Hpi baja 5b bogging in higher rpms

[hoodmekanik]

TO START OFF
ITS A 30.5 ESP PORTED HEAD, 2MM STROKED CRANK, WALBRO 813 CARB, GBE NOSE BLEED, EVERYTHING IS BRAND NEW.. I HAVE RAN ABOUT 2 GAL RUN THROUGH IT 93 W/ AMSOIL 100:1 OIL... TORCH CMR7H

NOW THIS IS MY ISSUE
THE CAR STARTS UP RUNS GREAT... BUT HOLDING WIDE OPEN THROTTLE FOR ABOUT 2 SECS IT STARTS TO BOG IN AND OUT... I RICHEN THE HIGH SPEED NEEDLE AND IT DOESN'T MAKE A DIFFERENCE... LEAN OU THE HIGH SPEED NEEDLE AND STILL NOTHING... I HAVE A VIDEO OF HOW IT RUNS...

IF SOMEBODY CAN HELP ME... I WAS THINKING ITS A GASKET... I REPLACED THE EXHAUST GASKET NEXT ARE MY INTAKE GASKETS...
AND IM GETTING NEW GAS

SPARK PLUG TEMP NEVER GOES OVER 88F after a couple WOT RUNS...

 

[46u]

Hello and welcome to the forums. Please take the cap lock off as it makes it hard to read and is like you are yelling.

Is the engine new? How much gas have you run through it? Do you warm the engine before you start making your high speed passes? Have you tried a new plug? Where do you have the needles set on the carb? What is the weather like where you live? Running at 88F is not good way too cool. I have found the best place to take a temperature reading is on the clutch side about half way down the cylinder. Not like you would do with a nitro at the glow plug.

 

[fourdollarbill]

Partial pinched fuel line. (between filter and tank)
Hardened fuel line. (nitro fuel line)
Fuel line air leak. (bell bottom shape at hose barbs)
Vent in the fuel cap plugged. (black rubber tank insert with incomplete hole)
Just some thoughts...
One of mine did that after I installed a new oem fuel cap and I found the rubber boot did not have a hole in it.

 

[mickey]

get rid of that torch spark plug and put either an ngk or champion in there . the torch plugs are garbage.

 

[98NYFinestVette]

Is there a site to where I can find a plug for a HPI 5SC? I like the idea of a NGK. I use them in my real race cars.
Thanks

 

[Baja_Matt]

When I rebuilt my engine to a 29cc I had a funny problem during the first tank, it would bog/sound like it was nailing a rev limiter, turned out the spark plug boot wasnt making a good solid connection, allowing a misfire at high RPM. Just a thought and something to check.

You can get the NGK plug at any parts store. I got a box of 5 at Napa for 18 bucks. Part number is 3066 and it is a CMR7H

 

[98NYFinestVette]

When I rebuilt my engine to a 29cc I had a funny problem during the first tank, it would bog/sound like it was nailing a rev limiter, turned out the spark plug boot wasnt making a good solid connection, allowing a misfire at high RPM. Just a thought and something to check.

You can get the NGK plug at any parts store. I got a box of 5 at Napa for 18 bucks. Part number is 3066 and it is a CMR7H

Thanks for the information Matt. Do you have a plug gap recommendation?

Thanks again

 

[motorman]

change plug to a new ngk. if that doesn't fix it, try cleaning the carb. if no improvement you may have a worn out cylinder. ive had worn out engines run like this. normally the plating is gone and it is trash. if it were an airleak it would show its face at idle and low revs aswell, but you say it runs fine down low, only the issue is visible at high revs.