Bonneville America Forums Forums Technical Forums Performance Mods Another CVK tuning/jet question

I am a bit hesitant to open a new thread for this, but the more I read about tuning the CVKs the less sure I am that I know precisely where to start. I just purchased a 2004 America. The airbox has been replaced by a pair of K&Ns and all the baffles have been removed. The previous owner could not recall exactly what was done to the bike just that the original jets were replaced. The told me there were 45s and 140s, but did not seem sure. I am replacing the main harness now and the carbs are sitting on the bench waiting for a cleaning.

What is the “consensus” on the starting point for idle and main jets with the above changes? I need to get some gaskets before opening them and if jets are likely in my future I’ll save a trip by buying them now.

I did try the calculator, but could not get them to open.

Thanks for any feedback you can offer.

Any riders from the Mass/NH area?

Rob

Try this version: http://www.bonnevilleamerica.com/dinqua/friar/

Without knowing how many baffles were removed (I assumed 2), or if the needles have been changed or shimmed (I assumed neither), and assuming your elevation is 1000-2000 ft., the calculator says 147.5 mains with 45 pilots.

Thanks very much, that link worked perfectly. Your correct for assumptions, but I am only a few hundred feet above sea level. It looks like 148s will get me a good starting point.

I just completed some work on my new 2004 TBA that included cleaning the carbs and changing the main from a 140 to a 148 (based on the jet calculator). The idle jet was left at a 45 and I balanced the carbs, (originally off by about -10 now at +/- 1 of each other). Following the directions for the mixture in the Haynes manual I was unable to detect any change to the RPM during adjustment. So, I set them back at the as found 1.75 turns out and tested the performance. The change to the mains was great, but now I have lots of decel popping. I would have guessed the original setting was too lean based on the very blue pipes and the very hot engine, but the sudden new popping makes me question that. The vacuum caps are all new and the carb to cylinder rubbers are in great shape.

Checking this site it would seem what I need to do is pull the plug wire and connect a spare spark plug, disabling one cylinder and adjusting the other only, each in turn.

Am I correct that this will then allow the subtle changes to the mixture to be detectable to the factory tach and is the best way short of some type of exhaust gas analyzer?

K&N Pods, AI removed, 2 baffles/side removed, TPS connected at factory settings,

Thanks for any feedback
Rob

STEP 1. Buy a can of WD40
STEP 2. Squirt WD40 on engine side on the carb holders. Squirt WD40 on the vacuum lines (if there are any). Squirt WD40 on anything that might be leaking air.

The decel popping is very likely air getting into your combustion chamber via a leak; more likely on the engine side. If you have also messed with your pipes, there may be some gaskets that might have been changed out as most are crush gaskets; usable only one time but as far as a Triumph I am not sure but this is also a possibility. If you still have smog junk on the engine, any compromise in a vacuum like will cause the popping as well. Also a higher than normal idle.