Awsome work, I got four motors I’m planning to get into this winter so, I’ll be plenty occupied, your tutorial gave me a nice heads up, those Allen key engine bolts looked slick on the side of the motor, Thanks
@@bottomupbuilds the mating face on my clutch cover has a couple of minor screwdriver gouges closer to the outside edge. Should I use a gasket sealer here. It didn’t appear that you used any gasket sealer , only the pre-cut gasket. I ordered a full set of Athena gaskets from DrAtv. Thanks again for your great post.
@@dennisthaemert8483 Personal preference I think. Where the clutch cover is easily accessible and easy to remove, you could run it without sealer and just see if it leaks. If it does leak just lean the bike over a little on the other side and you can remove the cover without having to drain the oil. Then you could clean it and try again with sealer. If the mating surface was one where it was difficult to test/remove then I would just seal it from the start.
@@bottomupbuilds I was researching gasket sealers/makers. Fairly daunting category. From reading way too much on the topic, it appears to me that a RTV product is the best bet. Seems like they don’t just make a “sealer” to use with pre-cut gaskets. Most offerings tend to be gasket “makers”. I appreciate you sharing your expertise.
Thanks for sharing this!! While there are some nice videos of breaking down or rebuilding these older Honda CT90 engines yours goes the length of showing the breakdown with rebuild in one video. I am in the process of restoring a K4 and find this invaluable.
I do recall getting an old 1965 ct90 from the neighbor, and he also had an old 70 passport that he also threw in, but it was in worse shape than the ct90. I recall my dad and I replaced the gears, but don't recall we took the head off, though. Maybe we did, but that was like 30yrs or 35yrs ago. Luckily the neighbor had the servicing manual which helped allot. I was able to ride it, but since I never had an endorsement, never took it out on the main road. Just rode it around an old golf course nearby. Ran it w/o the battery, and it worked fine, but was a little under powered.
@@idahoduckhunter The piston is stuck, and it has fuel corrosion all throughout. The machine shop is delayed. I tried acetone, and trans fluid but it is really stuck.
A few notes to bring out: You used a non-OEM gasket set. The odds of leakage of non--OEM gaskets are at least 50-50. I can tell because the clutch gasket is sticking out of the case. Honda gaskets fit exactly. When you re-install the AC generator you should apply sealant to the wire holder rubber seal. It only seals when it's new. The screws on the clutch cover are #3 screw size. Using a #2 screwdriver wears out the screw prematurely. When putting the 2 engine cases together.... place the case dowel pins INTO the engine case that is on the down side. By that I mean the case that you put the gasket on. By having a dowel pin in the base case and one in the dropping case you take a chance of mis aligning the gasket and splitting the gasket with the dowel pin in the dropping case. The engine screen(under the clutch cover) wasn't removed and cleaned. It is the 'oil filter' and needs to be at least inspected. The cam chain tensioner wasn't inspected. The plunger and spring should be removed and checked for smooth function. You did a very good job explaining cam chain timing and sprocket installation. Good Work. Your cleanliness was very good. Good Job
Just wanted to add here that the gaskets are great, I have 0 leaking, BUT Rayworx was correct in noting that the rubber part where the wires exit the top of the engine should have a sealer of some sort. I did not use any and while riding on city roads and flat surfaces I experienced no leaking, once I hit the trails and bumps there was some minor leaking there. Also, I had cleaned the oil screen prior to this video, when I put the engine together for the first time. You will want to clean that when doing your own!
I always wonder how High and Low gears sub transmission works on these CT90. I am from Sri Lanka and we only got the JDM version of this bike which is MD90 that has no High and Low sub transmission unit. I really enjoyed watching this and learned how that sub transmission works. Your workshop is really nice and your craftsmanship is so satisfying 👍
Top gear in low range is very close to 2nd gear in high range. So you can imagine how much easier it would climb a steep incline in low range first gear. Just much slower, but not burning out the clutch.
I inherited a 69 trail90 from my uncle when he passed away a couple years ago and it just sits in the garage because the trans sounds like a box of rocks when you roll it around. after watching this i might split it open to see if it can be saved.
Yr button head cap screws , i think.... will disappoint you as they have a shallow aperture for the hex drive socket or key and less material around the outside and often strip out easily . For this reason i no longer use themon any of my bikes or other bike jobs.... i try to only use socket head cap screws or orig' honda jis screws. Great video thanks 👍
@@bunnyman6321 Pobably not, that Stewart video was just to learn a little video editing for myself. I don't have much time to make videos, if I do from here on out it will likely be more CT90 or VW build videos.
Just came across your video today, I am getting ready to assemble the same motor. What a great video!!!!!!. . I will be referring to this video and watching it a couple times to refresh the brain. Do you have a list of sizes and amounts of the stainless cover screws that you swapped out??, That would save me some time . Was wondering why you didn't use them on the points cover where you will getting into more often. Such a great Video, Also where did you shop for most of your parts ?.
Thanks! I don't have a list of the screw sizes anymore, but I know I do indicate what size goes where in the video, hopefully that helps. I didn't use them on the points cover because I think those screws have a tapered head that fits into the cover... I think. Most everything I bought from dratv.com he has about everything you'd ever need!
Great Vid!!! How hard would it be to swap housings and retro-fit the dual range sub-transmission to some of the CT-110 bikes that deleted that option? (Like many Australian Postie bike versions)
I'm not sure, but I don't think the internals of the motor would match up and allow you to do this. I've never worked on any without the sub-transmission though so I can't confirm 100%
Not my sphere of expertise but that engine does not resemble engines sold in the UK in the 1970's. Not that the ct was imported here well at least not to my knowledge. cam shaft mounted points came in much later and the weird carbuncle by the drive sprocket was that some high low system? also not seen here. The numbers on the cases would indicate a much later date for the motor was it a replacement engine?
I'm unfamiliar with anything related to these bikes and the UK, but from what am to understand for the six digit engine & frame numbers, the first digit after the hyphen is usually the version identifier... 1 = 1966-1968, K0 2 = 1969, K1 3 = 1970, K2 4 = 1971, K3 Then the remaining 5 numbers are production numbers. I think in 1972 they went to a 7 digit code. I have no insight on those codes though.
Good video , it is going to help me out a lot , was it necessary to remove the stator and flywheel bolt in order to get the cases apart and expose the transmission ?
No, you do not need to. I can't remember why I did, probably just to show how you can get it off and re-install it if you did need to pull the flywheel.
I just watched it to see how to the differential works on this engine, in Europe the C50/90 cubs are much simpler, and they don't come up with a differential
Check out dratv.com he should have what you need. The kit I bought was from ebay and the rubber gaskets on the cylinder around the cam chain were garbage and it was missing the gasket for the sub transmission. I should have just got stuff from dratv the first time. As far as I know, they should be similar, but torque specs might be different on various items. buying a manual for $30 is money well spent.
The ct200 is very different. The cam shaft is in the bottom end and there are push rods to the rocker arms in the top end. The cylinder and head are completely different and the head is iron (heavy).
No, if the cover you took off was at the front of the motor and only contained the points, there should be no oil in there. There is a seal that should keep it out of that area. The end part of the cam shaft in that area, where the point spins around, should however have some distributor cam lubricant grease
Metric sockets and wrenches, screw drivers, should be all you need. You will also need a special socket to remove the clutch pack. In the video I use a tool that holds the clutch pack in place, but you can also put a penny in the gears to hold it if you don't want to find and buy a tool for that.
I believe it's mostly the same. There might be some differences in earlier or later years, but if the year is the same, I think everything is the same other than the cylinder/piston size.
I have a 1980 Honda ATC 110 3 wheeler and wonder if I can remove that Stator without removing that cover you removed with the high/low gear mine has that too. Would you know?
I don't think so, you can maybe undo the screws that hold the stator in, but I don't think you'll get it out without removing the side cover and to remove the side cover you'll need to remove the high/low gear cover as well
@@bottomupbuilds Darnit okay I was hoping not to have to go that much into it, I have the flywheel puller which is 16mm bolt to remove that and wanted fir a fast swap out of stator as I believe that is why I am getting no spark, it's going to be in the mail in a few days,
I didn't, unfortunately. I wanted to, because I did replace everything on the top end, but just didn't record it. If I ever do another I will definitely go over that part.
@@bottomupbuilds Thanks for reply. I am trying to put together a head for the '73 ST90 model right now but cannot seem to figure out the valve stem seals because schematics show 2 seals for the ST90 but only one seal for the CT90 and I believe they all used the same heads, cams, rockers etc?? The guides are still in the head but valves are out and just not sure how to proceed.
Thank you for the video very helpful. I have a 69’ CT90 with a kickstart mystery I can’t solve and wondering if you can help me identify. When I kick start the motor, something inside continues to spin and I have to wait for the rotation to stop until it catches again and I can position the kickstart for another attempt. Any thoughts ? Thank you again !
Maybe check your valve clearance. It could be they're out of adjustment and not allowing compression in the cylinder, which I believe is what will stop the motor from spinning for the most part. OR check your clutch adjustment...
have you taken it apart and put it back together, that you might have put it together wrong? Otherwise, mine does the same thing, I have to rock the bike back and forth a little sometimes to get the gear teeth to line up and slide in. I think its just a by product of the design being very simple.
I watched your video to rebuild the clutch in my 1970 K2. Just reassembling after top end rebuild and new clutch. Rear wheel will not turn with bike in neutral. I readjusted the new clutch per manual’s instructions. I did not touch the transmission when I put the new clutch in. I only rode the bike once or twice 8 years ago when I bought it and it seemed to shift fine as I recall. Any idea where I may have gone wrong. Thanks
Hmmm, I cannot think of any reason the wheel would not spin in neutral even if the clutch or top end was installed wrong. If you put the bike into a higher gear like 4th, can you push it around and have the tire spin? If so, the transmission must not be finding neutral like it should.
@@bottomupbuilds I split the cases and disassembled the transmission and I did not find anything that looked to be in poor condition or assembled incorrectly. The special bolt that secures the shift drum seemed like it could have been tighter but that was minor. I’ll put it back together when I get new gaskets and see if problem solved. Thanks again for your excellent video.
That is correct, facing up towards the top of the head. I guess in the video it looks more "left" than up, but it should be up towards the top of the head. Good catch! ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-nAHijBrGdl4.html
Based on the way you are viewing the motor at that mark, is it that black hole just above and to the right of the valve adjustment cap? If so, that is nothing. I'm 99% sure it just passes through to the other side, maybe to allow air passage
@@bottomupbuilds Thanks. I noticed after viewing your video, my bike had the same passage. I had never noticed it before viewing your video. Just wanted to insure everything was good. Thanks for your reply, now I know all is good.
Pls tell me that why honda dicontinued this high low gear system for their dirt bikes. i think it is not available for new CT 125 .Was it a failed system ? Thank you.
As far as I know, it goes off your VIN number. VIN's starting in 1 are K0, starting in 2 are K1, starting in 3 are K2, and starting in 4 are K3. After that I think the switched to regular VIN and year build classification.
Lots of different sizes, I tried to say what size went where on the video, but it might be faster to go to the parts section of a website like partzilla.com and you can find the size of all the bolts for the whole bike.
