Compression puzzle

[Jan_P]

I do believe I would go for the Original.
It has quality control performed ..on it for a major company at a time with legendary strict quality checks.
Which not necessary replacement firm parts has like Mikes.
There is also the aspect that a big manufacturer like Yamaha is a big customer .So the firm selling parts.
Are treating a purchase from Yamaha differently than a smaller parts dealer only.
Historically non factory parts came because they were cheaper but sometimes .Not of a even and good quality.
On the other hand chains are used at many places and are in that sense a more or less standard Machine Component
So a known company may be exactly the same as the stock..
But I notice Mr Grizid has personal experience.

.

 

[Jim]

Partzilla sez the OEM was also a Tubaki.
Misspelling of Tsubaki maybe?

 

[Jim]

Interesting... the complete guide to chains by Tsubaki.

 

[grizld1]

Maybe that stamping is a Tsubaki mark? Just pulled a new Tsubaki peanut plate cam chain (for 447 cam) out of the stash, and as I seemed to recall, the plates show no markings. Thought the OE chains were DID, might be wrong about that.

 

[stinky78]

as far as I recall D.I.D. do 3 chains in the series, FT, FTS and FTS(S) with the last being the heavy duty version with oval side plates, the FT has figure 8 side plates, can’t remember what the middle one is,

 

[5twins]

Yes, I think that box with the curved sides is an old Tsubaki emblem .....

 

[GLJ]

Update:
Spare engine back in and running. Don't have a ton of smiles on it yet but it runs well. Actually can't tell any difference between it and the original. And shouldn't because they are both 2nd over XS2 engines. I did replace the cam chain and installed E-Foot valve adjusters. I went with the cam chain from Mikes. Pros and cons for each so I flipped a coin. One thing I did different than normal was set both intake and exhaust valves at .006. After seeing how how intake valve adjustment affect compression I decided to set them at .006.
Another thing I did which some may think is not cricket is I didn't replace the head gasket. I didn't loosen the 3 small bolts that hold the head to the cylinder. So far no compression or oil leaks. Not replacing the head gasket made installing the new cam chain a piece of cake to get it on the cam sprocket. No prying necessary.
Now a tough but fun decision. How do I want to fix the original engine. Keep it stock or make it a 750?