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Discussion Starter · #1 ·
well...i have waited a while before i put the engine through a couple wot runs...about 10k from new. got 2 questions but i wanted to say first, wow. the vk just screams. sound absolutely beautiful at 4-6k rpm.

couple weird areas in the rpm band i wanted to ask you guys.

1st- at about 3k-3500 rpm the engine seems really unbalanced. is this normal? its not 'rattle bolts loose' unbalanced but its noticeable compared to the rest of the band. btw, according to the specs online, that is the peak TQ range if that matters. i have taken it in before to make sure the engine vibes were good. the dealers say its w/n spec but i wouldnt trust them w/ my bicycle lol.

2nd- at about 5k rpm, it seems to have slight dead spot. it is very quick and momentary, found this odd. i was running 89octane on stock tune living on the coast. is this normal and if so, what is the reason.

thanks in advance:)
 

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Broken motor mount? That could cause the engine to rattle around.

Try a tank of 87 Octane. That is what the manual calls for. I run 85 Octane, but I'm at 6,000' elevation so I don't need 87. I ran some tests driving through Wyoming on the different octane levels (85, 87 and 91). The higher the octane the lower my MPG.
 

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Discussion Starter · #3 ·
motor mounts should be fine as there would also be other indications, will check anyways. already looked at the tranny mount. i run 89 because im at less than 400' elevation. 87 octane is just a median for it to run on nationwide. i get approx 1.5-2mpg better w/ 89. thanks for the reply. it feels like the harmonics are off but...
 

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I think you are experiencing the "dead spot" in our powerband. I believe it's right around 45-50mph. Just feel's like it loses some power for a sec when accelerating?
 

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Discussion Starter · #5 ·
I think you are experiencing the "dead spot" in our powerband. I believe it's right around 45-50mph. Just feel's like it loses some power for a sec when accelerating?
guess so...its not a huge deal though. do you know why we have the dead spot?

what about the 3k mark? i revved it to 4k in P (ya i know thats hard on her), and it was the same way...at 1500 too, unbalanced compared to the rest of the band.
 

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I'm not sure... I've just heard it mentioned several times by different people.
 

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Discussion Starter · #7 ·
:bump: on the 3500rpm...
 

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hhhmmm, does it do the 3500 pause through all the gears, or only while parked? 'cause that could be the OEM WOT restriction marker??? might wanna get Up Rev Osiris and see if the data log shows the sluggish section, and maybe Up Rev can eliminate the low RPM pause with some target adjustments...
 

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Yes, the best way to check it is w/ Up/Rev. I would also suggest running a WOT 0-60 data log & see if there is a fluctuation in AFR or Ign.Timing at any time during the run. Do you know anyone w/ Osiris in your area?
 

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Discussion Starter · #10 ·
there isnt a pause at 3500rpm its just not as smooth. i guess testing it in P doesnt really prove much since its not under load. doing that is pretty much like taking the restraints off lol.

i dont have the $ for uprev and it is also under warranty. i dont want to risk it.
 

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I have noticed the same at WOT and 5k rpm. I describe it as a quick hicup. I have been blaming my BDGt?
 

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I have noticed the same at WOT and 5k rpm. I describe it as a quick hicup. I have been blaming my BDGt?
I don't know what it is, but that happens... I remember seeing a video posted showing someone's WOT run and it is noticeable on the tach too, the needle hesitates slightly in that range in 2nd gear too... Hhhhmmmmm...
 

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As far as the unbalanced part of your questions I do not think i am experiencing the same things as you. At the RPM range you talk about i dont have an unbalance i have the tq twist and it seems to settle in right when you say it goes away.
 

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For some reason our motors have a hick up at the 4500 - 5000 rpm range, I know that out power band goes up to 5500 but we the motor starts reaching it power limit at the 5k rpm. Look at DanBLP video post of his Jim Wolf cams video and you will see the hick up at the 4.5k mark, but instead of the reaching its power limit at the 5k mark, it continues to climb with cams up to nearly 7k. Revving it to 3.5k while park not a good idea, if your feeling something unbalanced by doing that, don't continuing doing it just MHO.
 

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Here is the link
 
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