Q: What happens when you have a backfire into a PVC manifold

[chuck c]

....that's held together by hose clamps and rubber? This:

 

[joedrum]

hmmmmmm sheesh backfire aint good ....this is down side to pvc ...it why i went with the grab bar one piece runners....it carb is off enough as in dial in right ..backfires can come rather easy ....also why i like c5 timing is so much better and never off ....sorry that happen chuck

 

[Denver]

A downside to P V C for certain!!! :roll: Hope you have better luck next try. :yes:

 

[mcgovern61]

Were your pieces glued? That sure looks like an awfully clean ring at each fitting.

 

[chuck c]

Oh, it's not over yet. It looks bad and was certainly very... exciting when it blew only inches from my crotch, damage was minimal. See, the rubber boots at the heads and rubber sections either side of the center "Y" piece blew apart. It should mostly just slip back together. I think one part needs to be reglued.

Note to self: cranking with the kill switch off and filling the manifold with fumes, turning it on, then cranking again is bad. Don't do that. :blush:

 

[chuck c]

mcgovern61 » Sat Jul 02, 2016 10:02 pm[/url]":2xs95sqv]
Were your pieces glued? That sure looks like an awfully clean ring at each fitting.

Not all of them. The rubber sections on either side of the Y had a piece of straight inside for smooth flow and to hold the shape but they were not glued so they could "telescope" a little. The rubber splices made assembly easy and allowed for expansion and contraction. Those rubber sections and the boots on the heads popped before the PVC blew and saved it, I think. I'll give it a closer look tomorrow.

 

[Dusterdude]

Wow!!

Sent from my LG-D850 using Tapatalk

 

[chuck c]

Damage report: I found all the pieces but one small straight piece that joins 2 elbows. It's probably in the next county, or possibly, orbit. A bit of sanding and re-gluing and it's good as new. :Egyptian:

Here's the interesting bit. It was runners 2 & 3 that flew 30 feet. The other 2 just fell next to the bike. Notice 2 & 3 have right angle 90 elbows where 1 & 4 are all 45s. It's a pretty clear showing that those 90s are more resistant to flow than 45s. They are obviously more vulnerable to minor explosions. :mrgreen:

The throttle was closed when it went boom so the expanding gas had nowhere to go. If the throttle had been open it might have done no damage.

 

[Dadster]

Hey Chuck

You want to hold the noise down. :shock: I went out in the front yard to see if someone set off a loud firecracker and found a small straight piece of plastic that joins 2 elbows laying beside my driveway.

Seriously, glad you didn't hurt yourself.

Bill

 

[joedrum]

LOL

 

[chuck c]

Dadster » Sun Jul 03, 2016 2:38 pm[/url]":l3ov42px]
Hey Chuck
You want to hold the noise down. :shock: I went out in the front yard to see if someone set off a loud firecracker and found a small straight piece of plastic that joins 2 elbows laying beside my driveway.
Bill

:smilie_happy: :smilie_happy: :smilie_happy:
For reference he lives about 20 miles away.

 

[joedrum]

thats great :hihihi:

 

[Ansimp]

:smilie_happy: :smilie_happy: :smilie_happy:

 

[chuck c]

Hey Dadster, did it have re-entry burns?

PS I did get it back together, on, and ran it so I may yet get to ride today if I can get the darned brakes to work.

 

[Daeouse]

LOL!!!
Glad no major damage occurred. . .

 

[joedrum]

hmmm im rather not pleased with the peformance of the intake boots .....

 

[Dadster]

chuck c » Mon Jul 04, 2016 9:00 am[/url]"]Hey Dadster, did it have re-entry burns?

No but it was stuck in the ground about 6 inches deep.

 

[chuck c]

I just got an idea. I can use the thin PVC as before but then wrap & coat it with fiberglass. Super strong. $25. DIY.

 

[slabghost]

Try using a T fitting in the center instead of the Y. Fuel doesn't just flow it bounces back and forth in the manifold. They Y will channel it back up the carb.

 

[chuck c]

slabghost » Mon Jul 11, 2016 6:43 pm[/url]":3r8y2b1f]
Try using a T fitting in the center instead of the Y. Fuel doesn't just flow it bounces back and forth in the manifold. They Y will channel it back up the carb.

hmmmm that makes a lot of sense.