Bridgestone Motorcycle Parts Discussion Board
Bridgestone Tech Talk => 175 & 200 Talk => Topic started by: johnrkeele on May 17, 2023, 05:16:12 PM
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I did a preliminary first start on the 200RS I'm bringing back to life. The rpms were high enough that I necessarily keyed on-off for the few seconds I ran it...until I noticed sparks occuring between the rectifier plates, and so then shut it down. I checked for the wiring connections being done correctly, then started again, and same high rpm and sparks happening between rectifier plates. I think I know what I need to do to get the engine speed under control.
Question...what silicon replacement rectifier are people using to replace the original 'three-phase bridge all-wave (system) rectifier' currently on the bike? Thanks, John K.
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You can use virtually any 3 phase, 5 wire rectifier but be aware of the size of the unit. Some are massive. I've sucessfully used these in the past on the 350 which used similar rectifier.
https://www.ebay.co.uk/itm/261313978134?hash=item3cd786df16:g:HroAAOxyGqZSX3NG&amdata=enc%3AAQAIAAAAwPrwwtBo03dn9CvUQNT7f%2Bj7p%2Fbzk1ymS%2F7wbtVDuR3NlOPIkz4%2BLaLyw7KQgUrO4lRVHEXjYKSTYzjW5592aNIe7uuG5WL%2F4r4Gn5nYGyxjyfFUvv3uonfMxTIMOrMqotdnb46lDzwgD5%2BNS%2BeNKdd1TbgcK7LEg8VujHZEy%2BwgObRyIZv%2BWEuu1bkRmW6MaB6UuYEPej6clHMOudoJ1vBt19ShMMZfe2Iz6qQdZxKGuzh1k28Fc6vd%2FSHpAqnxsQ%3D%3D%7Ctkp%3ABk9SR8TzlPOFYg
3 yellow wires from the alternator, +ve to battery, -ve to frame earth. I did have to attach a small heat sink. It works fine.
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Thanks, BRT-GTR. The rectifier you link to is the same one/source that I had put on my 'watch list' last night...and it makes me more confident on where I'm headed on it.
Now, topic shift, but same bike: I can't seem to find replacement carb bowl gaskets to buy. The one's I've made are showing seepage right away around the screw holes.
Looking for a source for carb float bowl gaskets.
Thanks,
John K.
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I bet Richard has those gaskets. Jeff Bar
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I've not received any response from Richard when I've emailed him, as instructed, for these gaskets, and previously for other parts. This has been the case
the several times I've tried to order parts from him.
John K.
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For carb parts I usually go to Sudco.
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Thanks for the note suggesting Sudco for carb parts. And I do have the silicone 5-pin rectifier ordered, but have the three-phase
rectifying accomplished with two 4-pin units arranged together to accomplish three phase while I continue with test start work/problem solving.
I thought I understood the immediate high speed from start problem, but I don't. I've made sure the thottle slides are in fact
fully closed, but starts immediately go to high enough rpm that I'm still doing the key-on-key-off to keep rpm from going too high.
I'm perplexed. Is it possible an intake air leak can result in high rpm...with the 'fuel' being 'auto lube' oil being fed in? I observed
abundant smoke I think coming from BOTH muffler exits (inserts removed). And did see when I removed the carbs very noticeable oil
in the left side...but surprisingly didn't find much of any in the right side. (and when I then checked the rubber header-to-muffler connection
I noticed some wetness on the left one but none on the right.) So that further puzzles me. The plugs both looked about the same
light oil wetness when I checked them following the short run time.
So the question...what's making the high rpm, with the throttles closed?
Thanks,
John K.
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(noticeable oil in the INTAKE CONNECTION on the left side)
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Well, I have more information now than I had when I posted this morning. First, I 'motored' the engine by turning the rear wheel
with the trasmission in second gear, for confirming good injector oil supply to the right cylinder as well as to the left...and found it to be so.
Then I checked again that the smidge of 'play' with my repaired throttle cable was getting the throttle slides to full closure...but it was
'fooling' me on that. So I did some further 'dremel' work on the cable stop on the throttle handgrip...and got results. Not quite all the way
there yet, but now expecting that a little more material removal with the dremel will get me there.
So I'm feeling better on the situation. Still need to get the carb float bowls to stay dry. Have checked that fuel level in the float bowls is at an
expected height below the top of the bowl. But my homemade bowl gaskets are not getting the job done. And I haven't found OEM spec
replacement gaskets yet.
John K.
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The float bowl flanges and mating carb body flanges are prone to warping, check with a straight edge.
Mikuni added strengthening webs on later carbs to reduce this. I have reduced the warp by spanning the bowl
or carb body across the open jaws of a vice and tapping down with a piece of wood and rubber hammer, (needs must or desparation).
As a last resort, I use Hylomar sealant on the gasket.
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I hadn't thought about the warpage possibility. Will check that.
Thanks,
JK
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The banjo fittings for the O.I. lines have a spring loaded check ball in them to prevent gravity flow when the engine is off. many times when you have one cylinder with an oily exhaust, that side will have a sludgy check valve leaking by and accumulating oil in the rotary intake area, or flowing down into the crank cavity where it gets pulled into combustion on start up until it gets evacuated and cleans up. Both of my 200's have this problem. Typical, especially after sitting for extended periods if the o.i. system hasn't been thoroughly purged and cleaned.
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I found that carb bowl gaskets for Suzuki K10 look same as for my 200RS, and have purchased those from patriotracingindustries.
Now I'm having trouble getting the 'neutral change case' and its 'neutral change plate' insert to install all the way back onto the
5spd/4spd rotary shift shaft/lever shaft. It seems to hang up at the point where the 'plate' (copper insert in the 'case') should be moving onto the larger OD at the base end of the shaft.
Any thoughts/guidance here?
I also don't understand for sure how the whole system works...the two wires from the case to the shift drum is where the ground occurs when the shift drum is in 'neutral' position.
So the 'case', and 'plate' unit must function together for managing current supply from the separate input wire to the 'case' when in 5spd 'return' position, and when in 4spd 'rotary'
position. But I don't see how the 'plate' works within the 'case' to make that happen.
Thanks,
John K.
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After working thru some fuel system and throttling problems, and with the 5-pin rectifier described earlier and installed,
I did a successful 'first ride down the road'. When I got back, I decided to get a multi-meter read on the charge rate voltage being
delivered to the 5amp AGM battery temporarily installed. After a few seconds, with no lights on, and at low to moderate engine rpm,
the multimeter was showing 15+ amps charge rate and still climbing.
With that, it looks to me that I'd better be using a rectifier-regulator combination unit instead of the rectifier-only unit that is
currently installed.
Any feedback/comments here?
Thanks,
John K.
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Hi John,
I doubt that the charging system is capable of providing 15 Amps, not at 13 volts anyway (and not without smoke).
I suspect your test equipment is providing bogus readings.
If we assume you have your meter connected & set correctly then the reason for the bad readings could be due to interference from the ignition system sparks.
This is quite common with motorcycles that have no spark interference suppression. Digital multimeters vary considerably in their vulnerability to this.
Try this for a start:
Disconnect your hook up for the charging current test, i.e. restore the bike to its normal connections.
Then clip your meter across the battery itself.
Note the voltage with the motor stopped and then start the motor.
If the voltage reading varies widely or does not seem believable then I suspect you have spark interference confusing you.
Analog meters are less susceptible to this but I suggest you add some spark suppression to the bike to allow the meter to read correctly.
Fitting spark plugs with a resistor is a very good idea and will drop the level of interference dramatically.
I recommend the NGK R series plugs, so for your bike BR8HS.
This will not reduce the performance of your bike at all and I suggest it may well improve it.
There is a technical explanation for this.
Don't fit suppressor type plug caps! If you have them fitted already replace for caps without resistors.
Resistor plug caps fail, usually intermittently, and are very difficult to diagnose.
I've never seen a plug with a failed resistor and you get a new resistor every time you replace a plug!
Let's hear if fitting R plugs reduces the charge current reading!
Best Regards,
Mike
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Mike...my bad...I meant 'volts', not 'amps'...seeing soon up to 15v on the multimeter where the battery was showing 12.5 volts before
starting and revving to moderate rpm for a few seconds. On further quick check yesterday, I did see that, with the lights turned on, the volt readings
went down to more reasonable number...more like 13 to less than 14v at the battery. Also, tho, on both rides, the engine responds well/runs well,
but with more than moderate/cruising throttle there is random engine miss, and would seem to get worse if more throttle applied.
Almost certainly is ignition based...ok again soon as throttle is reduced. Have not started to search this out. The right cylinder plug seems a bit less
'heated' looking, so I'm guessing that the miss MAY be on that cylinder only. (Before the second ride, I had changed from non-resistor 8H plugs to some
on-hand older 7H non-resistor, thinking that the plugs looked like they needed to be 'hotter' ones with the lighter riding I was doing.) I do take note
of your suggestion to use resistor plugs. since I have always assumed that non-resistor might be better for better running/less troubles.
Thanks,
John K.
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Ha Ha! Silly me then John - sorry for all the techno-babble!
The results you are getting is typical of a non-regulated charging system as in the Bridgestones.
Your idea of fitting a rectifier/regulator is a good one and will give you longer lamp & battery life.
The solid state rectifier you have already fitted will have raised the voltage a little from original.
I have obtained suitable rec/regs units from Tony at the link below for both my GTR350 & HS175.
http://www.oregonmotorcycleparts.com/VRRPM.html
His VRRRPM3S would be a good choice I think (this size wasn't available when I bought mine) - but ask Tony. He is super helpful guy.
If your ignition condensers are not new ones then they would be likely suspects for the cause of your ignition misfiring.
Your description does sound like an ignition fault.
The best way to decide if a misfire is caused by ignition or fueling is to ride the bike with buds from an AM radio in your ears.
Tune the radio off station. You will hear steady firing all the time if all is OK with the ignition. Or you will easily hear any ignition misfiring as it occurs.
Especially without R plugs fitted, as the signal generated by the sparking will be stronger.
All the Best,
Mike
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Mike, thanks for guidance to Tony and link to his rectifier/regulator...will check that out. Also thanks for your thought on condenser
being a potential failure mode on the engine random miss. Since sending my last response, I did a stationary restart...and now it was
running just on one cylinder...the right header pipe was not warm at all. Tonight I pulled the tank off to start checking the ignition
system out...and noticed that the right coil has had a brown colored leakage, from the area where the wire to the spark plug exits
the coil (took a photo...will attach it if I can figure out how to do). I can't remember when I've EVER had a failed coil on a
Japanese motorcycle... possibly this is the first(?).
John K.
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Hi John,
The brown dribble does suggest that some coil insulation has oozed out, perhaps due to high temperature.
Also of concern is the corrosion of the steel coil former. This is composed of many layers of thin steel sheets called laminations.
These were coated individually with a protective coating originally. This coating also electrically insulates the laminations from each other.
The insulation is important for the coil to be magnetically efficient and to produce a good spark.
Eddy currents are reduced by the insulation and if present Eddy currents produce heat apart from reducing the spark output.
The coil may still spark (in air) but the output will be reduced and strong, consistent firing in the engine will no longer be possible.
The insulation has clearly failed so I would replace both coils, leads & caps. This may not fix your miss but they need renewing anyway.
The coils used in Bridgestones are quite good but no ignition coil lasts forever. They have a hard life.
May I suggest you get some of the neon spark plug caps at the link below:
https://www.ebay.com/itm/202780295435?epid=2108732310&hash=item2f36a5c10b:g:r1sAAOSwYp5j2NPf&amdata=enc%3AAQAIAAAA4IQMgY%2BeD%2FL6fYKmbYz33CEHYQF6frtS0metLrBvYF2iA9X2%2FQnTzFi%2BbSSZwwSFUHiAuovZ5IECE6eF4eoM%2BOcXKKws8iIpmmvb0GjGqj4H%2FAdka%2BWf4BtTiaoyIpb5hibQQW8KGnEy3%2FbhgbObqdes8h8j%2BsD534llPkRkHpr8%2F2pBRh0N0Y7y%2BzahJvePAZ7124BI89kdUKfQZHVlp1WRQnS%2FpQtmZkSd1A3wUGJg%2Bvo7MsdbhhQyvKiLNdWPvSHaDPGk0L%2FJd7oO3Zz7kB6W818oOdlkCw0d0y8cIpJA%7Ctkp%3ABFBMiuzIn59i
These are cheap, flimsy Chinese made parts but they are really useful for finding all kinds of ignition faults, especially intermittent misfires.
The behaviour of the light they emit gives a clue as to what's wrong. Dull light = low output; light flickers = misfires;
light reduces slightly with increasing RPM = normal - due to fixed Dwell Angle; etc.
Best used in the shed as they are not really bright.
Low tech test equipment is often the best for electrical problems!
Regards,
Mike
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Mike, I take note of your observations and thoughts toward replacing both coils including the plug caps. Tonight I set up for doing a test,
hopefully tomorrow, to see if switching the leaking coil to fire the opposite cylinder (the left cylinder) results in the right cylinder coming
to life, while the left cylinder misbehaves and its header pipe stays cold. (I've switched the white and black wires at the points to the
opposite points set, and switched the plug caps to fire the opposite cylinder.)
I also appreciate your suggestion on having some neon plug caps on hand for helping do doing ignition troubleshooting.
John K.
in Indiana
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The testing today showed the same happening as before the ignition paths were switched. So, I'm thinking a first thing left to check out
is the right side points and it's connections.
One more thing that I will mention...at first start, it has always been the case that I've needed a puff of starter fluid use to get
the first start. After that, it starts immmediately on its own. This is different than on other 2-strokes I've worked with.
John K.
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Yep John, you're on it.
That test will show up a bad coil if that is what you have.
If the fault does not shift to the other cylinder then it is likely you have a bad condenser.
Coils & condensers can be bench tested but you need the right test equipment.
These days few people have that. You would need to find an old-school ignition guy to get meaningful testing done.
So substitution, like what you are doing, is the best approach. Although substituting with new parts is a better approach.
Condensers don't last forever either as just like coils they have hard life.
All this electrical work is good for your little two stroke. They love good sparks.
Good Luck!
Mike
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Mike, the test I did switched everything to the other ignition path, including switching to/thru the condensers.
The only thing not switched was the contact points. And the behavior was as before switched...the right cylinder would be firing/running
at the initial start, but would very soon start to randomly miss, especially with some throttle, and then not long after that. it (that
cylinder) would cease firing completely.
So I think the first next step is to check out the right cylinder ignition points. (The points were in good condition originally; were easy
to clean up and re-use, so I'll be surprised if the point surfaces are already bad to the extent of misfiring.) Will see what I find.
John K.
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Hi John,
I'm confused. I sincerely hope you aren't.
This cylinder swapping approach on a twin can be confusing.
It's hard to believe you did all that de-soldering to achieve a left/right swap of the coils & the condensers
which would entail extending the short leads from the condensers to the points to the opposite side of the alternator?!
Did you really do all that?
I would have just swapped the coil leads up at their coil ends where there are bullet connectors.
If you really did swap the condensers as well as the coils then certainly you should focus on the points - particularly checking their insulation from ground and their opening gap.
The points though are a less likely cause of the symptoms you describe.
I think you didn't actually swap the condensers side to side and these will be your problem.
Your description of the fault does sound very much like condenser trouble.
But don't let me confuse you - it doesn't matter if I'm confused as long as you are thinking and acting logically you will succeed.
Best Regards,
Mike
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Hi Mike, thanks for getting back on this. I agree that my problem description does sound like what happens from a bad condenser.
What I did was simply swap the plug wire-and-cap from the right/leaky coil/bad cylinder over to the spark plug in the left cylinder (the
spark plugs have been changed back and forth and to 'hotter' plugs several times before this 'test', without any change in results, so
I don't think the plugs are the problem)...and then simply swapping the black wire that goes from that coil down to/thru the 'black wire' condenser
and normally to the 'right cylinder' points,...connecting/swapping it instead to the 'left cylinder' points. It seems to me that that gets
the 'problem suspect/normally right side' condenser over to supplying the left cylinder...and when I did that,
the left cylinder still continues to be the cylinder that is working.
I'm anxious to find out if I'm missing something in my analysis...there's little pride to be lost.) :)
Thanks,
John K.
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Hi Mate,
Ha, Ha then - I told you this can be a confusing process!!
Let me try to understand & try to help.
That's all I'm doing (trying to help), I'm not trying to show off, be smart, show you up or run you down.
I'm reading in to your words that:
1. You didn't physically move any condensers about.
2. You didn't disconnect any condensers from their original points set. Originally short (black & white) wires were run from each condenser to its points.
If 1 & 2 are true then you only swapped over the coils (electrically).
Which is good (swapping one thing at a time is the best approach).
If all this is true then you have proved that both coils will fire the good, left cylinder.
And during that test the left points & the original left condenser were still being used (to fire the left cylinder).
So we might suspect the right condenser which is still wired to the right points set.
If you have another condenser it would be good to connect it up to the right points and disconnect the original right condenser.
Any condenser from a car (with a distributor) or other bike will be close enough in value and its physical arrangement
doesn't matter as long as you ensure you make the case connect to ground.
You are just trying to do a short term test to discover what's wrong.
0.2uf (or 2 micro farad) is a very common value for an ignition condenser.
If you can't get hold of another condenser then you could swap them over but this will probably get messy & may confuse.
You could unscrew them and shift them from side to side or, disconnect the short wires from the points and temporarily extend them
so they will reach the other set of points.
Thanks for letting us know how you are progressing John!
Wishing You Luck!!
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Mike, thanks for getting back.
1. I didn't move the condensers at all.
2. I DID disconnect the condensers from their original points set. I switched the black condenser wire to the left/opposite
points set, and the white wire to the right points set.
I haven't checked the points themselves yet...I suppose there might be a chance that the condenser is bad enough that
the right points have already deteriorated enough to be the problem. Will check it as soon as I'm able to get to it.
John
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Thanks John for clarifying that!
So you are correct to focus on the points themselves.
Check the insulation of the un-grounded contact remembering that there is 200 to 300volts here not just 12!
A very wide gap would produce your symptoms.
Maybe though the ignition is actually OK, or at least good enough.
Your stumbling engine might be a fueling problem after all and the best way to test that is the method I mentioned earlier:
Listen to the ignition with an AM radio. If the buzz from the sparks is consistent then it is a fueling issue.
I made a mistake in my last post, sorry. The condenser value should have been written as 0.2uf or 0.2 micro farad.
A replacement condenser must have a 250 volt rating. Most automotive ignition condensers (not suppressors)
have values around these or very close.
Best Regards,
Mike
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I'm happy to report that the Mk2 ran just fine as I rode it down the road yesterday evening (~2.5 miles round trip). One of the
insulation disks (it was the one that happened to be in the 'outer' location under the spring) on the right cylinder points set connection
had a visible crack. And Mike, it was a revelation to me that the voltage in that area is a lot higher than 12v!
(There was also another thing that was adding to my confusion on trying to analyze the problem...I finally figured out that
my fuel hook-up for the stationary testing was not working consistently, and sometimes depriving one or the other of the carbs
with fuel flow. And it was apparently happening to be on the cylinder that was being suspected/tested on the ignition problem...
which explains the cylinder going dead with further running, and attributing it to be part of the ignition problem. A bit of DUH! here.)
Thanks for the valuable inputs.
John K.
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Whoopeee! Well done John!!
Thanks for letting us know how you did.
It's nice to share the joy of riding these things when they are running sweet.
Insulation failure in ignition primary circuits is often overlooked.
I use an insulation tester to check primary circuits and it tests at 500 volts DC.
This meter shows up bad ("leaky") condensers as well as other insulation failures (like "kill" switches in bikes with magnetos).
A multimeter tests at only a couple of volts so they won't show up insulation faults that only occur
when high voltage is applied.
Careful observation (as in your case) will usually find suspect insulation without having to resort to an expensive tester.
Knowing where to look though is handy (visualisation is super important during any electrical diagnosis - as you can't see electricity!).
The ignition condensers in your 200 are rated at 250 Volts D.C. Working (250VW) and all the wiring and terminals
in the primary circuit have this sort of voltage applied to them. Along with peaks of short duration up to 300 volts.
So it is important that all the insulation is in good condition.
So the dribbly coil lives on.
Enjoy riding it John!
Best Regards,
Mike
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Onward with the Dec 1969 build Mk2...real enjoyable to ride...noticing the 'tall-ish' gearing with the 16-36 sprocket combination, which
I calculate to 11.5 mph/1000 engine rpm (with tape measured 79" tire circumference). In comparison, the 1971 Yamaha 200cc CS3 that
I have, which with its standard sprockets, calculates to 9.4 mph/1000 engine rpm. So the Mk2 is geared 22% taller than the same
displacement Yamaha. I also definitely notice the taller first gear on the Mk2...gear 'range' on the Mk2 is 3.02 (first gear
ratio divided by top gear ratio), where it's 3.37 on the CS3.
Two things I need to accomplish on the Mk2...I'd like to find replacement exhaust header gaskets (1142-5000), and haven't found any
as yet. Also, there is a seepage from the oil sight glass that's enough to make a drip from the bottom of the oil reservoir. At first, I
assumed it was the oil tank outlet connection leaking, but then noticed the oil on the tank below the sight glass.
Has anybody had this problem and fixed it with some kind of a 'sealer' application to the existing unit? (I think I saw the high priced
new sight glass from Richard suggests sealing the new unit with 'permtex #2'.)
John K.
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At the AMA Vintage Motorcycle Days meet last weekend I was able to fine exhaust header gaskets that I think I have
successfully modified to fit. They are for Yamaha YL1, and also Yamaha YG5 appears to use same the same gasket
John K.