This FAQ last updated: 24.04.2024
Please ask questions in the FORUM where issues are discussed in greater detail.
Q: When can I expect the 500cc set to ship?
A: Now
Q: Do the 410cc or the 500cc BB kits require a widening of the engine body?
A: No – both are “plug and play” with regards to fitting.
Q: Do I need anything on top of the BB set for the 410cc upgrade?
A: No. This upgrade is very well handled by the OEM ECU of the bike itself. However, if you own a Meteor or a New Classic Bullet you may want to change to the throttle body/ecu combo of the Hunter as that one does not have the rev and speed limiter your bike will have. The part number for that particular TB is RLT00187. See also:
https://forum.himalayan-tools.com/threads/different-ecus-or-mapping-for-the-three-models-using-j-engine.496/
Q: What kind of piston do you use for the 410 and 500 BB kits?
A: We use a RE OEM piston for the 410 BB kit (which is cast) and a forged piston of our own design for the 500 BB kit.
Q: What additional ECU can I get for air/fuel and timing management of the 500 BB kit?
A: We only know of the Powertronic V4 made by Racedynamics in India at the moment. However, other vendors may come up with one in the future as the market for the J-engine is huge covering 3 of the best selling models of Royal Enfield.
Q: Are you offering maps for the J-Engine PT V4 and the 500cc BB kit?
A: Yes we do but with the caveat that these maps where done for a Meteor and even then they may need additional tweaking to fit you specific bike if you have changed the air filter, exhaust or any other element of the fuel/air flow.
Q: Is there a appreciable compression increase with the 410cc or 500cc BB?
A: There is some. The 410cc has a 3-5% increase and the 500cc about 6-9%, both if nothing else is changed. In our experience the 410cc will still run with “normal” fuel of 89 Octane without knocking. The 500cc the we currently test in a Meteor requires 95RON which would be “normal” in most western countries (but not in India) and a slight adaption to the ignition timing in the Powertronic along with add. fuel in the mapping.
If the bike has run some km already and the timing chain lengthened a bit 2 or 3 foot gaskets could also reduce compression and widening the head to the new circumference of the larger piston/cylinder would have the same effect. But reducing compression will also reduce power output and this is kind of contra productive the the task of adding power by a BB kit.