Thought I had carb problems

[FryeVRCCDS0067]

The scooter started out running rough this year. Seemed normal above 2000-2500 but the right bank sounded like a popcorn machine at idle. It also sounded like an occasional backfire through the carbs was happening and I was getting lots of "cackling" during engine braking. With the glasspacks, misfires are noticeable and annoying.

I ran a half can and then a full can of seafoam through it with no improvement. replaced the plugs, got maybe a slight improvement but still not right. Checked the headers of course, they were all tight. Checked the intake boot clamps and intake mounting bolts, all good too.

I assumed I had at least one idle jet clogged and had pretty well resigned myself to doing some carb work. Then I found the problem. Several of the intake runner vacuum caps which cover the carb sync ports had holes in them.

I traced a gas smell down to one of these on the right side several years ago. The right side caps seem to pool a little gas when she's on the kickstand, a bad cap will let it soak out and stink when she's sitting. I've replaced these caps every year since then. But, since I had just done it in the fall I assumed they were still good.

This time, I replaced the cheap autozone vacuum caps with OEM Honda caps. The OEM caps seem to be made better and I'm betting they last way longer too.

OEM part#16215-MV4-000 for vacuum caps in case anyone wants it.

[rodeo1]

yep, always good to troubleshoot first, wrench second -- good catch frye.

[sandy]

I took the 3 unused nipples out and went to ACE and found bolts and brass washers to replace them. No more problems. The OEM nipples are in a ziplock bag and stored under the seat in case I need them on the road.

[Farther]

I took the 3 unused nipples ..... found bolts and brass washers to replace them.

  I have been thinking of doing the same thing.  The only issue would be during syncing the carbs but then you just replace the nipples for the sync and replace the bolts when done.  Another source for caps is: http://redeye.ecrater.com/p/3301919/vacuum-cap-kit-version-5-three

[FryeVRCCDS0067]

I took the 3 unused nipples ..... found bolts and brass washers to replace them.

  I have been thinking of doing the same thing.  The only issue would be during syncing the carbs but then you just replace the nipples for the sync and replace the bolts when done.  Another source for caps is: http://redeye.ecrater.com/p/3301919/vacuum-cap-kit-version-5-three

That's a way better deal, wish I had known. I just ordered 6 caps and retaining clips from the local dealer to replace my stock. $2.97 each for the caps and $0.97 each for the clips. Ouch!

[Hook#3287]

When I desmoged, I just took some vacuum hose and cut small pieces, then inserted some screws I had hanging around.  Been working for 5 years now.