Chunkstyle Posted August 7, 2012 Share Posted August 7, 2012 hi guys -- i've got an old ct1-175 i've been working on, off-&-on, for a few years with my son. the time has come to pull the cylinder & check its diameter, to see if the cylinder needs boring oversize. if someone could please answer a couple questions about this, i'd appreciate it. 1. i don't have an inside mic nor a regular mic big enough for the cylinder diameter. i do have telescoping gauges and a pretty good mitutoyo vernier caliper. would the caliper work & be precise enough for checking the cylinder? 2. the odometer reads 2145 miles. is that really low mileage for one of these bikes? i've got this hope that, possibly, the cylinder will be largely unworn. this is my first motorcycle, though, and i don't know anything about typical mileage & wear on a bike. 3. similarly, is there a decent chance that the main bearings in the engine & trans would be good with this type of mileage on the bike? i've already spent more $$ than i'd like nickel-and-diming on various parts for this bike, scrounging on ebay & such, and don't feel like shelling out more for bearings. on the other hand, though, with the engine split open, now would be the time for the extra insurance of new bearings. thank you for any help anyone can offer. drew Link to comment Share on other sites More sharing options...
jim*jimbo Posted August 7, 2012 Share Posted August 7, 2012 Hi Drew, my advice would be to get a compression test done assuming you haven't already got the engine in bits! Any decent garage will have a guage and you only have to remove the spark plug. 2000 miles is nothing for a bike of this type if its been used on the road - even if its been thrashed off road for most of the 2k miles its still not a huge amount. I had a DT175 that covered 25k hardish miles before it needed a rebore. Even when relatively new this engine had a characteristic top end rattle thats nothing much to worry about. Big end bearings should not be noisy though. Good luck Jim. Link to comment Share on other sites More sharing options...
Moderator Cynic Posted August 7, 2012 Moderator Share Posted August 7, 2012 Firstly you can't compression test a 2 stroke the same way as a 4 stroke as the case seal is as if not more important than the piston seal, which is marginal at best on a 2 stroke. Your basically tossing a coin here, 2000miles in 40years could be a death sentance or it could be ok, mainly its down to the seals. They age and can perish and that i would say is your biggest worry. The pot and the piston are unlikely to have issues bar maybe gummed rings so long as the bore hasn't rusted. The gearbox internals may also be fine, but again could be part fine and part rusty mess due to the oil not moving for 40 years. Basically if you live on the cost and it was last run in 1978 it may well be shot, but if your in texas and it has been used 4-5 times a year to blow the dust off it could be good to go. Can't say more really....... apart from replacing all the seals and bearings, available readily enough here in the uk for under £100 (cheaper if you chance the crappy pattern stuff) so its hardly a disaster if the seals have gone. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted August 7, 2012 Moderator Share Posted August 7, 2012 hone the barrel and fit new rings, at such low mileage the bore and piston will hardly be worn at all, my 175 has done 40000 miles and is only on the 2nd oversize piston Link to comment Share on other sites More sharing options...
Recommended Posts