surging engine

GoldenMotor.com

eDJ

Member
Jul 8, 2008
530
1
18
Wayne National Forest
Reading thru this just piques my curiosity.

In another thread recently a question was asked about installing and running a centrifugal
clutch. One respondant mentioned the additional weight served as a heavier flywheel and
tended to smooth out the vibrations. I've looked at the centrifiguls and there are several
setups but the one that catches my eye (if I understand it) allows for recoil starting and or bump
starting.

Would doing this and tuning the HT to deliver more torque at a lower rpm and using a numerically
lower sprocket....say a 36T :confused: give adequate power and speed to the satisfaction of most of
us ? I mean staying within the speed limits of our state and still getting the 150 MPG+.

I'm still convinced that the basic kit with some out of the box tricks on the carb/petcock, replacing the threaded fastenings with stronger ones, and the addition of a expansion chamber & silencer
would be the best bang for bucks one could want. (while staying within the law)


There are just a lot of problems associated with going for HP at high RPM. Espeially with a simple,
if not primitive, little motors like one of these HT's.
 

ljg17

New Member
Nov 23, 2010
8
0
0
NorCal
Just wanted to crypto-thread this one and say that a loose motor mount caused this exact surging behavior on my bike his week.
 

Arnold Layne

New Member
Dec 3, 2010
81
1
0
Nebraska
:-||I installed an upgrade air filter and put an O-ring in the manifold a couple weeks ago, was really pleased because it allowed me to break the 30mph barrier, went from a top speed of 29 to 32, on my cheap digital speedometer fwiw. Really ran great for about 5 miles then it started surging and getting slower, and slower, and slower. I was about a mile from home and I noticed the engine visibly vibrating, sure enough both motor mounts were loose. Tightened them and instantly the engine ran great again. As a side note, I probably do 90% of my riding on gravel roads and I was suprised to see how little air filter the stock engine kits have.
 

chanson

New Member
Mar 7, 2011
1
0
0
nebraska
I had a problem like this and I adjusted the fuel valve while riding and I need to RESTRICT the flow a little to get maximum performance.
hey, I have a CNS carb and had to basically turn my idle screw down till it almost died and turn my air/fuel screw all the way in. I have a 66cc grubee skyhawk. im 180lbs.
i shaved my head gasket, about half, but did the same thing before, sputter! after 1/4 throttle and couldnt get to wot. now with 14:1 ratio, screw air fuel mix all the way in, let engine warm up, idle, and lower idle till it almost dies. this seems to lean or give me less advance effect (more on the leaner side), and expasion chamber chamber.
last thing from me experimenting with compression i found my engine ran like crap with higher compression, but wait......put washer under spark pug to where it can keep a seal and slightly lower cmpression back down and vwolla! 5500 rpms. oh and broke off the 2 of 3 prongs on my factory spark plug, giving more room in the cylinder, lower comp. hope that helped

1. more oil (makes you run leaner)
2. turn air/fuel mix down all the way.
3. the biggest differents even with no exhaust. BACK THE SPARK PLUG OUT!!! BUT KEEP IT TIGHT! RPMS WENT THROUGH THE ROOF! LOL
4. CHANGED TO 91 OCTANE.
5. on flat land 26 mph down hill 36mph. (with sbp jack shaft)
6. lower your head when speeding.lol
ALL IN ALL YOUR TO RICH! CHOKE MAKE RICH ALSO.
 

fredric3144

Member
Oct 22, 2012
110
1
18
76
lufkin tx
Darn my motor has been surging as stated at WOT . First I checked petcock removed the fuel filter out of it and it was pretty smashed up and I have a second inline filter , so I thought ah ha problem solved . WRONG Then I read about the carb so I checked it the knurled cap was totally loose so screwed it back on right and thought ah ha #2 problem solved . Wrong I looked some more saw gas dripping found the bowl was not tight so tightened the two screws now no leak thought ah ha #3 problem solved . Wrong I adjusted the throttle tube where the cable goes in it was way out and not allowing much the throttle to work very well thought ah ha #4 problem solved PARTLY I now have a bit more of my speed back like from 15 mph to 20 mph and the surging again . I have lost some enamel off my teeth and the curse word jar is getting full of quarters . I just read about the motor mounts haven't checked those yet but I will as soon as it get day light out side its 4;00 AM if the mounts are tight don't know what to check next oh yeah I also tried a new spark plug no help .