Friends: I just purchased (rescued?) a 2002 Triumph Bonneville America that had been poorly treated by its prior owner. Aside from the many other defects that I won't bore you with, the bike pops (and even backfires a little) significantly on deceleration. It has short TORs and the A.I. has not been removed. It appears to have a stock airbox. The carbs certainly need a good cleaning out and synchronization. I plan to tear into it this weekend, but before I do, I thought I'd solicit some troubleshooting help from the many of you on this board who are far more talented and knowledgeable than me about such matters. Subject to your advice and guidance, here's how I plan to proceed: 1. remove header and TORs and re-install with Permatex Copper sealer on header gasket and high-temp silicone between header and TORs (make sure there are no exhaust leaks) 2. remove A.I. 3. remove carbs, clean and check jet sizes 4. reinstall carbs and balance them 5. play around with pilot air mix screws (richen) to see if popping lessens Other than rejetting/shimming, is there anything else I should be doing? Can anyone recommend a jetting set up (assuming carb has stock jets in there). Thanks for your help!
My decel popping stopped as soon as I removed the air injection, but started back with aftermarket pipes. I adjusted the idle mix screws to richen it up and the popping almost went away.
Find answers/discussion at bonnevilleamerica dot com forum. Great sources for parts are bellacorse dot com, and newspeedmaster dot com. I don't know any European sourses for aftermarket bits.
If you exhust system has any leaks it will **** air in on deceleration and then pop as the air bubbles
exit the tail pipe
The popping is caused by the emmisions control system (fitted for the american market),to cure the popping buy a emmisions blanking kit,to fit it remove the emmision control system, simply remove all the fittings and the pipes(they are situated on the cylinder head at the side of the spark plugs).replace them with the blanking studs and follow the pipes back to the carbs,remove all the rubber piping and gadgets and the popping ceases ,The exhaust will not go as blue once this has been done,
The blanking kit can be obtained from Norman Hyde triumph specialists.
There seems to have been an extensive debate on various thread whether popping\backfires are healthy\normal or unhealthy\abnormal. I've read in 2 different threads completely opposite opinions, with mechanics explaining in great detail that a properly tuned engine will naturally pop on decel, and on another thread seemingly just as qualified people saying that its bad for the engine, and its either running to rich or too lean, and how to fix the problem. Personally as an owner of a popper, I'm still curious (but not as concerned) over whether this is normal, or something that can\should be tuned out. It seems to be common for bikes with after marked pipes, and even after getting fully tuned up, mine still pops often, although not as much as it used to.
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