RSV Carb Intakes

[Rick Butler]

Folks,

 

I know this topic has been brought up just recently so I'd like to share what I've found out while servicing my 02 Midnight.

 

When I checked my valves just recently I decided to remove the carbs and disassemble and clean them up while I was in there. It was the then that I saw that there appeared to be some significant cracks starting in the intakes. So I then decided to replace them all since I plan to keep this bike for a long time to come now that I have it where I want it.

 

But as many of you know, I like to take items apart to see what's inside. so this is what I did to one of the intakes, of which I have attached a picture to show how far the inner aluminum base goes up. My intakes are about 6 years old now and even though there were cracks starting to form, I can tell you that in the end they were all superficial. The rubber on these intakes (above the aluminum base that is molded in) is so thick that I seriously doubt that a crack will make it all the way through. But I could be wrong, especially on older intakes.

 

As a special note, when I was finished installing the new intakes, I checked the compression before I put in new plugs. This engine now has about 90k on it and all cylinders produced right at 180 lbs, which I thought was pretty good.

 

Hope this is enlightening,

 

Rick

[spear]

Thanks Rick.

I used to say in my old LEO Forensic days - you can never have too much information. All you gotta do is work out which bits you wanna keep and which bits you didn't need in the first place.

Spear

[RedRider]

Rick,

 

Thanks for the info. I had noticed several cracks in my carb boots and was intending to replace them during my winter maintenance. I will rethink that now. Not concerned about the looks of the cracks as long as they don't leak.

 

RR

[Condor]

I found some cracks in the manafolds of the '87VR, and even though they didn't appear to go all the way thru I went ahead and painted them with a product called Plasti-Dip. It's a rubberized spray that you can find at Home Depots. The cracks filled and disappeared after a couple of coats. I may not have accomplished anything, but it made me feel a lot better.....

[pegscraper]

Notice how the top of the base is where cracks appear first and where they get the biggest. The ring of cracks can be seen in that area on the intake on the right.

[Rick Butler]

Guys,

 

I think Condor has come up with a valid solution to help keep these intakes from becoming a possible problem. I think I have seen a similar product in the electrical section called Liquid Electrical Tape.

 

Rick

[Condor]

Guys,

 

I think Condor has come up with a valid solution to help keep these intakes from becoming a possible problem. I think I have seen a similar product in the electrical section called Liquid Electrical Tape.

 

Rick

 

Plasti-Dip isn't quite the same thing Rick. I use the Liquid Tape all the time when doing marine wiring, and have even used it a couple of times on the bikes. It's applied with a brush and is kinda gooey. Plasti-Dip comes in a spray can and puts a pliable rubber coating on the item, and when it dries you can hardly tell the surface has been painted. Lowell (Wild Hair) turned me on to the stuff after he used it to coat a couple of diaphragms with pin holes. That's what I originally bought it for, but so far haven't got around to using it on the diaphragms. It also seals joints in rain gutters quite well.......

[V7Goose]

I suggest that anyone looking at the cracks in rubber parts not completely trust their eyes. Do a search for my posts last summer concerning deceleration popping (after-fire) and the cracked rubber nipples on my intake manifolds. I would have bet money that the cracks in those little nipple covers were only superficial, but testing proved that they were not.

 

Anyway, the bottom line here is that if your intake manifolds or the rubber covers on those nipples are cracked enough to leak, you WILL be getting some popping on deceleration. Soooo, if you are not getting any after-fires, then it is safe to assume all cracks are superficial. However, if you have the popping and have not been able to get rid of them by balancing the carbs and tuning, then you probably really do have a leak in your intake somewhere.

Goose

[Floyd]

I had my boots replaced last year at the dealer's suggestion. They saw the cracks when I took the bike in for that infamous whine problem.

 

The bike's whine problem, not mine...

 

BTW, both the clutch basket and the boot replacement were covered under warranty.

[BuddyRich]

A real quik way to tell if the crack is all the way thru is to spray it with a little carb cleaner. if its all the way thru the engine would change speed. We use to check for intake manifold gasket leaks on cars like this

[V7Goose]

A real quik way to tell if the crack is all the way thru is to spray it with a little carb cleaner. if its all the way thru the engine would change speed. We use to check for intake manifold gasket leaks on cars like this

Excellent suggestion - either carb cleaner or WD40 works well for this test. Doing the test at idle is probably the best time, as that is when the manifold vacuum is normally high, and any change in engine speed or smoothness is easily noticed.

Goose

[KiteSquid]

Plasti-Dip isn't quite the same thing Rick. I use the Liquid Tape all the time when doing marine wiring, and have even used it a couple of times on the bikes. It's applied with a brush and is kinda gooey. Plasti-Dip comes in a spray can and puts a pliable rubber coating on the item, and when it dries you can hardly tell the surface has been painted.

 

Plasti-Dip also comes liquid in a can so you can dip thinks in it... the spray version is newer.....

 

Both work well in different applications.

 

 

Click HERE to go to thier website