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About sdm

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  • Bike
    76 TY175 Cota 247

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    North East Calif.
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  1. I have gotten my bearings from Speed & Sport for my Cota. Matt has a nice website and can fix you up with bearings and seals. Also he is here in Cali and caters to the vintage bikes of all types. www.speed&sport.com
  2. They are a bit notchy or stiff to shift compared to other bikes. An easy thing to check is to make sure that you are getting full travel from the shift lever in both directions without any interference of the lever with the engine case or anything else. Sometimes they can get pushed out of shape in a crash and interfere with other parts. Also the shift shaft is connected to linkage that goes to another main shift shaft behind a small cover . It is on a spline. If the linkage or spline is worn, it could cause the trans to only partly engage a selected gear or popping into a neutral. I assume you were at Bushey Ranch? Sam
  3. sdm

    Cota 247 losing power

    Also check to make sure the exhaust isn't partially plugged with carbon somewhere. That could cause the symptom you describe also and seem to run ok at low throttle.
  4. If the po was running premix the oil injection is probably not hooked up. The stock throttle cable is a split cable with one end going to the carb and the other going to the oil injection pump. If you take the oil pump cover off(right side front of the engine) you can determine if the oil injection pump is still connected. I believe Yamaha calls for 10w 30 engine oil for the tranny and allot of people use ATF. I would use a good quality motorcycle oil 10w30 like Yamalube. Matt at Speed and Sport can help you with all your other questions and probably has the parts in stock. He is a good source for all vintage Yamaha stuff and has a good web site. I think he has manuals also for your bike. www.speedandsport.com He has done allot of the Domino/ throttle cable conversions for the TYs and may be able to send you what you need from memory or tell you what he needs for measurements.
  5. sdm

    Ty175 piston

    If I'm not mistaken your piston looks to be 2nd oversize over stock. The correct procedure to do would be to measure (or have it measured) the cylinder bore at different spots to see how much taper or out of round it is. A shop manual will give the correct specs for measuring.That would tell you for sure where you need to go as far as a rebore and oversize. If the engine runs very rattly also check the main bearing play by trying to wiggle the crankshaft flywheel.If you detect any movement you will probably need main bearings... and while you have the crank out might as well have a new rod pressed in for good measure. You don't want to do any work you don't have to obviously but don't short cut it either.. Sam
  6. Yes they can be changed without splitting the cases. You will need a magneto flywheel puller for the magneto flywheel, and a good stout puller to pull the primary gear on the clutch side. There are seal housings that unbolt from the main engine cases making seal replacement very simple. Sam
  7. sdm


    Like Turbo said some pics would be helpful.. I replaced the clutch basket with one off a DT100 which is basically the same as the TY 175 and I got it used off of Ebay. Mine is a 76 TY and the driven gear on the basket is the same as the 77 DT100 with minor differences. The only thing is the replacement basket I got off Ebay has the same slop in the gear between the basket and gear that the old one had. I figure I will just run it and assume it is suppose to be that way... Sam
  8. Always good to resolve a problem on these old bikes. They all seem to have little hidden issues for various reasons ...
  9. sdm

    Show Us Your Ty

    Wow ! Very nice Rock...I like the yellow and all the bits you added. I didn't know the RD 350 inlet boot would work on the 175 so that will be a good resource to look for. Did you use the stock air box and carb to airbox boot? Sam
  10. sdm

    Show Us Your Ty

    Mine looked like that about 2 months ago but is up and running now.. Love the bike and plan on doing some vintage trials soon. The cool thing is parts are available out there if you have some good bones to start with.
  11. Yes it does which I hadn't planned on but is nice. I no longer slam my heel into the foot peg when kicking!
  12. Yes I did drop the foot rests some.. I was too scrunched up with the stock position and dropping them improved my riding position (for me) quite a bit. The rear brake pivot kind of dictated what I could do but in the end I like the results. I also dropped the brake pedal pad some with an extension that I welded on. Looks kinda cobby but it works well. Sam
  13. sdm

    Show Us Your Ty

    Here is my 76 175 that followed me home after an event... I just got the engine back together after sending the crank out for a new rod,mains etc and a fresh bore and piston. A friend did a nice job on the tank and exhaust guard and I resprayed the frame. Lots of small bits to get it back to reliable running and I have about 2 hours break in so far. Loving the light weight and handling.
  14. I finally got a pic of my 74 247 Cota that I ride regularly in AHRMA events. It has been good to me with the exception of things I have done.
  15. sdm


    I assume you have already tried Southwest Montesa in Arizona and Matt at Speed & Sport in Calif....
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