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This morning I have read and reread a couple of threads on sprocket sizes and carb jetting.

Yesterday a riding friend send me pictures of his new to him Volusa - with shot gun pipes.

My wondering this morning is how come folks think that they can do more with bolt on parts that the kazillion engineers at Yamaha can?

One thread this morning talked about jetting for weather. I am confused - jetting as I understand it - and I freely admit that I am not an engineer - has to do with the amount of fuel sucked into the intake for the engines How could the weather impact on the amount of fuel being used? Where does the idea that temperature impactss on jet size. Altitude yes but temperature?

The other threads this morning related to sprocket sizes - the stock machine came with what I will call a Universal Ratio of 14/50. This means that for the average rider on the average road conditions - Yamaha engineers worked out that this was the best combination. Why do folks think that mysteriously they can somehow improve on the performance of the TW by tinkering with these ratios?

As for the shotgun pipes - well I value my hearning to much to even want to hear that engine running.

It seems to me that a lot of bolt on stuff - iridium spark plugs, different jets, different sprockets noisy or non existent mufflers is simply folks tinkering.

Does that tinkering really make much difference or is it mostly for personal satisfaction?

Just wondering
 

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The impacts of well thought out mods are real. Most mass produced products are under optimized to meet price targets, fleet emissions standards, and average consumer needs. The vast majority of folks a good with that. Some people need more.

My VROD has modified exhaust, intake, and EFI fuel maps that completely change the personality of the bike. It functions far more efficiently. Many of the enhancements made by users were adopted into subsequent model year designs.

Last night I was at Cruising the Gut in Vancouver and there were several hundred folks celebrating their modifications.


Personalization is fun too, but the performance mods can far exceed OEM limitations.
 

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Temperature affects how dense the air is or isn't. Colder=more condense air, More Oxygen. Hotter=means less dense. The right combination of oxygen+fuel+fire is what you want.
 

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Sure OEM can be enhanced but at what cost benefit ratio, in the hands of what amateur mechanic (or rocket engineer that really has a technical basis for his mod), and for what real purpose. I fess up to having a big tank which I've really only absolutely needed a couple of times.
Some folks just want to be different and thats ok. Some folks just think they know better and thats ok (as long as they do it with their money, and don 't endanger me). Some folks just feel better when they are spending money. I guess that's ok too as its good for the economy.
But . . . when I see the mods start within 24 hrs after the bike is bought, I suspect they might be motivated by something other than known performance, comfort, or dependability issues. It follows the old rule, you can spend as much money as you want on this little inexpensive bike. Adelante mis cuates. Tom
 

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I get what you're saying. I think some mods are for personal comfort and fun, like young children putting different clothes on a doll. As a FUTURE Owner, I have plans to modify immediately. And am budgeting into my plan:
Richen the mixture
Seat concepts gel seat
Jimbo shield
Rear Cycle rack
Foot pegs
Lever guards
Skid plate
Turn signals
Add rear trunk, Panniers

I will consider performance mods like sprockets, different carb, cam, pipe, after I've ridden a few thousand miles.

Some modifications customize for rider needs, others are for performance. No doubt one can get a "stronger" engine with some mods, but from what I've read here, and learned through trial and error with previous bikes, bolting on a diffeent pipe is unlikely to facilitate a noticeable increase in performance unless you change the carb, air filter, cam, etc.

And we just like tinkering with our toys!

AT
Go WOT- That engine is not going to redline itself.
 

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With sprockets you said it right, Yamaha decided on the best "overall" combination for this machines dual purpose use. Guys who love the down and dirty trails and mud holes are not necessarily the "overall" standard riders of these bikes. I'm not either and it is doubtful I will ever get far off a beaten path on mine but I will poke around on lots of rural roads 99% of the time. I might find a little taller gearing to be beneficial for my needs.

i always look at any modifications as purely personal and the ones I will do should dial in my machine for my needs. These are certainly not Go Fast bikes and the minor things we can do will not change that. They are however pretty sharp looking and well suited for their designed purpose.

i am planning on an oil cooler, lever guards, re jetting from the 114 to a 118 and removing the plug so I can adjust the air/ fuel mixture and hopefully lose the surging I feel at 50-55. I already changed to a much softer grip set and added a Cycle rack for the tail. When my tires get worn I will probably go to something more road friendly and less aggressive. If my stock pipe needs replacing I will bet the OEM one is twice as expensive as an after market one.

One other very important point about doing mods is that as long as I am paying the bills I get to do what ever I want to it.

Gary
 

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Don't think that just because these bikes were designed by engineers that they are perfectly optimised. I am an engineer with many years of product development experience so I know the game well. Manufacturers have to balance performance with price point. They could send the bike off the production line with iridium plugs and top-of-the-line everything else, but then they'd have to put a BMW decal on it (and price it accordingly). It's about price point.
Another issue is giving the customers what they want. If you want the BMW they're already available. Most of the folks who buy the TW aren't looking for the BMW but rather something that they can tinker with - it's half the fun. Here's another example: I also own a KLR650. The KLR has issues (e.g. doohickey for one) that Kawasaki has known about for years. It would be very easy for Kawasaki to address these issues, but then the buyers would have nothing to work on.
The stock sprocket ratio is based predominantly on the fact that this is a dual sport bike - meaning part street and part dirt. The stock ratio is not optimal for either one but designed as a compromise. I ride 99% on the street, so I changed my ratio to 14/45. Some folks who ride mostly dirt switch to 15/50. If you ride 50/50 street/dirt, then the stock ratio is okay. Since we don't all ride the same way, customization is a great thing.
Enjoy your TW and those glorious mods.
 

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Enjoy your TW and those glorious mods.
Totally agree. For those that ride street, lower the rear sprocket, for those that ride dirt, raise it. If you're somewhere in the middle, leave it alone. Its whatever works for you. As for jetting, same thing, what works well at one elevation stinks for another. I can tell you that the way the new ones are coming out of the factory do not work well at sea level and almost out of necessity have to be adjusted for ride-ablity's sake. I understand these bikes come with different jetting and sprockets depending on what country you live in, so its not just engineering. Its also cost, local laws and regulations, and target markets. I just appreciate this forum being here to give me the information I need to help me decide what works best for me.

Now some folks go to the extreme with high dollar mods so far that they are changing the nature of the bike. You have to wonder why they didn't buy another bike to begin with, but hey, modding and personalization are fun, so if that's their hobby, have at it.
 
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