Triumphrat

gritkisser · 06-01-2008, 10:13 PM

I've recently removed the snorkle and performed a bafflectomy w/ a few drilled holes through the first 2 plates on my '07 Bonnie. How do I determine if I need to re-jet and if so, what size jets? I've pulled the plugs a couple of times since doing all this and they look fine to me. I'm fairly close to sealevel (< 100ft) if that matters.

dledinger · 06-01-2008, 11:40 PM

Go here and try Pat's jetting calculator. For my bike...it worked out to be pretty darn close.

http://www.dinqua.com/

gritkisser · 06-01-2008, 11:47 PM

That's cool! Thanks.

whoa · 06-02-2008, 02:20 PM

Looking up jetting in a book begs the question. How do you know if you are too lean or rich? I need to do this since I recently changed exhaust.

Running a dyno is probably the most direct method to check tuning. But what about a quick method we can do ourselves? The common answer I've found is to run the bike for a short distance with new plugs, kill the engine and look at the plugs. I'm pretty sure this is discussed on this forum, and a google search got me this page:

https://www.johnsmotorcycleparts.com...uning_tips.htm

"ride around at part throttle gently accelerating but keeping below ½ throttle. You want to stay on the low speed circuit as much as possible. After about one mile, pull in the clutch and kill the engine. Remove the sparkplugs. Look at the insulator from the tip down as far as you can see."

BillT100 · 06-02-2008, 03:39 PM

If you leave the snorkel off go up 2 main jet sizes to 115, if you keep the snorkel in go up 1 size to 112(112.5). Back out the pilot jet screws to a total of 3 turns. Unless you dyno the bike you won't know for sure but this should be close enough considering you haven't made any major modifications. You also may be able to get by only going up 1 jet size even with the snorkel out, I would try that first and see how it runs.

gritkisser · 06-02-2008, 06:41 PM

Quote:

Originally Posted by BillT100

If you leave the snorkel off go up 2 main jet sizes to 115, if you keep the snorkel in go up 1 size to 112(112.5). Back out the pilot jet screws to a total of 3 turns. Unless you dyno the bike you won't know for sure but this should be close enough considering you haven't made any major modifications. You also may be able to get by only going up 1 jet size even with the snorkel out, I would try that first and see how it runs.

Thank you. Now, I'm off to find the thread explaining how to do this.