Bonneville America Forums Forums Technical Forums Performance Mods IT's THROTTLE POSITION - NOT RPM! NOT SPEED!!

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Phil,

I'm hardly the expert around here but no one seems to be answering your question so I thought I'd jump in with my tuppence worth.

The head mech for the old Trump site here in Buffalo just pulled out of the driveway half an hour ago with my bike to do the 20k check up and other work. We got talking. He told me that the difference between the Mobile T-1 or whatever it is that Triumph demands we put in our bike and the "non-Triumph" Mobil equivalent, is the sticker on the bottle. It's marekting hype; same oil exactly. Anyhow, I've been using Valvoline 4-stroke oil for over two years now and I get better transition between gears than I did with the Mobile stuff and at $4.00 a quart too.

As is the case with a lot of the stuff I've done to my bike, Gary James is my reference. He says he went and did the research and it specs out as good or better than the recommended Mobil stuff. I tend to take people at their word if they throw it in their bike too and if there's an anal retentive guy out there that beats Gary for attention to these kinds of detail, I haven't met him yet. So anyhow, I use the Valvoline 4-stroke 10W-40 (I don't have a bottle sitting around but I think the Prod. # is VV 740) in the early season and to clear out the grunge from the bike sitting. Then after about a month of riding, I swap it out for the 20W-50. (Prod. # VV 743) Also, in both cases, I substitute half a quart of Lucas Oil Treatment for half a quart of the oil.

Hope this is useful.

BB


http://www.valvoline.com/pages/products/product_detail.asp?product=76

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When the throttle is posistioned on the left handle bar, the motor is running about 4500 rpm and I am in 3 gear, what jets do I use? Do I need to change jets when I use 89 octane, the motor is running at 5000 rpm in 4th gear and going 65 mph headed west into the wind? Sometimes when I am flying to Alaska or Chicago, I have to change jets in Seattle or Mineapolis. But they won't let me take needles on those jets much less change them. Do I really need shins on my needles? I have shins on my legs, sometimes I bump them and it can hurt. I have never tried to pull a vacuum with my bike, does that mean I can't coast down hill on the red line? I hope not because all the lines on the roads are either white or yellow. The pressure I usually get is when they tell you at work tomorrow what they tell you what they want done yesterday. When that happens, what jets should I use? Because it appears to me that the throttle is still positioned on the right handle bar grip and I don't think I should change that. Or should I?
Soren

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Holy crap soren this answer was great!!!! I laughed my asss off

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From what i have been able to learn here...even through the sarcasm ... is that throttle position(1/8th turn, 1/4 turn, 1/2 turn, WOT) is not relevant or relative to speed or RPM...

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...when measuring performance(HP/Torque)BUT how well the fuel to air mixture happens in the carb. Basically what you are looking at is the ability to consistently generate the proper mixture so you can take advantage of it at any speed or rpm... I think that's it anyway

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Yes, but why (or rather, how) is the question. Measuring the throttle position allow you to target the specific components of the carburator system. The carbs deliver fuel through a series of point. Closed throttle to about 1/4 throttle is mostly the pilot system, 1/4 to 1/2 is mostly the needle jet, 1/4 to 3/4 is the jet needle, 3/4 to WOT is the main jet.



The reason for using throttle position is to isolate the individual parts of the fuel delivery circuit for tuning to maximum efficiency.

Here is a pretty good web page....http://www.dansmc.com/carbs2.htm


Clear as mud?

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Arrrrghhhh!
I don't mind answering questions at all, don't misinterpret this, but read read read!

I must get 4-5 emails everyday asking the same general questions...."What jets at this rpm? What jets at this speed??? My bike runs bad when I am in 5th gear??"

Setting up carbs is done by using the throttle position! DO NOT use a specific RPM range or a certain speed. They will do nothing but get you confused and possibly into trouble.

Read this CVK Tuning guide (same as ours but a larger carb - STILL the same) AND the Mikuni Tuning Guide for reference on how to actually use the throttle with small pieces of tape for markers.

It's not rocket science (unless you want it to be). If I can do it, so can anyone else just by following the steps outlined in these pages.

Throttle position is the secret!

Ok, rant over, and it's beer thirty.

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This CVK Tuning guide (same as ours but a larger carb - STILL the same) is dead.

This mud_dog450 is alive.

this is not Thu Apr 13 2006 07:16am: this is beer thirty for all yous throttlepostitionmeisters.

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My wife tells me to stay away from the carbs,
And have more protein

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LIke it, Pete. So is your bike older than an 07? To load up on protein I convince myself everything tastes like chicken.