Bridgestone Motorcycle Parts Discussion Board

Bridgestone Tech Talk => 350 Talk => Topic started by: erniegroen on May 11, 2020, 02:12:29 PM

Title: Crankshaft seals
Post by: erniegroen on May 11, 2020, 02:12:29 PM
I bought a 350 gtr basket case and now started the restoration. The first problem I discovered with the crankshaft. The previous owner has renewed the outer bearings and probably destroyed the seals 09090-117 during disassembly. I think the seal is important for the bigend lubrication! I want to use the oil pump later and I am thinking about making new seals. Is there anyone who still has old (or new) seals left and wants to sell them? Or can someone help me with an image or drawing of this seal? I am also looking for a good used or new piston.
Thanks in advance, Ernie
Title: Re: Crankshaft seals
Post by: AlanJohn on May 11, 2020, 03:12:50 PM
Your on the right site l take it you've asked the site owner Richard Clarke he's the man you need to talk to
Title: Re: Crankshaft seals
Post by: BS Mechanic on May 12, 2020, 07:56:46 AM
It is my belief that the seals were added as a design requirement by the marketing department so they could advertise the "pressure lubrication", NOT by the engineering department.  The seals provide no benefit to the bearings, and instead pose a very real risk. 

Although most will stay in place, a few do become loose and cause catastrophic damage.  They are definitely NOT worth the risk, as Bridgestone determined during production.
Title: Re: Crankshaft seals
Post by: OldSwartout on May 12, 2020, 08:27:52 AM
They took them off briefly in production, but then put them back. They are needed, but probably only if you run high RPM for extended time, IMHO. The rods do not have slots to allow fuel mix to get to the bottom end bearings like most high performance two-strokes. To get adequate fuel mix to the bearings through the drilling in the crank pin requires a collection annulus.
Title: Re: Crankshaft seals
Post by: bert Lilley on August 27, 2020, 02:05:26 PM
 I roadrace my 350, never used them never need them, felt they where a hazard in a high revving engine just something to go wrong, but i don't run oil pump same thing just something else to go wrong.   Bert VRRA 98