Bugeye Zuma to Aerox Fork Swap

[imatt]

2005 USA 2t Zuma

I went looking to see what could be done about the suspension for more sporty riding. Came up empty on searches for modifications you can do to the stock forks. So that rabbit-holed quickly to sourcing what I'm thinking will work;  2003-2012 Aerox 50 2t 30mm forks. Found sets on ebay, but they all seem a bit crusty for the money. From a EU Yamaha parts site, new, the whole fork/triple assembly, can be shipped to the states for about $300. Better yet figured out the clone of the Aerox, the MBT Nitro. You can get Nitro forks shipped to the US for $206

From all my research, I think I also need a prebug style caliper (prebug zuma/aerox/bws.. etc..)

One thing I don't have confirmation is the stock bugeye rotor working. I see that the aerox is 190mm but the bugeye is 180mm. Looked at associated wheel options to swap as well, to get me a 190mm rotor, when I stumbled upon a few replies on posts from aeroxbud. He showed a BWS with aerox forks swap, using the stock wheel. The bws also has the 180mm rotor??? So if anyone knows, will 180mm more or less work??

Anyone that can chip in with a sanity check for value fork options for a bugeye? Maybe I blocked out something obvious looking into the Aerox idea??

Thanks!!!

[ryan_ott]

The Zuma might not have the best suspension but honestly the Aerox isn’t the greatest either. I’ve been running the Aerox forks for a number of years and they are so/so. Keep in mind if you swap to the Aerox they are longer so either your front will be higher if you don’t modify either the forks or cut the Zuma stops so they will slide higher. I’d suggest adjusting oil level/weight and or adding spacers to the Zuma legs and see if you can accomplish what you are after.
Yes you’d need a prebug caliper and the rotor offset may be off so some shimming may be required.

49ccscoot.proboards.com/thread/21089/aerox-jog-zuma-swap-info

[imatt]

I did stop and considered different weight fork oil. But only for a brief moment

You did get me to reconsider though. Picked up some 30w Belray from Cycle Gear this evening.

Found the service manual, says it’s 10 weight stock. Right now the front end has zero hydraulic control when doing a bounce test. Figured I’d just skip right past the 15 and 20w… I’m really looking for some sort of improvement with the front end.

As I get the legs apart, I’ll consider what I want to do for adding some preload to the springs.

Thanks for the input!

[imatt]

I finished up the stock zuma forks just now. 30wt oil and went with 9mm of spacer to add preload to the springs in each fork leg. Interesting that you have to put the fork cap on after the tube is installed in the triple clamp. Took a moment to figure out how to compress all that preload, while up in the fender/fairing, but figured out a method.





I measured what came out of each leg. Caliper side had clear-turned grey/black fluid. The speedo side had red fluid. Have no info on previous ownership or maintenance. Dash shows only 1800miles on it though.

[aeroxbud]

The 30wt oil is going to be a lot, lot heavier than the standard weight. I'm probably thinking too much so, but wait and see.
If you are going to use nuts as spacers I would at least put two nuts on each side to lock them. They will probably move as the springs compress.
I would of changed one thing at a time to see what affect each had. You can get steel pipe that will fit into the fork tubes as a more permanent spacer solution once you know how much preload you need.

[imatt]

They are actually exhaust studs, the threads don't go all the way through. The nuts are impact gun'ed til the end of the threads on one side, that how I arrived at 9mm lol.

I would have to say so far the 30 weight has made no real noticeable difference regarding the control of the speed of the compression or rebound. I understand that the increased preload now could cancel out some thicker weight oil benefits. I may pull the spacers out just confirm. (The fork caps come off in seconds, with no disassemble required)

My guess is it's a no technology type setup, prob just a oil hole in a tube. Not my first time trying to spruce up a set of forks to make improvements. But usually switch to something with a valve stack in it.  This is how I ended up arriving at the Aerox fork swap idea. Of course never bounce tested Aerox forks. Maybe they are disappointing too, but I've seen the internals so I know they would be a better starting point to modify. I am trying to make a decent improvement with the suspension. After taking the stock stuff apart, I see the lip that would need to be removed inside the clamp area, to allow for the taller forks to slide though more.

Googling around, I see that once upon a time Stage6 made a BWS type fork with external valving control. Looks to be unobtainable now days.

Still debating on what to do for the rear shock. Found the YSS mono prox for about $60 shipped to the states. Have my doubts that it's going to provide the results I'm looking for. I also found another shock right at $100, the RDR racing 290mm:

Hope it works out with the centerstand still. If not I can cut off some threads on the shock body to get back a few mm. Obviously no reviews found for this kind of stuff. But something about the way it looks... just seems more promising lol

[aeroxbud]

The genuine Aerox forks a very stiff. I like that after having lots of sports bikes.
The aftermarket pair on the BWS were not as good damping wise. But worked okay for the price.
Rear shocks are a Crap shoot. You !can never know exactly how stiff they will be. If you go much longer than stock, you might find the centre stand might not work as well.
On the BWS you can't get to the plug now through the plug hatch because it's at a different angle with longer shocks.