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Sir Real Ed

2018-2019 EVO GAS CAP CROSS THREADING

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It is extremely easy to cross thread the gas cap on my 2019 Beta during installation.  A friend said the same is true with his 2018.  I have read that older Betas had aluminum caps rather than plastic like the 2018-2019 Betas.

Any cross threading situation can be cured by changing one or both threads to blunt start threads.  The attached picture shows the modified gas cap.  Modifying the female thread in the gas tank would require careful flushing of the gas tank afterwards so I opted to only modify the gas cap male.

I used an exact knife to remove about two full threads from the gas cap which creates a male pilot to properly align the gas cap.  I then used a Dremel tool with a small end mill like cutter to clean up the removed threaded area to a diameter smaller than the female thread minor diameter.

The O-ring was removed before modifying the threads.

A picture is worth a thousand words:  

bluntstartthread.JPG

Edited by Sir Real Ed

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 It not the threads, it swells slightly with the fuel. Total crap. The Sherco/Scorpa caps and TRS caps have venting issues.

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I've read that the cap swells with time.  But a bike that is less than a few days old, that has the cross threading problem, before any fuel is put in the bike, tells me that it is definitely a thread geometry problem.  

Changing the cap to a blunt start thread fixes the cross threading problem immediately.  A blunt start thread is a common solution to a thread geometry problem.  It is very common in the nuclear and aerospace industries.

I don't expect it to fix the swelling problem, as that is a material problem.  My Sherco had the swelling problem, but it had rounded threads.  So five minutes with a 1/16" diameter drill and some 220 grit sand paper was an easy fix.

I'll probably go the bling route with an aluminum cap eventually, but with the holidays and the weather, the post office is running about 10 days late with a lot of mail right now.

I expect someone to reply that going to an aluminum cap will add weight and ruin the balance/handling the bike.

We trials riders are an anal bunch.........? 

Edited by Sir Real Ed

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I've just change my fuel cap to the csp,really nice bit of engineering.My only concern with the csp is when i need to use the hebo extra fuel tank, no place on the csp to mount the fuel pipe.

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7 minutes ago, welsh beta said:

I've just change my fuel cap to the csp,really nice bit of engineering.My only concern with the csp is when i need to use the hebo extra fuel tank, no place on the csp to mount the fuel pipe.

I've noticed this one in addition to the CSP:  https://shop.betausa.com/p/evo-billet-aluminum-gas-cap

So obviously, Beta is well aware of the problem.

Any specific reason you went with CSP?  I see two different pictures for the CSP.  Which one do you have?

Did you notice any adverse effects on the handling/wheelie-ability of the bike??

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My Beta dealer called today and said that due to the cross threading and swelling problems, Beta is replacing plastic gas caps with aluminum gas caps under warranty.  I do not know if this applies to 2018 Betas also.  I have read that prior to 2018, Betas had aluminum gas caps.

If you have a 2018 or 2019 you might want to call your dealer to check if you are eligible for a aluminum gas cap.

This will obviously increase the weight on the front of the bike.  Don't forget to adjust your suspension and riding technique accordingly.......

Edited by Sir Real Ed
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Mine hasn’t swelled but I’m running VP with no ethanol. Then again I wouldn’t pass up free bling if they throw it my way.

Edited by dan williams
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Additional outlet breather spigot on frame + Gas Fumes = Problematic Gas Caps 

Defined and known

Stay tuned

?

   

Edited by billyt

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7 hours ago, dan williams said:

Mine hasn’t swelled but I’m running VP with no ethanol. Then again I wouln’t pass up free bling if they throw it my way.

Staying away from gas with ethanol is always a good habit in my book.  I only use the E10 gas in my car and truck.  Everything else gets non-ethanol 93 octane and I add Sta-bil.  Just as an experiment, my last batch of fuel was 1 gallon of 112 octane mixed with 1.5 gallons of 93 octane.  I don't notice any difference from 93 octane.

Edited by Sir Real Ed

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If the octane is sufficient there’s really no difference other than residues. I used to run 93 pump gas all the time and the bike ran fine except once in a while I’d get a bad batch and the bike would run awful. After one particularly nasty crash from bad fuel I just said the hell with it and switched to VP C-12. The main advantage is consistancy. The engine always runs the same. No aging issues with fuel and no funky residues in the carb. Worth the money to me.

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THE NEW PHONE BOOK, er, uh, I MEAN THE NEW GAS CAP IS HERE!  THE NEW GAS CAP IS HERE!

 

not the high bling red gas cap, but aluminum just the same. bottom cap is the plastic one that comes on the bike.  

Beta gas cap.jpg

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