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Post by chicoscoot530 on Oct 23, 2017 16:59:35 GMT -5
Ok here’s the jet sizes, K42 , and K 95
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Post by chicoscoot530 on Oct 23, 2017 17:32:08 GMT -5
Ok, have adjusted clip to middle pos and mix acre to 1&1/4 turns. But before I reassemble and install the carb I want to have proper jetting, So if that means I have to order jets today and wait till they arrive to install them to ride to school that’s fine and thanks again everyone for your input
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Post by spaz12 on Oct 23, 2017 18:27:46 GMT -5
It would be very hard for us to tell you exactly what jets you need. Even two bikes with same setup sitting next to each other could have different jetting.
You'll need to do some plug chops to get a better idea of what is going on inside the motor.
First, I start with getting the idle set. I want to be able to blip the throttle and have it return to a nice idle quickly. If it hangs then I know I'm lean. Sometimes the A/F screw can fix it and if not than I go with a bigger jet and keep doing that until I get it right.
Then I work on full throttle. I know that sputtering is too rich and bogging is lean. I always try to go large and make it sputter because rich is always better and lean can ruin a cylinder. Anyway, get it to sputter when you twist the throttle and then start working your way down through your jets until it stops sputtering. Now go back up one size on the main. This is when you start doing plug chops, which is you warm up the motor, take it for a wide open run for maybe a mile, kill the motor and pull the plug. Look DOWN into the plug to see the ring. You're wanting a nice chocolate color. Look at the electrode at the top as well. (I'll try to find you a pic of a nice looking electrode.)
Once you have your WOT set with either jetting or needle position, then you will do half throttle plug chops, which is the same as above, only part throttle. If you're not getting good color here then it is time to start playing with different needles. Hopefully jetting and needle position (needle clip position) will get you what you want, but sometimes the needle changes are required. It takes time and patience, but it's just something that needs to be done.
And I would say to buy a few jets above and a few below what you have now. One can never have too many jets.
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Post by benji on Oct 23, 2017 18:56:49 GMT -5
eBay if you know what your looking for, jetsrus.com is good I think. You want alot- way more than you need. Buy a combo kit if possible. 30-45 range for pilot & 80-115 range for main is probably a good start, but by all means not definitely what you need. I'm currently running a 150mj and a lean needle on my vm26 w unifilter.
If your confident which jets you have, put it together and try to ride around the block, or really try to see if it starts and idles. Then start doing plug chops. White is bad, black/wet is bad, tan/coffee/mocha color is perfecto.
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Post by gooddog on Oct 26, 2017 8:40:30 GMT -5
As mentioned earlier not sure what problem is other than peace of mind. has anyone used a temp gauge and would that allow someone with these issues to run their bike wot without much worry? or does a 70cc bike overheat too fast to do much about it if it happens? I imagine there is not much room for error with overheating.
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Post by pinkscoot on Oct 26, 2017 10:31:07 GMT -5
When tuning a new 70cc BBK at CHT is a very helpful tool. It will tell you to stop and let your engine cool and richen the mix. here is information from the directory: 49ccscoot.proboards.com/thread/400. For more information click on the directory button on the floating menu to your left. |
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