Bridgestone Motorcycle Parts Discussion Board
Bridgestone Tech Talk => 350 Talk => Topic started by: Steve Swan on August 09, 2021, 07:21:26 PM
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Hello All,
This is Steve Swan in Fort Collins, Colorado. It’s been much longer than I want to admit since I last posted anything about my GTR. In advance, thank you for all the willing and kind help I received when I took delivery of my ’68 GTR back in June of 2018. At the time I was in the middle of graduate school and so my anything to do with motorcycles was a welcome and limited side relief… Last year was a horrible fire year in Colorado, finishing up graduation and then working full time off and on… So much for2020.
I did get to ride the GTR a bit, long enough to get a bit more familiar with it to realize the clutch seal was the cause of blowing smoke out the right exhaust and then the large pool of oil that would accumulate as the bike rested on its center stand…
The last service shop I worked in was a good friend’s and since his retirement he accepts jobs of his choosing; I’ve been waiting since late 2019 for his schedule to clear so he could put the GTR on his lift and give it a thorough going over considering it was a survivor with 6,600 miles on it. Ray has raced and ridden 2-strokes the past 58 years of his 74 years, so I really feel fortunate that he would take the GTR on even though it is the first Bridgestone he’s ever put his wrenches to… I took the GTR to Ray’s the week before last and he has since called with a fairly extensive (expected) list of additional seals, O-rings and a couple more gaskets than I had brought up to Ray when I dropped of the bike. Apparently the GTR is leaking oil from just about any place that oil can leak from…
I placed an order with Richard through his email and his 6x6 site last week and since I’d not heard from him, I made a call. A gentleman answered my call who was not Richard and told me that it’s going to be “several weeks” before Richard catches up with parts orders and couldn’t be any more informative that that and as I am not a pushy person, I thanked him for what he told me and that was that. The gentleman’s answer seemed a bit puzzling to me as I had bought a gasket off Ebay from Richard and it arrived all the way from Indiana to Colorado in 4 days which exceeded my expectations… I am wondering if any of you fellows have placed orders to Richard using his email and/or his 6x6 site and if you experienced an extended delay of several weeks or got your parts in less than a several weeks…? To me “several” means 6 or 7 weeks… Maybe this gentlemen’s answer was designed to not get my expectations up in the case the parts would be shipped in a shorter period of time…
In the future, I will not go MIA nor be so delinquent with my participation as I never felt good asking for the help in 2018 that was so freely given to me including a warm new member reception and then disappearing sight unseen until now.
Anyhow, I am attaching a picture of my GTR taken shortly after I took delivery of it. 2019, another friend of mine modified a spare kick lever so I could complete the RH shift/LH brake conversion, so that is pretty darn cool. 2019, I was able to take the GTR out for 45 mile ride and it became apparent before I would out any more miles on the bike, it would need some service work to make everything right.
In closing, I want to repeat my thanks to Karl, Brian and Moonpup for all the help you gave me when I first introduced myself.
Thanks in advance and kind regards,
Steve Swan
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Oops, sorry for double posting...
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Just to follow up, Richard has sent the parts out, he had every part that i needed. mostly all rubber parts, s anywhere the engine could leak oil from, it did... The parts will be here Wednesday, so i am looking forward to getting them to my buddy Ray. The oil pump looked like it had been apart, there was ThreeBond suggesting it had been apart... So, Richard sent me a new oil pump. Pretty amazing when one thinks about the readily accessible parts availability for a 53 year old motorcycle. i am grateful to Richard for having the long ago foresight to buy 30 tons of nos parts when BS went belly up...
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Hi Steve, welcome back and glad to hear you still have your GTR and by the sounds of it, getting some needed attention. Hopefully it'll run like a top when finished. Good luck and keep us informed.
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Thanks Moonpup! i looked through all my records and regretfully could not find your name. Indeed, i shall be more active as the future unfolds. Yes, the old GTR is getting a much needed thorough going through; we are making progress. Just placed a second order for a few more parts a few minutes ago with Richard. The neutral switch and contact are a couple of them, the 53 year old plastic has degraded to the point of no return...
A bit of a part number conundrum on the float valves... The factory parts book calls for 1660-9000, when i ordered them from Richard, he asked if i was sure of that pn, triple checking myself, i answered yes, pn 1660-9000... What i received was 9 mm seats; 7 mm is what is needed. i would appreciate it anyone could add some illumination as to what is what...
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Steve, the 9mm float valves are for the carbs after serial # 21H. Basically that means all the 70 GTO's and 71 GTO's / GTR's. The part number for these is 1660-9010 and that is what you apparently received.
You need the 7mm (1660-9000) for the 67-69 GTR's. I don't believe Richard has any of those left, but I could be wrong.
Good luck,
Mike
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Hey Steve,
We are all still here, even if we don’t post that often.
With the float valves, I had trouble getting the 7mm ones for my wife’s Kawasaki Samurai, so I drill out the carbs to 9mm and can now use new off the shelf float valves!
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Mike. You have it backwards, 1660-9000 are 9mm and 1660-9010 are 7mm, I went through the same thing, yes I did end up drilling the carbs to use the 9mm ones, as there were no 7mm ones to be found.
Sam Keys
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Thanks, Mike, Sam and all. Richard already replied and does not have the 7 mm float valves. My friend is going to see what he can hopefully cross reference. The other thing i imagine you folks have run into is the plastic of the neutral switch being degraded, which in the case of my GTR is allowing oil to leak. it sounds like Richard may not have that one. What have you fellows been doing in cases where your switch needs to be replaced? Kind regards, Steve
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Mike. You have it backwards, 1660-9000 are 9mm and 1660-9010 are 7mm, I went through the same thing, yes I did end up drilling the carbs to use the 9mm ones, as there were no 7mm ones to be found.
Sam Keys
Sam, I must politely disagree with you. The information in my post is absolutely spot on!
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I agree with Sam. I have a whole unopened bag of the 9mm ones, with part number 1660-9000
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I agree with Sam. I have a whole unopened bag of the 9mm ones, with part number 1660-9000
Congratulations Jeff on being the proud owner of a bag full of mis-labeled float valves! banana
https://bridgestonemotorcycleparts.com/index.php?topic=3219.msg16527#msg16527
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Everything I have indicates the 9mm float valves are for the carbs after serial # 21H which is the 70 and 71 GTO and GTR. Part number is 1660-9010.
The 7mm is for the 67, 68 and 69 GTO and GTR. The part number is 1660-9000.
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Yes You are correct as always, I have a bag of parts that BS labeled wrong.................
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Thanks, Mike, Sam and all. Richard already replied and does not have the 7 mm float valves. My friend is going to see what he can hopefully cross reference. The other thing i imagine you folks have run into is the plastic of the neutral switch being degraded, which in the case of my GTR is allowing oil to leak. it sounds like Richard may not have that one. What have you fellows been doing in cases where your switch needs to be replaced? Kind regards, Steve
To follow up on the early 7 mm float valves... My friend was going through his carb parts and found that the float valve for the 1967 Yamaha YR1 is the same as the pre-70 GTR's. So, i ordered a pair and will report back...
On the broken neutral switch, talking with my friend, apparently 2 of the tabs are broken off, these tabs being approximately 1/16" thick... I've not seen one of these switches, if Richard doesn't have a switch, then I'll be going up to my friend's to pick up the switch and see if i can do some of my good 'ol farm boy fabrication magic on it... Who has had success conserving one of these wounded switches back to use? Or does anyone have a switch they would sell?
Jeeze, if it wasn't for Richard's foresight, a lot of us would be screwed.... :-X
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Glad you got the valves sorted, if you need to find some dimensions on sizes, try www.mikunioz.com . Tom Hatrick is very knowledgeable in this area.
Also, Did I spot a J model Harley in the background?
Hardy
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Glad you got the valves sorted, if you need to find some dimensions on sizes, try www.mikunioz.com . Tom Hatrick is very knowledgeable in this area.
Also, Did I spot a J model Harley in the background?
Hardy
Hi Hardy,
Thanks for the link to Mikunioz. i have it in my files. yes, indeed you have spotted a J model. 1927 JD. that was a nearly 4 year/700+ hours build, modeled after my Dad's '27 that he bought new in 1927. I have many pictures of him from that time. i built a 2nd '27, it has Carrillo rods, JIMS pins, Venolia pistons, electronic ignition to name a few goodies that make it care free road worthy. My taste in bikes is pretty diverse, my collection consists of bikes i owned and rode as a kid and bikes i lusted after but couldn't own. The GTR is one bike that never left my mind after seeing ads and reading road tests when i was a 15 year old farm boy back in 1967. I'm really looking forward to getting my GTR back after my friend finishes it up and see how the factory intended it to run when new. Thanks for the tip on Mikunioz. Take good care!
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i'm happy to report that 1967 Yamaha YR1 Keyster carb kits contain the very same 7 mm float valves fitted in the pre-70 GTR carbs. Thanks to my friend Ray, i snagged a pair of kits off ebay. I hope they are not too hard to find for anyone who wants to go this route.
On another note, it was surprising to find excessive wear in two towers of each carburetor that hold the pin that holds the floats in position. Worn nearly 2 mm larger that the diameter of the factory pin. New ones were made from the necessary diameter of drill rod. I can only imagine the wear results from engine vibration...?
i have a full set of the rubber cushions the engine is mounted to. Is it possible to replace these cushions without removing the engine from the frame?
i was able to epoxy together the two halves of the neutral switch, so that is a welcome save.
Thanks in advance and kind regards.
Steve
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The lower engine mounts must be removed upward. There is a shoulder at the bottom of the bore in the frame to keep them in place, so they can't be removed downward. The only way I've been able to change them is to remove the engine. Improvise a puller using a long bolt and a couple of sockets to pull them upward. That usually results in ripping out the guts, leaving the shell in the frame which then has to be cut or collapsed with a chisel.
If anyone else has figured out something different, chime right in. :)
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The lower engine mounts must be removed upward. There is a shoulder at the bottom of the bore in the frame to keep them in place, so they can't be removed downward. The only way I've been able to change them is to remove the engine. Improvise a puller using a long bolt and a couple of sockets to pull them upward. That usually results in ripping out the guts, leaving the shell in the frame which then has to be cut or collapsed with a chisel.
If anyone else has figured out something different, chime right in. :)
Thanks for your reply, Karl. Once i have the bike back home, i'll look things over a bit more. Not having the bike here is a disadvantage. i can't help but wonder if all the engine to frame fasteners were removed if a jack couldn't be placed under the engine so it could be lifted up high enough to remove those cushions. Or, once the engine is unfastened, and as it is raised in the frame does it hit the frame before it can be raised high enough to get the cushions out of the cups? The only problem with my idea is that it is not founded in your experience, so i can only imagine that it is something undoubtedly you have already tried...
i'm also wondering if the cushions are bad, how this affects other chassis parts, i.e., bad vibrations... 8) https://www.youtube.com/watch?v=Eab_beh07HU&ab_channel=StephenMcElvain
Even with good cushions, does the engine vibrate so much that it wears the holes in the towers that the float pins go through?
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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.
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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
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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...)
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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.
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Per the float post repair kits, check with either Richard or CPC... won't know unless you ask. 😁
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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.
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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
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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.
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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...
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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.
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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.
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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..?
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Testing 1 2 3
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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
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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?
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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...
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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!
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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
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Oops 😳 , forgot all about that.... please excuse the massive brain fart! 🤣
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Mike, no worries! Seems we're all doing pretty well for old men ;D 8) ;D
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Dang! Winter is here in Colorado, cold temps and lots of wind! Mid and upper 50's temps forecast in the next week, so hope to get another ride in!