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Swapped gears 3 and 5 successfully

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Hi Everyone, I’ve just completed swapping my gears around as per a discussion on this forum ages ago. I’ve taken a set of 3rd gear cogs from another gear box and put them in the place of the 5th gears in my gear box. 

Its all worked out well, I put a BB on at the same time. Bikes back together and everything working like it should. 5th gear is now considerably higher than standard. Gears 1,2,3 and 4 are unchanged. 

It was reasonably straight forward to do. I haven’t done anything like this before - never taken a motor right to bits anyway. Big thanks to my bro though who was a trained bike mechanic back in the day and kept an eye on me throughout. There was quite a bit of grinding to do to alter cogs to get it to work.

I’ve put a video up on You tube for anyone who’s interested to see what’s required to complete the project. It’s a pretty shitty vid sorry - not my forte never made one of them before either, but it explains everything that needs to be done.

<https://youtu.be/B--CGuYNmQA>

It’s an inexpensive way to get a better top gear for the highway. cheers.

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Hi Everyone, I’ve just completed swapping my gears around as per a discussion on this forum ages ago. I’ve taken a set of 3rd gear cogs from another gear box and put them in the place of the 5th gears in my gear box. 
Its all worked out well, I put a BB on at the same time. Bikes back together and everything working like it should. 5th gear is now considerably higher than standard. Gears 1,2,3 and 4 are unchanged. 
It was reasonably straight forward to do. I haven’t done anything like this before - never taken a motor right to bits anyway. Big thanks to my bro though who was a trained bike mechanic back in the day and kept an eye on me throughout. There was quite a bit of grinding to do to alter cogs to get it to work.
I’ve put a video up on You tube for anyone who’s interested to see what’s required to complete the project. It’s a pretty shitty vid sorry - not my forte never made one of them before either, but it explains everything that needs to be done.

It’s an inexpensive way to get a better top gear for the highway. cheers.

Link to the video?

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2 minutes ago, Backwoods-Bomber said:


Nope, nothing. You should be able to open the vid in YouTube and click share, then copy and paste it into your post.

https://youtu.be/B--CGuYNmQA

I think this is working now ?

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1 minute ago, Half Assed said:

5000rpm at 70mph, that's a pretty huge drop from the original gearing. 

Yep, it has increased it quite a bit, I'd say from memory about 700 to 800 revs from where it was before. I might chuck a 44 tooth on the back or a 14 on the front ( which ever ) and see what that's like, possibly doesn't have to be as long legged as is with the 41/15. 

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3 hours ago, Auguste88 said:

Nice! I was thinking doing the wide ratio this winter but with this I am gonna save money! :)

Yep the ACT gears would be awesome but at approx $1200 NZD with shipping it’s too much.

I’m pretty sure the 5th gear in mine now must be very similar to the ACT 5th as there is virtually no

clearance left to get a bigger cog in there.

 

I’m off for a three day ride next weekend so after that I can report back with an honest opinion of what

the new set up is like before anyone takes the plunge. Happy to help if there’s any queries, I know the youtube

vid is bit sketchy but I have all those photo’s in high res etc 

 

Here are the six easy steps to complete the job.

 

1.) New Fifth Driver ( Factory 3rd driven )

- Reduce thickness of cog at centre to ensure circlip on driver shaft will fit. ( shop job )

- Shave down outside lip on opposite side of cog to match existing ( original ) Fifth Driver ( shop job )

 

2.) New Fifth Driven ( Factory 3rd driver )

- Grind dogs off to match original cog. ( where 5th sits next to 3rd side )

- Increase inside diameter of dogs on opposite side of cog to engage 1st driven

- Reduce thickness of cog at centre to accomodate circlip on shaft on 3rd gear side. Circlip must ultimately sit flush with face of cog. This is important and only exposes itself when closing cases up again. In the last mm of cases coming together everything will bind if this step is not done. ( another good job for the shop or a mate with a lathe )

 

3.) Existing Third Driver

- Increase inside diameter of dogs where they engage the new 5th driver.

( this is the only alteration needed doing to an existing cog that goes back in bike. This would

STILL work with the original cog if decided to restore engine to factory standard )

 

4.) Fifth Driven Selector Fork

- Grind side of selector fork to allow for bigger 5th Driver

 

5.) Grind casing slightly to allow for bigger 5th driver.

 

6.) Grind inside diameter of fifth driven selector fork to fit new 5th driven gear.

 

 

 

 

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Yep, it has increased it quite a bit, I'd say from memory about 700 to 800 revs from where it was before. I might chuck a 44 tooth on the back or a 14 on the front ( which ever ) and see what that's like, possibly doesn't have to be as long legged as is with the 41/15. 

I applaud the innovativeness of this job and willingness to share with us the procedures, but i know i would not like the huge jump between 4th and 5th. That big jump i believe would dictate my pace of riding in certain area's, rather then riding at the pace i want and not having to lug or over rev the engine.
Good job though, well done, hope it works out for ya.
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That was my thought as well , I have a bike with a big gap only between 3rd and 4th and it's always an issue when ridding at a steady speed . However with the price difference opposed to the other option it may not be so bad . Would be even better if a person could get just the ACT 4th or even the NOVA WR 4th to narrow that gap .

 

 

.

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32 minutes ago, bucket list said:


I applaud the innovativeness of this job and willingness to share with us the procedures, but i know i would not like the huge jump between 4th and 5th. That big jump i believe would dictate my pace of riding in certain area's, rather then riding at the pace i want and not having to lug or over rev the engine.
Good job though, well done, hope it works out for ya.

Thanks Bucket List, fair enough about the gap. I suspect this wouldn't be the best mod for a lot of dirt riding although I haven't tried yet. I'm mainly road and gravel/4WD with some dirt stuff so was keen to try it. I dropped the front to a 14 tooth the other night and did about 150km (100miles) tarmac/gravel. Top gear proved pretty handy with this setup. 5th gear pulled strong from 70 through to around 120km/h ( 44...75m/h). 100km/h was a lazy 4900rpm and 112...115 around 5500rpm. Keep in mind my bike's possibly putting out reasonable power which would help handle the taller gear.

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That was my thought as well , I have a bike with a big gap only between 3rd and 4th and it's always an issue when ridding at a steady speed . However with the price difference opposed to the other option it may not be so bad . Would be even better if a person could get just the ACT 4th or even the NOVA WR 4th to narrow that gap .
 
 
.


Never heard of the NOVA WR 4th mod before. Can you reference the tread for me please.

Thanks!

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Looks like you bolted the motor to a 3x6 (?). Is that pretty stable for working on the motor?

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2 hours ago, Rib Eye said:

Looks like you bolted the motor to a 3x6 (?). Is that pretty stable for working on the motor?

Yeah it worked pretty good actually. Its a bit of 4x2 with a couple of old engine mounts. Probably the mounts from the front of the frame off the Z would work too.

IMG_6590 (1).jpg

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