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MPHorvat

Free Mods + Exhaust on stock jetting?

8 posts in this topic

I'm working on aclimating to my new-to-me 05 WR450F. I've done the Gray Wire, exhaust restrictor removal (otherwise stock tail pipe section still in-place), throttle stop trim (though apparently not all the way, gonna remove it again and trim to a bottom of head-to-tip of screw length of 0.720", currently a bit longer than that). Yet-to-do are the airbox mods (snorkle removal, right side box open-up), AIS removal, PMB exhaust insert, and jet kit/Zip-Ty.

Will the bike, in its current configuration, still run well if I simply remove the derestricted tail pipe section altogether w/ the still-stock jetting? Anticipated riding conditions will be 60-95 degree, approx. 600ft elevation.

TIA, Mark

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Yeah, I saw that link and if interpreted literally, then "ALL" free mods are not done and therefore, I ought NOT to need to rejet. Cool.

However, the mentioned AIS Removal is not technically "free", and while it talks of the de-restricted pea-shooter, it does not explicitly mention "removal of the peashooter/tailpipe altogether". That's my specific question du-jour: tailpipe "removal" + Gray wire + throttle stop but NOT airbox mods: re-jet needed? Prolly not, but I wanted to ask to be sure.

(Of course, the REAL answer is, "TRY IT!") I'm working on that.

So I guess I'm feeling that I'm somewhere in between the two cases mentioned in the link.

Thanks again.

Mark

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Don't do the Snorkle and airbox mods till you find out if yer gona do the AIS or not. It will run lean unless you rejet or remove the AIS. One or the other. The AIS kit comes with the required jets and throttle stop. I cut mine down first and the throttle kept getting stuck in the wide open possition. I installed the one that came with the kit and Walaaaaaa! My 05 is still completely stock accept for the free mods and the AIS. No pipe, no header, no motor work what-soever. Still runs like a champ.

As a matter of fact, still have the stock spark plug:ride:

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So, snorkel and/or airbox side cutouts will require re-jetting one way or another (simple rejet, or AIS Removal, which w/ the GYTR Kit involves rejetting. Why does the TT kit not include jets? Is it assumed that the user will rejet anyway?). :ride:

As a side-note, the snorkel removal on the 05 seems to provide only limited benefit, since the battery is there, i.e. the effect is less than on earlier versions, where "snorkel removal" opened up the whole top of the box.

I hope to have an opprotunity to run an experiment w/ the de-restricted 05 tail pipe in vs. out completely.

Mark

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AIS removal is NOT a performance enhancement and therefore requires no rejetting. Any one who tells you different is incorrect. Removal simply facilitates proper jetting diagnosis as the popping from the AIS is removed allowing a lean condition due to improper jetting to be more easily discovered...SC

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AIS removal is NOT a performance enhancement and therefore requires no rejetting. Any one who tells you different is incorrect. Removal simply facilitates proper jetting diagnosis as the popping from the AIS is removed allowing a lean condition due to improper jetting to be more easily discovered...SC

Your statement seems entirely reasonable. I guess what's confusing me is that the TT AIS kit contains no jets, whereas the GYTR kit does. If AIS removal does NOT necessitate jetting changes, why are there (presumeably different than stock) jets included w/ the kit?

Is it just because the bike needs to be fattened up anyway, regardless of the AIS being on or off?

Also, what might the JD kit do over the jets included in the GTYR kit? Is it the multi-taper needle? Are there both blue and red needles included w/ the JD kit? Does it justify the $100+ for that route (TT AIS kit $35 plus JD Jet kit $72'ish), vs. $35 for GTYR which appears to include needed jets? :ride:

BTW, thanks, all, for your comments and helping me to understand.

Mark

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Your statement seems entirely reasonable. I guess what's confusing me is that the TT AIS kit contains no jets, whereas the GYTR kit does. If AIS removal does NOT necessitate jetting changes, why are there (presumeably different than stock) jets included w/ the kit?

the GYTR AIS kit is a complete kit for "de-restricting" your bike. If you read the instructions with the kit, it tells you to do all of the free mods. it even comes with a replacment throttle stop that is the correct length.

in effect yamaha designed all of the free mods and the GYTR AIS kit is what you are suposed to buy to implement the "free mods".

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