Bonneville America Forums Forums Technical Forums Performance Mods My newbie question...jetting

Ok...so right off the bat I'm going to say..yes I'm new and I don't know anything...that being said... I just ordered a pair of Khrome Werks slip ons for my bike and I absolutely no idea what to do about jetting when I put them on. Some of the pipes I've been looking at say that they don't need re-jetting, and some plain don't say anything at all. So my questions are: how do you know when you need to re-jet your bike and will I need to re-jet it for the Khrome Werks slip ons? Thanks!

All depends on how restricted they are. If you have those short turn out pipes then you will need to rejet. Most after market pipes , even the ones that say you don't need to rejet, you should re-jet. There is a jetting calculator on Dinquas web site you can download. You will find it in the tech vault. Jetting depends on many things,first is the levation you live and ride at, then is how restricted your exhaust is, then there is how restricted your intake / filtration is. Our bikes come lean from the factory so it is best to re-jet. once you get it close the best thing to do is take it to a dyno and have it run on there to get a reading of what your air fuel mixture is. The dyno sheet will tell you what you mixture is at a certain RPM so then you know where you need adjustments. ALWAYS MAKE 1 change at a time so you know what that change did. If you make more than 1 at a time you won't know for sure what one was good and what one was bad or if maybe both were bad.

heh, heh... didn't take long for ya to start making changes did it, Heh, heh. I wonder what your ride will look like in a year! Anyway, the real experts here will direct you better than me, but the most basic way to tell if rejetting is needed is to take your spark plugs out and inspect them. If the color on the end is whitish looking, it's too lean. The color should be a nice lite brown. Excessive popping noises on deceleration is also an indicator of leaness, although the AI (air injection system) causes this also. Thats why there are so many guys here who take the AI off. Good luck, Mikky girl!

Wow...lots of good info here! I knew I'd get some help! I too wonder what my ride will look like in a year haha...but I knew from the day that I test drove it...and from everyone going "is that bike running?" that the first thing that was going was the quiet pipes...and then I see the thread on here about the 20.00 krome werks and that they were loud..and I was sold. Thanks so much for the help to both of you...I really appreciate it!!! (and everyone here calls me Mikki too...how weird is that)

Yep good idea to remove the AI and checking the plugs is a very good indicator white = lean , Brown or tan to greyish brown = good ,black or sooty = rich.

And also, as to plug color, Green means you've been drinking too much and need to pull over, purple means you're a closet Prince fan, Pink means you're a communist.

hi speedmastergirl an everyone! another newbie here jus got a 2006 890cc America,to replace the Harley 1200 sporty!i got after pipes[v&h] fitted at the shop as part of the deal[after my harley it was bloody inaudible!!] an a rejet came with them,i love the distinctive sound an it does pop!but i like it!!but i dont know what it would have been like if i had left the stock pipes on as i didn't really have much of a test ride!it goes well!! but i am lookin for sixth gear!!!but it;s a lovely bike ,as you say what will it look like in a few months!!!but thats part of the fun!right! what do i do about ratio;s!!!new bars new ............

Hey SMG, as they say, the fact that you know that you don't know anything means you know a great deal.

You know to ask.
Our very own Dinqua can help. Go to Dinqua.com and check out the Jetting Calculator. The perfect cheat sheet.

so much great info here...I'm glad I found you guys! My next question...where to get a kit to re-jet..are there different kinds?

mine came with the pipes.shop fitted em.

even cheaper and same jets is Honda,or other Jap bike shops they used the same carbs on many of those bikes. I paid $3 each and Triumph wanted I think $6 might have been $8. I bought them at a Harley shop but Harley used a couple different versions of those carbs and all 3 took different jets.

SMG (speedmastergirl)- if your air box in stock, put is some 45 pilots and you will be okay. You do need to 86 the Air Injection (AI removal kits available at many places, some of which are members here at BA.com), or the bike will backfire and you will likely wind up with blue/gold headers.

Hi SMG
I just rejetted my TBA to 125 for stock TOR's. I just went back to my dealer parts department. Spent less than $6.00 for the pair. You may want to adjust and balance carbs also.

always a good idea to balance after carb work.

Another vote for Dr. Dinqua's jetting calc application.
Right handy he is with the code slingin'


This is well worth a read or two as well
http://www.triumph-bonneville.com/images/Jet6.pdf


Some controversy on plug color reading.
Someone here (I don't recall who)
pointed out that aside from the extreme ends of mixtures lean or rich,
plugs may only represent the last mile of the ride.
I sure wouldn't rule that theory out as incorrect.
Dunno for sure.
I do know that Dinqua's calcs should get one extremely close to optimum air to fuel.

I was my understanding that reading plugs takes a little practice. Like you need to run pretty much WOT for a mile then cut the motor... Like get on the highway, and when you see "rest area, one mile" drop it into 3rd and go, then kill the motor and coast to a stop and then pull the hot plugs out of the hot motor... Watch your knuckles

Reading plugs can be tricky but you don't need to cut the engine after WOT you can stop normally and shut it off ,wait for it to cool and read them. That will give you a good general indication of mixture. If you are concerned about a certain part of the RPM range you can run it at that range for bit and check them. Plugs don't color imediately so shutting down at WOT and coasting to a stop and pulling hot isn't needed. Just ride normally and check after you let the bike cool.You shouldn't let it sit and idle when you stop if you want to check them though.

Use the JC Whitney pipes instead of the Khromewerks one the calculator. I've had both- they are essentially the same pipes.

thanks guys!

A lot of pipes, such as the Epco Stainless ones, come with a set of jets if they are needed.
Once the pipes are installed, start the bike up and let it idle a little bit to warm it up. Then, open the throttle and see how it runs. (don't hold it open more than a few seconds!) If it starts missing, it is certain that you need to rejet.
If the exhaust pops excessively on deceleration, it could mean that your idle mixture needs to be readjusted. Adjust for highest idle speed. If the idle mixture scews end up out more than 3 1/2 turns, you probably need a bigger pilot jet.

Popping could also mean that you need to add some high temperature sealer to the joint where the mufflers connect to the headpipes because fresh air leaking into the system can cause that. Which gets us to another thing that you will probably want, this kit http://www.newspeedmaster.com/html/ai_removal_kit.html to stop air being injected into the exhaust system on purpose. This is done to reduce emissions a little by burning any excess fuel before it gets out into the atmosphere. Unfortunately, burning fuel in the exhaust system heats the pipes up to the point of damaging the finish.

By the way, poke around the newspeedmaster site a little if you dare, you will wnd up buying stuff!

hi! some of yu know all about changin front sprocketts, i have a 18t front sprockett[42t rear] on my 2006 865 America ,is there enough room to fit a 19t as it looks a bit of a tight sqeeze!.and has anyone done this an can say if its ok!i want to tour an find i want to keep changing into '6th' on long straights!thanks [i know the answer is out there!]

It fits, but spinning the motor is always better than lugging it. You gain about 200-400 RPM.

cheer's my man ,happy new year to you!