J-Engine 500cc Thread


Staff member
477 Owner
While we do the J-conversion to 500cc I will update here on our progress

So far we have successfully changed the cylinder/piston combo of a Meteor utilizing a slightly used 83.5mm piston that had run previously in a 477 Hima (that was upgraded to rocket status with a 500cc upgrade).
After a small hickup with the head gasket which was cut out not sufficiently (based on the 410cc piston) we had to undo it, reshape the gasket and do it again. but I have to say, the second go was already much faster than the first. After this the engine started and ran OK in low rpm of course but would not hold idle (too low).
After we installed the PT V4 with stock mapping the idle stabilized - however I will have to "guess" my way to a good mapping - based on what I learned from the Hima PT4 maps that should not be that different.
The Meteor OEM ECU has a rpm limiter (I think shut-off is at 6500) and also a speed limiter. I have no idea how those will affect the riding with a rocket like 500cc engine. If all else fails we will swap the ECU for the Hunter version that apparently has none of those limits.

The conversion was filmed (with my mobile) - and when I find the time a How-To YT video will appear.

The tools we needed where all very common and anybody having even just a decent tool collection will own them already - except one special tool to fixate the timeing chain sprocket. This is available only from RE (but should be easy to manufacture - even in small numbers individually by our genius welder)


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These are the tools - plus a few more wrenches from my complete collection and some sealant (substituted with glue) and some fuel for cleaning parts:


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we had to combine these 3 to get to the correct value for the exhaust valve:


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A word about installing the PT V4: It just about fits under the seat. The unit itself fits into the "paper compartment" on top of the battery - but barely and with the extra cabling from the map switch its a very tight fit. There is no room for a fuelx pro** and only with a lot of luck I can squeeze a bluetooth dongle somewhere that I will need for the engine ECU values to check during mapping. This is so far also the only way to get a grip on the RPM readout although I may install a tachometer later***.

**Update: Later I added the fuelX pro+ - it fits nicely under the pillion seat
***I added a Daytona Velona - that did not work, had to send it back to the dealership. But the TORQUE app is quite sufficient
Still working on the tacho install - scheduled the mechanic for Thursday. However very good news from the PT4 front:
I just copied the +25% fuel map from the Hima - with absolutely no changes - and the bike is now a bloody rocket compared to before.
In comparison to the Hunter 410 which really only shows improvements from 3000rpm onwards the Meteor JUMPS forward when touching the throttle. Also no more cutting of in cold idle. All looks perfect. I have not checked the mileage though - will do next time I fuel up.
For lack of pistons this one won't be available for a while (another month?) - but everyone is welcome to pre-order which would help me in calculating how many pistons I should get.
I even made a small sticker to put on top of the obsolete 350 marker:


500 Meteor Logo.jpg
Our attempts to get this cheap 10 bucks tacho (rpm) meter to run on the Meteor have failed. There are numerous videos on YT how to install it however, they are ALL only covering carby bikes.
I have now ordered a proper USA made Tacho and hope to have more fun with that - based on the fact that a guy in Germany was able to get it to run on his Scram. But 130 Euro plus some customs once it hits India I fear, Quite a different category. But it also taps into the oil temp sensor in the head, so I do not have to get my cheap china oil temp to work where I do not know where to put the sensor.

UPDATE: crappy instrument, malfunctioned out of the box.

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Did you decat the exhaust pipe and mounted a free flowing air filter? What about the cam? what other mods did you do?

I guess that map is rich for your configuration (assuming everything else is stock) but good to know it works!

It would be interesting to compare that to a classic 500 UCE.
If this mods proves viable it might respark my interest in the new classic Reborn...
I have done none of the above, just the 500cc and the PT V4
I got a decat for my BS6 Hima though - pops a lot but otherwise no great difference
While we do the J-conversion to 500cc I will update here on our progress

Congratulations about your project! You have done very impressive job so far!
I have a RE classic 350 reborn with many aftermarket accessories (free flow intake and exhaust, powertronic fuel X lite, powertronic ecu). I feel that with more displacement the character of the bike will be marginally improved. So i have some questions:
-How exactly do you ship to Greece ? ( shipping company, customs, total cost)
-I see that you had difficulties to "feed properly" the biggest kit 475 cc due to ecu issues. Have you tried to swap the throttle body/ecu from euro 5 Himalayan/scram to j 350 engine? This could be a very interesting and more "factory" option (than powertronic ecu) to correct fueling for overbore kit and remove the speed limiter as well.
-Have you thorough to develop just sleeve and overbore piston kit? This could be cheaper and easier to sell and ship with no limitations about cylinder availability. I wonder how difficult is for a machinist to press the new sleeve on the cylinder?
-What is your suggestion about the more wise kit to choose? 410 or 475, searching the ideal balance between reliability, pleasure and performance?
Hi Kostas, welcome to the forum. Please add a picture to you avatar and maybe leave a few pics of your bike in the "show me yours" section.

I already answered your "how do I ship" question via email and its OT here so I omit it.

While you are right that the absolutely optimal configuration would entail the changing of the TB to a bigger one (possibly the Hima or even for a 500 the 535 Conti TB if the Hima is a BS4) the aim for ME is to make the best possible plug & play solution insofar as as little as possible additional add-ons should be needed to make the thing run.
In that light the absolute minimum is something to regulate the air/fuel flow which in the case of the BS6 can only be the PT V4 (no other option that I know of) and the BB kit itself. With these component one can get quite a bit more punch out of the 350 engine. Yes, getting the perfectly correct setting for the PT would require a dyno which I do not have access to - but with guesswork from some expert friends (namely @Sasa) I got quite far and with the latest improvements even the knocking went away.
If the bike in question is a Meteor it may also help to buy a HUNTER TB because that one does not have the rev and speed limiters BUT the essential upgrade in all cases, regardless of what else was done, is to increase the displacement. Everything else is secondary and people who believe they can get the same torque and engine characteristic just by replacing the camshaft (though it helps) are mistaken IMO. I have tried it and the BB is the best improvement although not the cheapest.

I have tried to sell just the sleeve and piston but nobody was interested. That is no surprise considering the price of boring and honing in the west. Our BB sets are easily cheaper than doing the work in the west by some workshop (unless it is your workshop) and frankly some people prefer the insurance to be able to go back to the OEM configuration should anything go wrong, they like to keep the 411 cylinder and piston.

Regarding the "best" BB kit: the 410 obviously has a price/performance plus for people who have not yet invested in a PT. You simply do not need it for the 410 upgrade. If put into a Hunter it may be all you want or need. The only other BB kit we offer is the 500cc kit and that definitely requires a PT. So on top of the BB being more expensive itself the PT adds a chunk of money.
I found the FuelX (Pro) quite superfluous, I had it but then disabled it because it did not in any meaningful way improve the performance - however at position 10 it seem to influence the fuel efficiency in a negative way. That was on a Himalayan. On the Meteor I never installed the FuelX and there seems to be no space for it once the PT is installed.

In terms of reliability I can not really say anything. The 500cc pistons are FORGED that means it is unlikely they will ever fail - but even the 410cc being an OEM RE piston that ran up to 100.000 km without failing I do not see this as a big concern. Once anyone reaches that kind of mileage we will all drive electric bikes anyway :cool:
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Thanks for your responce. I think that your way makes sense. I will keep on the safe zone. I have ordered allready the 410 kit. I will post details and review after installation! For the moment i will wate...
Yes, please let us know how it performs in a Bullet. so far we only have it in a Hunter. I will need to drive to Dehradun tomorrow just to get your foot gasket :cool: ... but thats OK. So far we have only ONE more set 410 because it is very nearly impossible to get the cylinders from RE.

Also: future feedback for the 410cc please in the 410 thread - not here. this is the 500cc thread.
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Testing with the 500cc Big Bore kit have been concluded. The Meteor runs great and this upgrade will be available in the shop from now on.
Unless you have access to 100 Octane fuel you may have to modify the head to avoid knocking - that is a very easy task if you own a dremel and is described here: (Alternatively you could use 2 or 3 base gaskets)

Update to what I wrote in Jan:

To avoid knocking altogether unless one uses 100 Octane fuel there is need for a small modification of the head (description in another thread)
The FuelX Pro+ (plus is important) really does make a difference on the 500 Meteor. I would guess a 10% gain in torque
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