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Discussion Starter · #1 · (Edited)
ok i posted similiar before, but now that i have some time on the motor, i really got the chance to run it and now i'm fine tuning.

here is what is done to the motor....

100.5mm wiseco piston, no base gasket on cylinder, hot rods stock stroke crank, mild port and polish (basically just blending bowls and smoothing the casting out) proflo intake adapter with k&n filter, no airbox lid but has outwears cover, big gun full exhaust with no spark arrestor, the carbs are jetted with dynojet kit with a 146 and 148 mains and needles on 3rd clip, also has big gun cdi box. im running a 12 44 sprockets.

the motor seems to run really good all around, has good punch and response off the line, and good broad powerband, really pulls hard from idle on up. now since i got the trail tech vapor, i have really been watching the rpms closley.

i have this hill the is about 1/2 mile long and about a 20% grade. i never really watched in 1st, 2nd, or 3rd, but 4th and 5th the motor wont rev past 9000rpm, if i hold it in 4th it pulls hard till 9000rpm then just kinda keeps pulling. if i hit 5th same thing it pulls hard till 9000, and im doing about 65mph in 5th gear.

the plug doesnt look bad, has a light tan color to it, but seems dry, there is never a tad bit of wetness to it. it runs about 150* to 180* on road and around 210* to 215* through the woods.

now is it only pulling 9000 rpm cause it is runng a good load up the hill? i weigh close to 230 or 240. i still think in 4th it would pull all the way to rev limiter. also it doesnt seem to "bounce" off a limiter, it just stops reving, kinda like a valve float.

a few members said i should definatly put in 25 pilots, and run 160 & 165 mains with the dynojet needles, but that sounds like alot of fuel......maybe not.....

anyone have any suggestions before i spend $20 on jets, or $50 on another jet kit? help would be great i dont know why it wont rev more, seems like maybe i'm worrying to much, but i dont wanna leave power on the table lol, or maybe this stupid tach is off, or what about this speed limiter i read about sometimes........ so any help would be great! thanks dan
 

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9 grand isnt enough???
 

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Discussion Starter · #3 ·
is that good? im not sure, i race go karts and build my 450 cc lawnmower engines that will turn 11k lol, just curious i thought maybe it should turn more then 9000
 

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im like 95% on 9000 being the redline, so if your pullin nine grand in 5th, i think its time for taller gears
 

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Discussion Starter · #5 ·
nah i like the low gearing, that was just out on a dirt road a little hill..... i smoke my brother, but all he has is a yoshfull exhaust with 12 40 sprockets....e has to keep it in 4th cause 5th bogs to much, if the road was wide enough i could have passed him..... was barely on it in 5th.

i just wanna make sure my jetting is right..... i might just switch to mikuni jets anyways, but was looking for a second opinion on the 160 and 165 jets with the dyno jet needles......
 

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he's got a vapor
 

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The stock cdi has a rev limiter that kicks in at around 9k rpm, your big gun pushes that to 10k. There is a speed sensor kicking in and cutting timing out because you are pegged in 5th. You can disable or fool this sensor but you really should gear more appropriately if you're going to make long wot top speed runs a common occurrence. The stock valve train won't live all that long at 9k-10k rpm and as you suspected you are quite possibly floating the valves in top gear and others along the way. The expectations and comparisons to very different engines do not reflect the capabilities and recommended operation of this atv motor.
 

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Discussion Starter · #10 ·
ok after sitting back and thinking about it, that is what i kinda thought. yes you are very correct, my go kart engines are not the same, similiar but not. i have probably close to 4000 bucks in the one motor, and they make hp close to the raptor. thanks for the help guys, i guess those cdi boxes are a crock then. oh well thing runs good, really good, just was looking for a second opinion on the jetting with dynojet needles. i think im definately going to put the 25 pilots in it though.
 

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nah i like the low gearing, that was just out on a dirt road a little hill..... i smoke my brother, but all he has is a yoshfull exhaust with 12 40 sprockets....e has to keep it in 4th cause 5th bogs to much, if the road was wide enough i could have passed him..... was barely on it in 5th.

i just wanna make sure my jetting is right..... i might just switch to mikuni jets anyways, but was looking for a second opinion on the 160 and 165 jets with the dyno jet needles......

It's time for you to help your brother - he shouldn't be bogging. Most likely mains - probably a bit rich.

You're jetting sounds right, DJ 146L/148R is about equivalent to Mikuni 160L/165R. The 25 pilots will help you with just off idle throttle response and reduce any popping on decelaration you may have.

With your mods the power should start dropping off before 9,000 RPM - the aftermarket CDI's with higher RPM limits only help if you have modded the engine to move the power band up in the R's with cam, etc.
 

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Discussion Starter · #12 ·
his runs good, it is just the steepness of the hill and his is a original 01 motor, mine is fresh with 02 tranny upgrade. i always get him on the holeshot, but if the distance is long enough, he always catches up and then blows by me.
 

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Master of the Electron
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his runs good, it is just the steepness of the hill and his is a original 01 motor, mine is fresh with 02 tranny upgrade. i always get him on the holeshot, but if the distance is long enough, he always catches up and then blows by me.
Your 12/44 vs his 12/40 might well be the difference at the end. You are geared extremely low - your top speed will be about 10% less than his (~62 vs. 69, assuming stock rear tire size)
 

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The highest power on a fairly stock raptor engine is at about 75 to 7800 rpm, after that the power falls off quickly, plus the rev limiter and the speed limiter which can activate in 5th gear will probably keep it from reving any higher then 8000rpm.........
The speed limiter senses off the output shaft, this can be fooled by removing some of the teeth from the reluctor wheel, but the raptor still wont rev much over the highest power rpm............
 

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you guys are so smart. i have much learning to do
 
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