Bonneville America Forums Forums Technical Forums Performance Mods america performance question

I've had my America for about a year. Most of that time I have had debaffled pipes, and recently I had the 12,000 mile service, a freak installed, and the AI removed. My concern is that I am not feeling a performance gain; I know the top end is lower than it used to be (pushing past a ton was easy before the mods). It sounds different, but it does not feel like more horsepower is available. Kieth at RPM also said that I went from 140s to 180s with 2 shims when they rejetted, and I would notice a decrease in gas milage. That seems to be quite different from most of what I read here on the board. Another symptom I do not like is that it acts like I am running out of gas unless I am accelerating. It never had that before either... Am I crazy? Is it just me being overly paranoid?

Seems to me your running way rich.
180s with 2 shims?
I don't think Pats program goes THAT high!!!

HOLY SH!T !!!! 180's!!! isn't that close to just removing the jets altogether and running with the open holes!!! I don't think there's anybody running those Jet sizes even the BB guys with the super High Performance Pipes and freek kits...she must be puking gas out the pipes!...I must agree with the to rich! (incase the preceeding didn't let you know that)

You are way to rich. Put in some 150 main jets.

Is that a Harley shop? How did they determine jets/shims? Dyno with exhaust sniffer or trial and error? Our jets are smaller than HDs. At WOT, I would back off and get a surge in power with 130 mains. Local HD shops and mechanics did not have anything smaller than 150. Also, the Jenks site
says not to shim stock needles (Too short?). Change to Thunderbird Sport needles.

Hey Lonzo, you have a link for Jenks site?

Okay, so I should be concerned. RPM is a good Triumph only shop in Dallas (part of the Big D Cycles crew made this shop). Kieth has built some of the best Triumphs to date; he is famous for it. I trust them, but I do not think my bike is running better.
I did forget to mention that I have to start using choke, and leave it on when I start riding or it will die when I come to a stop. When I bought the bike, I never used choke. Aroung 7000 - 8000 miles I had to start using choke, but once it was running, I could turn it off. Now I have to leave it on for a while (I'd say about 10 minutes into my drive I turn it off).

Way rich. I don't have gitted pipes, but I do have the freak and I run 155s. Lots of guys run 150s. Also go back to no shims and start there too.

Here you go Erwin!!

Jenks' Bolts

Yep, waaaay to big. I am in Lewisville, also have the freak with D&D pipes and my mains are 160's. I still think I could do with 150's. Have Keith swap 'em, or better yet, go talk to Steve (mechanic). He'll know what to do.

Okay, I went down and talked with Keith and Steve, they said they followed instructions from Brent's Freak kit and that the jets were with the kit. They were more than willing to have me drop it off again and have them play with the jetting.
They did emphasize that the Freak puts more air into the engine, so you have to have more gas (and I was running a little lean anyway). They also explained that those jets do not influence how the bike runs unless the throttle is wide open.
I know NOTHING about working on engines. I have never done this kind of thing; I leave all my vehicles stock until I trade them in. I need help with this. I wanted the Freak because I wanted the bike to run better and have a little more power.
This seems like a lot of money to limit the top end and make the bike run worse.

I am beginning to agree with you. This is not what I normally do to my vehicles; most of the time I leave them stock. I did not want to increase noise (and it is fairly quiet compared to several other bikers around here). I wanted the power, and MANY people on these boards and other Triumph boards recommend these changes, and more, to get more power and better running engines.

I was looking through their PDF, and it does not have any info on my set up. I have removed the AI and airbox, stock needles (apparently with 2 shims) on a 2005 America, and have removed a couple of baffles on my stock pipes (not all of them because it was too loud).
No airbox means no info available. I can guess, but that seems like a bad idea for me to do at this point.

Jetting Calculator
This will get you 95% where you need to be, very simple to use.

Hey Dinqua, I would try the jetting calculator, but .exe files do not work on a Mac. I have read just about everything on your site, and it was very informative. I still would not be able to question a man that helped set several motorcycle land speed records and has spent a lifetime making Triumphs perform better than most people think they can. Keith's reputation in the motorcycle community is very good. He has a much better rep that where I bought the bike.

What pipes do you have? I'll plug the numbers into Pat's calculator. I think the guys mis-read the jets, and they aare 160, NOT 180. 160s came with mine from Brent. I bet the shims are the culprit for the craptacular performance. And I would be willing to bet you can still go down to 150 or 155.

I have a set of stock pipes with 2 or 3 baffles removed. I hope they misread the jets; they did say they used what came with the kit.

Not sure of your elevation, but I put in 1000ft, and it came up with 149.5 which is basically 150.

Thanks Benny! I guess I will be back down there when they open on Tuesday. I am also assuming that the shims should be removed (nobody thought that was a good idea with stock needles).

While you are ordering parts.... pick up a set of TBS needles. They are about 12 bucks... And KEEP the shims, because they are simple to add later, but I would go back down to none and start there.

Oh I put in two shims in the calculator cause that is what you said you had.

The sparkplugs will tell you for sure, but I'll bet that your high speed mixture is way too rich. With wide open exhaust and a freak kit, you will still usually find your optimum jets will be somewhere between 150 and 160.
To give you an idea just how touchy the mixture is, the idle and transition jets come back into play as a 'power enrichment' circuit (to borrow from Carter carb terminology). I gained a bit over 5 MPH at the top end just by readjusting the idle mix for best idle speed instead of rich enough to cancel deceleration popping.

Bill,

go away.

panda, not flaming Keith, just making an observation. He may build great bikes, Triumphs included, but may not be an engine or carbs man. He may another guy who does that while he does frames, design, fabrication, etc... Same goes for setting records, you can be great driver in Nascar for instance, but not be a very good wrench at all. So, yes, the credentials sound good, but may not tell the whole story. I've bounced several things off of Pat in years past, and he's always been spot on with the recommendations. I've got a good Triumph shop, and they recommended 120's when I rejetted and went to Bubs, I told them go with 130's(or is it 135's I don't remember right now), and they called me afterwards to say that I (Pat!!) was right and they had to re-rejet the carbs after 120's were lean. I've been lurking around here for 3 1/2 years and about the highest I've seen anyone go was 160's with no shims and that was on the Freak.

Keith is the man to speak to if you want to make OLD triumphs go fast. The new breed of Triumph twins are not his specialty, but the shop is still the best in Dallas for our bikes. If they installed the jets that brent sent they can't be 180s unless there was a mistake when the freak kit was assembled.