[intercepter]

Hello All,

I am in the process of rebuilding a 1965 CB160 and I've run into a snag. I ordered a set of CL175 off ebay: Herehttps://www.ebay.com/itm/68-73-HONDA-CL175-STANDARD-PISTONS-SET-2PISTONS-INCLUDE-10-CB175PS/142127376067?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

I also bored the cylinders based on these pistons. Bottom line, these pistons have too large of a crown and won't fit into the cylinder head. I realize i'm in a bit of a pickle here already so i'd like to ask for your thoughts on the best options.

1. Does anyone know of a 52MM Piston Kit that has the correct dimensions off other vintage hondas?
2. Is there another cylinder head that would be a direct bolt-on that would open up a slew of other challenges? This option is much less desirable in my opinion but should probably be an option.

Thanks in advance

 

[80cb400t]

I think unfortunately with cb160s the solution is to buy the 2.00 over kit, or assemble a kit from david silver spares and other sources. The aftermarket support is pretty bad for these relative to the 175s/350s

 

[intercepter]

Thanks 80cb400t, I was pretty much drawing that same conclusion but I did stumble across an article from a 160 racer and it looks like the big bore Honda 90 Pistons could be a good match. I have a CT90 that I could check the specs on bit i'm not keen on taking the top end apart right now. I may do it mid-week and see if the height looks reasonably close. I'll report back if I have success.

 

[ancientdad]

don't know if you know about it, but this website helps check various piston dimensions and is helpful for wristpin sizing

https://4-stroke.net/library/honda-piston-size-chart.html

 

[mike in idaho]

We used to use 160 pistons in the S90,back in the day, pin height, dia. are ok.

 

[intercepter]

THanks Mike in Idaho. I pulled the CT90 Piston I have an it looks like a near exact match in dimensions.

Wrist Pin and Height look like it'll work out nicely. I'll report back on the results. I ordered the CT90 Oversize Pistons from DRATV.

 

[intercepter]

I just wanted to report back. The 2.0mm over CT90 Pistons are an exact match to the CL 175 Pistons in bore size and dimension (minus the large crown that the CL 175 has). I was really fortunate that the bore job wasn't an issue. So, if you are working on a CL/CA/CB 160, and you need pistons, then the oversized CT90 pistons should work nicely. I think they go up to 54.00mm but I don't know if that is recommended. I'll report back one final time once i get the engine fully buttoned up and in the bike. Thanks all.

 

[intercepter]

Well it seems that the I've run into a snag. I thought i was going to have a glorious afternoon getting everything reassembled but the new pistons are hitting the cylinder head. I assume the 160 cylinder head is a couple mm small in circumference now post-bore to 52mm. Any recommendations on getting the head machined to match the new bore. I presume this is my only option. Any suggestions? New Post? THanks

 

[66Sprint]

Did you appropriately upsize the head gasket?

 

[intercepter]

Yep, i got the 175 head gasket, dowels are all aligned. I think it has to be the interior "dome" portion of the cylinder head that is too small. I'll take some measurements and pics of the old piston vs new piston tomorrow hopefully. But from what I recall, they looked the same in basic dimensions.

 

[chaindrivecharlie]

Ask your machinist if he can recut the dome of your pistons, if that is the problem. But how far is the piston coming up into the cyclinder barrel?

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