This is the latest report on the ongoing work on my 2021 Royal Enfield Interceptor. I had traded my 2017 Triumph Street Cup with the new water-cooled 900 motor for the new Interceptor following an unscientific drag race with a friend. The Triumph got off to a good start, but once we hit third gear, the Enfield took off and smoked the supposedly more powerful, more refined Triumph. After a few weeks, and learning that my local Triumph dealer, New Mexico Motopia, picked up the Enfield line, I made the switch. I went with the “Mr. Clean” because the badge on the tank is so much better than the lettering on the Continental GT. Here she is on the floor…

I had them tear the awful plastic fender extensions off and install S&S pipes with baffles, and the flyscreen. I added a K&{N air filter and DNA airbox removal next. Stock, these bikes are supposed to make about 47hp and 34ish ft/lbs of torque at sea level, but the gearing overcomes a lot of the supposed anemic power. She certainly was capable of taking on the Triumph. the first few weeks of playing with it, we found she would reliably hit the ton, but just barely, and occasionally could squeak out a titch more. But there was more there, so in a moment of insanity or COVID-restriction induced insanity, i decided to do something I don’t do: we did engine modifications.

The dealer had never done this, of course; they were new to RE and the S&S guys haven’t really thrown a lot into advertising or explaining these modifications. Point of fact, it seems very much like they’re insinuating some of this stuff is plug & play. I bought a 650cc bike and I didn’t want to bore it out. If i wanted an 865cc, I’d have gone and gotten an old air-cooled Triumph Thruxton. So we installed the high power cams and high-compression piston kits. Allegedly, we would be looking at a 14-18% increase in power. Right off the bat, she was torquier, but I was getting serious lean knock on the motor. The dealer had a look and adjusted the timing, which was off almost 4ยบ from the stock. Once corrected, she seemed better, until I really thrashed it on the local mountain road — a 12 mile stretch with 120 turns and an elevation change of over 4000′. That’s a lot of altitude change, and the bike was detonating like crazy! Fuel booster didn’t help. A booster plug to fool the bike into thinking it was cooler to get more fuel didn’t help.

We turned to the folks at Speedin’ up in Farmington, New Mexico — the only guys with a decent dyno setup. Motopia installed a Power Commander V and took her up to Farmington to get dyno’d. This was also not as easy as you might expect. The probes for the 02 sensors were getting a lot of interference and the guys were suprised by the amount they had to enrich the fuel map (upwards of 60% in some places.) The welded in bungs to get the sensors away from the headers and get a cleaner read. Nope — still needed a massive push in some places, but by the time they were done, they had a serious improvement. Here’s the dyno chart from the final run:

That’s a hell of a torque “curve” — a flat line at 42-43 ft/lbs. from 3500 to redline, with a max power of 49.25hp. Now that doesn’t sound like much of an increase ’til you factor in the altitude. Farmington sits at 5,220′ in elevation; about the same as Albuquerque, where I live. Figuring the (altitude in feet/1000)x 0.03 xHP gets you a rough horsepower of 39.7hp for the stock motor. So the jump to 49hp is about 18.5% increase in power! On return, Scott at Motopia took her for a ride and declared in an unqualified success. I was a bit dubious after five months of messing with the bike…but he was right.

The first run up the Crest road had no knock or detonation, although since then I’ve gotten it to mildly knock by whacking the throttle open hard in sixth gear or higher on the highway. Torque and throttle response is fantastic, and she’s a solid match for many of the 600cc sportbikes. Fuel mileage, of course, has been impacted, but nowhere near as much as I feared. I went from high 60mpg (and as high as 72mpg) to the mid-50mpg range…about a 18-20% decrease in fuel mileage. That seems a fair tradeoff for the performance increase.

So was it worth it? The bike was nearly a straight trade for my Triumph, with $600 for the pipes, $100 for the filter/airbox, $1500 for the cams and pistons plus install, and $750 for the PCV and dyno. That’s a total price of around $9000 compared to similar performance out of Triumph’s 900 classics, which are another $2000 or so out the door. Yes, it’s worth it.

If you choose to do this particular set-up, you’ll find that no one else seems to have done it. Big bore kits, sure; not the heavy-piston and cam kit for the 650. You will want to get a PCV for the Royal Enfield, and you will need a tune. DynoJet doesn’t have it, but you can get my map from the guys at Motopia (see link above.)

I also did the usual cosmetic mods expected of people with this sort of bike to “make it my own”: a chrome fneder to match the tank, bar-end mirrors and shorty levers, the proper Interceptor side plate, not the US “INT-650” (up yours, Honda!) and a side panel bag for hat and sunglasses, and the flyscreen.

There’s a lot of ink and pixels spilled over these little devices, and most of the folks opining seem to have no experience with them — which makes them obvious experts! Then there’s the people that swear by these. We’ve got one in Albuquerque’s Royal Enfield community. I did some research and the basics are this: the booster plug fools the ECU into thinking it’s cooler than it is, getting the computer to kick more fuel into your mix. Pretty basic. There’s a lot of folks that then go on to sing the praises of this device, which apparently cures everything from rough idle to hair loss.

As mentioned in other posts, I’ve gone temporarily insane and had the bike hopped up seriously — S&S pipes, the high performance cam, 11:1 pistons in the 650 cylinders…and after scouring the interwebz I seem to be the only guy that’s done this and not gone big bore. I’m also a mile up, so there’s that. As a result, I’ve been having issues with hard starting and mild to moderate detonation under high throttle between 4500 rpm and up in 5th and 6th gear. Initially, there was a serious timing issue that we sorted, and the problem lessened with the “summer gas” here in New Mexico. (They stop putting the ethanol in the gas — so you get better gas mileage and performance.)That got me thinking that my 65-72mpg I’m getting on the 91 octane (the best we get here), I might be running way too lean.

We’re going with a Power Commander V to try and sort these issues, but we’re waiting on a slot to dyno my Interceptor out in Farmington (5-6 hours away…) What the hell? I thought; if this widget sorts being lean, let’s try it. So does it work?

First: TEC Bike USA was excellent to deal with. I explained the situation and they told me if it didn’t solve the issues to return it, no questions asked. I got here quickly, and I popped it in without issue. You simply take the seat off and there’s a big white connector right there. Pop it apart, stuff the leads from the Booster Plug in and shove the sensor somewhere out of the way. You’re done. If it doesn’t work, you can just as easily pull the plug and reconnect the original sensor.

She fired up easily and the idle did seem smoother. Around town, in the lower gears and rarely getting above 3500rpm, she was smooth and did seem to be pulling a bit more. No scientific, I know, but basically, it seems like there is a minor improvement in the fueling at the lower gears/RPMs. That’s not enough, however, to know if this was going to sort my issues, so I took the bike to the Sandia Crest road — a long twisting 10 miles that climbs 4000 feet from base to top. It’s perfect for putting a heavy load on a motor. On the ride out I noticed the bike seemed to be running a bit cooler, indicating she might be a bit closer to balance on the fuel and air.

What I found quickly was I was getting detonation at 3500rpm in 3rd and 4th gear under heavy throttle! She hadn’t done that since the initial modifications when she was way out fo time. I returned to the bottom of the crest and pulled the booster plug, then did the same run and about the same speed, snapping the throttle where I had, leaning on her hard in the same spots. No detonation in 3rd gear, and mild detonation in 4th and 5th gear at 4500 to 5000rpm, then it settled down. Two tries yielded the same results.

So what does that mean? Keep in mind, I’m not a mechanic, don’t play one on TV, and won’t claim to know a ton about motors, but… This does make me think that 1) yes, this enriches the fuel/air mix a bit, and 2) most of the effect is going to be low down in the power band. It didn’t sort my issues, but it was a handy diagnostic tool, as it now suggest that in addition to being lean, I’m still a bit off on the timing — something the new PCV can sort on both fronts.

Is the booster plug a replacement for a good fuel map and/or PCV on a heavily modified bike? Nope. Might this be useful for a stock bike running a bit lean? I think so, although at $125-175 (that’s what I’ve seen these go for), the price might be a bit too much for folks looking for real improvements in the bike’s operation. If you want a quick fix that isn’t too expensive (the PCV will set you back between $325 and 400, then if there’s no map for you, there’s a dyno run or the autotune module at about $500) for minor improvements, it might be worth a go.

So is it snake oil and useless? Provisionally, no. It depends on what you want out of it. It’s not going to turn your 45ish HP Enfield into a Ducati, but it might smooth out some minor foibles caused by manufacturers bowing down to Euro4/5 emissions requirements.

In my previous review of the 2021 Royal Enfield Interceptor, I had alluded to the ability to upgrade this lovely piece of work that the boys in India have given us. I had the dealer install the S&S slip on pipes (with baffles…I don’t hate my neighbors that much), and I had swapped the air filter for a K&N with a DNA airbox eliminator. This had made her a bit beefier at the altitudes we right here in New Mexico (between a mile and two miles up) and she could reliably hit the ton in 6th gear.

Next up was cosmetic fixes — Hitchcock bar end mirrors in stainless and black shorty levers to go with the short RE flyscreen, and a little tool bag for some kind of storage. But the big mods were still forthcoming: I decided to have the S&S high-performance camshaft installed, as well as their high-compression pistons. Why? Honestly, I don’t know; I’ve never done anything to modify an engine before. I figure the engineers are more experienced than I am, so leave well enough alone. But I sensed she could be more…

The local dealer has just picked up Enfield, but they have built race bikes before so I felt fairly confident they could do the job. The labor was about eight hours on top of the parts, or about $1500 out of pocket. After researching about i was fairly confident we could squeeze about 15% more horsepower and torque out of her. When I got it back, the low end torque and power was brilliant! Then I took it up the Sandia Crest road (where these pics were taken.) It’s a climb of about 4000′ over ten miles with 120 turns in the road. On hard acceleration up the mountain, she was rattling and sounding like she was going to come apart. Then she cut out. The bike fired right back up, but had to be ridden very gently. Even at highway speeds (out here that’s 70mph), she was getting detonation.

Back to the dealer. The timing was off by quite a bit, so if you do this, the cam does not line up as it would with the original cams. Have your mechanic (or you) do a timing wheel to make sure. Once that was done, we were able to pull 115mph indicated out of her. Low end torque is brilliant, and she dusts the stock Continental GT my friend has in acceleration. However, she was still getting light detonation with heavy throttle in 5th or 6th gear once she got hot. i threw some octane booster on top of the 91 octane I use (the best we can get easily in NM) and the problem occurred rarely and only when really hot. She’s also picked up a rough idle and gets all Ducati about starting in the morning. Some of this was further mitigated as our state went to “summer gas” — the ethanol content drops about this time of the year — and the octane booster hasn’t been needed. So it seems to be a fuel/air mix issue now — no surprise since the compression got bumped to 11:1.

I hadn’t heard it for a week, then we took the bikes for a long 150 mile run that included a lovely stretch of arrow straight road — flat as can be — that rarely has traffic. Going for the ton with a quick throttle snap and there it was; bad enough to start losing power. Downshift to 4th and hammer it got me to the ton before a quick double shift up to 6th and while you could heard the detonation, she still hit 110mph into a strong wind with my heavy ass on the bike.

The next step is to get a Power Commander 5 on her and see if we can pull the O2 sensors to get a good autotune on her. S&S and Dyno don’t have a map for this configuration, nor does Powertronics. Dyno-ing her isn’t really an option. There’s no dyno in Albuquerque who I’d trust with her, and the nearest is a 5 hour drive to Farmington.

So is it worth it? On the camshaft, I’d definitely say yes. Even with the fueling issue, it’s pulling like a tractor at low RPM (about 2500-3000) and where it would top out about 100mph and 6500RPM, she’ll run out to the redline and still has more. On the pistons? I’d shy away from this until someone has built a reliable map (hell, that might be me, soon…) You’ll save a lot in time and/or money and still get plenty out of the bike without the finicky fuel issue.

Update: It looks like we’re going with the Power Commander V route, and the dealer is going to split the cost for a dyno run with me to clean up the fueling/timing. That means they will probably have a map for sale once we get this sorted out in June.

I’ve been riding the new Triumphs since 2004. Their sport touring 2001 Sprint, the naked streetfighters — 2006 Speed and the 2010 Street Triple; the wonderful 2010 Thruxton and the equally excellent 2018 Street Cup. They’ve all been great bikes but all have had electrical gremlins (with the exception of the Thruxton, which was flawless.) I’d kept the Thruxton for just shy of 7 years, and traded it for the Street Cup, which other than a lackluster top end, was better in every way.

So why the hell am I riding a Royal Enfield Interceptor now?

One of my riding acquaintances showed up with one a few months back — a lovely creature with chrome tank and classic styling that Triumph tries to evoke, but Enfield just does. He let me ride the thing and it was surprisingly fast and nimble…easily as good as my Triumph. Most importantly, it was fun. Fun in a way the Thruxton had been but the others never were — fun at slow speeds, fun doddling about, as much as ripping up mountain twisties. I went back to my bike and was perfectly happy…then my local Triumph shop, Motopia New Mexico, started carrying the Enfields at the start of the year. This coincided with some electrical issues the Street Cup had started having, usually the harbinger of a whopping big repair bill on the electrics in the near future: my heated handgrips wouldn’t work save sporadically, my four-way turn signals would keep my normal turn signals from working (a fault in the starter switch module.)

And there was the Interceptor. I’d looked at the Continentals when they first came out, but we didn’t have a dealer in Albuquerque at the time, and having ridden the Bullet 500…well, that was not a bike to blow your kilt up (but it would put your hands to sleep from vibration.) A friend of mine and I decided to test ride the new Conti and Interceptor, trading off halfway through the ride to get a feel for them. I liked the Continental riding position better, but that chrome tank with the classic badging was calling me. My buddy bought one.

One day on old Route 66 (yes, that one), we decided to see how they compared. The Triumph was kicking the Enfield’s ass for the first 30mph or so, then the Conti with its 650cc motor hit third gear and blew the Street Cup with its water-cooled 900cc away. While getting the electrics sorted on the Triumph, I noted the presence of a chrome Interceptor on the floor. I went home on her.

After that long way to get to the point, here we go. The Interceptor is a 650cc parallel twin motorcycle in the style of the old British bikes (including Royal Enfield). It looks the part, it doesn’t just crib some styling queues like Triumph’s Modern Classic line, or the BMW R9T; a new bike pretending to be a classic — like the Moto Guzzi V7, this is a legitimate “old school” bike with a few new tricks up its sleeve. Yes, it has ABS and it works okay on the ByBre brakes. (Apparently ByBre is Brembo made in India…) It’s got electronic fuel injection and the map is very good and adaptive to conditions. Other than that, well, that’s it.

The frame was designed by Harris Performance and the steering geometry and weight distribution is fantastic. The bike is very nimble — easily on par with the Street Cup — and fast enough for what it is. The suspension is pretty basic, although the rear shocks (no, the reservoir isn’t real) are adjustable to five points, and with a tick over the bottom setting, it’s done quite well on most terrain. The front definitely needs progressive springs; it’s soft in hard bumps. The stock tires are the same Pirelli Phantom Sportcomps the new Triumphs use. They’re also the ony ties I’ve had slip on me in damp. Not wet, damp. They’ll be coming off first opportunity, but they are serviceable and some folks really like ’em.

The motor is smooth, sounds good (especially with the addition of a pair of S&S silencers and a K&N air filter with DNA airbox removal), and on paper is anemic as hell, producing only 45ish horsepower at my mile up. (I probably made back the altitude changes with the pipes.) It’s not anemic. The gearing on this thing is superlative. Once you hit third, the Interceptor runs hard. Hard enough to smoke a 900cc Triumph. It’s getting about 60mpg for me with mixed highway/city riding and a few miles lower in town. I figured this out by calculating the mileage at gas stops; the gas gauge is, not to put too fine a point on it, execrable. It shows me as on reserve with a good 1.5 gallons left in the tank. Low end, you should get about 160 miles on the tank, high end 200ish. Fueling is smooth and gives no hiccups. You can use lower octane if you have to, but I’d stick with premium.

And the looks… That chrome tank (soon to be joined by a chrome fender instead of a plastic silver one.) That classic badging. That motor: sculpted, clean, shiny. Everything about this bike comes together beautifully.

The downsides: The foot pegs are in an awful position when you stop. They’re right under your feet. When just out of the crate, the handlebars are way too high and forward. I had the mechanics rotate them about 30 degrees toward me. It’s not a cafe position, but it’s much more comfortable. The saddle’s a bit hard, but I did a 230 mile day on her the other weekend with just a bit of butt and hip soreness. The instrument cluster is very basic and compared to the gorgeous brushed aluminum of the Triumph, it’s a letdown. But you also won’t crash while admiring your dashboard. Another unfavorable comparison with Triumph: the Enfield’s gearbox is so-so. It shifts well enough but you’ve got to give it a kick; it doesn’t like a leisurely throw. It’s nowhere near as smooth as the Triumphs, which are some of the best shifting motorbikes I’ve ridden.

To give my Triumph a good send-off, I named her Lakshmibai, the Rani of Enfield as a tip of the hat to the (in)famous queen of Jhansi who led her troops against the British in the India Mutiny of 1857. That’s three history jokes rolled into one.

My buddy bought the white and silver/blue striped Continental, and nearly all the comments about the Interceptor hold for it, as well. The Conti shares most of its bits and bobs with the Interceptor. The footpegs are further back (and those rear sets will eventually make it onto my bike.) It has low cafe-styled bars that are well positioned but might be uncomfortable for those with back issues. I found them more comfortable. The tank is GP styles, instead of the classic teardrop. Otherwise, same bike. They do a lovely chrome one for the Continental, as well, but you don’t get the badge.

Out the door, the bike was a hair over $7000US with a 3 year warranty and 1 year roadside assistance, and was almost a straight trade for me. I had them removed the awful plastic mudguard extensions on the fenders, drop the S&S cans on, and over 1300 miles, she’s been flawless. On a “spirited” trip through the Valles Caldera and the twisty Route 4 to Jemez Springs, we were pushing these bikes hard in the turns and they were on par with any modern bike I’ve ridden.

But sometimes…that’s not quite enough. S&S has partnered up with Royal Enfield to develop a line of mods to improve the bike. This weekend, the Interceptor went in to receive a new high-performance camshaft and a set of pistons that brought the compression up from 9.5:1 to 11:1 — and it is glorious! My butt dyno tells me this thing is much faster off the line, with power coming up pretty much immediately. Where she would just scratch 100mph maxed on the throttle at 6500rpm (so at least you won’t blow up your motor…), she’s hitting 75 at just under 7000rpm in second gear! Cruising at about the same throttle position and revs, I’m getting about 5mph faster on the freeway. I anticipate (but cannot yet confirm) that she will probably bury the needle at the advertised 120 on the speedometer. Parts are ridiculously cheap: about $600, but labor is pretty intensive, so the labor costs if you don’t do it yourself are going to be spendy.

So if you are looking for a machine that will happily doddle around at 40 while still entertaining you, but can still carve canyons with the other bikes, the price point is definitely right.