Topic: 400F pinches carb bowl gaskets

[jakec]

Stupid spring load jets on this bike means you have to install the bowls awkwardly, often resulting in pinched gaskets. Oddly enough this isn’t a problem on the 350 twin because the gaskets are willing to stay stuck in the groove on the bowl. Not on the 400 though. These are 4 gaskets of mine that pinched over the years.

Eventually I started using superglue to hold the gaskets in place, which worked great. But then, not sure why but the bowls started leaking like crazy. I think due to the gaskets drying out but also being held in place by the glue. So I guess I won’t be doing glue anymore. I’m scraping off the glued on gaskets now and about to install new. Wish me luck. I may use a dab of assembly lube to hold them in this time.

[denward17]

I used a dab of grease in each corner.  No leaks so far, only been a couple of months though.

[Mark1976]

I used a dab of grease in each corner.  No leaks so far, only been a couple of months though.

Been doing it that way for decades.

[jakec]

Been soaking these new gaskets in gas for 2 hours trying to make them larger, they aren’t fitting. I have had this problem before with 350 gaskets. Not sure about the 400 though. They’re taking their sweet ass time

[jonda500]

I have used super glue on the round ones and grease on the house shaped ones to hold them in with no problems - they originally seem to be glued in with gasket goo or similar?
Bowls leaking like crazy (assuming the bike is upright) would indicate a problem with the needle and seat valves as well as leaking gaskets - maybe you have the too small diameter rubber cross section ones that have been showing up on ebay lately? - they should sit proud of the slot they sit in...
John

[jakec]

The bike was running fine for a couple thousand miles, #2 carb started a small slow leak which was caused by a pinched gasket. I replaced (from the set of 4 I’m using now) and used super glue and it was fine for a couple hundred miles. Then #3 cylinder went coldish one day, and I pulled the carbs installed same old gasket from years ago using super glue again. Bike ran good after that, but after running it for a while I realized the two carbs that I’d used glue on were pissing gas out the top (indicates bad gasket to me, not valve or float as there was no overflow coming out).

I think what happened was I used too much glue and then the gaskets shrank while the carbs were off the bike, and the gaskets got stretched or out of whack somehow.

So I have used 1/4 gaskets from this set without problems for a couple hundred miles, I think they are fine. I’m pretty sure it was just going way overboard on the glue and then letting them dry out

[jakec]

Just said #$%* it and did glue again but used like 1/10 of what I did before

[jonda500]

The brass overflow tube is higher than the top of the bowl and the fuel level (assuming fuel valves are all good) should be just under the top of the bowl?
John

[jakec]

True but if there’s no seal on the bowl then the level can’t get high enough to reach the overflow tube. It’s all back together now and seems good. I tested for leaks before installing on the bike this time.

[Ozzybud]

Super glue will destroy the o-ring gaskets.

Use a tiny bit of permatex gasket sealer in the corners just to hold in place. Or grease.

[bryanj]

Never had a problem using ordinary clean grease

[Mark1976]

Never had a problem using ordinary clean grease

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