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Old 09-16-2009, 07:18 PM   #31
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Whohooo! I guessed right on page 1. Am I now an engine expert? (nevermind the preairfilters wrapped around my face)
Anyone who wears a pre-air filter as a ninja mask automatically qualifies as an engine expert.
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Old 09-16-2009, 07:28 PM   #32
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I use self clinging gauze to cover the outer filter
on my engines. Wrap two or three layers around
your filter and it really collects the dust. It's
cheap and even if you rewrap your filters between
each round of racing, a roll lasts a long time.
http://www.northernsafety.com/Produc...uze.html?PFM=H
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Old 09-16-2009, 10:29 PM   #33
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Turn the temp gun right side up and stop reading it upside down.
Engines will not run at 155 unless it's on the box idleing. That's right about where my engines get up to operating temp on the box.
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Old 09-16-2009, 11:18 PM   #34
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The mid needle on 3 needle carbs is the fuel regulator needle. This should rarely (if ever) be monkeyed with. By turning it in you are restricting the total amount of fuel & air allowed into the combustion chamber. Basically you've "underclocked" your engine to use a computer analogy. This is why it's running okay but very cool. Your engine head has a volume of .21cc but you're filling it up with <.21cc of fuel/air mix (probably running that .21 like an .18) so the amount of compression is much less and you're not getting the full performance from the engine. As others have said, running the engine too cool is worse than running it too hot due to part wear.

Put the mid-needle back to flush with the housing (roughly 3 turns out). Put it back full in while pulling the carb slide out as having the slide in will give a false stop location as the mid stop bar hits the LSN needle and then go 3 out. Reset your LSN & HSN to factory and re-tune from there.
Thanks for the great information!
I honestly did not really understand the Mid-range needle until now.
I knew to never touch it, but not exactly why.
Good stuff.
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Old 09-17-2009, 02:08 AM   #35
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Turn the temp gun right side up and stop reading it upside down.
Engines will not run at 155 unless it's on the box idleing. That's right about where my engines get up to operating temp on the box.
little warm where he lives!
So "D" you staying in or selling out?
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Old 09-17-2009, 06:30 AM   #36
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You said you leaned out the midrange needle 2 hours. Why?

This could be the issue. If you set this overly lean your engine will transition immediately from the bottom to top end giving you the feel of a leaner more powerful engine. If you richen the top does it fall on its face?

I bought an used EB Mods V-Spec. When I first installed it we were indoors racing on a really tight high grip track and it ran incredible but when I went to another track that was bigger and low grip I realized the engine topped out too quickly and I had to let off the throttle really early or it felt like it might grenade from running at max rpm because it would top out in the first 20-30ft of the straight but as soon as I backed off the top end an hour it would fall flat on its face though. I was confused and figured maybe it had to do with being modified until I read on the sgrid the low speed needle was best set at 2 oclock. I checked mine and it was 4:30 so I set it to 2 oclock and went back to the track. Now the engine ran really rich through the midrange and top end and I was able to lean it out considerably on the top end. When I was done the powerband was much more usable and smooth with better fuel mileage.

I dont check my temps so I dont know what they were during this time but knowing that backing off the top end even an hour would cause the engine to fall flat on its face it had to be on the rich side. I do know when that engine was tuned and running its best after getting it right it only ran about 220-230 so if it was considerably richer than that its feasible it was in the same range as yours.
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Old 09-17-2009, 06:32 AM   #37
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My JX BO1 midrange needle is about 4:30 now which is where it was set from the factory.
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Old 09-17-2009, 07:16 AM   #38
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My JX BO1 midrange needle is about 4:30 now which is where it was set from the factory.
+1 on leaving the mid needle alone. I have 2 speeds and I never touch the mid needle. I have a hard enough time setting the top and bottom needles. My engines always run well with a rare flame out. You gotta be an expert engine tunner to go messing with the mid needle.
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Old 09-17-2009, 07:32 AM   #39
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First of all if your not aN engine pro at tuning - NEVER EVER TOUCH YOUR MID

Second, I would stongly suggest to go back to factory settings and before you go and try to tune, take it to the track where you can find someone that understands tuning,( what to look for, how it sounds ect) my son runs the ninja in his RC8T and depending on the weather, he runs around 210 and 240 with the average of 220ish after the 4th or 5th tank. He runs 30% Byrons.

Remember after you finish running to make sure your at DBC this will save you ALOT of wear on your sleeve.

Second if you run to cold, your engine will wear fast and depending on how many tanks you ran at 130 degrees if could have damaged the piston and sleeve already, I have seen this many times. Guys running the the early spring with snow still on the ground. Running to rich is worse that to hot. You know not 500 degrees but you get what Im saying
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Old 09-17-2009, 09:35 AM   #40
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First of all if your not aN engine pro at tuning - NEVER EVER TOUCH YOUR MID
Wow, you make it sound like you can never get the mid back to where it was. Just mark the location and don't go more than 2-3 hours in or out on the mid. It is a very coarse adjusment compared to the low needle.

As far as this guys engine, who knows how "good" it is running. Some peoples definition of good is that it is just staying running and not dying. I have seen one of the JX engines run "good" at 185, but it was rich on top. Lean it out on top 2-3 hours and it would be 220-230. Thats all that is probably needed.
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Old 09-17-2009, 09:48 AM   #41
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Wow, you make it sound like you can never get the mid back to where it was. Just mark the location and don't go more than 2-3 hours in or out on the mid. It is a very coarse adjusment compared to the low needle.

As far as this guys engine, who knows how "good" it is running. Some peoples definition of good is that it is just staying running and not dying. I have seen one of the JX engines run "good" at 185, but it was rich on top. Lean it out on top 2-3 hours and it would be 220-230. Thats all that is probably needed.
First of all if your not an engine pro at tuning - NEVER EVER TOUCH YOUR MID
Especially 2-3 hours - alot of pros and engine modders I know will actually seal the MID screw with ummmmmm hell i cant remeber but they seal it so it will NOT move. I have seen way to many guys - average racer - that messes with the MID and NEVER get it running again....... Way to many...... To each is own, but I will take the experianece of the PROS I have met that have told me that...............
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Old 09-17-2009, 09:57 AM   #42
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Wow, you make it sound like you can never get the mid back to where it was. Just mark the location and don't go more than 2-3 hours in or out on the mid. It is a very coarse adjusment compared to the low needle.

As far as this guys engine, who knows how "good" it is running. Some peoples definition of good is that it is just staying running and not dying. I have seen one of the JX engines run "good" at 185, but it was rich on top. Lean it out on top 2-3 hours and it would be 220-230. Thats all that is probably needed.
+1 on "good"
except that the mid is a coarse thread... it's actually the same thread pitch as the LSN.. and i tune my mid needle you just havta now that it's a give and take thing with your lsn... once you found your tune you can adjust your powerband with the mid and lsn.. example lean your lsn 2 hours, then richen your mid 2 hours,, and vise versa..
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Old 09-17-2009, 10:22 AM   #43
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Ive been known to tune the midrange needle for the size track I was racing on. It can be quite useful when done properly. When I was running V-Specs I liked how I could smooth out the powerband by running it a little rich from factory.

Ive been running the Ninja for a year now and think leaning it 2 hours from factory would be a mistake. What pipe are you using? What car and what gearing?

I run a RC8B with Ninja mated to a 2050 pipe geared up a tooth to 17t with 1 aluminum and 2 carbon shoes 1.0 springs. Its usually in the 240 range when its running really good. My prior Ninja was mated to a 2060 stock 16t bell with carbons and 1.0 springs. It also ran in the 240 range. Both were run on both 7mm and 8mm restrictors depending on whether I was aiming for speed or runtime.
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Old 09-17-2009, 10:49 AM   #44
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if your mid does get turned how do you set it back stock? I just do not understand including it if it is not to be used?
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Old 09-17-2009, 11:12 AM   #45
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Should be perfectly flush I think.

Better engines don't have the mid needle:
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