Alternate Tank Vents

I know the flapendectomy is the prefered method of eliminating the venting problem, but the following is an alternative. It also avoids the vent pinching issue altogether with the difficult/stupid – imo – location of the original vent lines. It is just so easy to pinch them. I have had no problems thus far with the mod. Nor has the dealer, who has done many.

Mark over at Nevada Motorcycle Specialties in Reno does a tank vent to prevent the dreaded overflow problem. This February, while in Death Valley, I wound up with gas all over my right foot after some dirt riding up around Cerro Gordo. I decided to try it after talking with him. He has seen no problems with the following mod and it completely eliminates any issues related to the maze in the gas cap. I also terminated the existing vents into the fairing thus eliminating the pia caused when puting the tanks and fairings back on the bike.

First, obtain a suitable vent. This is the oem one with a neoprene 1/4 washer from home depot.

Second – the fun/nerve racking part – start a small pilot hole in the top most portion of the tank. I put mine in the middle between the corner and the ridge to the support point. WARNING: This causes clearance issues when inserting the oem elbow vent. See picture of vent insertion below.

I advise slowly going up in drill size because of the issues of drilling into plastic and so as to avoid too much material like this:

Otherwise the plastic shavings come out along the bit and avoids much of the shavings going into the tank.

Final bit size for me was 7/32. Mark recommends the final bit size of 6.5 mm. I had to use 7/32 since I only have SAE bits. It is slightly smaller but worked out well. Then tap the hole with 7mm x 1mm, assuming you use the above vent. Tapping in progress:

Insert elbow vent. As I said centering it can cause clearance problems when inserting the vent. I decided to sacrifice – read cut – the vent at the small rise in the middle for better placement on the tank:

I used a little fuel resistant gasket sealant because theoretically these don’t need to come out. Cut 1/4 hose to desired length. I ran mine down to the taps at the bottom of the tank. Zip tye. Again I cut short the existing vent hose and terminated the same – with a 180 and zip tye – into the fairing. According to Mark any venting now primarily occurs out the new vents. Makes sense – no restriction whatsever. So the couple of drops of fuel/condensation now come out those hoses.
Final product:

As I said Mark has done alot of these and reports no problems thus far. We will see. If there are any major problems I will report back and maybe a pair of Aqualine tanks are in my future. Lets hope not. . . .

Advertisements