Long lost new member reintroduction...

[moonpup]

Steve..... yes, the damaged float posts were such an issue that Bridgestone/Rockford ended up producing a repair kit consisting of 2 brass bushings, an extra float pin and instructions for installing. Here's some old discussion about this issue....

https://bridgestonemotorcycleparts.com/index.php?topic=1154.msg3905#msg3905

The kit instructs that the damaged post holes are to be drilled out (with a drill press / not by hand) using a 5/32 drill bit. If you can fit this size drill bit freely through your posts, then this kit would not work on your carbs. Let us know what you find out.

[BRT-GTR]

   Hi again Steve, you asked about other effects of vibration on the frame etc. It is known that the rear engine mount bracket on the downtube can develop a fracture, usually at the front near the weld to the downtube. I have had one of the rear triangular engine mount plates fracture.
   Good luck with your restoration, Brian

[Steve Swan]

Steve..... yes, the damaged float posts were such an issue that Bridgestone/Rockford ended up producing a repair kit consisting of 2 brass bushings, an extra float pin and instructions for installing. Here's some old discussion about this issue....

https://bridgestonemotorcycleparts.com/index.php?topic=1154.msg3905#msg3905

The kit instructs that the damaged post holes are to be drilled out (with a drill press / not by hand) using a 5/32 drill bit. If you can fit this size drill bit freely through your posts, then this kit would not work on your carbs. Let us know what you find out.

Hi Mike,

Thanks for that tip and link to the very interesting thread on this vibration problem affecting the posts.  The holes are smaller than 5/32"  Are these kits still available...?  (i'm kind of assuming not, but...)

[Steve Swan]

   Hi again Steve, you asked about other effects of vibration on the frame etc. It is known that the rear engine mount bracket on the downtube can develop a fracture, usually at the front near the weld to the downtube. I have had one of the rear triangular engine mount plates fracture.
   Good luck with your restoration, Brian

Brian, thanks for your reply; good to hear from you.  i imagine sooner than later i will replace the cushions. It's a bit dismaying there's this much vibration, but on the other hand i'm not surprised; pretty typical of machines from that era and earlier.

[moonpup]

Per the float post repair kits,  check with either Richard or CPC... won't know unless you ask. 😁

[Steve Swan]

   Hi again Steve, you asked about other effects of vibration on the frame etc. It is known that the rear engine mount bracket on the downtube can develop a fracture, usually at the front near the weld to the downtube. I have had one of the rear triangular engine mount plates fracture.
   Good luck with your restoration, Brian

Brian, thanks for your reply; good to hear from you.  i imagine sooner than later i will replace the cushions. It's a bit dismaying there's this much vibration, but on the other hand i'm not surprised; pretty typical of machines from that era and earlier.

Check with either Richard or CPC... won't know unless you ask. 😁

Thanks, Mike.  Will do. 

[Steve Swan]

Hmm.  I am wondering why pins couldn't be made from Delrin rod.  i've used Delrin in the past, it has many applications.  is even used for making ball bearings, automotive parts and much more.  if the pin was made of Delrin, then the float wold not be ratting against hard metal.  i could turn the Delrin to the size of the existing holes with a very minimal interference fit, just enough to push the pin in by hand.  Here's a link about Delrin  http://www.complast.com/delrin/DelrinData.pdf

[OldSwartout]

Delrin sounds like a good idea. I have broken off a post before, trying to drill it. 

It is also possible to make bushings using 5/32" brass tubing from a hobby or hardware store, then insert a 1/8" piece of tubing inside that and use a #40 drill bit shank for a float pin.

Check your email, I sent a message regarding the BS repair bushings.

[Steve Swan]

Delrin sounds like a good idea. I have broken off a post before, trying to drill it. 

It is also possible to make bushings using 5/32" brass tubing from a hobby or hardware store, then insert a 1/8" piece of tubing inside that and use a #40 drill bit shank for a float pin.

Check your email, I sent a message regarding the BS repair bushings.

Karl, thank you for your kind reply; i replied to your email.

Yeah...  drilling out those posts is a bit of a scary thought; one i will need to approach with forethought and care. As i recall, the posts are not degraded.  I'm glad to hear you think the Delrin is a viable option.  I'm just trying to think outside the box, if you will...

[moonpup]

Steve, the attached pic is an example of how I hand drilled out a set of posts on a set of carbs that needed the bushings. The carb pictured here is my already destroyed unit that Ive cut apart to examine the various passageways in the body.

I just used my tap handle with the 5/32 bit to slowly open up the hole to the correct diameter.  This way I could constantly keep check on the bit's angle. (use oil and go slowly..... don't force things.) I also went straight through to the other post to insure that the float pin would be straight and not bind.

I don't have a drill press, so this was the best way for me. It worked out great.

[Steve Swan]

Steve, the attached pic is an example of how I hand drilled out a set of posts on a set of carbs that needed the bushings. The carb pictured here is my already destroyed unit that I've cut apart to examine the various passageways in the body.

I just used my tap handle with the 5/32 bit to slowly open up the hole to the correct diameter.  This way I could constantly keep check on the bit's angle. (use oil and go slowly..... don't force things.) I also went straight through to the other post to insure that the float pin would be straight and not bind.

I don't have a drill press, so this was the best way for me. It worked out great.

Mike, thanks for your reply and the great picture!  Although i do have a drill press, i am inclined to drill the holes by hand, I'm pretty good with my hand work.  I did order some 3/16" Delrin rod, so once i have the rod, I'll measure the holes in the posts and see what diameter the rod would need to be turned down to fit the undrilled holes and decide what I might do from there.  Delrin is pretty rigid, so i would think in that short distance that small diameter of Delrin won't flex and won't rattle around like the brass pin.  Karl has graciously offered me a set of bushings, so if the Delrin does not work out, i can go with the bushings.  if i can get away without drilling, i'd feel better...  Was nice to find the YR1 7 mm float valves as with drilling and tapping, i only get one chance to make it right.

[MitchB]

Reading through these posts re. the carb "difficulties" - one has to ask: is it possible to simply buy new carbs? Are they still being manufactured, or is there a viable alternative..?

[disc valve]

Testing 1 2 3

[disc valve]

When i repaced my cusion mounts i tried to set the upper 2 sets of mounts taking most of the weight of the engine because theres not a lot to stop the weight bottoming out on the lower mounts otherwise

[Steve Swan]

When i repaced my cusion mounts i tried to set the upper 2 sets of mounts taking most of the weight of the engine because theres not a lot to stop the weight bottoming out on the lower mounts otherwise

Thanks for your reply!  Could you give a bit more context of you mean that you "tried to set the upper 2 sets of mounts taking most of the weight of the engine because there's not a lot to stop the weight bottoming out on the lower mounts otherwise?" 

You installed the upper cushions first rather than installing the bottom cushions first? 

if you installed the top cushions first, was your engine already in the frame?

[Steve Swan]

So i picked up my GTR last week from my friend Ray with 58 years of 2-cycle experience!  As i have other projects tying up my 2 lifts and not that much experience with 2-cycle, it made sense to have Ray get the bike back to fine running order and that he did!  I never imagined the GTR could run so well, like a scalded ape!  I'd like to also thank Richard Clark for helping me out with his parts that otherwise without i would not have the bike on the road.  For being 54 years old with 6,781 miles on the clock, the GTR looks pretty good. 

A question:  Can the transmission oil level sight glass be removed from the outside and a new one pushed in from the outside?  Usually i would think the new glass would need to be pushed in from the inside...

[moonpup]

Hi Steve,  I'm pretty sure you can remove and replace from the outside. I'd make sure you had a clean oil free surface when installing the new one and I'd also recommend using some sealant when doing so.

On a side note, I noticed your bike has had the right shift/left brake conversion done. Just wondering if that was something you did or did you buy it that way. You're lucky to have the rare kick start lever!

[Steve Swan]

Hey Mike!  Thanks for your comment!  Yes, since i have some British bikes and since the GTR allowed for that conversion, i went for it after i bought the bike.  It's a nice touch that adds to the GTR's distinctiveness.  The kick lever is "converted" following the diagram Brian provided.  It was with your help and others that i found the parts i needed.  >>>  https://bridgestonemotorcycleparts.com/index.php?topic=4839.msg28951#msg28951 

[moonpup]

Oops  😳 , forgot all about that.... please excuse the massive brain fart! 🤣

[Steve Swan]

Mike, no worries! Seems we're all doing pretty well for old men