Petcock Rebuild

turk64 · Posted: September 6, 2005, 9:25 am Post subject: Petcock Rebuild

Hi all Turk again.

Ok in the process of breathing life into the 83 heritage Special (again) I noticed that the petcock was leaking when the tank was off of the bike so I bought a rebuild kit. But let me back up a bit...

This bike was bought for a deal $500! The guy I got it from told me that it was a father/son restore that lost its appeal. One of the 'restorations' was a tank painting. Which actually isn't horrable. The problem is that they failed to cover the opening where the gas goes in and there is overspray INSIDE the tank. The first time I tore the carbs apart for a cleaning and found a bunch of blue flakes inside the screens, jets, coating the bowls you name it. In the process of putting it all back together I put in an inline fuel filter.

Then one day I ran out of gas. No bigie just reach down and switch to reserve right? Ah no. If anyone is familiar with the stock petcock in the Heritage Special it has a screen and 'pipe' deal that fits into the top of the petcock to strain fuel and serve as the reserve level. This part was left out after the paint job. I had it on backorder for 3 months at the dealer untill I found an entire petcock on ebay! So now I have all the parts that I need to make this petcock work as it should.

Once i put it all together it still leaks, it is not a stream but a slow drip. When the bike is parked gas is dripping out of the left air filter box. I know all the parts are where they belong. The only part that I didn't replace in the petcokc rebuild was the gasket that goes arround the lever itself. When I had it on it took a bit of hammering to get in installed and once it was in it was impossable to turn the lever so I used the old one.

So if anyone has any tips on rebuilding a vaccum type petcock I would love to hear them.

One thing I noticed, when I took the stopcock apart the diaphram was stuck to the halves of the stopcock. Is there somekind of sealant that I should use on the metal surface where it touched the rubber?

grizld1 · Posted: September 6, 2005, 10:51 am Post subject: Re: Petcock Rebuild

The real problems with a vacuum petcock are that they all fail sooner or later and that you don't know they've failed until they're dripping fuel visibly. That doesn't usually happen until the slow drip you couldn't see has put enough fuel in the crankcase to do a nasty job of thinning the oil.

I only know of one good fix, and that's to plug off the vacuum nipples on the carb boots and replace the vacuum petcock with a manual shutoff from Mike's XS, or to fabricate a tapped alloy plate to accomodate some of the other aftermarket manual petcocks out there.

mo650chopper · Posted: September 6, 2005, 11:39 am Post subject: Re: Petcock Rebuild

It also means one of your carb floats is not working properly. I had the same problem on mine before I rebuilt the carbs. Still need to get a new petcock as my 80 vacum one does not shut off completely.

turk64 · Posted: September 6, 2005, 3:44 pm Post subject: Re: Petcock Rebuild

I had a suspicion about the float, there is a possibility that it is not on corrrectly. I have some work to do arround the house or my significant other is going to take away my tools! Do you know if it is possable to work on the bolw area of the carb without removing it? I am pretty good at removing the carbs by now but if I can avoid all those steps and just work on it attached it would be a time saver.

I am leaning toward grizald1s idea, To put it mildly I am looking for the cheapest solution and throwing money at it is the quick fix, not because the stopcock is that much money but because there are several things I could get from mikes Smile

and the temptation is pretty strong.

I need to research the site (Mikes) but I am not looking to fabricate a plate to accomidate a manual stopcock, will the ones he sells match up?

Currently the fuel line is detached and above the stopcock so my driveway won't look like an Exxon tanker wrecked on it, the weather is damn nice though and I am missing some good riding! Perhaps after my other chores (cutting moulding for the bathroom and mowing the lawn) I will make up a pot of coffee and take a look at it again.

As alway thanks to all.
Turk

mo650chopper · Posted: September 6, 2005, 4:46 pm Post subject: Re: Petcock Rebuild

You "Can" do it with the carb on but I would remove it to make the repair easier. As far as I know Mike's has a direct fit replacement that is manual instead of vacum. It's defintely getting to be some nicer riding weather here in Missouri. Almost chap and glove weather in the AM and below 90 on the way home.

turk64 · Posted: September 6, 2005, 8:39 pm Post subject: Re: Petcock Rebuild

Yea I saw the stopcock, as a bonus it has little filter condoms for the ends! So hopefully it will end my paint flake nightmare as well. Time to get out the charge card.

The more I think about leaving the card on the bigger of a pain in the ass it looks like it will be to get that pilot valve in and connected to the floats. I am just going to take them off.

Anyone know how to balance the carbs without any special tools?

Turk.

grizld1 · Posted: September 7, 2005, 9:21 am Post subject: Re: Petcock Rebuild

That's a negative, Turk. You can ballpark the synch by removing the carbs, taking out the slides, and looking for light under the butterflies, but you'll only get an approximate setting. Good dial gauges are expensive; on the cheap ones, damping is touchy to the point of making many of them next to useless. Mercury column synchronizers work, but they're delicate; they have to be stored vertically, become contaminated easily, and break if they're dropped, releasing mercury into your environment. Morgan makes a column synchronizer that uses stainless steel tubes instead of mercury. It's compact, cleanable, accurate, and easy to use. It's a little more costly than the cheaper mercury units but much cheaper than usable dial guages (about $85 including shipping if I remember right). It's available online at www.carbtune.com. It's shipped direct from the manufacturer in England. Morgan advertized 8-day shipping to the USA. I figured that was going to work out to 2 or 3 weeks in the real world. I placed my order on a Thursday. A week from the following Monday my synchronizer was in the mailbox.

By the way, as long as you have your tank off and drained for the new petcocks, you may as well take it to the carwash, stick a high pressure hose in the filler hole, and give the inside a good flush. Those paint flecks can block the petcock screen solid, and many a rider of old motorscoots (myself among them) has reached for reserve, only to find the reserve fuel port blocked by crud.

turk64 · Posted: September 7, 2005, 12:34 pm Post subject: Re: Petcock Rebuild

The car wash idea is a good one. I think I may even dump in some paint remover to soften up the paint that is still there before I give it a good blasting. As far as the sync goes I think I will just take it to the shop, at this point I can't see spending the bucks for something that I will not use so often.

I ordered the stopcock, spare condoms, and vaccum plug this morning.

I uploaded a pic of the bike I am going to attach it. Just so you all can see what you are helping me out with!

650twin · Posted: September 7, 2005, 4:16 pm Post subject: Re: Petcock Rebuild

Hi folks.........my first post ever!

I am having the same fuel problems.....petcocks and floats. A quick, cheap and positive fix for leaking fuel is an $8.00 in-line fuel shut-off valve from Briggs & Stratton. Install one downstream from the origional. Turn them off a quarter mile from home and by the time you get home, the float bowls will be down enough the floats won't have too much pressure on them.................just a thought.

Howard

650twin · Posted: September 7, 2005, 4:25 pm Post subject: Re: Petcock Rebuild

Turk64

Carb sync.......You can use the old vac gauges....just shove a small main jet up the line to settle the needle down. Picked up a couple of vac gauges couple weeks ago at a swap meet for $1 apiece.

Howard

mo650chopper · Posted: September 7, 2005, 5:45 pm Post subject: Re: Petcock Rebuild

Nice bike turk64. I just picked up a seat like yours on Ebay a couple weeks ago. The wife likes it much more than the stock one. Nice Blue!

excesstoo · New Member Joined: Aug 01, 2005 Posts: 8 Location: T.O.

Sounds like all you need is a needle/seat assembly for the float bowl. It's a dirt cheap part and easy as pit to replace. You've probably got a paint chip in the seat not letting it close.
Had the same problem years ago on mine and that's all it was. Been fine ever since.

turk64 · Posted: September 9, 2005, 8:29 am Post subject: Re: Petcock Rebuild

Great ideas-but firstly Mo650chopper you are lucky I was inbetween payperiods on that seat deal! There were two seats of that style at that time one went for silly cheap. Just kiddding I am glad that you got it, it is not like I am able to use it anyway LOL.

Saturday is a motorcycle day, hopefully the stopcock comes today, I had it sent to me at work. I will pull the carb, check the floats and internals.

As far as syncing the carbs goes if i am understanding everything correctly what i am looking for is that the slides (that brass cylinder that is visable from the rear of the carb) have to be in the same position. So my theory is that i can hold the throttle open, say half, and secure it so it stays open. Then I can measure the distance from the bottom of the slide to the carb body and adjust the screw inbetween the carbs so that both slides are in the same spot at the same time. That should get me in the ball park.

I like the vaccuum guage tip, I hit the flea markets from time to time i will keep an eye out for them.

I will let you all know how I make out.

grizld1 · Posted: September 9, 2005, 9:23 am Post subject: Re: Petcock Rebuild

The visual sych. is usually done at the butterfly with the carbs off. Take out the slides and look through the carbs. Tweak the adjustor till both butterflies show a little light at the same time. It helps to work in the dark, with a lit-up piece of white paper for a screen. If you try to measure slide position, don't use half-throttle. That engine will be revvin' like depravity. You want a measurement at a normal idle or just above. Use the throttle stop screw to hold position.

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