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sbest

1978 TY175 overhaul

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Hi, I'm new here, new to trials, but not new to motorcycles. I ride mainly KTMs, however I overhauled a 1979 CanAm 250 last winter. 

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I use the term "Overhauled" because I have no intentions of a complete restoration at this time. I just want it safely ride-able. 

So I picked up a non-running 1978 TY175:

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It is in fair shape, complete, but with a few problems. 

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  • Carb floods out and bike will not start due to flooded condition 
  • No air filter,  ordered on Partzilla
  • Oil pump off, but it does have the split cable, I ordered a single cable
  • matching engine# and I have a 1979 frame as well, no other spares
  • My switches are banged up, button broken. Haven't started, don't know if work
  • The pipe and silencer are very heavy, I suspect carboned up. 
  • Tank is very rusty inside
  • Chain and sprockets are shot
  • No front shock damping at all, spring only
  • Tires are hard and weathercracked but hold air!
  • As I dig I find wrong and stripped fasteners, loose stuff, 

So far I have:

  • cleaned the carb and replace the critical mainjet "O"ring. 240 main and 25? pilot
  • Swabbed the carb inlet needle seat with toothpaste
  • Checked the reeds (good) and crankcase sealing (poor). 
  • Cleaned frame and replaced fuel, fuel lines and filter
  • Checked for spark, strong (compression good too) 
  • Aired tires to 12psi 

Pulled exhaust off and heated it up on the BBQ. It smoked for 2 hours. It weighed 3.5 kg before I cooked it

 

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The photos did not capture how much smoke came off this. My neighbours are gonna hate me. 

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This is where I sit now. Any suggestions? Any Canadian suppliers?

 

Edited by sbest

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Do you want to keep the head and tail/brake light ? I not ( as most rider ), it's a much easier job.

Guy

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That's looks like a good unmolested bike that should respond well to some TLC, and yes, with the optional lighting kit - mine also has these lights and I have a UK "MOT" so I can ride day and night on it 🙂, not that I go far on the roads.

Does yours have a horn?  Mine didn't and I found out the hard way the electrics are unregulated AC (nominally 6 volt) so it needs a special AC horn.  And the bulbs need to be the correct wattage.  Also if you over-rev it the bulbs blow as there is no voltage regulator (or rectifier)....

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I do want to keep the bike unmolested and to keep the lights working. It is dark at 6pm here this time of year and a good brake light prevents rear end collisions. Some of my riding buddies are CRAZY, you know? 

No horn, no battery and the stem sticker says "competition only" so I am guessing I will not be able to register for the road:

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(last digits fudged)  Generally the DOT will not allow vehicles with this on the highway. We do register them for off-road. 

I have road registered non-batteried off-road bikes before. The orange KTM is mine. 

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I did opt to install a tiny battery and DC full wave rectifier circuit for the horn, signals and to keep the head and tail light on if I was to drop the bike on a dark rainy night road. It also allowed me to use bright 20w brake and signal lights that would work engine on/off or low rpm. I still used the AC for the headlight. The voltage regulator is just a 14.3v voltage limiter (shunt). This all adds weight and complexity to what was originally a very simple bike. No plans to do this to the TY175, although it sounds like a voltage regulator might be in order?

Guy53, do you have to order parts out of country? 

Edited by sbest

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If ever there was a trials bike not exclusively designed for use on competition circuits then it's the TY.  We just used to use 24 volt truck bulbs to prevent blowing back in the day.

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Most of what you will need for parts is available at the Yamaha dealer  ...lots of TY parts are common with other models 

 I get a few things at rpm cycle and I order some from fortnine..

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As Bmonk said there are some parts avalable at your friendly Yamaha dealer, but I found that some dealers don't sell the parts at the '' retail '' price. Yes I ordered parts from all over the world with, most of the time, no problem. It's winter time so you have time to look around before buying.

Guy

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