Bullet 350 UCE weird behavior while applying the front brake at 20 km/h

The motorcycle does not show this symptom when running at higher speeds.

BHPian adrian recently shared this with other enthusiasts.

Going through a weird issue with my 2011 Royal Enfield Bullet 350 UCE.

It all started with a wheel trueing incident, post which the front drum brake began to act like ABS brakes. It grabs and releases at one point.

Things done so far

• The brake drums are not oval and both shoes are grabbing in tandem with no drag (can easily lock the front wheel using the twin lever drum brakes).
• Steering races are tightened and without play.
• Wheel bearing had some play and had been replaced.
• Shock absorber has been overhauled.
• There are no cracks in the chassis.

The only clue

When the front tire is off the ground, only at one point, the wheel has a wee bit of lateral play (no sounds of loose spokes though) and the wheel spokes at the region are tight, but not ringing like the other spokes when tapped.

Other facts

• The wheel trueing had been done by an expert in Trivandrum.
• The wheel had some rust issues, which were sanded down and painted with zinc chromate.
• The front tyre is of the MRF RIB type with a lot of treads but was installed in 2018. There is no bulge in the tyre and it is in good shape and has no run-outs.
• I use front brakes heavily.

Any ideas on what to look for?

End note

If nothing works, I plan to upgrade to the disc brake version in the proper way by changing shock absorbers, wheel etc.

Adding one more thing

This ABS thing does not show until the motorcycle is about to stop (sub 20 km/hr speeds) when braking. Speed scrubbing at higher speeds does not show this symptom. And no, the motorcycle does not hop up and down at any speed while running. The motorcycle shows this symptom, only with front brakes applied, only at sub 20 km/h speeds.

This was how it was before

The rust issue

Actually this is the only rust I have in my 12-year-old Bullet. Again, this was avoidable, if I had removed the tyres periodically (say around 20000 Kms) and had gone for a wheel trueing. Bullet owners take note of this factor as well.

After painting

The trueing incident

I had given the wheels for trueing like this (without the bullet and without the tyres)

I didn't mention the diving to the right side to the wheel trueing guy. To my amazement, when I went to pick the wheels up in the evening, he asked me whether my Bullet was pulling to the right. I said yes and also said that for the very same reason, the bullet dealers (Marikkar Motors) had collected money from me in 2011 for getting the wheels trued.

Actually, I had ruled out an untrue wheel as the cause of the Bullet diving to the right, after the dealer did the trueing and had assumed that I had an out-of-alignment frame, which some Bullets have as a manufacturing defect. It was then that the wheel trueing guy said that the hub was not perfectly in the centre of the rims and that was the reason the bullet was diving to the right. To be true, the issue has been resolved after 12 years.

So the lesson learned: Always take a second opinion before giving upon something (especially if the first opinion was given by an RE ASS technician).

The tyre in question after trueing

Here's what BHPian tharian had to say about the matter:

I remember having this issue years ago on my bike. I think the mech removed and cleaned the drum and greased the pins and it was fixed. It used to happen after a water wash and I used to initially think it was the cable and oil it, but that helped when the front brake lever never used to pop back to the released state.

I doubt if it is related to the trueing.

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