DIR Return Create A Forum - Home
---------------------------------------------------------
CycleKarts GB
HTML https://cyclekartsgb.createaforum.com
---------------------------------------------------------
*****************************************************
DIR Return to: Tech Forum
*****************************************************
#Post#: 13366--------------------------------------------------
Messing with the governor spring
By: Ade Colmar Date: June 25, 2025, 5:26 am
---------------------------------------------------------
I'm looking for a bit of advice related to increasing the max
RPM with the governor still in place.
My build is progressing, but as a diversion from the many
remaining tasks, I decided to have a play with the governor. My
plan for the first few runs is to leave the governor in place,
mainly to improve reliability until I get to know these engines
better. It has a custom exhaust and the original carb has been
re-jetted (80), but otherwise the engine is standard.
I have a clip-on digital rev counter which showed 3,650 RPM max
on the engine as it cam out of the box with the spring in the
hole with the red dot (see attached photo). When the spring was
moved to the next hole the max RPM increased to 3,850. I then
drilled an addition hole (the one with the spring now fitted)
and the max RPM increased to 4,350rpm. This was perhaps a bit
more than I intended.
My question is: am I at risk of destroying the governor by doing
this, or is this a reasonable half way house until I am ready to
remove the governor mechanism?
Thanks
#Post#: 13367--------------------------------------------------
Re: Messing with the governor spring
By: NewbieNick Date: June 25, 2025, 8:50 am
---------------------------------------------------------
Hi Ade, personally I would remove the governor now & have done
with it. There have been cases of governor assemblies falling
into the engine at higher revs. Resulting in scrapped engines.
Cheers Nick
#Post#: 13380--------------------------------------------------
Re: Messing with the governor spring
By: Ade Colmar Date: June 26, 2025, 3:10 am
---------------------------------------------------------
Hi Nick,
Mmmn, thanks for the note of caution! I agree that the governor
would be better removed altogether in the long run. However, it
seems such an easy win to move the governor spring attachment
point for the early test runs. I don't want to get too involved
with the engine until after I have a driveable chassis. Maybe I
will drill another spring anchor hole and aim for 4000rpm. That
would be a useful increase on the 3,600rpm stock setting and
hopefully without threatening the governor integrity!
#Post#: 13381--------------------------------------------------
Re: Messing with the governor spring
By: Jimr1999 Date: June 26, 2025, 3:40 am
---------------------------------------------------------
Morning Ade, Looking through some dyno results of an engine in a
similar tune to yours, peak power was at about 3700rpm and
pretty flat after then, altering the ignition timing had the
peak power at about 4200rpm with a re-jet but barley any more
power than at 3700 with a slight flat spot (dip in the graph) in
between 3700 and 4200. My point being if you are geared for the
higher revs, rock on, but if not, I would not bother for testing
and shakedown.
You will probably be better with the increased revs after
governor removal, tuning and getting the bite point of the
torque convertor up a bit.
The engine we tested at 10HP on the Dyno, the max power was at
5450rpm.
JimR
#Post#: 13389--------------------------------------------------
Re: Messing with the governor spring
By: jon.pearce Date: June 26, 2025, 11:22 am
---------------------------------------------------------
Hi,
I honestly think that there is pretty much, one simple route to
getting a good, usable motor for a Cyclekart.
Remove the entire Governor and Oil switch assembly. (Tap and
plug the holes).
Fit 18lb Valve Springs.
Fit a GENUINE, Honda, heavy, Cast Iron flywheel with advance
key.
Fit a 16 or 16.5mm bored, GENUINE Honda Carb and fit a High Flow
Air Filter and Adaptor.
Modify the VANES on the plastic fan assembly.
Fit a high flowing exhaust.
Use a semi synthetic 0W-20 Oil.
#Post#: 13390--------------------------------------------------
Re: Messing with the governor spring
By: DavidandCarolynne Date: June 26, 2025, 1:49 pm
---------------------------------------------------------
And/or add lightness. Keep the weight of the Kart down and add
a skinny pilot. Got to be worth 2HP!
#Post#: 13391--------------------------------------------------
Re: Messing with the governor spring
By: Ade Colmar Date: June 26, 2025, 2:23 pm
---------------------------------------------------------
I'm working on adding lightness, pies are off the menu! ;D
Thanks for the engine mod recommendations, Jon, but I know what
I'm like, I risk get involved in dreaming of speed and not
finish the cyclekart this year! So I think I will keep things
simple and set the governor spring for around 4000rpm, just to
give a few more MPH to start with. I take your point about
gearing, Jim, I have acquired a collection of sprockets for use
with an idler shaft. The first set for use with a governor
giving around 7 or 7.5:1 final drive and a second set for later
without a governor and they will give around 8.5 or 9:1
#Post#: 13394--------------------------------------------------
Re: Messing with the governor spring
By: Jimr1999 Date: June 27, 2025, 12:35 am
---------------------------------------------------------
Add pies! life is too short to live it without them. My 6'4"
frame would need surgery to get to your weight Ade ;D :D :D :D
*****************************************************