Bonneville America Forums Forums Technical Forums Exhaust Shorties Popping

Hello to all, I'm a new member and am looking forward to getting aquainted with everyone. Just brought home a mint condition '02 BA this evening...I'm the second owner. I tried researching the archives but did not find an answer to this question: Can the popping be eliminated with the Triumph Shorties and if so, how? I'm at about 1500' elevation here, if that makes a difference, and I don't know if the air injection has been removed. The previous owner says no jetting or intake mods have been done. I like the sound of the pipes but holy cow...that popping

I'm going to bet the AI has not been removed. The shorties will certainly pop if it hasn't.

air screws might need to be turned out. they are under the carbs and have anti-tamper plugs. most bikes are way too lean from the factory. some found their air screws almost closed.

they should be 3.5 turns out or so.
carb stuff

you don't have to remove the carbs to get the plugs out. most people use a sheet metal screw and screw it into the plug and yank it out. yours might already be out. use a mirror and see.

hope this helps...

cat
btw, the links are from dingua's site, our mechanical guru...
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I have the Triumph shorties, AI removed, air/fuel mixture screws turned out 4 turns and I still get some popping, but not bad. After about 3000 miles the shorties got much louder too.

Thanks all for the helpful hints. I'll now begin to remedy this problem the best it can be and then consider it solved. BTW...I stopped by the dealer today to check on some things and found that they want the better part of a $100 bill for an oil change. Uhhhhh, no thanks...I can change the oil myself!

yeah, change your own oil. it's easy.
if you have a sears type jack, it's even easier.
so is lubing and adjusting the chain. use it once and it pays for itself...

cat oil change

Unfortunately, you still come out at around $60 if you do it yourself, using the Mobil 1 15W40 that is spec'd in the owners manual. And to date, there is no direct replacement for this viscosity. You can use 10W40 or 20W50 from Mobil 1 or Amsoil, but no one makes a synthetic MOTORCYCLE 15W50 in the states that I've found.

I also bought an '02 used, with long off-road pipes and no changes. Popped like a son-of-a-gun and the owner was frustrated so practically gave the bike away. I fixed it in about 15 minutes by adjusting the air/fuel screws. Also removed the AI, but the air/fuel adjustment removed the popping. Mine were 3.25 turns out. My left side was completely closed and the right only out 1/2 turn, impossibly lean.

A few months later, I rejetted with a kit from Bella Corse. He recommended 125 mains which proved to be a terrific setup, fattened the torque curve up a bit. I later added louder (Specialty Spares) pipes and rejetted again. The plugs looked great after 6,000 miles with the 125's. Give it a shot.

I went with the $10 bike lift in the "Links" section. Perfect for chain lube/adjustment and cleaning the wheels. Stores easily. Save my $70 or so for other accessories!

You may even want to consider larger main jets. the "how to" is in the link you were sent in previous response and it's more time consuming the hard. If you do, I suggest replacing the stock phillips screws in the float bowls with allen head screws/bolts. By doing that you can change jets in 15 minutes if need be.

OK...I installed the AI removal kit and backed out the mixture screws 3 and a half turns. It cut the popping down by (rough guess) about half. Since there was so MUCH popping, that still leaves a lot more than I'd like, but hey, it's a real improvement. One of the odd things (to me) is that the majority of the popping was and is from the left cylinder and the pipe on that one is colored much more than the other one. Obviously was and is running leaner...wonder why?

I also got some 130 mains and want to install them. I don't have a service manual yet...I'm assuming the carbs need to be removed to change the jets? Any tips on this would sure be appreciated.

BTW, I've found that riding hard through the rural twisties and straights the bike gets about 46 mpg and a mix of 75 mph freeway and easy riding on the rural twisties seems to yield 54 mpg. Not bad. The handling of the TBA continues to amaze me!

Danny

Check out the carb stuff link that Cat included with his post.

Nobby

You might need to balance your carbs. Again, check out Dinqua's web pages. He da' man!

Carb Syncing Instructions

Also, if you do much carb work you might consider getting some super-duper stainless, hex head carb screws from newspeedmaster.com. They don't strip out like the stock brass screws. It eliminates a high degree of cuss-factor.

Carb Screw Kit

John

Make sure your header pipes are snug where they bolt into the cylindar heads. If one is loose it could explain the popping on one side.

John