Ended up ordering a genuine Honda 6305 bearing from David Silver but he didn't have the 6206 so I went for an SKF 6206 ( described as STD clearance ) so actual price is very close. When I have both it will be interesting to compare relative "looseness".
Phil
CB72/77 Gearbox Bearings Clearance ?This is just an observation as the data is too confusing.
I got a Honda 91003-KY2-003 bearing ( supersedes 6305HS ) from a Honda dealer and an SKF 6305N from a bearing stockist and compared them. The Honda bearing is an NTN made in Japan and is marked 6305 x 14N x 17 JAPAN 15C-5 ( so C5 clearance I guess ) and the SKF is just 6305N, so STD clearance. Looking at old bearings most of the equivalents were made by NACHI and marked 6305HS4 with no "C" markings ( could the 4 mean C4 ? ) I then put the new bearings in the soft jaws of a vice taking care not to put too much pressure on the outer race, and attached a dial gauge sitting at right angles to the inner cage and pushed that cage upwards - note I did not "rock" it. Did the same for the NTN 6305N made in Taiwan bearing that had been in the engine. Readings were :- NTN 6305 15C-5 0.008"-0.009" ( Imperial Dial Gauge ) SKF 6305N 0.005"-0.006" NTN 6305N 0.022"-0.023" - this is the one that came out of my engine. The only real conclusion I can come to is that the 6305 that had been in the gearbox is goosed. The 2 new bearings do have different sideways clearances but seem to have negligible "rock" measuring by feel. If the HS4" bit on original NACHI bearings had any significance regarding clearance then the new one from Honda is different. Its all very confusing and I think I am going to use both the SKF and the Honda bearings in different engines and presume all will be well. Oh, did contact a bearing supplier and he thought STD clearance would be OK in a gearbox but obviously he is not a 250/305 expert. Thanks to all for their thoughts on this, Phil
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