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Author Topic: UPP Intake Boot Ripped  (Read 2887 times)

Offline F-Red

UPP Intake Boot Ripped
« on: June 15, 2019, 05:28:44 PM »
UPP oversized boot tore like torqued. Maybe from the ridged ESR filter mount to the frame. Need to re-think for flexibility. 
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Offline Jerry Hall

Re: UPP Intake Boot Ripped
« Reply #1 on: June 15, 2019, 08:46:34 PM »
I have seen these UPP boots do this many times.  It is not the fuel that you are using..............it is the material and the process that UPP is using.

Offline F-Red

Re: UPP Intake Boot Ripped
« Reply #2 on: June 16, 2019, 04:00:14 AM »
I have seen these UPP boots do this many times.  It is not the fuel that you are using..............it is the material and the process that UPP is using.

Hey Jerry, long time no hear. Glad to see you around.

Well that sucks. Are there other options available?
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Offline 2Nubs

Re: UPP Intake Boot Ripped
« Reply #3 on: June 17, 2019, 09:45:59 AM »
Fred, I use an OEM boot. If you hit it with some light heat it will stretch out for the larger PWK's.

Glad you caught that before taking a ride through the sand and dirt.
86 330

Offline F-Red

Re: UPP Intake Boot Ripped
« Reply #4 on: June 17, 2019, 09:53:41 AM »
Myles,

I believe the OEM is too restricted. Need more volume for the fire breathin' motors.
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Offline croat1

Re: UPP Intake Boot Ripped
« Reply #5 on: June 17, 2019, 10:02:27 AM »
Fred, if you get a chance can you post a pic without the hose clamp

Joe

Offline havinnoj

Re: UPP Intake Boot Ripped
« Reply #6 on: June 17, 2019, 03:11:44 PM »
Cracked / blown out on methanol but never had an issue on race gas with ESR "floating" air filters on the back of the carb.

Offline Jerry Hall

Re: UPP Intake Boot Ripped
« Reply #7 on: June 17, 2019, 03:57:28 PM »
F-Red:

Using an OEM type carb clamp will make life easier on any intake boot.  The clamp that you are using above, makes life a little more difficult on the hose because that type of radiator clamp tends to "bunch up the rubber" on one side of the hose.

Offline 2Nubs

Re: UPP Intake Boot Ripped
« Reply #8 on: June 17, 2019, 04:27:34 PM »
T bolt is definitely better than a worm gear.

I did not realize they were restricted Fred. I just figured the opening was not large enough for the PWK users.
86 330

Offline F-Red

Re: UPP Intake Boot Ripped
« Reply #9 on: June 17, 2019, 06:35:28 PM »
Fred, if you get a chance can you post a pic without the hose clamp

Joe



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Offline F-Red

Re: UPP Intake Boot Ripped
« Reply #10 on: June 17, 2019, 06:44:52 PM »
F-Red:

Using an OEM type carb clamp will make life easier on any intake boot.  The clamp that you are using above, makes life a little more difficult on the hose because that type of radiator clamp tends to "bunch up the rubber" on one side of the hose.

I respect your opinion Jerry. Been using these style clamps on boots forever. Ill look for another style. It started when using ESRs air box eliminator kit. A ridged mount to the frame. The only movement the air filter has, is at the boot. 

UPP said they have never seen this failure before. They did agree to replace. Hallelujah!
 
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Offline F-Red

Re: UPP Intake Boot Ripped
« Reply #11 on: June 17, 2019, 06:45:55 PM »
This is for you Myles. The pic is a little misleading. But there is a significant difference.


« Last Edit: June 17, 2019, 06:48:11 PM by F-Red »
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Offline 2Nubs

Re: UPP Intake Boot Ripped
« Reply #12 on: June 18, 2019, 10:56:45 AM »
Yep definitely much bigger.
86 330

Offline Jerry Hall

Re: UPP Intake Boot Ripped
« Reply #13 on: June 18, 2019, 06:39:40 PM »
This is for you Myles. The pic is a little misleading. But there is a significant difference.





There is a huge amount of development that goes into the OEM rubber type connector between the reed and carburetor.  There are 3 things that I feel are very important about this engine component that is viewed by most as just something that connects the carburetor to the engine.  The air flow characteristics, the length and the proper amount of heat isolation/vibration damping for the float bowl carburetor.

I have seen enough burned up pistons to fill a few 55 gallon barrels because of improper vibration damping when using old hardened oem manifolds,  billet manifolds with the short 2-bolt rubber flanges and reed assemblies that incorporate the carb to reed adaptor as a one-piece casting with a short hose and 2 hose clamps.

These one-piece reed assemblies have excellent air flow characteristics for engines below 55 to 60 hp that use carburetors smaller than about 37 to 39mm.  It has been my experience that the special short molded hose that connects the one-piece reed casting to the carburetor, does not offer enough vibration damping on most engines especially the ATC/TRX Hondas that have the big bore kits.  The rubber durometer appears to be too hard and the 5mm or so of rubber between the one-piece casting and carburetor is too short for the necessary damping to prevent fuel "frothing" in the float bowl.

I have observed the fuel "frothing" problem many times when doing steady state dyno testing or performing long run time acceleration dyno test.  If the fuel frothing problem occurs, it occurs at one and sometimes two points on the usable RPM scale while conducting a test.  The three vehicle applications where I see the most problems are on recreational vehicles, flat track and land speed racers.  Drag racers, Stadium racers, and motocross racers seldom experience a burned piston because these vehicles cross through the problematic RPM range in a second or less. 

Flat track racers may dwell for a few seconds at one particular RPM in the corners. Recreational vehicles often cruse down a road or trail at a constant RPM. Land speed racers accelerate slowly due the the high speed gearing.  Land speed racers accelerate through the RPM range where fuel "frothing" may occur, slow enough that the carburetor will go lean long enough to burn a piston.  Flat trackers and recreational riders carburetors can also go lean when running at the RPM where fuel "frothing" occurs.

Fuel "frothing" is obvious when dyno testing.  When the engine reaches a certain RPM where the carburetor vibrates at a frequency that causes "frothing", the main jet sucks a foam of air and fuel,(very lean)  the floats drop to the bottom of the bowl causing more fuel to enter the float bowl and is instantly turned to foam and fuel gushes out of the vent lines while the exhaust gas temperature goes much higher.

The first time I observed this phenomena it did not make sense.  How can the exhaust temperature suddenly go much higher while the floats were stuck open.  I though the fuel level had gone extremely high due to the fuel gushing out of the vent lines.  I removed the carb, cleaned the fuel flow/float valve passage way, and checked the float level.  I conducted another dyno run and had the same problem.  I repeated the dyno test again but this time I touched the carburetor with one finger when fuel started gushing out of the vent lines.  Fuel immediately stopped gushing out of the vent lines every time my finger touched the carburetor.  I could not feel a change in the intensity of the carburetor vibrations from any of the other RPMs where fuel frothing did not occur.

I have also seen the fuel frothing problem occur when the carburetor is allowed to touch the engine cases or frame.  I have also seen the fuel frothing problem occur when the carburetor is not properly supported on the air filter side of the carburetor.  I have also seen the fuel frothing problems occur with some of the aftermarket rigid intake tubes and air boxes. 

Every engine and chassi many have a slightly different resonance frequency.  Some guys may not ever experience the problems described above while others are having problems burning pistons and have not found out why.  Focusing a camera on the vent lines while riding may help eliminate one more possibility

Offline tosaw

Re: UPP Intake Boot Ripped
« Reply #14 on: June 18, 2019, 08:48:35 PM »
Very informative thread, thank you for sharing that info with us Jerry!