This FAQ last updated: 03.06.2026
Please ask questions in the FORUM (https://forum.himalayan-tools.com/) where issues are discussed in greater detail.
Q: I ran a hosting search for your domain and found it is hosted in Germany. Are you an Indian or a German company?
A: We are a company registered in India (a private limited) run by Germans with a 10% Indian share. All design decisions and quality control as well as customer relations are in German hands.
Q: I live in the USA, are there currently any taxes or import duties to be paid by me when I order from you?
A: While the situation is fluid and changes a lot, we update the current rules and regulations here:
https://forum.himalayan-tools.com/threads/shipping-to-usa-current-situation-updates.1081/#post-7377
Q: I live in the UK, do I have to pay any duty or tax on your stuff?
A: We had ONE case where a customer had to pay VAT, all others went through without any added fees.
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: Are you using the factory liner bored to 410/500cc or are you providing the cylinder with a new liner when upgrading to the BB?
A: For both BB sets we use a new liner that will however still fit into the engine body without any changes to the latter.
Q: Are there specific break-in rules I must follow?
A: Yes, there are. The engine should not be moved beyond 3000rpm for the first 500km. Then an oil change is needed and for the next 1500km 4000rpm should only be surpassed for take over. It can take up to 2000 km to reach full free running, up to this point top speed can be used for short moments but not sustained. After the initial 500km break-in full synthetic oil should be used exclusively.
Q: Are there any instruction for doing the BB upgrade by myself?
A: Yes, there is a video on Youtube showing the process, however some experience in mechanical work will be required nonetheless: https://www.youtube.com/watch?v=bxAkhdM-Ato&t=846s
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. Update: There is now the optional FuelX Pro+ for this engine and in our tests it showed a real improvement in torque and response.
Q: Are you offering maps for the J-Engine PT V4 and the 500cc BB kit?
A: Yes we do but we add 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 other elements concerning 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 4% increase and the 500cc about 9%. In our experience the 410cc will run with 95 Octane fuel without knocking. The 500cc requires 100RON which would be called “Super” in most western countries. To completely avoid knocking issues we have opted to slightly modify the head by carving out a section that is very easy to work with, the pictures shown on this forum thread demonstrate this simple 30 minutes task: https://forum.himalayan-tools.com/threads/500cc-j-engine-compression-reduction.589/
Q: How about vibrations?
A: The 410cc has no perceivable additional vibrations whereas the 500cc has some but nothing annoying. We got used to it in a very short time and do not notice it anymore.
Q: I have a question not covered here, what do I do?
A: If it pertains to sales or ordering please contact our staff by email or the contact page. If you have a technical question please register in the forum and ask there.