Air Intake O-Rings

[tjohnson]

I know that this will spur great advice and information from the VRCC family.

July 2014 I purchased my phat gurl. 99 green/silver I/S, 84k on the odometer. Rides like a dream as I clocked on another 4k. Been lucky to ride throughout winter, only letting her set for 28 days for the longest strecth.

So, late last year I noticed the brownsih puddle at bottom of air intake tubes. Hours of researching tells me that I need to replace the air intake o-rings, of which I purchased this past Monday and will be doing that this weekend. I have at least 3 spots where this brownish goo has puddled, but I am changing all of them. So my question is this, besides the obvious leaking, what other symptoms will be noticed? I ask because it seams as if the RPM is running around 1300, just seams too rich for me. Last fall it was around the 750-800 and idled superbly. And my final question, by changing the o-rings, will this help my idol issue, or should I try something else?

Thanks all in advance for the responses.
-Tim

[Gavin_Sons]

It could effect the idle. Mine idles at 900 rpm. Could also have a vacuum leak sucking in air if it has not been desmoged.

[tjohnson]

Not been desmogged, yet. I am considering this as well, however they are out of the desmogging kits. I will try the starting fluid trick to see if I have any vacuum leaks. Thanks!

[Gavin_Sons]

Yes, red eye said it will be late april or early may before they have the shiny kit avaliable.

[tjohnson]

Will the desmog kit improve or worsen the performance? I do love the feel twisting the throttle around hearing that Mark T exhaust growl from behind it. Don't want to lose that if possible.

[salty1]

A desmog can only help to improve the performance if vacuum leaks already exist. However, a desmog really does nothing to help a well serviced engine run better. It basically prevents future problems with vacuum leaks.

I would say that increase in idle rpm could be the result of those failing intake Orings. After you replace them see if the idle drops back. FWIW, you might also want to consider synchronization of your carbs if it hasn't been done in a while.

[BigBad1]

I am curious about your brownish goo. Are you sure its coming from the intakes? Sounds like you may have clogged drains in your spark plug shafts and rusty water is overflowing from the spark plug shaft. Remove the spark plug wires and spark plugs at the cylinders where you see the brown goo and see if the spark plugs are rusted and rust in the shaft.  If they are, you have clogged drains in the spark plug shaft.  Theses drains exit at the bottom side of the motor near the exhaust. Run a stiff wire up through the hole to clear them.

[hubcapsc]

Even if you're desmogged, there's still the vacuum line
from #6 to the petcock.

I happily noticed a good improvement when I changed that
vacuum line (and the Orings you're looking at). I didn't see
any obvious cracks in the vacuum line, but it was old and
stiff, so I changed it since I was working around the carburetors.

A real happy and easily gotten improvement.

While I was in there I changed out the carb drain lines. Some
of them were rotten and cracked, and with the intake runners
off it was much easier to get to them. They don't make your
bike run better, but good drain lines are better than rotten
ones 

-Mike "YMMV"

[tjohnson]

BigBad1, it is not the plug holes. I have taken off all 4 I can get to, all 4 are dry and clean. This goo is resting in the dimples beside the spark plug wires. There was just a recent pic reflecting this exactly, but I can take and show one here also. The bike is exceptionally clean, except for the road debree that seams to accumulate on top of the engine just out of reach, and now these puddles. I can only see 3, but will be changing all the o-rings this weekend. I typically do all my own mechanics, and this is nothing I am nervous about. I will be checking all the vacuum lines as I have it partially opened up. I will take hubcapsc advice and change that vacuum line from carb #6 to the petcock. (Thank you hubcapsc for the tip)

-Tim

[BigBad1]

I think I saw the post with pictures that you are talking about and that's defiantly leakage at the O rings.  Since there was not any pictures on this post, I just wanted to make sure it was due to bad O rings. I replaced bad intake O rings on a bike I had a few years ago and it made a huge difference in performance.  Good advice from hubcabsc about replacing the #6 vacuum and the carb drain hoses. 

[The emperor has no clothes]

Even if you're desmogged, there's still the vacuum line
from #6 to the petcock.

I happily noticed a good improvement when I changed that
vacuum line (and the Orings you're looking at). I didn't see
any obvious cracks in the vacuum line, but it was old and
stiff, so I changed it since I was working around the carburetors.

A real happy and easily gotten improvement.

While I was in there I changed out the carb drain lines. Some
of them were rotten and cracked, and with the intake runners
off it was much easier to get to them. They don't make your
bike run better, but good drain lines are better than rotten
ones 

-Mike "YMMV"

I recommend the vacuum line from red eye . It has a hard line inside of the soft rubber line.

[sandy]

No one has mentioned it, but did you get O rings made of viton or did you buy OEM rings? The OEM rings will wear out again but vitons will last as long as the bike.

[RonW]

Maybe this pic. In my case I hadn't ridden it for a few months so perhaps the inactivity caused the rubber to dry up.

[DK]

I was not aware of the drain in the spark plug shaft until reading this.

Can you clear it by blowing out the shaft with compressed air?  This needs to be done in any event before removing the plugs.

Should it clear out with compressed air with the plugs in place or do you need to blow out the shaft, remove the plugs & then blow out drain hole?

Can you run stiff wire downward thru drains after shaft is blown out & plugs are removed or must you run wire upward from below as mentioned even after plugs are removed?

[old2soon]

Had the similar goo around my intake O-ring area. R&R the O-rings. On a similar note while taking my tank off to R&R air filter the big fuel line split while removing. ALL that stuff is 16 years old so a new fuel line new vacuum line to #6 and a desmog goin on.  Sides-it are rainin here and idle hands yada yada!  RIDE SAFE.

[BobB]

I was not aware of the drain in the spark plug shaft until reading this.

Can you clear it by blowing out the shaft with compressed air?  This needs to be done in any event before removing the plugs.

Should it clear out with compressed air with the plugs in place or do you need to blow out the shaft, remove the plugs & then blow out drain hole?

Can you run stiff wire downward thru drains after shaft is blown out & plugs are removed or must you run wire upward from below as mentioned even after plugs are removed?

Running the wire down would be preferred, else you may get debris in the combustion chamber since your plugs are removed and the top hole is right next to the plug opening.  I had one drain completely gummed up this winter, where I had to come at it from both ends.

I don't believe compressed air alone would do the job. 

[tjohnson]

Sandy, yes I did order Viton o-rings. I didn't even consider OEM. Got them today, and am excited to start this exchange.

[tjohnson]

Thanks to everyone for the great advice. I changed all 6 o-rings in 1 hour 20 minutes. Fired the gurl up, didn't see any leakage around the intake tubes. Then noticed the antifreeze leaking onto the floor. Further investigation revealed the upper radiator hose at the thermostat neck. So, 2 hours, 1/2 gallon of antifreeze and 2 hose clamps later that also done!

The rubbing alcohol tip was the best.

Ride safe

-Tim

[westnek]

Not been desmogged, yet. I am considering this as well, however they are out of the desmogging kits. I will try the starting fluid trick to see if I have any vacuum leaks. Thanks!

  hi tjonson. West here  question.  how do you do a starting fluid [ trick ] to check vacuum leaks  Thanks

[dpcarson]

Subscribed to hear the answer to that question

[Pappy!]

Not been desmogged, yet. I am considering this as well, however they are out of the desmogging kits. I will try the starting fluid trick to see if I have any vacuum leaks. Thanks!

  hi tjonson. West here  question.  how do you do a starting fluid [ trick ] to check vacuum leaks  Thanks

Even easier...just take a propane torch, turn on the gas without lighting the torch and direct it where you think the intake leak may be. Nice and clean and will definitely find an intake leak!

[desertrefugee]

Not been desmogged, yet. I am considering this as well, however they are out of the desmogging kits. I will try the starting fluid trick to see if I have any vacuum leaks. Thanks!

  hi tjonson. West here  question.  how do you do a starting fluid [ trick ] to check vacuum leaks  Thanks

I'll give this one a go.  New here, but I've been members of other GL forae for years.

Intake leaks are sucking air.  Whether they be runner o-rings, butterfly bushings or vacuum lines, the extra air they suck creates a lean condition - usually in a fashion that affects only one or two cylinders.  The resulting fuel mixture imbalance between cylinders results in rough idle, lazy throttle return, reduced performance, etc.

The starting fluid trick (which can also be done using an unlit propane torch) is done by passing this gas source across suspect areas while the bike is running at idle.   If the gas finds one of those "sucking" vacuum leaks, it'll be drawn into that leak and the idle will suddenly change - sometimes up, sometimes down, sometimes it will smooth out nicely if it's a gross leak.

This method is very old school and has been used for years.  It is very effective in isolating troublesome vacuum leaks.  Just be careful spraying flammable gas around potential ignition sources. 

[tjohnson]

Westnek, both Pappy and desertrefuge have great suggestions. I prefer to starting fluid method, I use a staw to help pin point where the vacuum leak is located. Follow desertrefuge's advice and you will find a leak if it exists.

Good luck!

-Tim

[Stars and Stripes]

Is there a write up on changing the intake o rings?

[dpcarson]

There may be in shop talk but it really doesn't need much of a write up.  Loosen the black phillips screw on the clamp of the rubber boot at the top, then take out the two bolts at the bottom of each intake.  Then just slide it out of place.  Pull the old boring out, use a little gasket compound to put the other boring in place, then slide it back in, seat the rubber boot at the top, loosely put the two bolts in the bottom to make sure everything is fitted up, then tighten everything back up.  5 minutes max per o-ring.  When I had mine off I also wiped down the bottom of the intakes with steel wool to remove the little bit of rust and corrosion.

[big bear craig]

I just did mine today, and it's not difficult at all.  The bolts are 8 mm and that is also true on the clamps for the rubber tubes at the top of the runners.  If your bike isn't desmogged, you will also have to disconnect the vacuum hose from the carbs which have them.  I put a little silicone grease on the new o rings to hold them in place and to make it a little easier to slide the intake tube back into position.  The bolts are supposed to be torqued at 6.6 ft. Lbs or 78 in. Lbs.  Don't forget to tighten the clamps on the rubber tubes at the top of intake tube and reconnect the vacuum lines that you disconnected

[Woton]

Tacked this task yesterday at 55K.  Easy Peasy after dickering to remove and reinstall that Kury intake/spark plug cover. 

Love that custom piece, however.  Price it around if interested - including EBay.

http://www.kuryakyn.com/products/1245/intake-runnerspark-plug-cover

O-Rings were flattened a bit but still pretty flexible.  New ones from Carolina Bike and Trike.