Topic: CB400F 54.5 Piston Kits

[Owned]

I've seen with some regularity 54.5 mm Japanese Piston Kits on eBay for the CB400F.  Does anyone here have any familiarity with these?  They seem to be complete:  pistons/rings/clips/pins and head gasket.  The price seems to be affordable. 

Can I run the std carb set up?  Jet tuned of course.

Thoughts?

[david 750f]

Dynoman sells the 54.5 mm piston kits for the CB400F as well.

http://www.dynoman.net/engine/pistons/custom.html

[Owned]

Dynoman's are $650.  This kit is under $200.

Does anyone have experience with this seller's product?

[Kevin]

The kit's on eBay for $250.00 are made in Taiwan, the seller is in Japan. That's about all I know about them.
Dynoman's kits are $700.00, 10.3:1 compression ratio.
The 400Fourstore has 10.5:1 466cc kits with Total Seal rings for $750.00.
The Total Seal rings are a must for race engines.

[Tim2005]

Those $250 kits do look good value, his feedback seems pretty decent too. Don't forget to factor in the cost of boring, plus a new camchain and tensioner blade while you're in there. You can run std carbs with a 460, try 85 mains as a starting point if you're using stock airbox and exhaust. Once it's run in, if possible get it on a dyno to sort the jetting properly.

Talking of 460s, anyone know where there are supplies nowadays of rings for the old Yoshi 54mm kits?

[Kevin]

I would still be leary of the Taiwan pistons, good feedback doesn't count for alot when he may have sold five sets. I doubt that many (if any) have actually been run in.

If you find a source for the 458 rings I would sure like to know about it. I have been looking for years without any luck.

The 400FourStore has rings for the 54.5mm (466cc) pistons available.

[Tim2005]

I know what you mean, tho he's also sold numerous Kawa triple kits & the owners of them tend to know what they're doing. Of course, there's no way of knowing how long the kits will last though (or if you can get rings...). 

Is there anything particularly special or unusual about the 54mm Yoshi rings?  Presumably in the intervening 30 years (blimey!) there's been several bikes made with 54mm bores, certainly loads of 2 strokes were 54x54, so maybe there's a 4 stroke 125 or something out there that we could use the rings from?

[Kevin]

I do not know what is so special about the 54.0mmm rings, I have asked dozens of ring / piston companies and none were able to match the smaples I provided.
I import from Yoshimura Japan and even they can not get the rings.....