Just picked up '75 TY175 off e-bay as refurb project and as entry level trials bike.
The previous owner indicates the bike starts and runs (don't know, haven't picked bike up yet) but must be with bum start. Says starter shaft is misssing and hole is plugged with bolt.
Is the starter shaft going to be a major repair issue? How much tear down will be required to get the starter shaft replaced. I'm looking forward to the mechanical work, but this may put me in the deep end!! Am I better off to start looking for another engine?
Is the TY 175 engine same as DT 175 engine?
My plan is to practice some trials type riding around the area (live on small farm with mountail on back half), but still don't want to upset the neighbors with noise.
Will the stock TY175 muffler be suffecient? If the muffler is burned out, can it be repaired?
After the bike is starting with my foot verses by bum and I have some practice, you just might see me around at one of the events (probably Canungra)!! I haven't done a trials event since 1975 on my OSSA, sure wish I had the bike now!!!
Thanks,
Ted
TY 175 engine questions
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David Lahey
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It depends on why there is a bolt plugging the kickstart shaft hole. If it is just that the shaft is missing and no other problems, it would take an auto mechanic or bike mechanic about 15 minutes to fit a new one to a clean bike. It would take about 3 minutes to get the cover off and see what is wrong in there. New kickstart shafts are about $110 and clutch cover gaskets are about $25.
It's impossible to say how quiet your TY175 will be if even you haven't seen the bike to know what the exhaust looks like.
The standard exhaust on the 1N4 prefix model is quieter than the standard exhaust on 525 prefix models. The 525 prefix muffler can be serviced easily, the bulbous 1N4 type not easy. Both types of exhausts are much quieter than an MX bike of the same era. Aftermarket mufflers are available and are effective at keeping exhaust noise down.
Many engine parts are shared between the TY175 and some DT175 models. Not all DT175s are the same. The DT175s and DT125s from the same time (A,B,C and D models) had lots of interchangable parts with the TY175 (like kickstart shafts in case that is why you were asking).
It's impossible to say how quiet your TY175 will be if even you haven't seen the bike to know what the exhaust looks like.
The standard exhaust on the 1N4 prefix model is quieter than the standard exhaust on 525 prefix models. The 525 prefix muffler can be serviced easily, the bulbous 1N4 type not easy. Both types of exhausts are much quieter than an MX bike of the same era. Aftermarket mufflers are available and are effective at keeping exhaust noise down.
Many engine parts are shared between the TY175 and some DT175 models. Not all DT175s are the same. The DT175s and DT125s from the same time (A,B,C and D models) had lots of interchangable parts with the TY175 (like kickstart shafts in case that is why you were asking).
Thanks David!
Very helpful response, I really appreciate the information!!
Cheers
Cheers
The same basic motor was fitted to a LOT of bikes: DT100/125/175, MX100/125/175, IT125/175, and YZ100/125 (and the rare-in Australia RT180 and YZ175).
My experience is with the YZs and (to a lesser extent) the DTs, but here goes:
Lots of bits are interchangeable, but they were very much a case of 'grand-father's axe'.
Things to watch out for:
*Barrel to case stud spacing (got larger for larger transfer ports for 1977).
*Gearboxes - not only the number of gears and the ratios, but the diameter of the shifter drum changed from 1974 to 1976 to 1977.
*Shifter shaft. Pre 1977 the shaft was two-piece with a short lay shaft on the LHS - later had a shaft running the whole way through.
*Height of barrel/depth it goes into the cases - some bikes had a shorter barrel that spigots deeper into the cases compared to others. This seems to match which type of piston they used (pre 1976 and post 1975, IIRC)
*There's two(?) different types of cranks - IIRC the later (1979) YZ125/100 have a smaller tapered section where the flywheel attatches - or maybe it was that the DT175s were larger? Argh, too many beers break brain... May also be differences with the bikes that ran auto-lube?
Most internal bots are the same or directly interchangable - stuff like cranks are mostly the same, rods are all the same and I believe they've all got the same kick start mech. Primary drives and clutches all seem to be interchangeable, provided you match them together.
I guess what I'm saying is that even if a TY175 bit comes up "NLA", you can probably find a bit that works perfectly from one of the other bikes.
Just while I'm in brain-dump mode, I'll liist the years of the bikes with the appropriate engine (although I reserve the right to stuff it up....):
YZ125 until 1980 (later ones have chain on the RHS, so are easy to spot).
YZ100 until 1981 or 82 (ditto).
YZ175 all.
DT100/125/175 all (beware the LT1/LT3 with the leg-burner pipe).
IT125/175 (as for YZ100).
My experience is with the YZs and (to a lesser extent) the DTs, but here goes:
Lots of bits are interchangeable, but they were very much a case of 'grand-father's axe'.
Things to watch out for:
*Barrel to case stud spacing (got larger for larger transfer ports for 1977).
*Gearboxes - not only the number of gears and the ratios, but the diameter of the shifter drum changed from 1974 to 1976 to 1977.
*Shifter shaft. Pre 1977 the shaft was two-piece with a short lay shaft on the LHS - later had a shaft running the whole way through.
*Height of barrel/depth it goes into the cases - some bikes had a shorter barrel that spigots deeper into the cases compared to others. This seems to match which type of piston they used (pre 1976 and post 1975, IIRC)
*There's two(?) different types of cranks - IIRC the later (1979) YZ125/100 have a smaller tapered section where the flywheel attatches - or maybe it was that the DT175s were larger? Argh, too many beers break brain... May also be differences with the bikes that ran auto-lube?
Most internal bots are the same or directly interchangable - stuff like cranks are mostly the same, rods are all the same and I believe they've all got the same kick start mech. Primary drives and clutches all seem to be interchangeable, provided you match them together.
I guess what I'm saying is that even if a TY175 bit comes up "NLA", you can probably find a bit that works perfectly from one of the other bikes.
Just while I'm in brain-dump mode, I'll liist the years of the bikes with the appropriate engine (although I reserve the right to stuff it up....):
YZ125 until 1980 (later ones have chain on the RHS, so are easy to spot).
YZ100 until 1981 or 82 (ditto).
YZ175 all.
DT100/125/175 all (beware the LT1/LT3 with the leg-burner pipe).
IT125/175 (as for YZ100).