Stainless gas cap provider
- Thread starter loka
- Start date
rockcitycafe
I make things.
got vent?
loka
Active Member
this cap has a spring loaded top and seal system. It is not completely airtight but if the problem of airlock/flow arises i just may drill some vent holes in the inside plate to get the juices flowing.
BTW Carpy has been selling these as is and makes no mention of adding an additional vent.
cheers
JJ
BTW Carpy has been selling these as is and makes no mention of adding an additional vent.
cheers
JJ
pacomotorstuff
Coast to Coast
I think the bigger issue with a non-vented gas tank / cap is the fact that you could seize the motor due to woefully inadequate fuel flow - makes the engine run lean. Seen it happen on race bikes, street bikes and if you want proof positive, when I get the Bridgestone engine apart I'll take a photo of the piston for you (no, it wasn't me who used a radiator cap on the bike for a gascap).
A gas cap vendor should state in their literature whether or not the cap is vented / nonvented as a lot of caps are offered either way.
I have my issues with vented gas caps. It's a personal choice, I guess, but on the last half dozen or so gas tanks I've built, I've used aircraft-style caps with a separate venting / check valve system (3 tanks had fittings bonded in to use GSXR screw in check valves and the rest had Ariete inline check valves). Both systems vent excellently and when you do a sky-grounder, the check valve shuts off the vent and the fuel. I don't know if anyone makes a gas cap with a built-in check valve or not, but I feel so strongly about check valves on gas tanks that I sell the Arietes for what they cost me - about 20 bucks.
I do like the look of the stainless caps in the photo and will check out their website for cap alternatives. Thanks for the post.
Regards,
Pat Cowan,
Pacomotorstuff
A gas cap vendor should state in their literature whether or not the cap is vented / nonvented as a lot of caps are offered either way.
I have my issues with vented gas caps. It's a personal choice, I guess, but on the last half dozen or so gas tanks I've built, I've used aircraft-style caps with a separate venting / check valve system (3 tanks had fittings bonded in to use GSXR screw in check valves and the rest had Ariete inline check valves). Both systems vent excellently and when you do a sky-grounder, the check valve shuts off the vent and the fuel. I don't know if anyone makes a gas cap with a built-in check valve or not, but I feel so strongly about check valves on gas tanks that I sell the Arietes for what they cost me - about 20 bucks.
I do like the look of the stainless caps in the photo and will check out their website for cap alternatives. Thanks for the post.
Regards,
Pat Cowan,
Pacomotorstuff
dielectric
Grouch.
Hee hee, we had a bike come in for warranty work, where the OEM gas cap failed to vent properly and the thing tried to suck itself inside-out. The whole top side of the tank caved in. It gave me a whole new appreciation for a relatively low vacuum pressure spread over a relatively large area.
Swagger
Putting boot to ass since 1967!
These caps aren't vented as they are for boats where stray fuel vapors are deadly. In this case it'd be simple to drill a single .030" hole in the spring seal plate, that's pretty much what's done on the stock caps of my bikes. Alternatively and far cooler....while you're adding this cap add a small 1/4" steel tube for a vent hose, run the hose to your airfilter. instant badass
loka
Active Member
I will tell you what i did but it's not general, it was specific to my tank.
My tank is from an 82 cb750. I cut out the old filler cap and surrounding areas. Welded in a new piece with a 1/8 cnc flange the same as the base of the new filler cap. Drill and tap mounting holes in flange, then get out the filler and prep for paint.
My tank is from an 82 cb750. I cut out the old filler cap and surrounding areas. Welded in a new piece with a 1/8 cnc flange the same as the base of the new filler cap. Drill and tap mounting holes in flange, then get out the filler and prep for paint.
loka
Active Member
Welding gas tanks is very tricky. The metal is very thin and prone to warping via shinkage. When you cut out the old filler area make the corners radiused as it will lessen the warpage. The cap mounting plate was separate and was plug welded to the sheet metal before attachment to the tank. If you are not skilled in the art of welding it wouldn't hurt to farm it out . I can lay a decent bead but i enlisted the skills of a friend of mine who i have seen fabricate rear lambo panels out of aluminum. The body-filler and finishing i took on myself.
