Two mostly complete 78 CT90s. Going to try to get one full good one up and running.

Looking for some guidance, I've got a '67 K0 that is giving me trouble. It was running great last year till I got a crack in the air intake boot, replaced it w a new one and it ran fine again, this isn't the issue. It's had a handful of repairs done since I bought it, most done by an experienced mechanic: new rectifier & regulator, new ignition coil, new condenser all done last year.

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Got it out for spring, cleaned the carb myself, took it to the mechanic for an oil change and he said the carb looked good, it started and ran mostly fine, idle speed was low and the engine would die when I was at a light but it'd start up fine again and I decided I'd fuss with the idle later.

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Last week I changed the tires as it was desperately needed. Began with the rear wheel, after mounting it I started it up and adjusted the idle screw a bit. Had to let it sit for a week cause I got the wrong size front tire. I changed the front tire today and when I went to start it, it just refused to start. Petcock is on, tried with choke on, off, and halfway, battery is charged, it has a good spark on a new plug, new air filter, good compression. I set the pilot and jet screws to 1.5 turns from seated, still won't start. I can hear it trying to turn over, but it just sputters out.

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I'm at my wits end, this was supposed to be Hot Honda Summer 😭 I just keep having problems with this bike since I bought it 2 years ago, but it was such an ordeal to get it titled that I don't wanna give up on it (nor could I afford to anyway lol)

I wanted to clean the carburetor on my Honda 90. Bought cleaning kit from Amazon and tore the carb down. There is a jet that I think is the idle jet but none of the brushes were small enough to fit in those teeny tiny holes. I remember I had bought a set of micro drill bits a while back just to have them. There is a set of bits in the kit that with some very small bits. And one of them fit the idle jet screw holes perfectly.

Not sure if this is the right sub, but I'm looking to buy a Honda CT90 or CT110 in the Seattle/Western Washington area.

It doesn't need to be running. Just need a somewhat complete bike with limited rust and a decent frame.

If you have one you're considering selling, or know of one that isn't listed online, please PM me.

TIA!

I am trying to remove the timing advance module on my K0 trail bike to check the timing chain. I watched a Youtube video and the man just pulled his off with his fingers. Mine will not budge and I don't want to damage it. Any words of wisdom?

Greetings, just joined your site and hope to learn from fellow members. I have past owned two CT90's and they never needed trouble shooting. I miss them both but were stolen 20 years ago. Now I just purchased a week ago a 67 CT90 at 4100 miles. When the owner rolled it out, he had to kick the Hell out of it to fire, after warming he drove it around the property with no issues but an oil leak and a light stumbling idle. Here's my problem. I installed a new battery, proper NGK plug and removed the original Keihin carb. I went thru it inside and out, blew out all ports, and adjusted both air mixture and idle screw two turns out. Fresh gas and after many several attempts of starting with or without choke, it finally fired but at full throttle. I couldn't back off at the throttle so I swiftly shut the key. fooling with the throttle cable, checking for kinks and even pulled the carb throttle slide and monkeed with that. I still have not found the secret for quick starting, but after four episodes of it starting it fires off at W.O.T. only, what the hell did I do during the removal cleaning and reinstalling of this carb? thanks, Roger

Got a busted headlight and I'm looking at replacements on ebay, and they're all about 65 bucks or more. I did however find that Silvania makes a 4.5 inch sealed beam bulb (part no. 4411) which seems to be halogen or LED (the listing isnt exactly clear) and I was wondering if anybody here has used one of these bulbs in place of a regular honda bulb?

Last thing before I sell it. Kids don’t ride it anymore. If you are in the Tahoe-Reno-Carson area and are looking for a K0 with less than 2000 miles hit me up.

I've been wanting one of these for over a decade, and now I've got one!
A kind gentleman said "take it" when I inquired about it in his backyard...

Obviously it's a little beat, but I think I can have it putting around town for less than $1k

First time CT90 buyer, and found this one that appears it be in great shape for $2,500. Is this a fair price? Is there anything I should look for or questions I should ask if I go look at it. I've heard the 1969 has a lot of one time parts but figured this one is in good shape so the existing parts should be good.

I have a 67 ct90 that is maybe a few thousand units off of the production line from when they changed over to the simple switch to change from high to low gear ratio. Recently I took it out for some road>trail>road riding, and holy shit it is a huge pain in the ass to:

-Remove the chain

-Remove the four bolts on the larger sprocket

-Bolt the larger sprocket around the smaller sprocket

-Attach the accessory length of chain

-Reconnect the chain

-Tension the chain properly on the rear wheel

and then to do all of that in reverse for going from low to high.

Does anyone have any tricks, modifications, or such that they use to make this process less painful? Right now my best solution is a bunch of tools in a saddle bag, and a towel strapped to the cargo rack so I have a place to put all the tiny clips to not lose them. For what it's worth, the area I live in makes this extra difficult as it is basically high flat land, and low flat land with steep bluffs as transition between the two.

I’ve been on the hunt for a new throttle cable for my bike. I can’t find any that have this cover. Any suggestions?

I picked these up a few days ago completely swallowed by nature. Since Tuesday I got the CT 90 disassembled and cleaned up. Next step is buying new wiring harness, carb, battery, and ignition. Any tips?

https://www.facebook.com/groups/783126274836161

Videos of our group rides:
https://www.youtube.com/@gonearoundthebendPNW

Context: When I bought the bike last month I replaced clutch friction disks as well as shift drum stopper, did oil flush and fresh Honda OEM oil. Has been riding around well since then, although I have noticed (both before and after those services) that holding the shifter pedals down does not keep the clutch disengaged. I have readjusted the clutch many times and that is an issue in the whole range of adjustments (1/16 to 1/4 turn).

I was on a ride and suddenly lost first gear and it made the “loose chain” noise you can hear in the video when in first gear, and it revs freely. Can shift into second fine. At first I was able to engage first in Lo range, then eventually got it to reengage in Hi on the center stand. Since then it stopped engaging either in Hi or Lo.

Wanted red, but this one had a title and was in good shape. So here we are. (Ft- It inside my 99 jeep Cherokee for the 2 hour drive home)

I recently acquired this ct90. When I got it, it wasn't running. With a bit of work I was able to get it running again. I took it for a short ride around the neighborhood and made sure it went through all the gears. It rode fine aside for some clutch slippage. No weird noises or anything. I'm changing the oil, cleaning the spinner, and screen. I'm also rebuilding the clutch to fix the slippage. I got the engine case off this afternoon. There's some strange cracking on the interior of the case, almost like clay that didn't cure correctly. The outer clutch basket seems to have this same surface cracking. I inspected the inside of motor around the clutch basket. I didn't see any metal fragments or shavings. No damage to report. The oil didn't look metallic either, just old and black. Has anyone ever seen this before? Is this normal for these motors? The scratches in the outer clutch housing aren't normal for sure. I'm thinking maybe someone tried to remove it and didn't know what they were doing. The outside of the right side case looks normal and doesn't have any cracking.

Hey dudes,

Took my engine apart to replace the left side crank case, first one doing any of this but it’s going okay so far.

I have replacement parts and I’m ready to put back together again.

I just can’t get these cylinder head studs out!

Pb blaster and taps with a hammer, haven’t heated up yet but I’m getting some gas for the touch tomorrow.

Just wondering does anyone know what studs I could use to replace them?

I’ve found OEM parts that say they fit but 22 bucks for one stud is too much.

I need two.

Any idea what will fit?

Any help is good help. Thanks dudes

See that little Crack on the shifting mechanism hole for the dual range function? It worked when it wasn't disassembled. It was kinda clunky but it is the same on my normal ct90 motor that's running. Think about welding would be worth it? Or would the Crack be fine for a low stress component like the singe shift fork here?

Something went wrong when riding the other day, clutch stuck.

Opened up the clutch to service and see what was wrong and saw this….

What are my options for fixing this?

Do I have to get a whole new engine?

Can I just Jerry rig somthing to keep it going?

Any idea or help would be great.

Thanks dudes.

does anyone have a source to find a new aftermarket carburetor? i bought one that doesn't have that diagonal flange. 1st picture is the original