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About sbest

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  1. sbest

    1978 TY175 overhaul

    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: (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. 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?
  2. sbest

    TY 175 airbox

    I've done some work on Yamaha Blasters, KTM and other 2 strokes and found there is much more than air restriction going on with the airbox. I've found many high flow aftermarket intake airboxs lose power, as do many of the "common sense" mods that are suggested on the internet. One guy does it without testing, reports on it or posts cool pictures and it takes off like wild fire. As a rule, intake systems should maintain a steady cross sectional area from port to filterbox with some gradual decrease as it approaches the port. A slight coning (or trumpeting) as the intake port enters the airbox is preferable to broaden the affected rpm range. Longer favours lower rpm, shorter favours higher rpm. There are formulas (read up Gordon Jennings, Gordon Blair, A Graham Bell) but experimentation is still needed, especially with harmonics and Helmholtz box factors. The box volume itself is important also, and the same, bigger favours lower rpm. Often where you gain power at one end, you lose it at another. I have made long intakes that gave tractor like low rpm power but hurt top rpm output. Most of the time I was looking for mid-range to max, which I gather may not be what a Trials needs? All this said, to my eye the TY175 airbox does not look too bad, and the filter has ample area for the carb. An airbox lid is important for resonance, but if you feel it is restrictive, test with it removed. Ah, testing! That is the rub. Without a dynometer, I find speed testing on a hill the most repeatable. Fit a speedometer, digital bicycle speedos are cheap, accurate and easily adapted. Find a long steep hill and establish 2 markers on it. Pick a gear, enter at a fixed low rpm and give it WOT at the first marker. Record your speed at the top marker. This is you baseline. Now you will know if any mod you do makes more power or less.
  3. sbest

    1978 TY175 overhaul

    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. 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: It is in fair shape, complete, but with a few problems. 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 The photos did not capture how much smoke came off this. My neighbours are gonna hate me. This is where I sit now. Any suggestions? Any Canadian suppliers?
  4. sbest

    Show Us Your Ty

    I've bought a generic "O"ring set, but haven't tried to see if one fits yet. Found an OEM air filter on Partzilla, ordered I do have the oil pump, but it is not on the bike, it does have the split cable, I ordered a single cable It is a 1978 with 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. How to clean and repack? Tank is very rusty inside Thanks for the tips! I'm getting under way...
  5. sbest

    No Snap!

    I am new to the TY, but not to old bikes. The needle seat will often build up a coat of varnish. Try cleaning it up with a "Q"tip and a small dab of toothpaste. Swirl it around and wash it up before assemble. Usually works.
  6. sbest

    Show Us Your Ty

    Yes I am interested, but I have some work ahead of me yet: Forks have no damping, no oil for sure but what else? Need an airfilter, no source found yet Need the tiny "O"ring for the main jet, no source found yet Need sprockets and chain, ordered from England, but I hear other model stuff fits? All cables(ordered), grips, fuel lines needed of course. Tires are hard and some weather cracking Bike came from Lunenburg County. Engine has compression, steel reeds look good, brakes and wheel bearing seem good. I'll check the crank seals. A nice complete bike but aged bike. What else should I look at? Any Canadian parts sources suggested? DSCF5024. Is it possible to blue plate a 78 or 79?
  7. sbest

    Show Us Your Ty

    This is my first post here, and here is me bringing home my 1978 TY175. The adventure begins...
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