TW200 Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
188 Posts
Discussion Starter #1
The strangest thing happened the other day. I was sitting on the couch with my fiancee playing with our pup and she leaned over to me and said "So, I've been thinking about a bike and maybe I would like to go ride on some trails." I was shocked, but excited. She really likes the CT90s and Trail 90s, mostly because they are small, light, and auto clutch. So I hop on good 'ol Craigslist and, hey, a Trail 90 in my area with no dents! And no running engine... This is fine, I love engine swaps. The guy wants a little much for it ($400), but I figure it's worth having one that is REALLY straight and just needs an engine. When I finally found this one, I show it to her only to have her come back with, "Yeah, that will be a nice one to restore! How big of an engine can I put on it?" At this point, I'm sure someone has kidnapped my fiancee and replaced her with a female-version of myself (albiet better looking). So, long story short, I'm really excited to start restoring this bike with my fiancee, I really think we will grow even closer. And, just so you don't think I'm trying to kill her, I talked her in to only a 125cc since the 110ccs aren't really around anymore. She did ask about the 140cc+ though lol Here's a pic of the beaut.

00A0A_k9AxGQRvkcY_600x450.jpg
 

·
Registered
Joined
·
2,431 Posts
Ya done good, riding with her will be a blast.
 

·
Registered
Joined
·
603 Posts
I hate your guts!! :mad:

JK of course. Congradulations. I think you've got a keeper:)
 

·
Registered
Joined
·
188 Posts
Discussion Starter #5
Thank you all! After asking around, it looks like I am more inclined to fix up the 90cc. Since I'm betting the cylinder was trashed when the PO tried to install a new piston, I think I will just order a big bore piston, run the cylinder out, and throw on a 110 carb. It's funny how much info there is on these little bikes!! Odd balls.
 

·
Registered
Joined
·
503 Posts
kdick91, my riding career started with a ct-90. Mine was a basket case 'literally'. Took about 2hrs digging thru the guys barn for the parts, and three trips to the truck.

after many attempts to find Honda parts, and a lot of money to buy them, I finally took the plunge and went with a Chinese clone power plant. I also spent a lot of money learning the ins&outs of these motors.

couple of suggestions for you; if your gonna get a clutch motor, ensure the clutch arm is on top of the case, NOT THE FRONT. A 140cc motor on a ct-90 performs about the same as a tw-200, (the whole power to weight ratio thing) with proper gearing ofcourse. If your going auto-clutch, the 110cc is your best bet. Buy the Piranha brand motor. They cost more, but are worth the extra $. Far more dependable, and better electronics.

disclaimer time: going to an after market motor will open an electrical 'can of worms'. I ended up totally re-wiring the bike and making a new schematic wiring diagram. There's a couple floating around at various sites online that show how to cut-in and maintain as much of the original wiring as possible, but I found it less confusing to gut it and start from scratch (at least for me).
you will have to clearance the Honda frame as well as the motor mounts on the case. Its not that difficult the second time. You will have to rework the footpegs.

I got my motor from Akron Wholesale Cycle. Real nice folks. Google search should bring them up for ya.

PROS: brand new motor with zero miles, better electronics (cdi means no points to maintain), better charging for brighter lights, more power, 90+ mpg

CONS: Chinese. If and when it blows up, you get another one for less than repair costs.

I've built two of these and taken them from Ohio, and crossed the Mississippi river. Twice.

let me know if there's anything I can answer. TIM
 

·
Registered
Joined
·
188 Posts
Discussion Starter #7
Well, I really tore in to it over the weekend. I cleaned the carb... Well, it PURGES gasoline now. But clean gas :D I adjusted the points, the valves, and go fresh oil in it. Retimed the camshaft (was like 190deg out) and checked compression. After 3 GOOD kicks, I'm reading about 100psi :( So it needs rebuilding SOMEWHERE. All attempts are firing were useless. It kept catching the carb on fire. Then I was consistently getting backfires through the exhaust. Progress! Yay! So, after much research, I got a chinese carb and a 110 boot to fit it all up together. It costs less than rebuilding the factory carb and many people seem to rebuild these things 3-4 times to no avail. So, I will keep the factory carb, just in a box :p If it doesn't fire after that, I will start with rebuilding the head. I feel like sitting has damaged the valve seats (only 600 miles on it). At that time I can inspect the piston and bore. I feel like I will end up punching it out though. I am worried that I have an ignition problem though with timing... I won't dive in to it a bunch now, I will wait till I can rule out fuel/air delivery. But it sometimes seems very tricky to get the firing to happen right on the 'F'. I set it in time (static), rotate a bunch (trying to start), then when I open it back up, it's WAY out. Like more than the points plate can adjust. Then I will spin it 360 deg, then I can get the timing adjusted correctly. Bleh, this is the second time I've dealt with points (first on a '75 CB550) and I have fought with this one way more, surprisingly. I am dead set on maintaining the transfer case and factory wiring where I can, so the chinese engine will be me giving up. Not that there is anything wrong with them, but the cool factor is too much for me.
 

·
Registered
Joined
·
188 Posts
Discussion Starter #8
Fun update. I gave up :p I put a PZ22 carb on it and it still only back fires when feeding it ether. That's about all it's got. After pricing out all new Honda parts to rebuild... I can not justify dumping that much in to a 90 and still having it be as old as it is. So I found a Lifan 125 auto clutch, complete set (wiring, kicker, coil, carb, the works) for like $300. I couldn't pass it up. I pulled the engine in all of about 30 mins and gave the bike a GOOD cleaning with the engine out. Should be puttering around once I get the exhaust squared away!!
 

·
Registered
Joined
·
503 Posts
told ya. Let me know if you need advise with the retro-fit. TIM
 

·
Registered
Joined
·
188 Posts
Discussion Starter #10
told ya. Let me know if you need advise with the retro-fit. TIM
Yeah, actually I do have a few questions! I ordered the wiring conversion kit from DrATV. I'm embarassed actually at home much I ordered from him haha! Initially I was like, 'Okay I build all this, got the wiring diagram, mounts, easy, blah blah blah.' Then I got lazy and was really excited to have all my credit card paid off... So I got the wiring kit, mount kit, and a 6 volt regulator so I can keep everything 6V. I will convert to 12V once I get a couple of the electronics to fail. Right now, I just don't wanna order all new bulbs, new battery, new rectifier, etc. I found a CT110 intake boot really cheap, so all the intake side stuff is pretty much 100% taken care of, wiring done (until I find a problem), and mounting done... I just can't get a straight answer on the exhaust. Some people say the CT90 muffler works fine on the Lifan 125, DrATV says you need an aftermarket muffler or CT110 muffler. I LOVE the way exhaust looks, so what I was going to do is get the cheapest 'Lifan exhaust' off eBay, cut the flange off and weld it up to my CT90 muffler. But that is another $50 that, if I don't have to spend, I would like to save. So what has been your experience with that? Also, I keep seeing the shift pattern described a 4 up with a little diagram that has a circle and an arrow pointing to each gear. (So, a circle with 1->2->3->4 and 4 has an arrow pointing back at one) Does this imply that, in 4th, you can shift up again to go in to first?! If so, I am worried this engine may die a bit prematurely lol. Lastly, when riding this engine, is the best way to shift just throttle up through the gear, let off, shift, throttle up again? Or can you just hit each gear without revving? How's downshifting work? Sorry this is my first experience with a semi-auto! Thanks!

Kyle
 

·
Registered
Joined
·
503 Posts
not sure which brand motor you bought, but yes, some of them can be cycled from 4th to 1st. It sounds as though yours is, bad for you. If it is, and it were me, I'd try to return it or sell on e-bay/craigslist. Not a good situation to have even with an experienced rider.
as far as the fitment of the engine and accessories (carb and exhaust), so long as you can cut, grind, and weld, your 'golden'. I modded an original CT-90 exhaust to a Lifan. Hard part is getting a head pipe that bolts correctly to the new motor. I was lucky and had been given a pitbike that I used for a bunch of parts. Then bolt the stock muffler in place (cut the old head pipe off first), fill in the middle with pipe you have laying around. At least that was my method. I used a piece of galvanized fence post and the wrapped it with exhaust wrap to hide it.
the intake and carb that comes with the motor may work for you. I elongated the holes on the intake to allow it to index about 15degs, and this gave me enough clearance from the down tube on the frame. Hard part on the carb is shortening the throttle cable. Then rather than trying to fit the stock air filter, I put on a uni-filter and used the stock airbox as my toolkit. So long as your not puddle jumping, there's no need to use the stock air intake system.
shifting an auto-clutch is as you described. When you get quick at it, you can shift without letting off the throttle.
your in for a lot of work, as I'm sure your beginning to realize, but don't over think it. Just ensure it's safe
 

·
Registered
Joined
·
188 Posts
Discussion Starter #12
Well, I have great news!!!! 729653264_o.jpg No 4th to 1st! Woo!!! So now I only have exhaust to worry about! Would you happen to know the flange size needed? It looks like a few shops just use a piece of pipe and weld a flange on to it. I can make my own flange easy enough, I just have no idea what kind of 'interface' between the exhaust port and pipe is gonna be like. Engine should be here this week (luckily, my fiancee accidentally hit two-day teehee). Should I transfer the old shift lever or use the new?
 

·
Registered
Joined
·
503 Posts
no clue as far as exhaust flange. Too many different setups. Your'll just have to try it once it gets there. The best case is having to grind some off the stock head pipe. You will the probably find that the muffler has been shifted forward and will now longer mount. Cut it, add a piece to the middle, and re-weld.
stock shifter would be my choice, but that's if it bolts up.
 
1 - 13 of 13 Posts
Top