Topic: 1966 S90 - FRONT END SWAP SUGGESTIONS * PLAN B

[RAFster122s]

Yeah...I have found out that the S90 frame is different (3 bolt vs 2 bolt) but I have been able to find (fairly bad photos) of people that say they have fit Lifan's into them...So I believe it is possible and I am lucky enough to have a very skilled fabricator friend who is game to help. I still need to do some research on the wiring...will I have to completely rewire it or once the new engine is in, only a 12V battery and new regulator be required (lights also I suppose)? Again...much research to do...and yes, stopping is an issue already....I will find a front disc set-up from something and make it work....should be interesting

Would be nice if you found a CB125S2 mechanical disc front end to bolt up to your S90.I sold one last yr.

Is that a joke?  They are notorious for having issues.  A good properly sized drum can out brake a disc brake, but the disc brake will outperform when it comes to repeated use where brake fade comes into play given its ability to cool much faster.

[SKTP]

I am dragging this one back up...so after all this time I have been driving and loving my little S90. My CB build should be back on the road very soon, so I am goign to start amassing parts for the S90 overhaul. It will have a Daytona 190cc engine in it. so that mean I need a new front end with a modern disc brake to stop it. I am very open to all suggestions....I am thinking if I can fine one a 2001 Yamaha SR250 front end might be a good candidate? I woudl like it to remain an 18" wheel and keep the stock fender if possible.

EDIT BOOK MARKING AND ADDING PHOTOS FOR FUTURE REFERENCE:

Good build thread:


Examples of frame mods 3-bolt to 2 bolt:
Modified Frame for 2-bolt:

Stock 3-bolt Frame:

2 bolt engine in:
http://68.media.tumblr.com/db3e6d13b4cbcf5df43575d928cef2d9/tumblr_ope28cDXBK1qkjqdmo2_1280.jpg
Stock 3-bolt engine in:
http://68.media.tumblr.com/21397915018aa2c35c9a77ffaab449a3/tumblr_ope28cDXBK1qkjqdmo3_1280.jpg

[02z06dave]

Cool project. I was thinking that 190 Daytona motor would be good to go into a ct70. I'm excited to where you go with this one

[grcamna2]

Cool project. I was thinking that 190 Daytona motor would be good to go into a ct70. I'm excited to where you go with this one

Me too  I have an 81' CB125S w/ a modified XR200 engine in it and really enjoy it.I still have the stock drum front brake but also plan to upgrade to a disc brake.

[SKTP]

I am excited too...god I hope my CB750 rebuild in the last one...just put the engine in (for the third time) yesterday...

Took the little bike all over yesterday...can't wait to make it less scary-slow!

What front ends are you guys considering? I'm thinkign Dirt bike...but I have a lot of research to do regarding Spokes, rims and going from a 21" rim to an 18" is that tricky or mellow? I have no idea currently.

[strynboen]

i have taken the front of a chinese Yamaha 125(rd) copy..it have a nice strong discbrake front..and some thik bones in the front.
.it had some nice 18 alus.... hveels too...
 and the rear svingarm..så i can build the vhole setup over on a cd 50 or a Yamaha..

[SKTP]

Right now I am pricing out Honda CR125 dirt bike forks and seeing how expensive re-lacing it to an 18" rim would be....I figure a CR125 must have more than enough stopping power?

[02z06dave]

I'm having a similar dilemma. I have a cb160 in queue, I am planning on doing a cl175 sloper bottom end with a cb200 top end bored to 240. I would like to do an inverted fork front end with dual discs and modernize it, but all of those, that I've seen, would look way to big for the little cb160. I'm thinking maybe going to a cb350 front end would work and maybe try to fit a gt750 drum front hub for the extra stopping power and stick with the classic look of the drum brake.

[grcamna2]

I'm going to install a CB360 front end complete w/ hydraulic disc;I just need to find a machinist to make a bushing to install and weld the CB125S steerer tube from the orig. lower triple into the CB360 lower triple which is bigger.

[grcamna2]

Yeah...I have found out that the S90 frame is different (3 bolt vs 2 bolt) but I have been able to find (fairly bad photos) of people that say they have fit Lifan's into them...So I believe it is possible and I am lucky enough to have a very skilled fabricator friend who is game to help. I still need to do some research on the wiring...will I have to completely rewire it or once the new engine is in, only a 12V battery and new regulator be required (lights also I suppose)? Again...much research to do...and yes, stopping is an issue already....I will find a front disc set-up from something and make it work....should be interesting

Would be nice if you found a CB125S2 mechanical disc front end to bolt up to your S90.I sold one last yr.

Is that a joke?  They are notorious for having issues.  A good properly sized drum can out brake a disc brake, but the disc brake will outperform when it comes to repeated use where brake fade comes into play given its ability to cool much faster.

No,no joke;do you have any experience with the mechanical calipers on the CB125S & CB200T ?

They usually have water run into them and it rusts the mechanisms and then they are very lame;they also need to be adjusted(lever orientation and cable) according to the book.The other thing about them is you need 'just enough' special silicone lube inside to keep the 'mech' active but not so much that the pads get impregnated.. I have a CB125S mechanical caliper assembly which I took apart and replaced the 3) 7mm ball bearings which it 'ramps-up' for actuation and then replaced the thrust needle bearings and thrust washers,fully rebuilt w/ fresh oem brake pads and a new oem cable.I also have the CB125S front disc/wheel w/ front disc oem chrome fender.I will be offering them up for sale online soon.I learned that the front triples on my 81' CB125S are just about 5/8" wider than the front triples on the 1975-78' CB125S model/years so I will be going w/ the CB360 complete front-end.

[SKTP]

I am still totally in the "figuring out how this works" stage of this. I think I will be OK with a much wider triple tree from the dirt-bike swap from a visual standpoint. Actually the beefier modern inverted forks should look really cool...I will need to:
- make sure I can fit the stem in my frame and figure out what bearings or spacers I will need
- have the correct length to keep the right look/geometry (will need to look into cutting internal tubes ans springs although hopefully I can find a very similar length)
- Make sure an 18" wheel can work with this fork set up because again, I want it to still look like an S90 and use the stock fender (might have to make fender wider)

[Don R]

 What Frank said on the stud. I found tubing that slip fit over the shock mount, cut it an inch and a half longer than the stud, sleeved it with a stack of smaller tubes that fit the pilot drill, drilled through to establish the straight hole then drilled to size, then slipped a headless bolt through from the back side and welded it on the back.

[754]

Checkout cb 100, And 125  front end if you can handle the drums.
 Warning, dirt bike modrrn fork will need internal shortening... Really long travel vs what you need..

[SKTP]

That's a good point...So I need a front end that is dick with spokes that is from a modern-ish street bike

[grcamna2]

The CB125S w/ the front disc brake(any year as long as it has the disc brake w/ mechanical caliper/cable)is a direct swap onto the S90;all you would need would be the forks,wheel,etc. as they use the exact same part# for the steering stem.When it's set-up and adjusted correctly it's a strong disc;I would be using it on my 81' CB125S if it used the same triples as your S90 but mine and forks,headlight,meter bracket are just a little wider.

[SKTP]

That's good news..thanks...and it lead me to this:

[grcamna2]

Yeah  that looks nice. The guy does need to have a few more tools.

[02z06dave]

That aprilia front end looks sweet on there. I'll keep that in mind as an option for my cb160

[SKTP]

Still...I want spokes!!!!! And not to spend a crazy amount...the search continues

[SKTP]

Here's a contender

https://en.wikipedia.org/wiki/Honda_CMX250C

[02z06dave]

those look long. spokes can be done with that aprilia front end. Either with a custom hub or maybe a combination of spacers and different wheel bearings to fit the axle

[SKTP]

http://www.allballsracing.com/index.php/forkconversion

I put in 1980 CB125S...seems to be a great resource....now to hunt down fork lengths

[Jmed22]

Lobe these old bikes.. Have a 67 cl90 and is tons of fun to drive. Not a rocket but great bikes

Sent from my Life One X2 using Tapatalk

[SKTP]

http://lostabout.com/S90/parts/

This is very useful...but I do not understand how this works?



For example...is there anyway to know the part number for the main stand?

[SKTP]

Do CB350 front drums stop well? I liek the look of the entire front end on those bikes. It look liek I could pick up the entire front end and a front drum hub for not too much.

Would lacing the hub to an 18" wheel be a nightmare? I guess that might involve custom spokes?