lowest possible idle on gx390

[bajagokart]

hey guys! it's been a while,
quick question to those of you that know,
what is the lowest possible idle you can get on a gx390?
I know you take the idler screw down but I'm only getting it down to maybe 1400 RPM and then it starts to stall.
Do any of you guys know how much lower this engine can go?

 

[Russ2251]

1400 rpm is the Honda standard setting.

 

[r_chez_08]

I could imagine that if you removed the compression release it could go lower, but then it would be a **** to start. Why do you need it lower?

 

[Russ2251]

I could imagine that if you removed the compression release it could go lower...

Won't work. Compression release kicks in at a far lower RPM than 1400.

 

[Doc Sprocket]

I could imagine that if you removed the compression release it could go lower, but then it would be a **** to start.

Not to dispute you, Russ- because I've never tried this, but I think a member here did manage to pull this off. A minibike or -chopper, IIRC. Great... Now I gotta go searching!

EDIT- Located. There's references to this scattered throughout the thread, but pay particular attention to post #26. http://www.diygokarts.com/vb/showthread.php?t=5797&page=2

 

[Russ2251]

I often make mistakes.
If it does manage to enable lowering of RPM, it will be a pain to start...literally.
I 2nd the question posed by r_chez_8.
Actually, the higher the idle, the better I like it. Engine is less likely to stumble and will take off faster.
My engines are set at 1700 to 1800.

 

[Doc Sprocket]

I agree! (who doesn't?) Please note, I found the thread and edited my above post.

 

[devino246]

I could see someone wanting more of a low, lopey idle on a minibike or chopper.

 

[Russ2251]

Now I have to do some searching....
I thought I read somewhere that compression release is set for under 800rpm.
In other words...just enough to get it to run.
Poster in that thread makes no mention of his current rpm and further stated " i think i was right".
I would think it would be higher than 800.

 

[Doc Sprocket]

Yeah, I skimmed the thread hoping to find actual numbers but to no avail. Also, Dougthewelder hasn't been been active since March.

Russ, if you do find further info, please let us know.

 

[Russ2251]

In a quick search I found this...
http://karting.4cycle.com/showthread.php?t=285154

 

[bajagokart]

1400 rpm is the Honda standard setting.

Really? cause I just bought a 500 series TC and it's engaging as soon as I start the engine. I know that is normal but once the engine is warm it should kick down to its idle that it is set at. The reason I need it lower is because I have a comet gearbox and if my engine is always turning the TC I can't go into neutral or reverse with stripping some gears. What I was wondering is, if I could just lower my rpm (besides using the idler screw) then that would save me having to buy new springs for the TC.

 

[anderkart]

Yeah sounds like you just need the black or green spring: http://www.mfgsupply.com/GoMiniClutchTorq500cal.html/mv_session_id=B96caQWH

 

[Bluethunder3320]

i removed the comp release on a clone and it was a ***** to start. ate up a recoil.

on my warrior it has a nice low idle. if i go any lower, the comp release turns on and it still runs, but it just goes *cough*cough*cough* and barely cranks over... hard to tell if its running or not haha!

 

[bajagokart]

how hard is it to change springs on these?

 

[Bluethunder3320]

hang on.. is the engine running an unusually high idle? sorry if i didnt read it anywhere else in this post...

 

[bajagokart]

engine should be running at 1600 RPM if i remember correctly (gx420 clone) and the problem is that even once the engine is warm and it finally gets down to its real idle that it is set at, the driven on the 500 series TC is still engaging

 

[redsox985]

You may need a new spring in your driven to delay engagement. It may be worn out and weak.

 

[Russ2251]

Factory manual, see page 13 for correct idle speed:

http://engines.honda.com/pdf/manuals/37Z4F603.pdf

 

[Bluethunder3320]

i dont think it has to warm up to idle low, that doesnt sound right.

i have the idle perfect on my warrior, its just chugging above the compression release.