majorwinters Posted August 27, 2018 Report Share Posted August 27, 2018 (edited) recently bought a 1975 yamaha ty 80 b. i run fuel oil ratio 40 to 1. do you need expensive 2 stroke oil. will using i use semi synthetic cost around £9. should i use castrol or will regular scoooter motorcycle 2 stroke work.well. also what compression should a ty 80 have the haynes manual states 78 psi warm engine>?? 78 psi seems low. piston and rings look ok think there quite new by the looks. rings and bore seem ok. i can get photos if needed not an expert on engines just picked up some knowldge over time..iIhad to order new head gaskets studs becuase the owner before had used a cut off piece of gasket.it was circle had the edges cut offf and it failed. had exhuast gases blowing out from the cylinder. cost around £70 to buy 4 new studs 4 new bolts gasket set. i am an adult but becuase i dont have a trailer to transport my bike a ty 80 fits in the car boot. e.will the engine last carrying my weight.i know this sized bike was desighned for 5 to 12 yr olds not fully grown man but its a fun bike to ride.its my first motorcycle. Edited August 27, 2018 by majorwinters Quote Link to comment Share on other sites More sharing options...
section swept Posted August 27, 2018 Report Share Posted August 27, 2018 TY 80 is an old 2 Stroke design, no harm in using any 2stroke oil as long as it’s fit for purpose, semi syn is fine. A bit rich at 40:1 you are lowering the octane rating of the fuel so try 50:1 not a vast difference but it will help. Sounds like you paid an awful lot for a few studs and a gasket (set) try Yambits they are very good. As the 80 is a nice little engine it may even run quite happily on a diet of 60:1? 1 Quote Link to comment Share on other sites More sharing options...
majorwinters Posted August 27, 2018 Author Report Share Posted August 27, 2018 (edited) oh i tried yambits i couldnt find the engine cylinder studs out of stock. i orderd 4 studs and 4 new bolts plus shipping cost it came to around £60. so 50 to 1 isnt to lean? bloke i got it from ran 40 to 1 should i run 50 to 1? so 100 ml of oil per 5 litres of fuel wont sieze the piston? Edited August 27, 2018 by majorwinters Quote Link to comment Share on other sites More sharing options...
section swept Posted August 27, 2018 Report Share Posted August 27, 2018 Providing there’s nothing else nasty going on with the engine like leaking crankshaft seals, worn main and conrod bearings. And as you say you are a big bloke riding a tiddler.....who knows if it will seize, any way rider input and throttle usage will figure heavily in that conundrum. Leaks around the exhaust port can cause extreme temperatures and that alone will damage the engine. More oil wont necessarily prevent seizures. There will most probably be a TY 80 proficient person along soon to put matters correct. Quote Link to comment Share on other sites More sharing options...
majorwinters Posted August 27, 2018 Author Report Share Posted August 27, 2018 around 175 lbs. . everything else seems ok just need to put in the new cylinder studs fit new gasket. torque down cylinder head should be good to go again/. i would gotten 125 but ty 80 fits in the car boot while 125 wont/. . but the ty 80 is a fun bike to ride.. might try a 50 to 1 fuel mix and see if its better. Quote Link to comment Share on other sites More sharing options...
lineaway Posted August 27, 2018 Report Share Posted August 27, 2018 The League. A traveling TY80 Team. And they make alot of vintage riders upset. They have a better pit than most modern Teams. Ha! Ha! https://advrider.com/index.php?threads/the-compleat-yamaha-ty80-thread.574301/ 2 1 Quote Link to comment Share on other sites More sharing options...
brewtus Posted August 28, 2018 Report Share Posted August 28, 2018 Greeting from The League - We've been running 60:1/AvGas mix for several years now, with no problems. Our bikes are modified yes, but mostly chassis mods to haul around our beer-drinking a$$es (bar risers, tall bars, relocated pegs, etc). All the mods are documented on the ADV link that Line has posted above. 9 years of competition and we've never broken a frame, cracked a frame, or had to replace a clutch. These are amazingly tough little bikes and we've ridden competitions from 200ft. elevation to over 9,000ft. In fact, two of us are headed up to Wyoming this weekend to compete in a Vintage event that is being run concurrent with the Mosteller Cup. I'll post pics afterward. If we can't break them, I doubt you will. Our most famous shot with one of our youngest heros aboard - 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.