Service Standards Manual?

[bsracer]

I thought I may have asked before but has anyone ever heard of the Service Standards Manual? I have the early printing (Aug 65) of the 175 Technical Handbook. It refers you to "refer to Service Standards Manual" in many instances. I'm trying to see if there is a clearance given for the shift fork to gear. I'm going to have some shift forks hard chromed and it would be helpful to have the factory clearance.

Thanx   paul

[OldSwartout]

Paul, you might measure the clearance on some of your spare parts on the other shift forks. Some of them are probably not worn much.  Measure several and plot values on a graph, you can probably easily estimate the nominal clearance they started with. 

I've never seen a Service Standards Manual either (that I remember).

[bsracer]

Thanx Karl,

but I wish I was retired to have the time . I still have to make some kind of fixture to measure the forks (hopefully rob north will lend a hand) to see if they are bent , then grind them true so they can be built back up with hard chroming. The guy at the machine shop gave me a rough estimate of $1000 set up not including the hard chroming. He suggested I check them for true and grind down the scored areas to save some $$$. There is a Service Standards Manual of ebay for a 90. Do they give clearance specs like that or is that too technical?

http://www.ebay.com/itm/Bridgestone-Service-Standards-Manual-Bridgestone-90-/140790723543?pt=Motorcycles_Parts_Accessories&hash=item20c7c7f3d7&vxp=mtr

paul

[disc_valve]

Hi, Paul.

I do have a set of Service Standard manuals, but they are not too helpful in this case. None of the manuals give a figure for guide fork side clearance. The only related figure is one for fork end thickness, but the that is only given in the 50 Sport and 90 manuals, not for the 175.

So, I reckon your only route is to measure the thickness of the ends on a good fork if you have one and use that as a guide for any grinding. Are you sure, though, that you can't get another good used fork from a fellow site member (or even a NOS one from Richard). That's GOT to be cheaper than trying to reclaim a damaged one.

Graham 

[ziggy stardust]

z

[moonpup]

Here's another 90 manual on UK ebay...

http://www.ebay.co.uk/itm/Book-Motorcycles-Bridgestone-90-Service-Standards-Manual-1960s-Free-UK-P-P-/380284723494#ht_1853wt_1161

[bsracer]

Hi Graham,

Richard doesn't have any and neither does Certified. I'm after the other shift forks, shift fork A 2541-8000. I got a couple from Richard a few years ago but burned them up. I probably have a boxful of burnt up ones. I'm also trying to correct the transmission problems. Having a couple of more gears undercut then hoping fixing the shift forks will keep the bike on the race track.


paul

[slawsonb]

Thinking about this issue a bit. Hard chrome will make the surface more wear resistant, but so would a premium gear lubricant. Have you tried synthetic gear lube, heavier weight, etc? Sounds like you are pushing the design envelope. If this is ground you have already plowed, sorry to complicate the discussion.
...bert

[bsracer]

I usually run a non-detergent 30wt oil. I have seen problems with other vintage racers and the use of synthetic oils (Mobil 1 in particular) with the clutch slipping. The design is similar to Kawasaki H1 which were notorious for shift fork problems. Mass produced bikes were made without consideration for attention to shimming up the transmissions properly. If i get some good forks, I will also have to do something about shimming up the gears for better alignment. I did fit some custom pins in the forks to tighten them up, but that didn't help much. The degree of slop in the engagement gears (the ones the forks ride on) is pretty bad.

paul

[BRT-GTR]

Hi Paul,
          Just my pennyworth. As far as I know a lot of the BS models seem to have an issue with selector fork blueing/wear. I am starting to think the primary issue is, the gear dogs are too small,I.E. not enough surface area to drive on. The GTR, 37bhp, has only about 4x5mm= 20sq mm surface area on each dog tooth (just buried spare cluster in crate).  This allows side thrust to be generated which is resisted by the fork and guide pin,with consequent heat and wear. Plus maybe poor production tolerances as you mention above.
        My little Aermacchi, 25bhp at the back wheel where it really counts 11,  has 5x5mm=25 sq mm dogs (25% more) and I seem to remember a BSA Bantam, 10bhp if you were lucky, had about 36 sq mm of dog area, nearly twice as much for a quarter of the power !!!. Draw your own conclusions . The general finish/trueness  on the other dogs/gears does seem better. Maybe BS skimped on the box, not likely, or were not used to designing for the power a 350 would produce, more likely.
   Very early on, 2 months after production started, BS recognised an issue with dog blueing/scoring on the GTR and issued a mod for the 5th gear fork. The solution? was to grind a groove 5mm x 3mm x 0.4mm deep on both sides of the fork fingers at the base (inner end) of each contact area to get more oil in and improve lubrication,. Easily done with a Dremel. Might be worth a try. They obviously didn't just thin the fork to get oil in . Common sense says it might be better to put the groove on the upstream side of the gear /oil flow direction but don't know if this would give other consequences.(Can't give exact mod ref, didn't print on my copy but is on this site).

Hope this helps, Brian the Brit.   ( We started all this Engineering lark but didn't know how or wouldn't spend the money (more likely), to fully exploit or sell it, that why were not still GREAT Britain +a  few other issues )

[bsracer]

Thanx Brian,

I looked for the service bulletin but didn't see it. I looked at the 350 service manual and they give a spec for the thickness of the fork as well as the min thickness.

paul

[Bikenstein]

    that why were not still GREAT Britain +a  few other issues )

Then you would be Brian the Great