Hi All, I have a new (to me) 1970 CT90. It's got the 4 speed which I am told (and believe) has a 1-up, 3-down shift pattern. This is all well and good, except, if this is correct, than I have a problem. Let me set the scene: - I shift up to 1st to get going and everything is perfectly fine. - I gain some speed and shift down to get to 2nd, except I have to click down twice, because clicking only once lands me in neutral. Even with practice and different methods this is how it goes. Ok, not a huge deal. - I gain some more speed and shift down again to get to 3rd. Perfectly fine. - I gain even more speed and shift down again to get to 4th. Nothing, no more gears. So, if this bike is in fact a 1-up 3-down 4 speed I have a significant problem. Either I am missing 4th gear, or I am missing 2nd gear. Anyone else have similar experiences or have any ideas? Besides this the bike runs great. It smokes a little, but no crunching or anything in the gearbox. Honestly, if I hadn't been told it was a 4 speed and the speedometer didn't imply that it was, I would just assume it was a 3 speed and be happy with it. I'm going to have to look at the serial numbers to see if this is the original engine or if it's possibly from a different year. Also - do the 4 speeds also have the hi/lo option? How do I fiddle with that? Thanks!!
Hi Nick Neutral is all the way up and you step down ( with toe ) to shift to 1st then the same until 4th . So it's neutral all the way up and 4 down. To put it in low-range put it on the centerstand in neutral and spin the tire as you move the lever. It changes to a smaller sprocket in the front like shifting a bicycle. Darren
I agree. On that year, neutral is at the top. All gears are down. I have a '77 CT90. It is the opposite. Neutral is at the bottom on mine and all gears are up. No CTs that I know of ever had neutral between first and second like most other bikes.
I don't want to call you guys liars because I'm sure you know more about these than me, but I've ridden it about a dozen times and I really don't think neutral is on top. Any other years my motor could be from where this would make sense?
If the number on your engine is plus or minus 30 from your vin # then you have the original engine, they are never an exact match. As others have said your Trans is neutral at the top and then 4 down. If you are hitting neutral any where in between gears it could be something as simple as your technique. You have to give it a very deliberate sharp shift, almost a quick stomp. If you outside and hold the shifter down you will be in neutral, it actually shifts when you release the sifter, out rather that's how the clutch is engaged. Other things that can affect the shifting are oil level and quality. without detailing this into an oil thread these bikes do really well on shell rotella synthetic oil. If its still hitting neutral between gears it could still be something simple like a loose shift drum stopper plate our a broken shift drum supper. At this point head over to the ct90 forum on yucu. They are very helpful and pretty friendly.
Every time you shift the toe lever down you are going into a nutural briefly while it shifts. Like a clutch on a standard transmission. You are finding a faults nutural between gears. It is likely that your clutch plate needs needs adjustment. Your shifting pattern is n-1-2-3-4 from front lever up to down. You have a wet clutch that is lubed by the engine oil. Put the bike on the center stand. tap the rear shifting lever down three times you should be feel nutural by free wheeling the back drive wheel without the engine running.
Finally checked the engine number and it starts with CM91 I guess it's out of a Cub ? Time to research those...
Well either the old engine is missing a pin in the shifter drum for fourth, or it's very similar to the C-102 OHV hondas with their 1-Up 2-down, three speed transmission. My 50 cc Cub's original engine is exactly like your description, and of course maybe someone rebuilt this old engine from leftovers of other Cub engines?
Your shifter should be a long affair with a pad for your toe and one for your heel. There is no "up". You push down with your heel over and over until you reach neutral. You can't over do it. You should have a neutral indicator light at that point. Push down once with your toe and that's first. Push down again, that's second, toe down again, third, once more for 4th. Heel down now will get you back to third. And so forth. With the bike in neutral, running or not, using a 9/16 or 14mm wrench, turn the head of the low/hi bolt until it stops, about 30 degrees. In lo, you won't go very fast, but you can climb trees.
Yeah I've only got the toe shifter, not a heel/toe shifter. I have a neutral light, but I've only seen it come on once, so I'm not sure how reliable it is. I assume I'm in "hi" right now (if I have that option) because my top speed is around 40 in top gear (who knows what gear that is though).
If you're doin' 40, you're in 4th and HI. You should have a small pointy indicator down near the hi/lo nut and the case should have a casting mark telling you where you are. The 1980 model was the only version without the hi/lo option Try and locate a heel/toe shifter. Shifting a CT90 is not a delicate maneuver. You are disengaging the clutch and shifting gears and unless you are deliberate, you find a lot of neutrals. If this thing has sat for a while, the neutral light may become more reliable, but not if your battery is weak or not there.
I know this thread is old but in case someone is looking for an answer in the future: The CM91 motor originally had a three speed (you aren't missing any--that's all there is) with a heel and toe shifter. The shift pattern is 1st: (Heel); N: (toe); 2nd: (toe); 3rd: (toe) or with a single shifter like you have, 1st is up, 2nd is two taps down, 3rd is down. It requires two distinct taps down to shift between 1st and 2nd because it doesn't automatically skip past neutral like most bikes do . Also, there is no high/low range on this bike. This is the bike I learned on and it's real herky jerky till you get the hang of it but I'm sure you got it by now.
