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Old 11-19-2013, 05:26 PM   #1
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Default Adjusting clutch on 1/8th scale

Hi, I have been running of road for years and have just recently moved to on road, so just have two questions if anyone can help me out with.

First question 1. I have the Mugen MRX5 and seam to be having some slight issues adjusting the clutch on these on road cars.
This is what is happening.
I have found that you need at least half throttle or slightly more to get the car moving while on the ground, slightly less if it is on the starter box.

Now the manual tells me to set the clutch so that there is between .6-1.0mm clearance between the end of the thread and the nut that pushes down on the spring and also a clutch bell clearance or.3-.6mm.

So after all that write up, which way do you go to get the clutch to engage sooner, do i wind the nut in or wind it out?
As i am thinking half throttle is a bit much before it engages enough to make the car move, or am i wrong here?

I know in off road they grab pretty soon lower in the revs, but not sure with on road.

Second question is with the on road motors,, are they supose to have a high idle for a few seconds? like when you have done a few few laps and come in, the idle stays pretty high for a few seconds then drops down.
It seams that they like a very rich bottom end compared to off road, but if this is wrong, i will have to re look at my tuning.

Any help on these two questions would be greatly appreciated.
Cheers.
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Old 11-19-2013, 05:40 PM   #2
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If end play is at specs. You have Centax Style cutchbell. B/N the two pinion gears the is a hole for adjusting clutch engage timing. Use end of allen wrench to turnthe adjusting collar. CC engages sooner, CW delays.

Idle speed to your specs. I have mine idling like a Harley. Clutch engages
at a crack of throttle. Take time be patient. Adjust your LSN if want idle to drop, You'll have to set your HSN first, then Idle speed, then LSN. If it take time for idle speed to drop, richen the LSN.Make small adjustments
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Old 11-19-2013, 05:48 PM   #3
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Back the nut off to engage sooner. Tighten it to engage later.

That being said, onroad clutches should engage later/higher rpm than an offroad clutch. If it hits too soon, it will bog down off of slow corners and feel like it's down on power. Though you will want it engaging sooner for breaking in a new engine. A proper race tuned clutch will have a hard time engaging at all with a really rich engine.

As for the idle problem, lean the bottom end until the idle stays high and steady for a while (doesn't come back down after a few seconds) then back off the idle screw until the idle is low. It should be pretty close then. Don't do this until the top end is close to race tune though.
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Old 11-19-2013, 07:21 PM   #4
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Thanks for replies, Sounds like the clutch is ok then to me going by those ideas.
I have it set at .7mm, so it is pretty much on the loose side.
Sounds like most of it is the tuning of the motor going from that.
Will go back to the motor for a better tune, just seams to tune different than an off road motor.
I am trying to tune it the same was as you do for off road, that is after coming off full throttle, then hold the breaks on or let go of the throttle, the idle should drop right back down to a nice idle with out any high revs siting for a few seconds.

If this is correct for on road, i will start back on the tune of the motor.
Cheers.
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Old 11-19-2013, 08:26 PM   #5
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I personally like to run a closer gap .3-.4 and adjust spring tension for engagement rpm point but have friends that set the spring at a standard and adjust engagement by adjusting the air gap being closer earlier or farther later
i use wing racers way to tune the LS needle and idle it does make them so you can roll on the throttle cleaner just make sure you temp the motor every time you warm it for a qualifier or main for HS tuning
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Old 11-20-2013, 07:25 AM   #6
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Quote:
Originally Posted by Geezatec View Post
If it take time for idle speed to drop, richen the LSN.Make small adjustments
Actually, you should then lean the LSN, and also lower your idle.....
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Originally Posted by bucky1 View Post
I am trying to tune it the same was as you do for off road, that is after coming off full throttle, then hold the breaks on or let go of the throttle, the idle should drop right back down to a nice idle with out any high revs siting for a few seconds.
It's the same for on-road.


it's a pretty common made mistake. People tend to be on the safe side, and set there bottom end to rich, resulting in a to low idle rpm after running in the infield, then they up the idle rpm, and it's even making more idle rpm at the end of the full throttle straight, resulting in richen even more the bottom end, resulting in a lower idle rpm again after the infield......

Really, try leaning the bottom.
It's also depending your driver style, if you are a smooth driver, you can have a very lean bottom end, if you have a on/off throttle finger, you need to have a richer bottom setting.
Even playing with the throttle servo speed might help here.
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Old 11-20-2013, 03:18 PM   #7
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some good info there, appreciated.
Think i have it sorted.
Cheers.
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Old 11-21-2013, 10:55 PM   #8
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ACTUALLY. I have a slightly similar problem. When in idling,the temperature of the engine rises and the idle stays high for around 5 seconds before it goes down. Given my case,I should just lower the idle?mh7?
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Old 11-21-2013, 11:35 PM   #9
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Quote:
Originally Posted by GPXJOE View Post
ACTUALLY. I have a slightly similar problem. When in idling,the temperature of the engine rises and the idle stays high for around 5 seconds before it goes down. Given my case,I should just lower the idle?mh7?
It take 5 seconds for your idle drop to your set idle speed. Richen your LSN, To 1 sec. You can set it to drop immediately to your desire. You will find there wont be a flat spot on hard acceration, may be a puff of blue smoke. Make adjustment of 1/32 turns. Good luck pare!!
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Old 11-22-2013, 03:37 AM   #10
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Quote:
Originally Posted by GPXJOE View Post
ACTUALLY. I have a slightly similar problem. When in idling,the temperature of the engine rises and the idle stays high for around 5 seconds before it goes down. Given my case,I should just lower the idle?mh7?
Depending where this high idling occurs.
Is it after the full throttle straight, then yes, LEAN the bottom end, and lower the idle. Unless your engine is worn, then setting a good idle, is not possible anymore.

It is also normal that your engine temp. rises, at least the temp your are reading from your temp gun. Don't forget, the cooling head will read the coolest temp, at the end of the back straight, because most cooling wind went through it then.
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Old 11-23-2013, 07:50 AM   #11
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Quote:
Originally Posted by M7H View Post
Actually, you should then lean the LSN, and also lower your idle.....


It's the same for on-road.


it's a pretty common made mistake. People tend to be on the safe side, and set there bottom end to rich, resulting in a to low idle rpm after running in the infield, then they up the idle rpm, and it's even making more idle rpm at the end of the full throttle straight, resulting in richen even more the bottom end, resulting in a lower idle rpm again after the infield......

Really, try leaning the bottom.
It's also depending your driver style, if you are a smooth driver, you can have a very lean bottom end, if you have a on/off throttle finger, you need to have a richer bottom setting.
Even playing with the throttle servo speed might help here.
Quote:
Originally Posted by M7H View Post
Depending where this high idling occurs.
Is it after the full throttle straight, then yes, LEAN the bottom end, and lower the idle. Unless your engine is worn, then setting a good idle, is not possible anymore.

It is also normal that your engine temp. rises, at least the temp your are reading from your temp gun. Don't forget, the cooling head will read the coolest temp, at the end of the back straight, because most cooling wind went through it then.
Not correct. If his idle is hanging high it means he's already too lean and needs to richen it up. If the temps are rising at idle that's also an indicator that its set too lean. After WOT runs the temp should drop 1* every 4-5 seconds while sitting at idle. If it doesn't then its set too lean. Geezatec is correct.
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Old 11-23-2013, 08:30 AM   #12
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Not correct. If his idle is hanging high it means he's already too lean and needs to richen it up. If the temps are rising at idle that's also an indicator that its set too lean. After WOT runs the temp should drop 1* every 4-5 seconds while sitting at idle. If it doesn't then its set too lean. Geezatec is correct.
I agreed with M7H,you not really understand engine setting
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Old 11-24-2013, 09:01 AM   #13
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I agreed with M7H,you not really understand engine setting
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Old 11-25-2013, 04:43 AM   #14
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Quote:
Originally Posted by kyosho malaysia View Post
I agreed with M7H,you not really understand engine setting


Quote:
Originally Posted by RoketRdr View Post
Just let GPXJOE and bucky1, post there findings....
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Old 11-25-2013, 06:14 AM   #15
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Just let GPXJOE and bucky1, post there findings....
Even though you are right M7H, it is difficult for drivers because you are not there to let them see whathow it is done right. Laughing is a proof some are not there yet and it doesn`t matter as long we have fun. Better to let it go.

You have a PB by the way about some thing else.
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