Author Topic: Need Help: 1969 RS200 MkII, Melting Hole In Piston & Crank Seal Leak  (Read 1034 times)

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Offline robinkwmack

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Re: Need Help: 1969 RS200 MkII, Melting Hole In Piston & Crank Seal Leak
« Reply #20 on: November 10, 2019, 11:43:24 AM »
Hey there, sorry for the delay! I did not get any notifications about responses to this thread and I am still stuck with this issue and as one of you said, it really does defy logic. I have gone through the carb multiple times with carb cleaner and I am still having the same issue. I even adjusted the float to allow a little more fuel to see if that was the issue but nope, and ran like it was getting too much fuel.

I will start using 91 octane and change the ratio as you recommended. I have been using only yamalube as my mix oil. Going to tear into it all one more time and see if one of the vents is clogged, but I am PRETTY dang sure I have sprayed out every last crevice in that damn carb. I doubt it is the float valve sticking since when I remove the float bowl fuel will gush from the tank as normal (through the fuel line into the carb). So it seems to be refusing to let more fuel in once the float bowl is filled for the first time, when running or not. It is a true anomaly. Last thing I need to iron out before I can truly ride it more than 3 miles. Runs great except for this issue and maybe needing some new clutch plates, but that's for a later date.

Thank you all again for chipping in, hopefully I can get at least one solid ride in before it's far too cold here in Western Massachusetts.

I'll be checking back here more frequently than I have before now that I know responses don't always send notification emails.

Offline rwgibbon

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Re: Need Help: 1969 RS200 MkII, Melting Hole In Piston & Crank Seal Leak
« Reply #21 on: November 10, 2019, 02:53:20 PM »
I just finished getting a 350 GTR running and no matter how many times
I cleaned and adjusted the right carb I could not get it to run properly.

The right carb did not appear to be letting fuel get through to the right
cylinder. Even though it always had fuel in its bowl.

I finally put a different carb on it and it now is running like it should. It idols and
responds to the throttle.

No matter how good you think you have cleaned the carb sometimes there is
something in one of the galleys you just can't clean.

Have you tried swapping the carb's?

That could help identify if it is a carb problem.

Good luck and don't give up.

Regards

Randy



Offline robinkwmack

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Re: Need Help: 1969 RS200 MkII, Melting Hole In Piston & Crank Seal Leak
« Reply #22 on: January 12, 2020, 02:24:54 PM »
Alright, since global warming has decided to show its nasty head with a 65 degree day in January here in Massachusetts, I finally had some motivation to try and dive into this fuel issue again and STILL NO LUCK!!!.

So! I put on yet another aftermarket petcock, this is the second one because the stock petcok was long gone and if I remember correctly leaking. I think I just tossed it?

These are the petcocks that I Have used, has anyone used these without issue? I am starting to think this might be what is wrong.

https://www.ebay.com/itm/BRIDGESTONE-200-SS-FUEL-TANK-SWITCH-VALVE-PETCOCK-ASSEMBLY-22mm/142089114440?epid=2239374381&hash=item21152bd348:g:p14AAOSwK89ZwuER

So, I am still getting the same issue, no fuel to the right carburetor AFTER the float has been filled. The line and float will fill as they should, then I will ride the bike for 1-3 miles and an air pocket will form in the line up at the carb as if a vacuum has been formed.....But only on that one fuel line. Left carb is fine. Today I put the new petcock on, removed and VERY DEEPLY cleaned the right carburetor, thought the issue was fixed, got to a coffee shop, and walla! Air pocket is back.

Again, left carb is fine, both carbs are adjusted as they should be, bike runs like a top, just will eventually run out of fuel on the right side. (I have already replaced to pistons thank you very much, heh)

Also, tank is very much venting, I can hear it, I even drilled extra holes to be safe, this issue occurs with the cap on or off, does not matter. I am able to fill the fuel line by leaving the petcok on and pulling the fuel line letting fuel spill into the line and then plug it back in. (how I got home)

So here are my only thoughts, I bumped into a buddy of mine and he mentioned could be ignition timing is slightly off and that's causing back pressure to build up just slightly. I would think if this was the case it would not run like it does (well).

My other thought is that these aftermarket petcocks are just not meant to work with these bikes. Sadly mine is long gone so I will have to source one from Richard, or find an old crusty one and rebuild it.


If I can't get this figured out I will just be selling this bike and moving on. Heck, my dream bike is for sale  only about an hour or so away so my motivation to keep figuring out this dang issue is dwindling.

Hope to hear from some, or all of you shortly and again, thank you for all of the help thus far.

Offline BRT-GTR

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Re: Need Help: 1969 RS200 MkII, Melting Hole In Piston & Crank Seal Leak
« Reply #23 on: January 13, 2020, 12:46:08 PM »
        These two strokes can be fustrating !, I've spent months trying to cure a light load running issue without success. Can appreciate how teed off you are.

         I have one of those fuel taps and in theory the outlets/filter chamber could airlock. Try swapping the two outlet fuel tubes over on back of tap to see if the fuel issue changes to the opposite carb.

        If OK, I can only suggest checking the float on the right side to see if it is catching on the side of the float bowl. I have found the floats can vary in where they are soldered to the cross arm.  Beyond that I'm stumped.
                        Brian.
« Last Edit: January 13, 2020, 12:51:30 PM by BRT-GTR »
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Offline robinkwmack

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Re: Need Help: 1969 RS200 MkII, Melting Hole In Piston & Crank Seal Leak
« Reply #24 on: January 13, 2020, 01:01:02 PM »
Hey, I appreciate the reply and thanks for appreciating my frustrations, ha. I will try flipping the fuel lines and see if if it switches sides, but leave the same fuel line to the carbs, just switch it at the tap.

I did have an issue with the left float where it had a hole in it but that was fixed, is there a way of making it so this float fits better if it is in fact catching or do I need a new float? It's just odd because if the float was catching I should have running issues, either too little or too much fuel to that side. The thing runs like a top though, just will run when cold and then won't get fueled once warmed up and ran.

Another thought I had is maybe the fuel line is collapsing somewhere? It is new and pretty heavy duty so I highly doubt it, but did notice the line gets pretty flexible once the bike is warmed up. I might remove the line and open up the carb boot hole for it a tiny bit and see if that does anything.

Any more thoughts are greatly appreciated seeing as I am kinda hitting a dead end and considering just moving back to the trusted 4 stroke thumper world.

Thanks again.

Offline OldSwartout

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Re: Need Help: 1969 RS200 MkII, Melting Hole In Piston & Crank Seal Leak
« Reply #25 on: January 13, 2020, 04:29:52 PM »
If a float is catching or dragging inside the float bowl, just bend the bracket a little. I've done that a time or two.
Karl Swartout
Mooresville, IN
BS175 Roadracer. BS200RS, BS175HS
BS350 GTR

Offline BRT-GTR

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Re: Need Help: 1969 RS200 MkII, Melting Hole In Piston & Crank Seal Leak
« Reply #26 on: January 14, 2020, 07:33:09 AM »
            Another thought based on your response above. What is the internal diameter of the fuel tube you are using. needs to be at least 4mm to provide adequate fuel flow.
           We are limited in the choice of fuel tube we can use due to the diameter of the hole in the carb boot. A thick wall tube might be closing up sufficiently to restrict the fuel flow, so that's worth examining.
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Offline robinkwmack

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Re: Need Help: 1969 RS200 MkII, Melting Hole In Piston & Crank Seal Leak
« Reply #27 on: January 14, 2020, 09:41:47 AM »
I can't remember the exact measurements on the fuel line but it is larger than stock due to the larger outlets on the aftermarket petcock. I did drill the carb boot holes slightly bigger but I think I might need to make them slightly larger. My thought is, everything seemed fine for while on my ride, at least, longer than usual, but once I stopped and checked after everything had warmed up, that's when the fuel stopped flowing. So I am thinking once the bike gets warm and the fuel line gets warm and pliable, that's when it might be collapsing. Now it is back to normal cold temps outside so I will try and get it warmed up to temp without freezing my ass off and see if a larger fuel line hole in the carb boot helps at all.


Problem is, I did already talk to my bank about a loan for this new (1979) bike.......Which is my dream bike, but regardless I would like to get this thing to have no issues so I can either enjoy it fully, instead of only 30 minute rides, or sell it for top dollar.

Thanks again for the help all, I will report back.

Offline OldSwartout

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Re: Need Help: 1969 RS200 MkII, Melting Hole In Piston & Crank Seal Leak
« Reply #28 on: January 14, 2020, 10:01:08 AM »
Another WAG, but If you are using larger fuel line than normal, do you have it tightly clamped to the spigots on the petcock? BRT-GTR asked if it was possible that an air lock wouldn't vent the air back into the tank. I think that is the case on any bike with a sediment bowl on the petcock. The fuel doesn't come straight from the tank, but goes into the bowl first. Air would have to travel up the line, then downward into the sediment bowl, below the fuel level in it, to get back up to the tank, keeping it trapped in the line.

I have also seen plastic/rubber lines with a hairline split or slit that would allow air in, in case of any vacuum at all, but won't leak liquid out. You might try replacing that line and making certain it is clamped tightly to the petcock.
Karl Swartout
Mooresville, IN
BS175 Roadracer. BS200RS, BS175HS
BS350 GTR

Offline robinkwmack

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Re: Need Help: 1969 RS200 MkII, Melting Hole In Piston & Crank Seal Leak
« Reply #29 on: January 14, 2020, 10:39:27 AM »
Thanks for the recommendation, the fuel line is new and is VERY tightly press fitted onto the outlets, no clamps needed. The fuel line is either 1/4" ID or 3/8" ID, I do not recall exactly. I do know that it is a very tight seal. The issue seems to arise once the bike is warm, thus why I am leaning towards a collapse down at the boot. Going to let the bike idle until it's hot so I don't have to freeze my ass off and enlarge the boot fuel line hole slightly and see if that changes anything. Should have an update by tonight.

Offline robinkwmack

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Re: Need Help: 1969 RS200 MkII, Melting Hole In Piston & Crank Seal Leak
« Reply #30 on: January 14, 2020, 04:17:20 PM »
Okay, so.....I just got back from a ride, the same distance as the other day, and I am still having the issue. This is with the fuel line hole into the carb opened up a little bit more and a brand new fuel line.


BUT!!!! I have an idea........The banjo bolt on the carb is still using the original fiber crush washers........wish do weep a little bit.......I am wondering if this is my issue, if it is pulling enough air in through it to cause this problem. It would make sense because it seems to show up when everything is hot.

Offline robinkwmack

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Re: Need Help: 1969 RS200 MkII, Melting Hole In Piston & Crank Seal Leak
« Reply #31 on: January 14, 2020, 06:26:49 PM »
Well frig.......I tracked down 4 aluminum washers and they were the absolute last the motorcycle shop had in a random mix box of washers, lucky me.....unlucky mean, turns out the threads for the banjo bolt were beginning to strip (inside the carb) and I ended up driving it home all the way. The leak got worse and worse the more times I tried to install the bolt........I think the shop I brought it to caused this issue, just as they had stripped a bolt on my oil pump.....So, it's either time to helacoil the inlet threads, or get a whole new carb............The saga continues and Richard hasn't gotten back to me in regards to other parts yet. Hoping to hear back soon.

Offline robinkwmack

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Re: Need Help: 1969 RS200 MkII, Melting Hole In Piston & Crank Seal Leak
« Reply #32 on: February 01, 2020, 05:42:21 PM »
Well folks.....I think this may be the end for me and this ole Bridgestone. I picked up a used carburetor because I thought the issue might have been the stripped threads on the fuel inlet letting air sneak in......Well cleaned the carb up good, installed it and the bike ran like a top still......but then the air pocket returned. Again, only on the right side and not the left. It only occurs when you are giving it throttle, doesn't seem to occur during idle and only comes about ones the bike has warmed up. I am perplexed

BRT-GTR you had mentioned checking crank case pressure. How would I go about doing that? Could this be causing a fuel issue? I am just convinced it is an issue in the carbm, fuel line or petcock seeing as air wouldn't be coming from the engine backwards into the fuel line. It may even be the aftermarket petcock, but it only happens when the bike is warm, which wouldn't effect the petcock, unless it is an airlock occuring and it takes that much time to really build up the vaccuum? But that doesn't make sense to me


BUT
Lucky for me, I found my dream motorcycle that happens to be a 4 stroke and a motor I already know inside and out so this was my last attempt at ironing out this issue before selling the bike and figuring out what I would be listing it at. It's sad because it runs so damn good, I am the second owner, first owner parked it dead in 1971 and I got it running in 2019 even adding turn signals! It's been really fun to work on, it is really fun to ride and I would keep it around if this issue was not present.


I will be listing it locally on craigslist (now at the lower price because this issue is still present) and will also list it on here. Feel free to DM me about it as well.

Thank you all for your help, I will keep tinkering on it until it is sold, but my main focus will now be on this new bike.


Offline BRT-GTR

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Re: Need Help: 1969 RS200 MkII, Melting Hole In Piston & Crank Seal Leak
« Reply #33 on: February 03, 2020, 03:32:52 PM »
    Sorry to hear you're giving up on the Bridgestone but I might do the same in your position.
    We are all perplexed by this one !!
       I'm pretty sure it's that aftermarket fuel tap air locking. The outlet drillings are right at the top of the filter chamber, there's nowhere to accomodate any air that comes back up the outlet tube. This air is unable to vent. My GTR taps are drilled slightly down the chamber and can still pass fuel with a small air build up at the top of the chamber.
       Alternatively, long shots, have you tried swapping the right coil or condensers. Both can fail when warm and don't assume that new old stock parts are ok. That's caught a few people out.
        Good luck, Brian.
« Last Edit: February 03, 2020, 03:49:35 PM by BRT-GTR »
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Offline AlanJohn

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Re: Need Help: 1969 RS200 MkII, Melting Hole In Piston & Crank Seal Leak
« Reply #34 on: February 04, 2020, 09:16:44 AM »
l've got a few Bridgestones and all of them get an air bubble in the fuel tubes but it's never stopped one running and l ride them all on a around trip of 28 miles with no issues l personally don't think that your problems are with the fuel lines and air bubbles

Offline BS Mechanic

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Re: Need Help: 1969 RS200 MkII, Melting Hole In Piston & Crank Seal Leak
« Reply #35 on: February 04, 2020, 01:31:04 PM »
I'll second AlanJohn's experience.  I've noted the air bubbles in my 350 ever since I replaced the original black tubes with clear ones back in about 1970.  As he says, it's never caused any problems in about 50,000 miles of riding. 

My suspicion is that air gets into the line due to engine vibration, but only enough to allow a few bubbles to come up from the carb bowls.  The fuel flows around the bubbles just fine, you just don't see it.  It really doesn't take much fuel flow to run the engine.

I suspect that either you have other problems causing overheating or piston damage, or you're just chasing ghosts.

Unfortunately I don't have any suggestions to help figure out if the problem you are seeing is actually stopping the fuel flow or just visible bubbles.

 


Offline robinkwmack

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Re: Need Help: 1969 RS200 MkII, Melting Hole In Piston & Crank Seal Leak
« Reply #36 on: February 05, 2020, 11:47:49 AM »
Well seeing as I have melted holes in and replaced two pistons already due to the fuel line running dry, this is not just a normal air pocket. I'm thinking about drilling the holes inside the petcock larger and seeing if that helps at all. I am starting to lean towards the aftermarket petcock, but the problem is, this is the second one, same design though, but the same issue. It is clear that zero fuel is coming from the tank once this issue starts up, thus why I am leaning towards air lock in the petcock.

But out of curiosity, how does one know if they are over heating? Also, how would this cause the fuel line issue? I am following the fuel/oil ratio that Richard recommends, fuel is plenty, lubrication is plenty and the bike runs like a top, pistons and rings are in wonderful shape too.

It's extra odd because I rode around for 200 miles with the aftermarket petcock, fuel issue happened after local shop touched it. He deleted the oil pump (one of the bolts was leaking) it is still attached but he removed the drive gear so air wasn't pumped in through the oil tank.

I'm going to try and drill out the petcock holes larger/maybe even just make it so it always flows (no on off, which will be a pain and require draining any time I need to work on it.)

Offline Jeff Bar

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Re: Need Help: 1969 RS200 MkII, Melting Hole In Piston & Crank Seal Leak
« Reply #37 on: February 05, 2020, 12:54:13 PM »
robin i do not mean to be a smart #%@# but if the problem developed after shop took off oil pump, perhaps that is where the problem is. just trying to help.  see  you Jeff

Offline OldSwartout

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Re: Need Help: 1969 RS200 MkII, Melting Hole In Piston & Crank Seal Leak
« Reply #38 on: February 05, 2020, 01:06:48 PM »
I don't think deleting the oil pump could possibly affect the fuel line; however, the line from the oil pump to the right side rotary valve intake could leak air into the intake stream if not properly capped. The line runs from the oil pump, then across outside the crankcase behind the cylinders to a fitting on the right side of the crankcase, where it matches up with the rotary valve cover inside, which routes the oil to the intake throat. If that line is open anywhere along that route and sucking air, it very well could cause your issue with overheating and destroying pistons.

Also, if the oil pump is still in place, as it sounds like in your post, depending on the position of the drive shaft in the oil pump, and if the oil inlet line to the oil pump is disconnected or the oil tank empty, it may be possible to suck air through the oil pump into the line to the right (or left) side. If you are not going to use the oil pump, the fitting where the line attaches to the right side crankcase should be securely capped. Likewise, the fitting where oil enters the left side rotary valve cover should be capped.
« Last Edit: February 05, 2020, 01:19:22 PM by OldSwartout »
Karl Swartout
Mooresville, IN
BS175 Roadracer. BS200RS, BS175HS
BS350 GTR

Offline BS Mechanic

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Re: Need Help: 1969 RS200 MkII, Melting Hole In Piston & Crank Seal Leak
« Reply #39 on: February 05, 2020, 07:41:11 PM »
Is it possible that something is limiting the fuel flow, but not completely stopping it?  I can recall such a case, where the fuel flow was obstructed enough to limit fuel flow to just slightly less than the engine required.  It didn't become evident while driving till the fuel bowl got nearly empty.  The engine slowly got leaner and leaner, and finally just slowed down.

I found it by disconnecting the fuel line from the carb, and watching the fuel flow rate into a separate container over several minutes.  Initially the flow seemed good, but it slowed to a much lower rate, not enough to supply the engine at anything but idle.  The root cause was some sort of "fuzz" in the fuel inlet tube in the tank.  It was slowing but not stopping the fuel flow.

 


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