I have a 1974 dt125 converting to a 175. I have the cylinder piston and piston and head                    &    Head. My question is should I add a shim to the autolube pump to give it a longer stroke                Give it a longer stroke/ extra oil? It is set up correctly now for 125. Y.                                                          I’ve been reading your sight for awhile now and you guys are the best                                             The best. I’m a 40 year mechanic so just lead me in the right direction.                                             direction.   Thanks for any help Er

I did 'that' top end swap on my AT1 using a TY175.
Must admit i never considered the pump output being different between the two & mine is ok & had a good hard workout. I won't bore you with the video of riding it but will be up here somewhere on the site.
Best of luck & i'm willing to listen to someone that actualy knows the output answer between the two--if not the same.
No harm in adding a shim or two & worst case scenario would be over oiling cruising around town.
ps, where there's gaps in your writing is the something missing from those gaps we should know about like photo links etc.
Cheers & Welcome from NZ downunder. & what's it like to be 40--i can't remember haha.
Where in the world are you situated?.

                                                 Thanks Rt325. I was just puzzled by the different part numbers on the pump’s between.                  The 125 and 175. No pictures added. When typing the cursor starts way to.                                             To the left out of the white box. Once I get it in the box it looks correct till.                                             Till I submit it.     Thanks Er

Greetings from Tennessee USA.  

Make sure you use a 175 small end con rod bearing.

1974 175 pump has same pulley, gearing, and pump piston displacement as 1974 125 so same output. Fittings are different as the US 175 got the new engine architecture and the 125 electric start stayed with the earlier AT architecture.

Manual does say to align the "round bump" on the 364 pulley for a 74 175 instead of the "raised pyramid" that you use on a 74 125 when adjusting the cable. Most people don't do that right if at all so I doubt it really matters.

Thanks Mark T for info also. Glad to know pump is the same. Does the cylinder head from a ct3 have the same compression ratio as a dt175. I am using a dt175 piston and cylinder. I like the head better from a ct3 but don’t own yet. Thanks

Thanks Mark T for info also. Glad to know pump is the same. Does the cylinder head from a ct3 have the same compression ratio as a dt175. I am using a dt175 piston and cylinder. I like the head better from a ct3 but don’t own yet. Thanks

Compression is the same. Best to get the head that matches the cylinder or size/shape often won't match up to cylinder fins and it looks like an obvious mismatch.

You could use a CT3 cylinder and head as a set though.

Thanks again mark t. Unfortunately I was mislead locally and purchased a 1974 standard bore dt175. I then purchased a 66.25mm piston and rings. I just purchased this morning a ct3 head. From what you told me I hope the head is smaller O.D. than the dt175 cylinder so I can reshape to match Ct head because I have way to much money into this conversion.I wish I found this website with the knowledge of you guys. I’ve had motorcycles my whole life but new to this model. Thanks again

After thinking of this all night. I need to start over. I have a really nice ct3 head. Now i need a ct3 cylinder. Does anyone want to sell me a ct3 cylinder. Also i have a NOS piston and rings for a 1974/75 Dt175. 66.25mm first over bore. Will this piston be compatible with a ct3 head thanks again