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Discussion Starter #1 (Edited)
Hello,

I have a question for you the carburettor knowledge base. In 2005 I had the Trimph dealership in Austin, TX to install TORS during one of my visits. They stated that the bike was rejetted at the time.

Yesterday I finally installed my Togas on the bike :punk:. The pipes came with literature from Norman Hyde recommending that the bike be fitted with 114 mains.

I called Lone Star BMW/Trimph (the dealership that installed the TORS) and they stated that they usually go up to 115's when they place TORS on a T100. I found this curious. I may be wrong, but I figured that the NH's would be less restrictive with regard to air flow and would therefore require a larger diameter jet than the TORS.

I have been trying to better understand the intricasies of carb mechanics, and so far I understand that this "extra" diameter (relative to what the Norman Hyde literature calls for) will cause the bike to run more rich than it is supposed to. My questions are:

1. Does the 115 main jet they reported to me sound crazy for TORS on an otherwise stock setup?
2. Am I thinking about this the wrong way? The Togas should require a greater diameter jet, right? Could the info provided with the pipes been intended for the 750cc Bonnies (would this even matter)?
3. If everything is as it should be, will the 115 diameter jet make a huge difference? Is this something that can usually be corrected by
adjusting the pilot mixture screw?

The bike is running "ok". I thought that perhaps I would notice an increase in performance. I do get some pops on decel, which seem more pronounced than before. My AI is still intact, but that will change this week.

I am having trouble with this subject and appreciate any help. I have printed out the Jenks Bolts guide to tuning the "modern classic" family of bikes, which I found a link to on this site. It has helped me to understand some things, but I still need to know more.
I wish there was a class offered at the community college here based on either small engine repair or motorcycle repair.

Also, if anyone can recommend a particular website based on understanding carbs it would be greatly appreciated.

PC
 

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I don`t know jack about jetting,but I ran 117s AND shims with my STOCK pipes with no ill effects.
 

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Discussion Starter #3
If you dont know jack about jetting, why did you rejet and shim the needle?
 

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advice from trusted members of this forum.
What I have learned over the years with regard to jetting the Bonnie is that there is NO SET SETUP that works every time with every pipe/intake combo. My bike runs great with a 140main,while I was running open 2"TT pipes,while others use a 155 with Toga`s.A 114 or 115 with TORs sounds logical if,even a little small.Airbox mods or removal changes everything again.You will get plenty of good advice,but you will still have to tweek again and again to get everything perfect.Personally,I prefer to run my bike a bit on the rich side. It runs "cooler" and if I get stupid with the throttle,I don`t have to worry about holed pistons or burnt valves.I don`t extract the last living HP from my engine,nor do I have to rejet because of an air filter change or for a ride in the mountains.But thats just me.:D
 

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Discussion Starter #5 (Edited)
This is starting to make sense to me.
When i first got into motorcycles, which was only about 6 years ago, I thought that everything would be clear cut. It did not seem right that two identical machines, with identical components, could possibly need different settings in order to work at peak.

Its still hard for me to grasp, to be honest.

The dealership in town was trying to convince me that a dynojet kit would be a smart investment. I thought that paying 90 bucks was silly when I only needed two measley jets out of it. I figured they were just being salesmen.

Maybe not after all I guess. Its tough for a newbie to know the difference between getting ripped off and getting what is appropriate.
And to make matters worse, I am a natural skeptic, especially at any dealership.

How the heck are you supposed to know what is right for your machine?
 

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How are you supposed to know? Experimentation! :D

Luckily there is some really good background info on this forum to read through to get you started.

It is true - the TORs come with 115 mains as standard. I suspect that changing to the togas may not make that much of a difference if you don't alter anything on the air intake side of things.

The dynojet kit does make a difference - I installed it with my TOR's, and found the bike to be a bit snappier than stock.

However - I am now pulling the airbox off my bike, and putting on predators, which I think is where the big difference will come. I'm going to continue to use the dynojet needle and spring and see what that does, rather than go back to the stock needle at this point.

You should check out the great source of info sticky, there are a bunch of thread links in there to tuning stuff folks have done, if you read through there you will likely reach the conclusion that leaving the 115 mains in place for your togas will be fine, the bike just won't be fully optimised.

Only way to do that is to put the bike on a dyno with an a/f probe, but if you don't want to go to the extents of radically changing the air intake system, then test riding the bike will tell you enough. As long as your bike isn't surging all over the place (running lean) and feels like it's running well then you're OK.

Here's a linky link to some info on tuning and carb set up.

http://www.triumphrat.net/twins-technical-talk/91238-great-source-of-info.html#post1128200

http://www.triumphrat.net/twins-technical-talk/91238-great-source-of-info.html#post1097253

http://www.triumphrat.net/club-cafe/71457-main-jets-and-pilot-jets-3.html#post873630

I'm totally new to it as well to be honest, but there is some great info around!
 

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Good advice by all. I think what tripped you up initially was thinking there is a significant difference between 114s and 115s. There is not. I am always surprised when some comes up with an "odd" jet size, although with patience and a dyno you should be able to dial them in perfectly and need that "odd" size. For those of us without the a/f gauge or a dyno, it takes a fair jump in size for us to tell the difference (115 to 118 or 120, for instance).

As far as differences in bikes are concerned, there is a guy a few miles north of me with the same bike I have (Scrambler) that has always been able to run larger jets than I have. Same pipes, same intake, same altitude. Go figure.
 
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