Royal Enfield Himalayan Booster Plug fitting and test runs. Iridium plug and free flow air filter

I wanted to see what difference the booster plug would make to my Himalayan along with some other mods, so I fitted a free flow air filter, the booster plug and an iridium spark plug, all from Hitchcock's in the UK.
I already had a Lextek exhaust can fitted before I did this test.
The engine is set to run lean from the factory and adding more air will only make it run leaner and therefore hotter running.
The booster plug will richen the fuel/air mixture and the iridium plug gives a better spark resulting in cooler temperatures and less chance of burning valves and pistons.
That's the theory anyway.

[@ianowen4481]

Adding richness to the mix is a good thing anyway regardless of any performance gains because it's already been made leaner due to the Lextec and the air filter. Your engine will now run cooler. You've saved weight with the Lextec so that's a positive and have remedied the lean running that a free-flowing silencer causes. Any additional benefits of the plug will make themselves known in day-to-day running in the form of subtle character and 'feel' differences. Doing test runs, although useful, never tells the whole picture. Thanks for showing us how to do it. I'll be doing it myself soon for my Lextec/Delkevic modded bike.

[@daveinwla6360]

The free-flowing exhaust just lets the combustion gases exit more freely, allowing more intake charge to get in. It doesn't affect the fuel/air ratio of the intake charge.

[@himihuskyme6280]

Thanks loads for filming, looking to do the upgrade myself on our Himalayan Sidecar Outfit, as could do with a little more grunt

[@Gee-Man-Adventures]

It's worth doing to enrichen the fuel mixture. The bike seems much happier afterwards.

[@manchigsxf]

I also have a similar setup. Full gas there are hardly any differences. The difference is when there are only accelerations with partial gas loads: better and more forceful accelerations and also the engine works better.

[@chrisvredenbregt5952]

I have a 500 classic and diverted the crankcase breatherhose from the airbox where my AIS is located so no more warm gasses from the crankcase surrounding the AIS in the airbox I think that it has the same effect as the boosterplug in my point of view and cheaper anyway. I had expected more influence from the boosterplug . Anyway great bike have fun

[@classicrider5274]

I have fitted a Booster plug and Iridium spark plug but otherwise standard and find that the low to mid range seems to have more urgency when accelerating but I understood that when at a constant throttle opening it made no difference. Mine runs a little cooler and I can see a slight deposit in the end of the silencer which was not there before. The other change is a more consistent idle speed.

[@daveinwla6360]

With a richer fuel/air ratio, there is no benefit from the iridium spark plug except, perhaps, for longer plug life from slower erosion of the center electrode..

[@joegarrison8611]

A good video, at least now I know where to find the plug and how to fit everything in. Mighty Car Mods once did a review of stock and high flow air filters. They tested stock and high flow air filters vs NO air filter. Naturally having no air filter being the LEAST restrictive. As I remember, it was pretty much a wash on non-boosted engines. Try the same run with no air filter and see what the results are. I AM NOT recommending not using an air filter for riding. This is just another test against your control (stock filter). I am of a mind that the high flows when sprayed with recommended oil perform near on par with the standard filter, but your plug may tell you different if it gets leaner.

[@daveinwla6360]

With a decent fuel/air ratio, your iridium spark plug probably doesn't affect the performance. You can easily test its effect by simply replacing it with a copper plug. Racers know to change just one factor at a time. This is why.

[@pranaakhanda9154]

I really appreciated this video . But sir , please , how can we find , nowadays, this kit booster plug for BS3 , carburator , like urs ??? here in india i see online only for fuel injection himalayan ... can we get link to purchase for BS3 ???? any link will be appreciated sir .

[@PLAYINGAROUND]

You need to change the air filter cover for a free flowing one too, but the gain of doing all this isn't really worth it. As a project it's interesting, but the gain is, as you have shown, minimal.

[@JohnBraman413]

can you still use powertronic with the booster plug?

[@stankropiunik2539]

You should have got the NGK CR9EIX, it performs much better for cold starts and the engine idles better on lower RPMs. And now since you have installed a free flow filter, you also need a free flow exhaust, to open up the throttle or you can drill the last baffle through with two 1/2 inch holes to open up the exhaust but still keep the backpressure to a certain extent.

[@0xsergy]

cr8eix seems to burn hot on mine, going to a 9 on the next one.

[@poltergheist3388]

To notice a difference you should change also the exhaust line, I said line because is the collector exhaust wich restrict the more the gas. Is logic, you attempt to make engine breathing better by adding a high flow filter but if exhaust gas not quit the cylinder faster the only way to add more air is to compress thise gas and you have no turbo or forcing admission pipe. Is why most of peoples who change only exhaust or only air filter almost notice nothing. You should change both to make an engine breathing and then the richer mix will no more be richer because you will get more air .

[@johnrocker2986]

If you want a richer engine why increase the air flow from the airfiler?

[@Gee-Man-Adventures]

It was too lean after the mods. I was just trying to get it back a bit.

[@johnrocker2986]

The NGK Plug was not so good for my bike but on past experience changing to a Brisk multi electrode plug the machine ran fine with booster and standard filter setup.

[@gcprost]

It’s hard to hold a camera and work at the same time.