A possibly perforated pretcock

[jharvey]

Greetings all,


Running (original owner) a 1980 Suzuki GS400ET. (GSX400ET in the UK, and in the US, GS450ET (in the US case a slightly different engine, but same chassis/frame construction and parts).


So, two weekends ago,, I took the motorcycle out for the first time since I had put it into self storage a couple of weeks before (I live in Nova Scotia, and with winter coming, I put the bike in a nearby, heated, self storage business, so that through the winter, I can walk over and take it out when the weather is good and the roads are salt-free]. About 10 minutes into the ride, though, the bike started feeling very sluggish – very little response to throttle input – so I turned back toward base, hoping that I would get there before the engine completely failed (fortunately I made it.)

I had a sneaking suspicion as to what the cause might be but first when I got the bike back to storage, I removed the battery and saw that there had been a significant boiling off of the water in the electrolyte. (I had topped it off during the summer, and for the first many years of this bike, it seemed that I would only have to top off the electrolyte once a year, and then only the slight amount between the upper and lower fill levels – this time, and at least once before in the last couple of years, I get surprised with a significant dip in the electrolyte. In this case of the six cells, three were below half full, one was down by about 25%, and only two were as high as the lower fill level. The battery had already been putting out borderline voltage at the start of the summer, but I guessed – correctly – that it would get me through the season, but seeing those levels, decided done was done and replaced the battery with a fresh unit.

But this was coincidental to my suspicion (and it has to be said battery-wise, that the bike started up without any hesitation on that last ride). The last time I had symptoms like this, though they were more severe, it was a case of the diaphragm perforating in the petcock. On that occasion, the flooding got to the point of the engine actually only firing on one cylinder, but while the engine is still firing on both cylinders, this time, (at least so far), when I took out the plugs, while the right hand plug looked fine, the left hand – on the side of the petcock – was fouled and smelled of gas. I installed the new battery and fresh plugs, and ran the bike in the parking lot for about a half hour, during which it seemed to run fine – I had to leave immediately after shutting down, so I haven't had a second look at the new plugs yet, but I'll check this weekend. If the left-hand one ends up looking fine, I'll probably run it in place for another half hour and check again before risking taking it on the streets and potentially getting stranded.


But after all that preamble (thanks for getting this far), I have a couple of requests of your expertise.

First, do any of you know of, or have you encountered, a situation where a weak battery would result in insufficient ignition on one cylinder, but not the other. I seriously doubt the chances, but if this is a possibility, and both plugs look fine on next inspection, perhaps there's hope.

Then, assuming the battery isn't the cause, and that I have to get a new petcock, do any of you have suggestions for a source. Naturally, the original Suzuki petcock, and the designated replacement (44300-44170 and 44300-44172), are both out of production, and when I use their part numbers to try and find a substitute, I get nowhere (I expect because those parts have been out of production for so long). As much as I'd like to think that the mounting for petcocks is as universal as the threads on spark plugs, I know that isn't the case, so if any of you have done a replacement on this model (or even if you haven't) and can make suggestions of someone who ships to Canada, I'd really appreciate it. (I've also seen diaphragm repair kits, but I don't know if my mechanic has ever done anything like that, and I expect just replacing the petcock would probably be the best bet – not to mention the fact that the various repair kits seem to have a varying number of parts included in them, and the one I can find for my model doesn't even include a replacement gasket between petcock and gas tank.)



Thanks for any input,

[grcamna2]

Hi jharvey, you may have a very low voltage in your battery which will cause the ignition to cut-out;when you install the new battery next season,test the charging rate and check to see if the regulator/rectifier is not Over-charging.
I have a similar problem finding the OEM Suzuki 'fuel cock' assembly pt.#44300-44170 & 44300-44172 for my 1981' GS450E.
I Do Want an Original OEM Suzuki fuel petcock as I like the look and design/quality of it,plus it's well made:I've been hunting online for the better part of a year,looking for an NOS item.

[Rob S.]

I would not run the engine "in place" for 30 minutes. Even if it's cold out, these bikes are designed to have air flowing over the engine. If you must do that, get a big, strong fan.

[jharvey]

Thanks folks,

grcamna2 - Actually, the battery's already in there, and was for that 30 minute test with the new plugs. My normal winter practice is to get the bike out at least a couple of times a month throughout the winter (hence keeping it at a nearby heated self-storage business). In Nova Scotia, there's usually at least a day or two per month when, even if there's snow on the ground, at some point there's been enough rain to wash the salt off the roads. (My personal record is -13 centigrade, though in my old age, I tend to avoid anything beyond -5 now.)

In terms of low battery/voltage cutting out - so perhaps, if another 'test run' results in an unfouled plug on the left, the problem might actually have just been the battery? (Dare I dream?)

And I'm guessing a potenitally overcharging R/R could be the cause of electrolyte boiling off?

As for a petcock if necessary, yes, I liked the original design as well, and I've managed to keep the bike 'stock' all these years. This is the 3rd petcock on it now, and all have been stock (the current one was installed in 2014). But I fear I won't have a choice this time - assuming I can find one to fit at all. I'll definitely want a vacuum activated one though - especially after 44 years with one, I can see myself regularly forgetting to set the petcock to OFF after a ride with a manual version.



Rob S. - 4 degrees centigrade in a windy location (mostly idling at about 1500 RPM - periodic revs to check throttle response). It's a 'non-recommended' practice -especially for a strictly air-cooled engine- but I've been doing this to this bike periodically in the winter -long enough to get the engine up to full operating temperature- for more than 40 years now on occasions when I haven't been able to get the bike on the road for more than a few weeks (there are times when the salt just WON'T go away). I remember years ago hearing these engines described as bullet-proof (if I remember correctly, they were essentially under-bored 500 engine blocks), and this fall when I had some work done including an overdue oil change, the mechanic said the oil 'looked as if it hadn't even been used.' Hyperbole, no doubt, but at least it was reassuring to know the engine wasn't tearing itself apart and leaving pieces of itself in the oil.

All that said, if I knew someone with an air-cooled engine asking about running it in place for any period absent a strong wind, I'd also advise against it and invoke the time tested, 'do as I say, not as I do' clause.


Thanks again,
Jim

[jharvey]

Well, I've got my confirmation. I had a chance to pull the plugs after last weekend's 'test run' with new plugs in the parking lot, and here's the result...


53EM2808.jpg


After running for just a half hour, the left cylinder plug nearest the petcock is already starting to show fouling.

So if anyone has suggestions as to a supplier that ships to Canada (or perhaps even knows of a current Suzuki petcock that would fit the GS400/450 tank), I'd appreciate it.

Thanks,

[rphillips]

Thinking you need to look places other than the petcock, petcock supplies fuel to each carb equally.

[jharvey]

rphillips - I would have thought so too, but both previous times (2006 - 2014) that the diaphragm had worn out, the left cylinder was the one that flooded. (shorter tubing to the left side perhaps?) At any rate, it'll be confirmed or denied by the mechanic when I can get the bike to the shop, and in the meantime, in anticipation of a diaphragm three-peat, I'll have to maintain the search for a suitable third-party petcock.

Thanks,

[rphillips]

Well, It'd be hard to argue with you, as you've Been There Done That twice already. Good luck finding the petcock you're longing for.