This information is for customers who have purchased the 477 set [last updated: 13.01.2022]
Please read before installation
Raw Liner kit: Please check if the liner fits into the engine housing before you do the boring. There has been a case where the housing had an “edge” where the 2 halfs meet and this edge would not allow the liner to fit. It is a RE QC issue but obviously we can’t do anything about it. If the liner does not fit use a lathe to get it to fit before doing anything else. It is possible but much harder to fit it after you have it installed into the cylinder.
If you install the 477cc piston with only one layer of bottom cylinder gasket you will achieve a compression rate which is OK for 92 RON, the standard Indian fuel. Only in rare occasions and countries with even worse fuel (some parts of Africa) use 2 bottom gaskets which will reduce the compression even further. If you chose 2 bottom gaskets make sure you use one of ours and one OEM. If you use 2 of ours the timing chain could be too short if it is new. On an older bike the then elongated chain may fit even with 2 of our gaskets.
You will need the following additional items to do the update: (they may be included, depending on the kit you purchased)
One head gasket, one or two cylinder bottom gaskets, one exhaust gasket (copper ring). If you do the changes yourself you will need a tool to adjust the valves (available e.g. online at ebay, from RE and Hitchcock’s for 30 pounds) after installation. A torque wrench is advisable. Download the torque values here. If you have a carby bike you may want to change to a 130 main jet and a one size bigger pilot as well.
Break-in rules should be followed religiously.
It is recommended for the first 500km to never go over 4000rpm, onwards up to 1000km 5000 rpm should be the maximum. Riding conditions should vary as much as possible which means do not sit on one rpm/speed for extended periods. If you must use a highway still vary speed and rpm. Full break-in is achieved after approx. 2000km. After the initial 500km an oil change (with filter) is needed. Also then re-fasten the head bolts (otherwise the head gasket may leak oil) and adjust the valves. While the break-in oil can be any cheap oil from 500km onward only use full synthetic oil, the brand is irrelevant as long as it follows international norms for high quality oil, examples are:
- Motul 7100 4T 10W-50 API SN Fully Synthetic
- Mobil 1 5W30 Fully Synthetic
- Shell 5w-40 Helix Ultra Synthetic
Remember that oil is not only responsible for friction control, it also serves as coolant in the LS410 engine. The 477cc is a high performance variant asking for high performance oil.
If you have not done any operations on an open engine before but want to do it with this upgrade please watch our video on YouTube how to do it BUT, as mentioned above, use a torque wrench when re-assembling the parts. Experienced mechanics can do it by hand but it is a very bad idea to emulate that without years of experience under your belt. The torque values are available here.
Top and bottom cylinder gaskets are supplied with the piston. If you received a metal and a red mesh like head gasket only use the metal one. The red can be used in emergencies and also as a template to resize the hole of a OEM head gasket from 80mm to the required 84mm with a dremel.
Sometimes parts are not available or dealerships are far away. In that case you can make your own foot gaskets which are made from thin cardboard about 0.3mm thick. Such gasket material is available in sheets from Amazon and locally in hardware stores. Sometimes you will also find stores for automotive parts that can cut those gaskets for you (water cutting) or some print shops that cut labels and logos. We supply the layout for download in these formats in one ZIP packet: Corel Draw 2019, Corel Draw 12, PDF, [click here].
We are using the 477cc on carbureted Himalayans as well. The UCD33 carburetor is also used on the Bullet 500 with the same 125 main jet. We have changed that to 130 and one size bigger pilot and our bike runs OK when cold now. It will run with the 125 original jet but adjusting to a good cold idle is hard. If you venture into the high mountains change to 110 main jet or else the engine will lose ca. 50% of its power. Do not forget to change back to 125 or 130 when coming down or else the engine will run way too lean and get overheated.
EFI bikes with this piston must use a device to regulate fuel flow with a mapping according to the 477 which necessitates the purchase of the Powertronic or similar device. Some users apply the 462cc map available from Hitchcock’s. We supply our own 477 map and make it available for download in the forum. Recently RaceDynamics, the makers of the Powertronic, came out with a device called FuelX (or FuelX Pro respectively). These devices are much cheaper than the Powertronic and our tests indicate they are sufficient to run the 477cc without danger of damage. The engine may not achieve the full possible output but we are talking the upper 5-10% here. Alternatively, and only for the BS4/Euro4 models, we offer a full replacement ECU that allows all parameters of the engine control to be manipulated. Unless you use a map provided by us it also requires you to have knowledge about engine tuning.
While we do not offer a warranty for this upgrade we will replace a broken 477cc cylinder/piston assembly with a new OEM version (back to 411cc) for 100.- € plus shipping. It may take up to 4 weeks to get a cylinder sent to us from the factory in Chennai under normal conditions (no lockdown).
If you want to discuss your experience with this upgrade in the Himalayan community there are various general bike forums and some specific to Royal Enfield out there. If you are interested in replies from us we suggest you use our own forum which specializes in the Himalayan.