gears and send them to a gear making machine shop. They'd also need the Exact distance between centerlines of the two shafts. Be a lot cheaper if a number of people commit $ to buy at the same time.

07-06-2019, 01:41 AM	#1
Gaijin Join Date: Jun 2019 Posts: 85	Taller 6th gear? Is there any reasonable prospect of installing a taller sixth gear? I'm currently planning a long trip with plenty of off-road, and it really seems the RX3 would benefit greatly from lower gearing in the hills and off-road. I already installed a 46t rear, and picked up a 13t front). That will make the bike torquier and more responsive, but probably be fairly awful for the highway. I could use the 14t on the highway, and change to the 13t before setting out on the off-road portion, then change back to the 14t before heading home on the highway again, but... That seems absurd. I am thinking that the whole situation could be resolved with a taller sixth. If I could run all the time with the 13/46 combo, and had a tall sixth that compensates for the new sprocket ratio to deliver usable highway speeds, well, that would seem to be the proverbial cat's meow. Is it possible/practical/reasonable to do?
	0

07-06-2019, 06:28 PM	#4
pete Join Date: Jan 2012 Location: ChCh , NZ Posts: 2,261	Gas Gas used the Zongshen motor in there 6 day enduro bike after Yamaha's carbed WR motors run out and Yamaha would not sell them there new injected reverse cylinder motor.. So it is very possible Gas Gas used different ratios in the gear box... They may also have used different valve timing "cam" for more power.. As I can't imagine the motor as Zongshen use it would have been suitable for a competition enduro bike with out a few mods.... Gas Gas may have used a lower first gear... that would let you up the final drive ratio but still retain a low first gear.... .. __________________ 09 XT660R ... 06 TTR250 ... 80 Montesa H6 125 Enduro... 77 Montesa Cota 348 MRR "Malcom Rathnell Replica"... Current resto projects.. 81 Honda CT110... 80 Kawasaki KL250A1... 11 Husaburg TE125 enduro... "sold" along with another 31... Lifan 125 Pitbike.. "stolen" ... KIWI BIKER FORUM...... http://www.kiwibiker.co.nz/forums/content.php All the best offroad rides in NZ... http://www.remotemoto.com/ E-mail... xtpete1@gmail.com
	0

07-08-2019, 08:00 AM	#6
willy dog Join Date: Oct 2015 Location: vermont Posts: 238	The mighty Zong is not really made for off road. It is not a true dual sport You are gearing it way down with a 46 rear sprocket and 13 front. perhaps that is what you need. I have found that the 13 front and the stock 44 in the rear gives me a longer power band pulling the hills nice range in 3rd gear on the dirt roads with plenty of speed on the highway but that's what suits me __________________ Peace and Zong Life
	0

07-06-2019, 01:49 PM	#2
pyoungbl Join Date: Feb 2016 Location: Portsmouth, Virginia, USA Posts: 632	Is it possible? Yes, if you have a machine shop and the skill to machine a new gear set. You will also have to tear the engine apart just to get to the transmission bits. Bottom line, it's not a simple part swap like changing sprockets. As far as I know Zongshen does not offer different transmission ratios for different markets. Tako might be able to source something out of the China aftermarket.
	0

07-06-2019, 02:51 PM	#3
Gaijin Join Date: Jun 2019 Posts: 85	That's what I expected to be the case, but I figured I would ask since this forum is full of inventive/adaptive guys who have had this bike for a few years, and thought maybe they had figured something out...
	0

07-06-2019, 10:24 PM	#5
NzBrakelathes Join Date: Jun 2016 Location: Hell Posts: 2,408	No gearbox mods that I know of. There was a 5 speed in older engines that just didn't have a 6th gear fitted, I sold a 6 spd box upgrade to a Kiwi guy in Christchurch recently and I bet Pete prob knows the go kart guys lol. Maybe Gas Gad did make some of its own gears or parts in the Zong engine and I believe they assembled their own engines to manage quality in the early days.
	0

07-08-2019, 12:21 PM	#7
Gaijin Join Date: Jun 2019 Posts: 85	My experience with the RX3 in Colorado was that there were many highway hills that the RX3 just couldn't pull at all. I am headed back that way soon and wanted to address that issue. SpudRider here had praised the 13/46 combo, so I thought I would try it; sprockets are cheap. I figured I would leave the 46 on all the time, it should perk the bike up without impairing the top speed much if at all. Then I would swap in the 13t when entering the hilly off-road portion of the trip, where top speed isn't really an issue. But changing sprockets on the side of the road and bringing along the associated tools and all just seems like a silly excess. A true overdrive 6th (when using the 13/46) seemed like an all-inclusive solution. My ultimate solution will be the 300cc kit, which should add enough torque to eliminate the need of the 13t (and maybe the 46t). But I would need to do extensive testing before I would trust that mod, and this trip is happening before the 300cc kit even shows up, so it's not an option for this trip. Would be nice if there was a simple and cheap 6th gear swap possible, but it isn't. I appreciate the responses!
	1

03-20-2020, 12:47 PM	#10
Jackrides Join Date: Mar 2020 Posts: 3	Looked at a taller top myself. The only way I could figure is to buy the stock gears and send them to a gear making machine shop. They'd also need the Exact distance between centerlines of the two shafts. Be a lot cheaper if a number of people commit $ to buy at the same time.
	0