Hi Everyone -

This is only my second post, so go easy on me!

I'm resurrecting a 1969 CT1 175. I need front and rear wheels - the originals are pretty rusty and the rear wheel is missing 11 spokes and way out of whack.

Looking at the parts lists for this bike and a 1974 DT250, both the 5 digit part numbers are the same for the wheel hubs: xxx-25311-00 for the rear wheel; and xxx-25111-00 for the front wheel. Does that mean the 1974 DT250 wheels will interchange with my 1969 CT1 wheels?

Please say yes!

Thanks!

Joe from NorCal

Sorry, no.

The prefix is very important. The second five that are the same identify the part as a wheel hub.

Many of the manuals in the Tech Library have a section on the Yamaha Part Numbering System and I believe there is an article too.

I probably have some decent wheels but shipping might be the killer.

Perhaps not though, I do see he is in NorCal somewhere.

I compared my wheels with the DT250’s and the 250’s were indeed larger. Lesson learned!!

Thanks!

Hi Joe, I have a set of at1 wheels they are just a little smaller in width, but will fit. and I live in Northeastern CA, where do you live? If you are close enough and can come get them, you can have them.

Thanks for the replies, Guys -

I found a replacement rear wheel on eBay, so that is taken care of. My resurrection project is moving along. I have the frame repainted and have reassembled much of the bike.

So now the new topic - I took the engine down to the center cases. Had to replace the kickstarter gear and the idler gear as they were missing teeth. Did not split the cases as all the gears shifted before I started the project. Replaced seals and replaced points and condenser. I have good spark. When I pulled the head off, discovered that the top ring was broken. I don't think it ran with the broken ring, as there are no scratches or scoring in the cylinder. I was really careful pulling the cylinder up. Not sure why the top ring broke. The cylinder jug has "0.020" etched on the outside of the cylinder on the exhaust side (see photo). So now I"m looking for new rings.

I am near Marysville, CA. Just an older retired guy needing to fill the COVID boredom between visits to the grandkids!

Will post more pics as I make progress!!

Ignore the 020!

What markings are on top of your piston?

Wow, Mark, quick reply! Thanks!

Photos attached..

“5.13” stamped near the front arrow, and “980” stamped on the intake side. Maybe an aftermarket piston??

Thanks!

Joe C.

That's a standard size OEM Yamaha piston.

If you can get it cheap, buy it and take off all the ignition stuff, then resell. 74 dt250 has value, especially for the DT360 with bad CDI.

Dad3sons, you sound like me, COVID and grandkids.