Topic: Back at it! Picked up a Honda S90

[Flying J]

Got married and had kids which took away most of my time to wrench on bikes but I got bit by the bug again SO IM BACK BABY!

I was at a friends house and he had a S90 that I always wanted. He said to make an offer so I did and he said yes. But I had to take another non runner with it.

1969 S90



Non runner cb650



And because i was in the garage I pulled the 125 motor thats been on my shelf for like 9 years, finished putting it together and slapped it back in the SL100. I had planned on keeping the SL but I think I might rebuild the 100 motor put it back in and sell it. I Would like to put stock exhaust on it but they want $450 for a pipe.

SL100

[Mark K]

Good looking S90 and SL100. The non-runner looks like it has a lot of potential.

[Flying J]

The S90 was mostly there and basically stock. It had not ran in a few years so I replaced the leaky petcock and cleaned the carb. I also adjusted the valves and points.

The bike ran but was not really charging so I found a radioshack rectifier in my old parts to install. To get to the rectifier on this bike you have to drop the motor out of the frame! It took me a bit to figure that out. I took out the old one and swapped in the new one.  Then the bike would not run! I had lights on the dash but no spark or tail light. I spent the rest of the day trouble shooting with a multimeter to no avail and went to be defeated. The next morning I went back at it after studying wire diagrams and eventualy figured out that the rectifier on the S90 is used as the ground wire to the frame. Thats not how most other bikes work, but thats how this one does. With a jumper ground wire to the frame the bike ran again.

Side note: Pardue Brothers has a full LED replacement kit for these bikes to eliminate a lot of the electrical problems. Which Im still sorting out.

The front fender was missing so I bought a repop from china and they sent one with a pedestrian slicer mount. Im not about to wait 2 months for the correct one so I guess I need to make a pedestrian slicer plate now.


The headlight was not working so I got a new bulb and it blew out. The wires in the headlight are jerry rigged because the handlebars and controls are not stock so with my trustee wire diagram I sorted it out and permanently wired the second stage of the stator on so I can run the headlight.
So far so good. Somebody wired in a switch on the headlight housing for the headlight and the tail light since the switches on the handle bar are gone. I also installed a horn. The original bars had an internal throttle which I really like but the throttle tube alone is $100 on ebay. Ill stick with what I have for now.



At that point I took the bike out for a few short trips and got it up to 48 MPH on a short downhill. I think the motor might be tired?!!!

I took out the other day and it stranded me. Had to get the trailer and bring it home. Did some trouble shooting and found the float needle was stuck and the bowl ran dry. I need to get a filter. I cleaned the carb up again and im going to try and take it out tomorrow for a top speed run. I had it up to 50mph but at full throttle it just starts slowing down. Like its not getting enough fuel and sucking the bowl dry.

Front forks need oil. Seals have been ordered.

Rear shocks are springy. Has anybody rebuilt these old shocks or are they one and done?


I also have oil leaking from the rubber seal where the stator wires come out of the case.

[grcamna2]

Welcome back Flying J,
That's a decent blue color Super 90  .
The stator wires rubber case seal has probably shrunk where it seals into the case;get some Hondabond case sealer then remove the stator wire rubber seal,clean it all up around there and apply Plenty of Hondabond in and around it and let it fully cure for 3 days in a warm environment.
 The rear sprocket size looks larger than stock which may be topping the engine out for the street;they should pull to almost 70mph with you prone.

[Flying J]

Good eye. You may be right. I did a quick tooth count and got 25 teath around half of the sprocket which should be close to 50. Stock is 45 according to be the internet's. That would explain why I feel like it's so slow off the line and that I have to give it a push with my feet. I'll get some Honda bond and seal him up in in the best future.
 
70mph prone? I'm not racing the salt flats. I doubt highway patrol is going to be ok with me looking like Roland Free just trying to keep up with traffic.   

[grcamna2]

Good eye. You may be right. I did a quick tooth count and got 25 teath around half of the sprocket which should be close to 50. Stock is 45 according to be the internet's. That would explain why I feel like it's so slow off the line and that I have to give it a push with my feet. I'll get some Honda bond and seal him up in in the best future.
 
70mph prone? I'm not racing the salt flats. I doubt highway patrol is going to be ok with me looking like Roland Free just trying to keep up with traffic.   

Lol    By prone,I actually meant 'tucked' with your back flattened toward the tank & feet still On the pegs when you're above 60mph    How many times did that fellow Roland Free ride that way? is he still alive ? 

I usually go with stock gearing front and rear;that little bike likes to rev and it won't hurt it at all;you might do a warm engine compression test..

[Stev-o]

  I doubt highway patrol is going to be ok with me looking like Roland Free just trying to keep up with traffic.   

But you are Flying J, right?!   

I like the S90's, looked for one for my daughter but ended up with an S65 with a
big bore"... ha

[grcamna2]

  I doubt highway patrol is going to be ok with me looking like Roland Free just trying to keep up with traffic.   

But you are Flying J, right?!   

I like the S90's, looked for one for my daughter but ended up with an S65 with a
big bore"... ha

Stev-o did your daughter ride that S65 ?
The bike looked a lot like a S90.

[Flying J]

Did a proper count of the teeth and it's stock. 45 teeth. But I am missing the chain cover if anybody has one laying around. The nice thing about these bikes is most of the parts are still available from Asia. The bad thing is they are not cheap. I would like to do a full restoration in the future when my son is old enough to help, and appreciate it. He's 6 right now and loves motorcycles.

The rear wheel has done play rotationally in the cush rubber so I have a new set to put in.

Let's see a picture of that  s65

[Stev-o]

It's actually an SS65, they were not imported into the U.S.
We think the seller imported it from Asia when he immigrated [he barely spoke English]. 
I call it a "Big Bore" bike as someone fitted a 110cc cylinder kit on it, it runs great! 
My daughter is short so it is the perfect bike for her to learn to ride...one of these days.
She is now more interested in bicycles as she is a tri-athlete [swim-bike-run]

[grcamna2]

It's actually an SS65, they were not imported into the U.S.
We think the seller imported it from Asia when he immigrated [he barely spoke English]. 
I call it a "Big Bore" bike as someone fitted a 110cc cylinder kit on it, it runs great! 
My daughter is short so it is the perfect bike for her to learn to ride...one of these days.
She is now more interested in bicycles as she is a tri-athlete [swim-bike-run]

That's an SS65 ?  Very nice 

[Flying J]

Could not get the bike to go over to 50mph. It will only maintain 45 -47 mph. I did a compression test and it got me 130 psi. I guess that's just how fast this little guy is going to go.

[grcamna2]

Could your exhaust be clogged ?  I wonder if that Big front tire is messing with your speedometer accuracy ?

I guess 130psi is acceptable for a bike you're going to 'flip' but not optimum;I'd consider pulling the top-end and inspect that 1 cylinder. A valve grind,check the guides and piston/rings check,possibly replace the cam chain.

[RAFster122s]

Gearing and how tucked down to the tank as well as your weight will determine the top speed possible. 50-55mph is generally the max. They were built for small riders and only have about 8hp.
If you had a spare set for springs for the points weight you could delay the transition to full advance to change the acceleration a tad bit it won't give you any more top end. The trick or clipping a coil off and reforming the ends to delay the advance helps some older bikes especially with fuels today being less potent and slower burning.

[Flying J]

I lived the look of this bike but it was way too slow to ride anywhere in the city so I sold it. Looking at getting another cl100 to replace it.

[grcamna2]

I lived the look of this bike but it was way too slow to ride anywhere in the city so I sold it. Looking at getting another cl100 to replace it.

I enjoy my 1981' CB125S w/ the 82' XL185S engine 'mix'(the 82' XL125S cases are the same as the XL185S dimensions,plus 6 spd. strong trans., XL185 crank & XR200 top-end)as it does well with keeping up with the speed of traffic everywhere;I have it geared to cruise @ 70+mph,tops-out at almost 90 w/ a DSS repro XL185S camshaft,1978' CB125S #PD66 'atomizer plate' style carb. and headpipe & CB350 twin muffler.
The bike gives me a regular 80mpg when I mix 3) qts. of 91 oct. ethanol-free(Nevada pump)gasoline per 2.4gal. tank and fill the rest w/ 87 oct. Ca. gas. I don't get any pre-ignition(even w/ straight Ca. 87)now that I'm running the 83' ATC200x flat-top STD 65mm piston.
The 200lbs. & 18+H.P. encourages me to tuck-down when I get it over 60;the 1/4 fairing sure helps with the wind blasts.
I use it as basic daily transportation and it's reliable.
The engine # is on my registration as an 82' XL125S..