K&L Petcock Rebuild Kits

[93Bandit]

I wanted to share my experience on this incase anyone else wants to experiment.

I've read several threads over the years on GSR about rebuilding petcocks. Most of the seasoned members here say the rebuild kits are junk, just buy an OEM petcock. That may be sound advice for those who can find a new OEM petcock for their bike, but some of us aren't that fortunate. Our only options are some sort of aftermarket petcock or rebuild the OEM. I've seen countless mixed reviews on the ebay/chinese petcocks (see most recent thread: https://www.thegsresources.com/_foru...ck-replacement )

I decided to attempt a rebuild. Unfortunately I didn't take any pictures of the process, I apologize in advanced for that. I got started on it and got carried away, and by the time I realized I never took pictures it was reassembled on the bench. This is the petcock for my 77 GS750.

I used a K&L petcock rebuild kit that I purchased on Ebay. I replaced all the rubber parts, including the vac diaphragm. Before rebuilding I carefully compared all the parts and besides the age, I could not tell the difference between the OEM and the K&L parts. I spent some time carefully polishing all the metal mating and sealing surfaces of the lever, petcock housing and the tapered hole where the vac fuel valve seats. There was oring deposits on the seat that needed to be cleaned off. I used 0000 steel wool to do all the polishing.

So far I've put 100 miles on the bike with several heat cycles and no signs of leakage or other issues with the petcock, yet...

Like I mentioned before, several members caution against rebuilding the petcock, but I wonder what kits they've had bad experience with? The few who've mentioned successful rebuilds didn't mention what kits they used. The K&L kits claim to be made in Japan, so it makes me wonder if they're OEM equivalent quality? As I mentioned before, I couldn't tell the difference between the OEM and K&L parts. So far my experience has been good, but this is just one sample of one brand. I will be sure to keep this updated as time goes by and let you guys know if I have any issues with it. But at this point, I would recommend the K&L kit over the chinese petcocks.

[bwringer]

Awesome!

In part, you gambled and got lucky. I hope things hold up and your rebuilt petcock does its thing for many years to come.

There's no doubt your superior craftsmanship in carefully cleaning and polishing the innards played a significant role, and the fact that your petcock was not badly corroded inside; many, maybe even most, are too pitted inside to recover. You certainly can't just slap an old petcock back together without checking and cleaning the sealing surfaces carefully.

Nevertheless, I've attempted to use K&L parts many times when there was no other option, and the overall success rate is well under 50%. I once got a rear master cylinder kit and a front master cylinder kit to work, but there have been more failures than successes with MC kits, even when the base parts are in good condition.

For example, I've encountered K&L caliper piston seals that looked and felt good, and seemed to fit, but were either out of tolerance or the wrong material that swelled up, making the piston drag. I may have gotten one K&L caliper kit to work, once, when there was no other option.

K&L carb kits are, without exception, 100% worse than useless; I suppose the bowl gaskets are usable, but the rest of the expensive random junk in the kit will only cause wailing, weeping, gnashing of teeth and rending of garments.

K&L fork seals are sometimes decent, sometimes short-lived junk. They do generally fit OK, but you're not getting OEM quality no matter what they blather.

I just hate doing any sort of business with a company that peddles only a few potentially workable parts alongside so much incredibly dangerous junk. But sometimes, your options are limited. Just go in with your eyes open, and do your best to mitigate the issues and test thoroughly.

I'll agree we have a petcock problem overall, and I'd love to see some better solutions. I don't know what's so damn hard about making a petcock, but the failure rate for the Chinese ones is definitely much higher than it should be.

[93Bandit]

Ok, thank you for providing some additional background info on your experiences and K&L. I'm relatively new to the motorcycle world and I try to buy OEM whenever possible, so K&L was a new-to-me brand. Most threads on the topic I've found don't mention what brand of kits were used, so I wasn't sure if K&L was on the naughty list or not. I've only purchased the petcock kit from K&L, I didn't realize they make so many other parts that members have tried without success.

As for my petcock, the innards were lightly pitted around the lip of the 3 holes behind the lever, but otherwise was in good shape. Fortunately the steel wool smoothed out that pitting, hopefully enough to last a long time. We will see...

As for the difficulty involved with making a petcock, I agree it seems like one of the more simple devices on a bike and therefore shouldn't be that difficult to build a reliable one. I wonder if the pitting you speak of is the main culprit of a failed rebuilt petcock. If sealing surfaces aren't true, it won't matter what kit you put in it, OEM or aftermarket.

[Gorminrider]

if you have a "special petcock" with outlet on a different side or limited room and the Known Good Replacements available won't suit, a rebuild kit is the only option without experimenting with Ebay/Amazon generics...
I've got one of these peculiars on a GSX 400 and finally found a rebuild kit in England with the correct size of diaphragm stated to be oem K+L . Likely it was but I still had to futz with o-rings and springs to get it to hold back a full tank of gas and still work in all engine vacuum conditions situations (idling /coasting/up hill)....

I'm glad it worked for you. But overall, I'd say for someone who isn't interested in "failures and several tries" and would rather spend $80 on a Known Good Replacement that is returnable and that will fit.....do that.

[93Bandit]

if you have a "special petcock" with outlet on a different side or limited room and the Known Good Replacements available won't suit, a rebuild kit is the only option without experimenting with Ebay/Amazon generics...
I've got one of these peculiars on a GSX 400 and finally found a rebuild kit in England with the correct size of diaphragm stated to be oem K+L . Likely it was but I still had to futz with o-rings and springs to get it to hold back a full tank of gas and still work in all engine vacuum conditions situations (idling /coasting/up hill)....

I'm glad it worked for you. But overall, I'd say for someone who isn't interested in "failures and several tries" and would rather spend $80 on a Known Good Replacement that is returnable and that will fit.....do that.

So far the K&L kit seems to be working and I didn't have to make any adjustments to the spring. The bike has sat for a few days and I'm about to run an errand on it. We'll see if sitting has affected it's performance.

As for purchasing a known good replacement for $80, I would absolutely do that, no question. But I haven't been able to find one, hence this experiment.

Also, I mentioned in my first post that ebay claims the K&L kit was made in Japan, but the package says made in Taiwan. Hmm, Taiwan is better than made in China I suppose...

[Gorminrider]

Yes, Taiwan companies bought the plans or factories were bought by Japanese...Honda parts found as Lifan clones (Taiwan) ...Lots of examples of offshoring in the space of 30 to 40 years! ie: Shinkos are good enough tires- weren't they originally Yokahama ? IBM Thinkpads are Lenovo (China) I don't judge by country so much- I mean, why would any of us with Japanese bikes made in an era when "Made in Japan" was still iffy... what I don't like is when the seller lies about it.

That's shady and they are taking advantage of our prejudices....on the other hand, factories know this and are very careful putting home brands into the market.

[Gorminrider]

Just as an example of how tricky/peculiar it is, if I swap parts from two identical working petcocks that appear to be original, there's a good chance that one or both won't work.

[rphillips]

I've been lucky, I don't remember the pitting on anything on the inside of these things. Usually look clean except for maybe a little roughness , or build-up, on a gasket surface or trash or build-up on the seat. I'm sure I've used the K&L, they are probably the most available, not sure if used others or not... Congrats Bandit hope it stays good.

[93Bandit]

Rode the bike today after a few days of sitting with a full tank. No fuel on the floor beneath it, and it started right up and ran fine. So maybe I got lucky.