I have a HPI Baja 5B and am currently racing it in any race I can find. I have been having a problem with the steering returning to center. I have checked the battery and recharged it with no change. The servo has been changed with a Savox SV-0236MG “Super Torque” Steel Gear Digital 1/5 Scale Servo. Could it be the radio settings? I also have another issue with it wanting to pull to the left on throttle. This causes me to have to constantly countersteer. If you know the cars you know that ends up being more trouble if your trying to keep a straight line. If you have any info on how to fix these problems that would be great.
I’ve had various versions of HPI’s Baja 5B since the day it was released. The problems you are having are not uncommon, which also means there’s an easy fix (sort of). Let’s tackle the two issues separately.
Steering. This should be the easier of the two to troubleshoot. You’ve changed out the servo, which is good, but as you mentioned it didn’t fix your problem. Most likely the problem is with the servo saver. First, make sure the servo saver spring compression collar is tight. If this loosens up, your steering will be all over the place. My suggestion, since you now have a bad ass servo, is to tighten it up pretty tight. This will also increase the response of the servo, making steering a lot more snappy.
The next steering item we want to look at is the two pieces shown in the picture. These two pieces are what flex when the servo saver takes over and, after awhile, can get filled with dirt and other grit that wears these parts out. Replacing them (and tightening the servo saver) should help dramatically. You can also put a light dab of black grease on the angled parts before assembly; this will help keep the dirt and grit from getting in there as easily. You could also pick up a new servo saver system; something like Turtle Racing’s setup: https://www.ddmracing.com/Turtle-Racing-Billet-Servo-Saver-for-HPI-Baja-5b-5T-5SC-TR1481t360.html. This is a much improved system than the stock one.
On to your other issue; your 5B kicking out on throttle. If you are running a powerful engine (something more than stock), expect this type of thing to happen. When power is applied, these vehicles want to swap ends pretty quick since they’re RWD. It shouldn’t be too bad and can be controlled with throttle management, but if it’s severe you might have something else going on. First, make sure the drivetrain isn’t bound up. A sticky driveline or blown bearing can cause drag which will hinder one side of the car from moving as freely as the other. You might also give the shocks a look to make sure both sides of the car are compressing evenly and freely. The next thing I would look at is the diff fluid. When was the last time you changed it? Is there actually any fluid IN the diff, or maybe it’s too heavy. This is a bit more work but if you’re serious about finding the problem, this is one of those areas to check. I would suggest filling/re-filling the diff with 1000wt diff fluid; that’s a good place to start.
One last thing to check are the tires. Are you using the right ones for the track? Are the wheels bent or warped? Are the front tires gripping more than the rears?
Hopefully one of these suggestions will fix the issue you have. If not, let me know and I’ll see if I can delve into the problem a little deeper.