Honda Trail 90 Rebuild

I've had this CT90 for about a year now. I drove from Columbus down to Charlotte, NC and exchanged a couple RX-7 transmission for it. Loaded it up and headed back home through a snow storm.

I got it running with some fresh gas and a new battery. I rode it around for a little bit but never really put many road miles on it. It did not come with a title so I registered it in Vermont since they don't issue titles for motorcycles under 300cc and older than 20 or so years.

Last May I loaded it onto a cargo carrier on my Montero for a road trip out west. I was hoping to ride it in the mountains around Ouray, CO. During one of the early stops in Texas I was riding along some back roads and it started losing power. Eventually it died and would not start. I found out that it had no compression and strapped it back onto the carrier. It remained there as dead weight through the rest of the trip so I had to rent an ATV in CO.

After that it just sat in the basement and I forgot about it for awhile. The Vermont registration expired at the end of March so last week I decided I had to transfer that to an Ohio title while I had the chance. After getting the title I felt motivated to get it going again. I pulled the engine this week and started looking over the wiring. It was near a fire at some point in the past so the stock wiring harness is in poor shape.

The plan is to clean everything up and swap in a Lifan 140cc engine.

Here's some reading for you on these bikes(and swap)from ADVrider:

http://advrider.com/index.php?threads/new-face-for-an-old-friend-honda-ct90.1137855/

http://advrider.com/index.php?threads/very-successful-lifan-125cc-swap-into-1981-honda-c70-passport.1111996/

http://advrider.com/index.php?threads/the-lifan-engine-thread.662516/

Hey, YoooRay. My old stomping grounds Durango are just over the pass. Used to ride Ophir pass, and all around there. Beautiful country. Sweet bike, too. Is that the type with all the gears?

Have you checked valve lash? It's very common for hondas of this design to close up the lash so much they don't run well

I'd be intrested in the motor if you're going to part with it.

In reply to wheelsmithy:

Durango was beautiful, I wished I spend more time there and visited SKA brewing but I just drove through. I actually like Silverton more than Ouray. I camped near Silverton and rented the ATV there. I will definitely go back when all the passes aren't snowed over.

It does have the dual range trans.

In reply to 44Dwarf:

I have not checked valve lash. It went from running to not so quickly I figured it must be something more serious. I will check it out of curiosity but I don't think this engine is going back in. I would like more power for my commute on some 45 mph roads and 12v would be nice.

I'll let you know when I am ready to part with the old engine.

For stock replacement parts, get to know dratv.com

Great bikes! Here's mine. Dad bought it new in '74.

[URL=http://s7.photobucket.com/user/smokindav/media/A099CCC6-64C1-4C3D-AF7E-A1D6CCEC9D69-3547-000001FEFBA17937.jpg.html][/URL]

I could be mistaken, but don't the LiFan pit bike clone engines bolt in? They have 160cc lumps, you know.

In reply to Appleseed:

They do pretty much bolt in. A few modifications are needed for the CT90 chassis, they are more bolt in for the smaller CT70s. I am trying to hit a compromise between adequate power and a price that fits my budget, the 140cc seems to be the best option.

Sooo...it's been a while. I bought a Lifan 125 engine for it a few years back and halfway mounted it, then it sat for a long time. A few months ago I decided to get back to it and ordered parts and then got distracted. Last weekend I finally got it out of the basement and put it together enough today to start it and get a short test ride in. 

I bought a cheap pit bike exhaust on ebay but it isn't going to work out how I would like. I put just the pipe on it for the test ride but I am going to adapt the stock exhaust to the lifan engine. 

The fuel valve is from a CT70 since the CT90 has it integrated in the carb stock. I still need to make a bracket to mount it, it is just ziptied to the skidplate downtube for now. 

The boot for the stock aircleaner is too small for the Lifan carb and about an inch short of mating up. I found a radiator hose on a rx7 water pump housing in the back of the garage and used it to bridge the gap. 

Next up is making the stock CT90 exhaust work and getting a 17 tooth front sprocket. The engine came with a 13 or 14 tooth (I forget which) but with that gearing it probably won't get over 35-40mph. After some more test riding (and finding where the battery box went) I will build a wiring harness to get the lights working and put a plate on it. 

45 mph, downhill, with a tailwind and a few bottle rockets lit on the rear luggage rack is normal.