Modern Front end

[Nuno]

Might be geography too. I'm not sure I could find a Monster front end for anywhere near $300 CDN (rough exchange calculation...) Glad the stem fits, though!

honestly I payd 30€ (42US$) for the fork, 50€ for the clamps but they were bargain...150€ is the right price for both

The stems fit it you change the bearings and put a spacer under the lower one. Then new bearings on the front wheel (to match the new axle), new bearing spacer (it's hidden..is the little "tube" between the bearings inside the hub) and a spacer on the right side...done.

All the bearings are standard spares, SKF or cheaper brand.

 

[frwinks]

Might be geography too. I'm not sure I could find a Monster front end for anywhere near $300 CDN (rough exchange calculation...) Glad the stem fits, though!

maybe not duke, but you can get gixxer forks for under 300 on fleabay. The crisp steering and braking is well worth the upgrade IMO

 

[bentwrench]

frwinks, the fact that you've done the upgrade gives me hope.

But for now, I still need to build my new battery box, and maybe ride for a bit on the bike once it's firmly in "phase II." New forks mike be "phase III," though...

 

[Elle on Wheels]

How about the drive for the speedometer?
The original won't fit on the Aprilia spindle - correct?
Did you just do without a speedometer and put a spacer there instead?

 

[XSLeo]

A lot depends on the wheel you use. If you use the XS400 front wheel the speedo fits fine. If not then the speedo cable may fit and work ok with the new wheel.
You can always mount a speedo for a bicycle on your bike.
Leo

 

[LuckyEight]

Stock wheel + stock speedo drive = stock front axle = you have to make some bushings and spacers to fit your new forks
Maybe You can use stock Aprilia speedo drive...but you should find some speedo with correct ratio
Or just use new speedo with sensor instead

 

[Elle on Wheels]

Thanks guys!
I am sticking with the stock wheel. I didn't think the stock spindle would work with the Aprilia forks, and the word "make" in the sentence "make some bushings and spacers to fit your new forks" is daunting to me.
Any suggestions/pictures/dimensions on these bushings and spacers if you did this with your bike?

Otherwise, I have an Aprilia spindle on order and picked up new wheel bearings for it to fit my stock wheel.

Also, I've read elsewhere on this site that Aprilia 125 forks will work with the same bearings on the top of the steering column neck and a tapered bearing on the bottom. Can you confirm this? I'm sure that there were loose bearings top and bottom when I took it apart, do I not need both as well as the tapered bearing on the bottom when I put the Aprilia forks on?

Thanks,
Elle, aka Elle on Wheels,
Better rider than builder. Standing around scratching my head and reading this forum way more often than actually building anything!

 

[LuckyEight]

I did it...stock wheel, Aprilia axle, and spacers (I don't have any dimensions atm) and aftermarket speedo/tacho (no mechanical speedo/tacho drive)
Neck bearings - my both bearings are tapered (lower one is in different size, bearing on the top is the same size like stock one). You should change the lower one and you can stay with the loose one on the top. Don't ask my for numbers, it's 3 years ago since I did it and my memory is weak But you should find it here on the forum.
Here you can find more info how to use stock wheel, axle and speedo drive together with modern front end http://www.xs400.com/threads/my-1977-xs360-build-may-take-a-while-but-its-a-start.12819/page-2 Maybe you can pay someone to machine these parts for you? Btw sorry for my poor english

 

[XSLeo]

Is the Aprila axle larger or smaller than the XS axle? If larger can you drill the speedo drive out to match?
If smaller, by how much? Perhaps a shim cut from thin sheet metal wrapped one layer around the axle will be enough.
Leo

 

[Elle on Wheels]

Thanks guys!
The Aprilia spindle is larger. I'll look at the speedo to see if I can make it work, or maybe just go with a new aftermarket one.
Still waiting for the tapered bearing from Ebay to fit the aprilia forks into the Yamaha frame.

Here's where I'm at right now. Powdercoating done, time to start putting things back together!

 

[Elle on Wheels]

OK!
I ordered the Aprilia front forks on ebay and when they got to me I found one to be nice and firm and the other one was soft and squishy.
So...I searched painfully and finally found some new fork seals, I took apart the squishy one, I replaced the seal and added fork oil back in, and tightened it all back up again. phew!
Then...I pressed on them both and they are just the same as before!!!!!!! One is nice and firm and the one I just took apart and put back together is all soft and squishy!!!!!!!!!!!!!!!!!!
So - I looked up Aprilia RS125 front forks, and some people say that there is a spring in only one side?!?! And so it should be totally ok for one fork to be soft and squishy and the other firm - correct??

 

[LuckyEight]

You are right...only one spring