wheelieking
Novice Class
Posts: 41
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posted October 03, 2005 06:00 PM
valve adjustment and horsepower
I recently had a valve adjustment done and the dealor adjusted them to the LOOSEST end of spec.. Their logic is that I wont ever have to do another adjustment for a very long time ( muzzy joked and stated "what 10 years"...Muzzy guys also state that it will decrease horsepower. The shop states that the valves will tighten over time.
After speaking with several professional gear heads... the advice would be to put them in the middle.. a couple stated to even go a little to the tight end. I understand that going loose will reduce top end horsepower.. the dealor even mentioned this.WHAT IS KILLING ME is that after spending a couple of grand on mild mods.. full ti system, pc3r with muzzy (m204-dm3r) map I only dynoed at 163hp after the work was done.. buddy of mine dynoed his stock 12 and put out 160 on the same dyno. So I am thinking that the valve adjustment definately robbed some horsepower. It does feel strangely stronger in the mid range but it does not have the sling shot effect that it had before above 7k rpms... The bike is a 01 with 14k miles. I am thinking about re-adjusting the valves to the recomended spec.
Any opinions as to if this really detuned the high end output? I guess I am just I am just looking for a second or 3rd or 4th option before I take this task on..... Will do cam timing as well at the same time... 105 intake 103 exhaust measured at 1mm..(side question.. is this timing for more for top end, mid range, or low end power?)
  
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scooter trash
Expert Class
Posts: 407
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posted October 03, 2005 07:02 PM
Find a new mechanic.
If they are borderline you loosen them up one shim size but you most definitely do not loosen them up to the other side of the spectrum.
If you had your before/after readings that would help, but the blanket "loosen them up all the way to the loose side" does not fly with me. '-)
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fattkaw
Expert Class
Posts: 277
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posted October 03, 2005 07:02 PM
yes it will drop power. valve opens farther= more power. put the valves in the middle of spec. BTW take it to the dealer not the dealor.
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tuusinii
Pro
Posts: 1031
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posted October 04, 2005 12:16 AM
It is said that usually You should aim for the loose side because valve clearances go smaller over time. In theory it takes little hp from top, but gives You grunt in the middle. If they are within spec You probably don't even notice it. Most probably there is something in Your PC or somewhere else. It's much worse if the clearances are too tight so that's the reason You aim to the loose end. And by the way the spec is only 10 hunreds of mm so in reality the difference in tight or loose end is only 5 hunreds (one shim). So it won't make much of difference other than beeing on the safe side.
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supra5677
Pro
Posts: 1279
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posted October 04, 2005 08:17 AM
Intestesting post. However I had a full muzzy system and pc3r custom map and only got 164 on my zx12.. Took off the muzzy and changed to akrapovic and got 173. Akrapovic is a far superior pipe... Proper valve adjusment will increase horsepower..
Brian
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ZXLNT
Needs a job
Kawpuke Extraordinare
Posts: 2853
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posted October 04, 2005 11:28 AM
I got 166 on one dyno with the muzzy and 174 on another dyno with the Muzzy. That would appear to make my Muzzy at least EQUAL and slightly better than your Akropovic.....
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THEMADKAW
Expert Class
Posts: 211
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posted October 04, 2005 11:31 AM
Mine made 172 hp with full muzzy and 16k miles and custom map. I wanted to get mine adjusted too but was scared to let anyone touch it! lol!
but i will have it done when i tear it done for the 1290 this winter!
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VincentHill
Needs a life
Posts: 6520
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posted October 04, 2005 12:23 PM
back in the Days of Leaded Fuels and in the early days of Un-Leaded Fuels Valve Seats were a "Lot Softer" and the Valves were not much Harder *600 Ninja valve spring could pull the valve through the seat in a few thousand miles if you ran it hard enough*
Valve adjustments were at Most 3,000 miles and some as low as 1,500. In those days, what you say made perfect sense. Nowadays, as one person said, Middle but not more than the loose spec for the valves
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Made History @ Daytona and still one fast old man!!
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