Author Topic: Trail 70 rebuild. Opinions?  (Read 3783 times)

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Offline GroovieGhoulie

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Trail 70 rebuild. Opinions?
« on: March 01, 2006, 12:05:12 PM »
My dad said that if I take the time to rebuild one of the Trail 70s we have, I can have it.  Sweet.  We have 8 boxes of parts so I can rebuild 90% of it with stuff we have already.  All it'll cost me is time and elbow grease.

A few questions:

When I re-do it, should I stick to the factory paint scheme or do a custom one?  I saw a "military" styled CT70 on a website that looked really cool and would consider doing something similar.

The engine is not very good and needs to be replaced or totally reworked.  We have about 4 spare engines, the nicest being a factory 4-speed manual.  I know the manual versions were more scarce and desirable, but I read lots of articles that said that the 3-speed clutchless boxes were better for offroad/trail work as there is no need to be working a clutch all the time and you can better concentrate on rock-hopping.  Should I use the 4-speed motor or go through the 3-speed that's on the bike?  It will be used for trail riding.

Since the bike is arguably free, should I spring for one of those 120cc "big bore" engines with 8-12 hp?  Most are made in China, but I've found some good ones that are not Chinese.  Are they worth the $400 or so bucks?  How much faster does the bike get with one?

Is it possible to hook up an electronic tach to these engines?  The speedo has shift points on it, but I like a tach.

Thanks for any help.  It's not a SOHC4, but I LOVE these little bikes.

Offline bwaller

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Re: Trail 70 rebuild. Opinions?
« Reply #1 on: March 02, 2006, 07:51:55 PM »
Sounds like you've got a basket case project, go crazy. I'm not sure I'd sink 400 beans on a bigger bore though, the stocker will run till the cows come home!

You mention you had lots of spares, I need first gear on the countershaft (36 teeth) Would you have and be willing to part with it? Heres a pic, it's the largest gear on the shaft.

Offline bwaller

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Re: Trail 70 rebuild. Opinions?
« Reply #2 on: March 02, 2006, 07:54:26 PM »
Too quick on the draw, here's the pic- the gear with the bad teeth!

Offline GroovieGhoulie

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Re: Trail 70 rebuild. Opinions?
« Reply #3 on: March 02, 2006, 08:07:06 PM »
The bike (and parts) are back home and I'm not going to be heading there until the weekend of the 18th (3 weeks).  If you can wait a bit, I can check when I go.

Offline Bill Vaughan

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Re: Trail 70 rebuild. Opinions?
« Reply #4 on: March 02, 2006, 10:08:15 PM »
I restored a 1970 CT70 for one of my nephews a couple of years ago (auto-clutch).  If you've spent any time working on motors, you'll find this engine to be a refreshingly easy rebuild project.  All the parts are available from many sources and not out of sight in terms of price.  Cam chains and guides are usually in need of replacement and the rectifier is almost always bad.  There is a modified Honda part to replace the rectifier that plugs right up to the original connections.  My vote would be to stick with the original set-up.

If you search Ebay, you'll see that the CT70s in original condition command a decent price.  That said, the factory paint was usually a candy or metallic, so getting the original appearance is not a cheap (outsource) or easy (do it yourself) process.

Not sure that you'll really need a tach.  The engines are strong little beasts, but they don't rev all that quick or high under load.
1972 Z50A
1973 ST90
1975 CL360
1971 CB450
1975 CB550
1978 FLH
2003 FLSTS
2006 FLHRSI

Offline bwaller

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Re: Trail 70 rebuild. Opinions?
« Reply #5 on: March 03, 2006, 08:53:18 AM »
Groove, three weeks I can do, thanks.