Topic: kap384's CT70K1 Resurrection - Bonneville Pit Bikes (Washed and done-video too)

[kap384@telus.net]

So, a bit of a story to begin with.  This started mid-2013.  A group of us had plans to return to the Bonneville salt flats in 2014 as spectators for Speed Week, but after a previous experience in the heat, decided we needed pit bikes.  Uncharacteristically for me, I didn't do any research into an appropriate pit bike.  It was summer 2013.  A 1974 MT125 pops up, a model I was unfamiliar with.  Didn't realize Honda had jumped back into 2 strokes that early, so I grabbed it.  Unfortunately, it was too big. (Did I mention we'll need to fit at least 4 of these in the back of a pick-up?).  It was now close to Christmas, some alcohol may have been involved, and I jumped at a mint 1975 MR50 in the local classifieds.  I had never heard of the little dirt bike, but it was awesome!  It came home in the back seat of my truck the next day (PO insisted it stay inside out of the elements).  Problem was, not only was it too small, but it was way too minty to take on the corrosive salt flats.

So finally I do some research and realize that a CT70 or CT/ST90 would be perfect.


Low and behold I'm online when a CT70 pops up 10 min from my house.  Not running, but the price was right at $150.  Sold.

[kap384@telus.net]

Aforementioned first purchase - 1974 MT125


">


Yes, its got the wrong tank.  Also a keen eye will notice that the oil injection system and all lighting have been stripped.  Upon further inspection though, I notice most things were done quite thoughtfully (short of the hack job on the wiring).  There are nice machined block off plates and plugs for the oiling system,  a fabricated metal inner fender to take the place of the oil tank, and a nice small Honda dirt bike flush tail light out back.  Makes me think its what someone would do to turn this enduro into a full on dirt bike back in the day.  So I'm keeping it.  Only things I'm addressing are the wiring (I'll properly rewire it to have a battery-less headlight and tail light), putting a seat cover on and replacing the side panel.  It'll also has the proper tank now, though I need to de-rust it.  Oh yeah, I also had to do something with the exhaust. It was full of holes with all baffling removed, so this little 2 stroke was about as annoying as they come.  Well, a used pipe in decent shape was going for more than $200 usually. 


Sure enough, for around $300, this NOS Hooker header came up on eBay.  Seemed like a no brainer.


">

[kap384@telus.net]

And the other misguided purchase, the MR50


">


Back seat of my truck on the way home


">

[kap384@telus.net]

No love for a CT70?

[grcamna2]

Nice small Honda's kap 

[kap384@telus.net]

Nice small Honda's kap 

Thanks!

[RAFster122s]

You realize you change in piston was likely for the late bikes, in the case of the C70 it would correlate to 83-84 and when they switched to diff cylinder and flat top piston  & long rod as well as transitioned to 12v.  So, your piston ended up in the cylinder lower than before.  Ibuyisell on ebay sells stuff for both early domed and the flat top as well as does beatrice cycle, aka dratv.

A good coat of wax or boeshield on some stuff could be good preventive... I would be tempted to flush the chassis well and maybe give it a rust eating chemical dose inside chassis and follow up with a good spray of used motor oil.  Canadians would oil spray their cars' undersides years ago, not sure if they still can. It would really lessen the corrosion but made a drippy mess until dried/dripped off or got some dust mixed in.  Might help the chassis on the CT withstand the abuse much better.

If you are still going to the salt and have and use the little ct70 on the salt. I know, very old thread.

[kap384@telus.net]

You realize you change in piston was likely for the late bikes, in the case of the C70 it would correlate to 83-84 and when they switched to diff cylinder and flat top piston  & long rod as well as transitioned to 12v.  So, your piston ended up in the cylinder lower than before.  Ibuyisell on ebay sells stuff for both early domed and the flat top as well as does beatrice cycle, aka dratv.

A good coat of wax or boeshield on some stuff could be good preventive... I would be tempted to flush the chassis well and maybe give it a rust eating chemical dose inside chassis and follow up with a good spray of used motor oil.  Canadians would oil spray their cars' undersides years ago, not sure if they still can. It would really lessen the corrosion but made a drippy mess until dried/dripped off or got some dust mixed in.  Might help the chassis on the CT withstand the abuse much better.

If you are still going to the salt and have and use the little ct70 on the salt. I know, very old thread.

Thanks for the heads up on both fronts.  Haven't been back to the salt since, but did hit it with brushes and more elbow grease and no more corrosion has taken place.

[kap384@telus.net]

Ordered up points and condenser and all the carb internals. I may have damaged the jets by augering out the rock hard gasoline with drill bits so better safe than sorry.  New throttle cable and headlight switch and cable coming too.  Post install pics once they arrive.  New clutch went in last summer and cured my slipping kick starter. Added a luggage rack and vintage plate now as well. Have a stripped intake bolt hole to helicoil as well.

[kap384@telus.net]

Well, live and learn.  Based on how used and abused the entire bike was, I couldn't believe that the engine would be a different vintage than the frame.  Every part of the bike seemed to be as worn out as the rest.  Well after the new condenser and points didn't fit, I came to discover that the engine in my 1972 CT70K1 is actually from a 1976 CT70'76.  Waiting on those new parts and a few different (correct) parts for the carb, then I'll reassemble.

[kap384@telus.net]

Well, the latest parts are supposed to arrive today (re-ordered '76 bits).
In the meantime, I installed a new Hi/Lo headlight switch, fixed the horn and got it working and generally went through the wiring tip to tail in better detail than I had before.
Horn first.  It never worked.  Upon closer inspection, could see that it had suffered quite an impact at some point.  Not shocking!  I carefully pried the outer case away from the vibrating disc and after some fiddling, I had a horn!
No before pic, but here is the after pic with air gap all the way around the disc.





The headlight switch wiring was the crustiest, most bent of the original grey cables so instead of re-wiring, I just grabbed a new unit.
Old wiring:



New switch:

[kap384@telus.net]

One more thing before the parts arrive, I have 2 speedos, but both need work.  The high mileage one's neutral lens is almost completey washed out and the High beam absolutely is.  The low mileage speedo has a good neutral lens, but washed out high beam as well as a busted stud.  Goal is to find red and green nail polish or translucent paint to paint the lenses on the high mileage speedo.  That said, if I can only find red, the broken stud is the speedo to use and I've got a stud to fix.

[kap384@telus.net]

Speedo success.  Found both red and green translucent paint.  Was able to get a more even finish on the bulbs than on the lens.  So here are the painted bulbs, wondering if 1 coat will work?





And the end result. 





Very happy.  Remaining parts just showed up from CMSNL, so reassembly can begin!

[RAFster122s]

Testers hobby paints in the Model Masters lines have transparent amber and red paint the plastic car guys use to restore lenses on old models as well as change clear molded parts the needed colors for display models. I doubt they could hold up to a hot bulb for a long time but could be useful for the jewels if you cannot find replacements.

[kap384@telus.net]

Testers hobby paints in the Model Masters lines have transparent amber and red paint the plastic car guys use to restore lenses on old models as well as change clear molded parts the needed colors for display models. I doubt they could hold up to a hot bulb for a long time but could be useful for the jewels if you cannot find replacements.

Thanks!


I was thinking that about burn-off.  I wanted the Testors paints, but wiith COVID-19 shopping limitations, I couldn't get the Model Masters online.  If the paint doesn't last I'll try painting the lenses again with the paint I have.


New condenser and points installed and timing / point gap completed.  Next is dropping the motor to heli-coil one of the intake bolt holes. 


I'm bouncing between multiple projects in the garage so slow going.  Steering dampner mount install on my Africa Twin and some accessory wiring, fork seals and dampner mount install on my KTM 200 XCW as well as a rear Tub-liss install.  Wiring to sort out on my '95 VFR too.

[kap384@telus.net]

Heli-coil installed on the intake bolt hole. Waiting for a new heli-coil kit for one of the 8 mm bolts on the bottom of the case that holds the skid plate I'd forgotten was stripped.  It arrives Friday, then I'll reinstall the motor and work on the carb.


 

[kap384@telus.net]

Got a stellar 121 piece heli-coil kit (5, 6, 8, 10, 12 mm x 20 pieces) from Amazon for the price of a traditional single size.  8mm heli-coiled and engine installed.  New carb bits installed too.  New floats, float valve and seat, main and slow jet, needle assembly and slide, fuel filter, seal kit, throttle cable and carb cap (top section)  Set float level at 20 mm. Should've grabbed a new spark plug cap and plug to be thorough, but I didn't.  Install and fire up next.

[grcamna2]

The CT70 carb has the fuel petcock built-in to the carburetor,where's yours ?

[kap384@telus.net]

The CT70 carb has the fuel petcock built-in to the carburetor,where's yours ?

Correct, it is.  I'll post a finished pic of the bike shortly (and a vid of it running)  Runs great now, but still a little Bonneville salt to wash off. Unfortunately, the last time I installed the motor the crank case vent tube fell off.  In front of the rear wheel is where a lot of salt is accumulated.  I don't want to be pressure washing in there with the vent open, so I'm gong to drop the motor to get that vent on, wash her, and then she's done.


Next time I order from CMSNL, I'll include some spark plugs and and new spark plug cap to make sure that spark is tip top.

[RAFster122s]

CMSNL is cheaper than ordering from someplace like Beatrice Cycle ( DrATV) in US?

[kap384@telus.net]

CMSNL is cheaper than ordering from someplace like Beatrice Cycle ( DrATV) in US?

No, but if I'm purchasing parts for other vintage bikes, it usually has all of them (ie. '95 VFR and '65 CB450K0), so its a handy add on.  Shipping is still very fast in this COVID environment as well.

[kap384@telus.net]

CMSNL is cheaper than ordering from someplace like Beatrice Cycle ( DrATV) in US?

And in larger orders you get kick ass posters like this:

[kap384@telus.net]

Washed the '70 and the garage floor at the same time.  Grabbed some pics:

[kap384@telus.net]

And a vid of it idling.  Let me know if you can't link to the video.  My first time trying to post a vid.

https://flic.kr/p/2jaso9Y

[grcamna2]

That's a nice CX650T  When's the last time you rode that one ?