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Workshop => Carburetor, Intake, and Exhaust => Topic started by: F-Red on June 15, 2019, 05:28:44 PM

Title: UPP Intake Boot Ripped
Post by: F-Red 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. 
Title: Re: UPP Intake Boot Ripped
Post by: Jerry Hall 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.
Title: Re: UPP Intake Boot Ripped
Post by: F-Red 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?
Title: Re: UPP Intake Boot Ripped
Post by: 2Nubs 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.
Title: Re: UPP Intake Boot Ripped
Post by: F-Red on June 17, 2019, 09:53:41 AM
Myles,

I believe the OEM is too restricted. Need more volume for the fire breathin' motors.
Title: Re: UPP Intake Boot Ripped
Post by: croat1 on June 17, 2019, 10:02:27 AM
Fred, if you get a chance can you post a pic without the hose clamp

Joe
Title: Re: UPP Intake Boot Ripped
Post by: havinnoj 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.
Title: Re: UPP Intake Boot Ripped
Post by: Jerry Hall 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.
Title: Re: UPP Intake Boot Ripped
Post by: 2Nubs 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.
Title: Re: UPP Intake Boot Ripped
Post by: F-Red on June 17, 2019, 06:35:28 PM
Fred, if you get a chance can you post a pic without the hose clamp

Joe

(http://i63.tinypic.com/ajo32w.jpg)

Title: Re: UPP Intake Boot Ripped
Post by: F-Red 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. I’ll look for another style. It started when using ESR’s 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!
 
Title: Re: UPP Intake Boot Ripped
Post by: F-Red 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.


Title: Re: UPP Intake Boot Ripped
Post by: 2Nubs on June 18, 2019, 10:56:45 AM
Yep definitely much bigger.
Title: Re: UPP Intake Boot Ripped
Post by: Jerry Hall 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
Title: Re: UPP Intake Boot Ripped
Post by: tosaw on June 18, 2019, 08:48:35 PM
Very informative thread, thank you for sharing that info with us Jerry!
Title: Re: UPP Intake Boot Ripped
Post by: croat1 on June 18, 2019, 09:03:24 PM
Very informative thread, thank you for sharing that info with us Jerry!

X2 thanks Mr. Hall

Joe
Title: Re: UPP Intake Boot Ripped
Post by: 2Nubs on June 19, 2019, 08:08:12 AM
Excellent info, thank you.

I believe some of what I gathered from that bit is that the OEM works well if it is not dry or cracked?

I'm interested to see if my carb is properly suspended now. 

For anyone interested in how destructive harmonic resonance can be, Youtube search for "CH-47 Chinook Harmonic Resonance"
Title: Re: UPP Intake Boot Ripped
Post by: hickwheeler on June 19, 2019, 01:17:34 PM
Great info Mr. Hall. I think the info of that post should be made a sticky. Thanks for sharing your wisdom
Title: Re: UPP Intake Boot Ripped
Post by: F-Red on June 19, 2019, 03:13:58 PM
Leave it to Jerry to go the extra effort and BLOW our minds! Can we assume, Sonny's billet intake would be the answer?

(http://i67.tinypic.com/2lsim2d.jpg)
Title: Re: UPP Intake Boot Ripped
Post by: Skeans1 on June 20, 2019, 04:26:18 AM
Leave it to Jerry to go the extra effort and BLOW our minds! Can we assume, Sonny's billet intake would be the answer?

(http://i67.tinypic.com/2lsim2d.jpg)

This is from Jerry’s paragraph
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.
Title: Re: UPP Intake Boot Ripped
Post by: Tbone07 on June 20, 2019, 03:24:54 PM
Leave it to Jerry to go the extra effort and BLOW our minds! Can we assume, Sonny's billet intake would be the answer?

(http://i67.tinypic.com/2lsim2d.jpg)


Well if we're to take Jerry's analysis, I'd say that intake would only make the problem worse. Unless that rubber connector he uses is soft enough to dampen the vibrations.

The UPP boot is still probably the best route to go. Just gotta figure out the correct mounting so it doesn't torque the intake, and rip like the OP's did.
Title: Re: UPP Intake Boot Ripped
Post by: Jerry Hall on June 21, 2019, 01:54:46 AM
If you have any of the intake manifolds mentioned in my earlier post and are having detonation and or piston failures, I would run some test to determine if the manifold may be the cause. 

Running the upper vent hoses into a catch-can is another method of testing for vibration induced float bowl foaming. 

The vent line that comes out of the bottom of the float bowl on most carburetors should not be routed into the catch-can.  This vent hose is usually connected to a stand pipe that dumps fuel on the ground almost every time the brakes are applied. The fuel level in the front of the float bowl rises under hard braking.  The purpose of the stand pipe is to keep the fuel level below the pilot jet transition holes to prevent enriching the mixture or flooding the engine during braking.

The top of the catch can must be below the bottom of the float bowl.  The catch-can must be well vented.  The ends of all lines that dump into the catch-can must NEVER be allowed to be submerged in the fuel that may fill the catch can.  If the vent lines in the carburetor are pinched, partially restricted with fuel or partially filled with fuel, the float bowl chamber may not experience atmospheric pressure.  A carburetor that does not experience true atmospheric pressure at all times, can make the Air Fuel Mixture very unpredictable.

The billet manifolds in the pictures look like the style of manifolds I have had problems with.   I have also used manifolds that look like the ones in the picture and not had any problems.  I have used old hardened OEM type manifolds and Boysen type rad valves and not had problems.  Every bike has different vibration characteristics due to crankshafts that not true, loose main bearings or lose main bearing pockets, worn main bearing journals on the ends of the crank webs, improperly rebuilt counter balancers, pistons that are not the same weight as the OEM Honda piston, broken or missing cylinder head stays, loose motor mount bolts, cracked frames, after market frames (have a different resonance frequency than OEM frames), shock absorbers, tires, tire pressure....... the list goes on. 
Title: Re: UPP Intake Boot Ripped
Post by: SFricia on August 02, 2019, 10:46:00 PM
We all have to remember that we are dealing with a consumable part. Rubber doesn't last forever whether it is an OEM boot or a billet manifold.

I have been drag racing 2-strokes for over 20 years and I have had issues with both styles. Neither are without issue, but an issue with the UPP is the stress you put on the intake by trying to force it into an unnatural position to get it to fit inside the chassis.