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Post by scooterted on Nov 10, 2019 17:43:06 GMT -5
T is for tdc. I would assume f is for spark (fire?). At this time, i cant remember what exactly is on my flywheel, but i know i use t for cam timing.
A foolproof method to find tdc. pull the spark plug and line up the t with the cam on the compression stroke, then GENTLY (and being very careful not to damage the cyl wall) place somthing long and strong enough that it cant get lost or broken off in the engine in the spark plug hole against the piston. Then GENTLY move the flywheel back and forth and use whatever you put through the plug hole to determine that the pistion is indeed at the highest point.
Some chinese scoots have been found with flywheels mis-machined, you probably dont have this problem. If you did, it probably never would have run well and you would need a new flywheel.
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Post by scooterted on Nov 10, 2019 15:58:21 GMT -5
Yes, very much. Cam timing is very important.
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Post by scooterted on Nov 10, 2019 13:59:16 GMT -5
I dont think you're tuned enough for a final gear upgrade yet. I would expect you to reach at least 40 for that to be necessary.
I dont want to go over 40mph, so ill keep my stock gearing lol.
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Post by scooterted on Nov 10, 2019 11:15:38 GMT -5
Theres probably going to be gains to be had tuning the cvt. There are possible cvt restrictions. But im not familiar with them.
Gasket maker is fine.
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Post by scooterted on Nov 10, 2019 10:38:34 GMT -5
You can do a plug chop to determine where you are with main jetting.
Unless you're that far out with jets i would expect you to be moving a little faster than that. Im not really familiar with restrictions as ive never run into them myself.
Hows your cvt setup? Max rpm, belt travel, etc.
I would tighten the lash up a little. It would baisically give a teeny bit more valve lift and duration. Go ahead and recheck cam timing while you're there.
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Post by scooterted on Nov 9, 2019 17:51:29 GMT -5
This ia an excellent graphic that represents how differnt parts of the carb relate to one another.
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Post by scooterted on Nov 9, 2019 17:47:49 GMT -5
I have the same setup (i figured you did too. Im wondering if maybe its not such a perfect kit, especially in the 90s range. Ill have more data on that in a couple days.
I would not expect the pilot and main jets to have much effect on each other.
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Post by scooterted on Nov 9, 2019 16:36:47 GMT -5
If you havent tried it yet. Try changing the needle position, either by moving the clip of an adjustable needle, or by sticking a washer or two under the clip of a non adjustable needle. See if things change.
Do any of your jets make a change in the way it acts? Where did you get them? Im starting to wonder if youve got jets that are not actually sized in the way they are labeled.
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Post by scooterted on Nov 9, 2019 15:51:39 GMT -5
One end connects to the carb. The other end connects to the tank. Probably has a fuel filter and a fuel shutoff somewhere on it.
Probably have a vacuum operated fuel shutoff. Where it is in the fuel system, and if it is indeed there will determine how best to drain the tank.
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Post by scooterted on Nov 9, 2019 14:31:46 GMT -5
It definitely could be so rich it hits a brick wall. Do you have different jets to try? i dont have a pilot jet lower then 32, i have some different main jets i dont know if going below 90 is a good idea. something is very off. pretty perplexed right now. I would try what you have. You dont have to try it long or go racing down the road. A cheap janky trick temporarily to richen up mixture is to cover up part of the inlet to the aibox with tape.
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Post by scooterted on Nov 9, 2019 11:58:38 GMT -5
It definitely could be so rich it hits a brick wall.
Do you have different jets to try?
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Post by scooterted on Nov 9, 2019 11:41:26 GMT -5
Thats the same tach i use. I only use it for tuning. I tape it to the handlebars somewhere when i need it.
I usually go a little tighter with the valve lash. .0025 with the intake and .003 for the exhaust. But what you have is probably fine.
That surging is interesting. Will it run faster than that or does it hit a brick wall?
Usually, i equate surging with running lean. But since youve for a 35 with the mix screw all the way in (you're gonna need smaller pilot jets) and a 90mj i wouldnt expect you to be lean. What does youre spark plug look like? And how bout the spark plug gap?
Have you tried messing with needle position?
Edit: And perhaps most importantly. Engines often act different under load. Hows that? And hows the float position? Have you sprayed the carb out? Sometimes even new carbs have been found dirty.
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Post by scooterted on Nov 7, 2019 12:04:20 GMT -5
^^ That is excellent advice. One can richen a part throttle mixture by stacking washers under a non adjustable needle. Adjustable needles are better. This is probably the best how to article if you havent seen it. www.49ccscoot.com/faq/carbtune.htmlEdit: I like to spray out a carb when i go to tune it. Spray out the passages, especially idle passages with carb cleaner.
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BBK help.
Nov 7, 2019 11:46:36 GMT -5
via mobile
Post by scooterted on Nov 7, 2019 11:46:36 GMT -5
I find that if adjusting the idle mix screw and nothing, im way out.
Do you have different size pilot jets? Ive found that the pilot jet must be close to start easy. Sometimes ive been able to get it started and idle around 4000rpm and slowly start lowering the idle and swapping pilots until it gets down to where i want it.
It can be frustrating. I spent a couple hours doing it once (i was suprised how much fuel i lost constantly dumping the bowl, had an empty tank). A tach is nearly a must have, expecially for early tuning.
FWIW. I used a 31 pilot with my 47mm bbk and stock carb. A 30 worked, but the mix screw was more than 2 turns out and i kept loosing mix screws.
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Post by scooterted on Nov 7, 2019 7:14:08 GMT -5
I wasnt going to answer because i dont use it. But you're not getting much in the way of replys.
Fogging oil is usually an aerosol can of oil sprayed through the spark plug hole of a cranking engine for storage purposes.
Context: Im fortunate enough to have a few motorized toys, and live in a place i can play with them year round. But im busy (and lazy) enough that i might not mess with them for over a year, ive yet to have major problems. I do however try to use ethanol free fuel, and i Always use stabil and mmo (cause it makes me feel good). Also, none of my stuff is actually stored outside, in a shed or a tent at least.
If i were to intentionally store an engine for more than a year, or an unkown length of time i would without a doubt use fogging oil. Especially if it were stored outside.
A can is cheap enough, and a scoot engine is small enough that it might be why not use it. One can will probably last several years.
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