BONNIE MOD #10
British Customs Air Injection Removal Kit

Preface: Chronologically, this post is out of sync. It was more involved, requiring more write up and photos. Being my lazy self, it took a while to post.

After installing the TEC 2-1 Exhaust (see BONNIE MOD #6), the bike gained a lot more performance. Much lighter, quicker start off, and much cooler sounding for sure. Rock and roll! However, I suddenly had a lot of backfiring. It’s quite simple, really. Adhering to USA fuel efficiency regulations (dictated by California), the stock pea shooters have catalytic convertors. Not the TECs (hence their performance advantage – a slight increase in horsepower).

NOTE: I live in New York. Motorcycles have to pass a yearly safety inspection in order to get a registration sticker. However, unlike automobile cages, they are not subjected to any emissions testing. So I can make mods willy-nilly to the exhaust system and still pass muster. Your state may vary however, so please check beforehand. The strictest state is California, so Triumph builds their USA destined bikes to pass their tests, so I’ve been told.

The purpose of air injection is to create an atmosphere within the pipe that will burn off any unspent fuel rather than spitting it out with the exhaust. Without a catalytic convertor, there is a lot more unspent fuel that ends up sparking (noticeable as a ‘pop’, mostly when gearing down).

So… I had two choices (with my set up). Live with the backfiring (some riders think it’s cool sounding, and that’s totally okay, and greener) or don’t allow the backfiring in the first place. I opted to disallow backfiring. To do this, you have to NOT inject air into the exhaust mix, hence the Air Injection Removal Kit. Basically, you’re removing the air injection bits and plugging up the holes left behind. Not a lot of hard labor by any means (unlike the air box removal – that’s a post further down the road).

Not much is required – you take off a lot and add back very little. If you’re a seasoned mechanic, you probably have the necessary bits laying around. You could also try scrounging around Home Depot for the bits. It’s not a lot, really. I opted to go with the British Customs kit – two sump bolts and a pair of rubber hole patchers. Overpriced at $25, material-wise, (+ $8 shipping) but worth the performance boost. The kit has carb jet plugs (which I didn’t need) so it works for both EFI and carbureted models.

Okay, so let’s begin…

The seat and gas tank both need to be removed. Luckily, I’m now using the British Customs Quick Release Seat Bolts (install mod here) so the seat was easy peasy. For the gas tank, I followed a Delboy tip. Rather than unplugging petrol connections (and subsequently demeaning their seals), I ran the bike down to an empty tank and then unbolted it from the frame (the two bolts at the front of the seat), and merely shifted it sideways on the frame, making sure to use a towel to prevent any scratches and to help bed it.

I know that this is not a best practice but I’ve found that every original Triumph seal that I crack tends to leak no matter how much I tighten it. In this case, I didn’t want gas (can I say petrol now that I ride a British bike?) leaking onto the hot engine. I’m sure that I’m being silly. Do as you wish.

Now that you have easy access, you want to remove the air injection piping from the engine. Start by cracking off the crimping bracket from the top of the ai tube. I found this to be a bit tricky. What worked best was using a flat head screwdriver, inserting it into the crimp, and twisting until the crimp popped open.

Once that’s done, you’re free to remove the tubing from the top of the pipe and proceed to unscrew the pipe up and out of the engine. A box end wrench twisted in several (many) small movements works best.

Making sure not to over-torque it, the sump bolt now is screwed into place using an allen key. Oh… make sure that you use the copper crush washers. These will bind down and provide a good mechanical seal. So far, I’ve used these on the master cylinder and the exhaust – they are quite handy. I did NOT use any Loctite or other substance. I did not want to risk introducing any substance into the engine. (Let me know if I’m being overly cautious.)

Now move over to the left hand side of the bike, rinse, and repeat.

Okay. Air is no longer being injected into the engine. We’re done, right? I wish. Nope, there is all the supplementary gear that aided in the air injection process. It’s still hanging on the bike, like a withered grape on the vine – no longer of use (unless you’re making raisins). These bits need to be excised.

This part can be a bit daunting due to the fear of pulling off necessary bits, so let me post this next pic to help you out. It shows everything that gets removed during this entire mod. If you find yourself removing something, anything that is not shown in this photo, STOP! You might possibly be removing something vital.

Study the above photo well. Do not remove anything that doesn’t resemble anything in the above photo. You’ve been warned.

(One request from yours truly. I am, by no means, properly educated in the full inner workings of this system. Feel free to interject your knowledge of this system in the comments. I would greatly appreciate it. At this point, I am simply flying by on what works by trial and error and The Google. I would also greatly appreciate being corrected if I am using wrong terminology. Thanks.)

Okay. So what needs to be done is to remove the air feed tubing that goes from the air box to the solenoid (which will stay on frame) and the actual silver metal pump box (which gets removed) that pushes the air into the engine. As said, the valve will be left behind on the frame. Follow along…

Lots of spaghetti. First pull out the tubing from the air box and plug up the hole with the British Customs supplied stopper.

I’ve got to say, though… I’m disappointed in the plug that British Customs supplied. It did not fit well and wasn’t designed properly. In fact, it seemed like an off-the-shelf, kinda fits component rather than one specifically made for its purpose. Yeah, I’m being nit-picky but I spent over $30 bucks for this kit. Anyway, I had to crink it which left a gap. The sleeve should have been designed with grooves to allow it to mold better. Okay, it’s a plastic plug so let’s move on.

Now remove the uptake tube from the solenoid…

Now switch sides over to the right hand side of the bike in order to tackle the removal of the pump.

Since the solenoid will be staying on the bike (Why? More on this in a moment.), you’ll need to release the tubing from it that leads to the pump. However, no need to remove the tubes from the pump since that whole assembly will be chucked off the bike. In the above photo you’ll see that I’m removing the two bolts holding the pump to the frame. Once those are out, pull the tube off the solenoid and pull off the pump.

The air injection system has now effectively been removed. Holster the solenoid back into position. Perhaps you want to secure it but I haven’t found that necessary.

So why is the solenoid remaining behind? It is basically functionless at this point but is tied into the electrical system. Pulling it off will require soldering in a resistor. I plan on doing that but for the moment, this is the easier solution. If you were to start the bike now, you’ll feel timed puffs of air coming out it but that’s it. No harm, no foul. I imagine you’ll get a miniscule performance boost by removing it but I can’t imagine it much. As said, I plan on removing it. I’ll post a follow up when I do.

So… put back your gas tank and seat and there you have it, Triumph Bonneville Air Injection Removal 101. The bike is running much smoother. Remember, I did this in response to swapping out the stock exhaust with a non-catalytic system. I cannot speak to how this mod would perform with the stock Triumph exhaust system. If you’re putting in an after-market exhaust system, this is a must-mod.

Cheers.

Tools Required:
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Flat Head Screwdriver

Company URL:
British Customs

Price:
$40 + Shipping