$500 on parts and I'm still so slow??????  By  played1 (Read 3,528 times)

Have you done a plug chop? With the back and forth between jets, and changing your boar and intake plus exhaust, you need to determine if you really have proper a/f, and the only way to do that is with an expensive meter or a plug chop.

valves are set at
.06mm intake
.08mm Exhaust

About 4000 km

Possible red flags I'm seeing so far:





Which is it? 'Normal GY6 variator? 'Upgraded' from the kit? Saying it's 'about' 4.5" doesn't really help much. IIRC stock diameter is 112mm and the 'performance' upgrades are usually 115mm (I seem to recall seeing a 117 out there somewhere but I forget where). The difference between 112 and 115mm is about 7/64 inch (.118 to be exact)...not something most folks can 'eyeball' on a round part like a variator, even with a tape measure.

The reason this is important is the belt you have installed.

If I'm remembering my research correctly the 842 belt is for use with the upgraded diameter variator (115mm). Using it on a stock variator (112mm) will prevent the belt from fully opening the rear pulley when the front pulley (variator) is fully closed. This will create a 'hard cap' on your top speed. Having just replaced my clutch this very day, I can tell you with certainty that the belt on my (bone stock) 150cc is an 835 and it's functioning perfectly. 50mph (chinometer) is right at 6100rpm steady, with plenty of throttle to go (previous owner GPS'd the chinometer to be within 3mph when reading 50mph).

I'm going to '+1' everyone who calls 'over-carbureted'. Using the Geo engine/Holley carb example from my previous post, not only will a bigger carb NOT make more power on a stock engine, it can actually make it run worse.


My gut is screaming at me that this is just a tad loose, but I have no hard data to back that up, so I'll defer to more knowledgeable folks on that. For some reason I want to say .004 intake and .006 exhaust...not sure why.

First thing your carb is to big that is a given, to much fuel that is why it is popping at high rpms and the motor is loosing power. Just to give you an example I have the 157QMJ motor with a 62bbk and a 60 stroker crank so now its a 182cc motor from a 149.6. I have the original 24mm carb with #122.5 main jet and #38 pilot jet. A 125 main jet pops on me at high rpms and a #40 loads it up at lower rpms.
Just about all 150s come with a 24mm carb jetted with a Pilot #35 and a Main anywhere from 103-107, rule of thumb is you up jet 2 more for a free flow filter and 2 more for a free flow muffler. Anything else put on for performance like a CDI, COIL, Plug etc.. will do nothing for tearing up the asphalt. To get more top end speed you need a bigger Variator to create a bigger wheel to turn the smaller wheel more revolution in the Clutch pulley when the belt is all the way down. Also RPMS come into play most 150s they produce their max hp at around 7500 rpms. Then there is the taller gearing in the tranny for top end, but here again your motor has to have enough power to pull the taller gearing.

Lighter weights will raise your RPMS:
Heavier weights will lower your RPMS;
Rollers= For every 1 gram up or down it will change your RPMS from 500-600.
Sliders = For every 1 gram up or down it will change your RPMS from 200-350.

I always tell people fine the weights your scoot runs with the best and then get 1 GRAM heavier Sliders.
Alleyoop

I got curious and did a search. Not speaking to the validity of the claims (of being an 'true' 117mm) or to the quality, but it seems they do exist.

Variator
Drive face/Fan

The question then becomes.. which belt to use? Would an 842 be adequate? Is there an 843?

my mistake I thought you were asking about the 115mm , not showing me the 117mm .

John