8 speed 79cc revival

Alright, I've got the stock carb back on my engine, gonna get new jets for it. Any suggestions? I need it running rich at idle, so it leans out as I gain speed because of my air filter. It faces forward and scoops more air in the faster I go, so I need to tune for my target speed.

I contacted agk about being able to buy their flywheel outside the stage kits. I'm also looking at buying their cam and head service. I might just forgo the cam though, I don't really need it.

I haven't talked to my dad about the oil pump system yet, so I'm not talkin about that.

I also finally got that 1" suspension fork I've been needing to get. I'm taking it to a shop soon to have the threads extended so the crown race seats this time. No shortcuts. Feeling quite sketched out now, with the fork wobbling fore and aft the way it is.

The stimulus package is arriving now, so I'm going to use that to do what I can to get this on the road. (^) Of course, that includes vin application, insurance, and registration.:confused:
 
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Alright, I got a response from AGK about the flywheel! Evidently, they have the flywheels being machined now, and they're waiting for them to be finished and shipped. They will have no waiting list. Here's the email I recieved:

The 79cc billet flywheels will be available very soon. We're waiting for the machine shop to finish them and ship them to us. We don't have a waiting list however we should have plenty in our first batch to go around. Thanks
 
Ok, I got the fork threads extended, and the fork installed! She's ready to be test ridden now, minus the insurance and registration, and my own licensing... Gotta make sure I'm running rich enough to avoid running too lean at 40+ mph. Shouldn't be much of a problem with an 82 or 85 jet.

Found a billet flywheel for her from ARC Racing for $165. Gonna buy and install it ASAP. That should free up some HP.

It's also about time I drained out the break-in oil, added in my mobile 1 full synthetic, had an exhaust pipe made, and did a full port and polish. During this whole process, I will finally be removing the governor entirely.

I've been doing some extensive reading on how to perform all these tasks (minus the exhaust pipe welding). Still need to get my engine cc'd so I know my static compression ratio though. Once I know that, and figure out the point at which my intake valve closes ABDC, I can calculate my dynamic compression ratio and figure out just what octane I need, and set my ignition advance.

All these mods should get me up to 65mph maximum speed. If they don't though, I won't be disappointed. I'll still have a decent track bike once I pull off all the electronics and stuff. Before all that though, I'm gonna head to the High Desert Harley-Davidson and have my bike dyno'd.
 
Just found out that each tooth on the crankshaft driving the cam is equal to 18°. I don't want to take my bike apart just yet to open the engine up, so if someone has a 79er already busted open who could check the intake valve closing point, that would be much appreciated. Gonna do a few calculations to find my static ratio.
 
Unrelated to previous post: I have reinstalled the stock valve cover. I noticed a definite increase in throttle response, and a slight increase in acceleration.

Related to previous post: I still have yet to acquire the tools required for reading my chamber size. This will have to wait a while.

In the meantime, I will focus on improving braking strength. It must be able to stop within 25ft from 20mph to comply with fmvss. First step: compressionless brake housing. Second step: caliper adjustment. Mechanically actuated hydraulics are more complicated to set up than I first thought, and compressionless housing is essential for maximum braking power.

Final step: set up a test station and repeat step two as necessary.
 
Alright, I've got some carb issues I'm workin on fixin. It just won't stay runnin.

In any case, I'm about to get that new flywheel, so I should be able to hit higher engine speeds with better efficiency. I still need to get my brakes situated though. I'm going to be buying some more compression-less brake housing and a pair of avid speed dial 7 levers for my hybrid hydros so I can maximize their stopping power. The levers have adjustable leverage, so that will help make the most of the brakes. I'm also going to use half-sintered pads so I get heat resistance along with the grab of resin pads.

I might try reinstalling the jackshaft plate that came with the engine and using that shaft to run the alternator, but it'll take some fiddling to get a mount made for said alternator, and I may have to replace the drive shaft with a slightly longer one to regain the chain alignment. Another option may be to move the clutch to the jackshaft, put a pulley on the crankshaft, and drive the jackshaft with a 1:1 gear ratio, probably a 15t sprocket so I have torque on the clutch. This system would also allow me to adjust the engagement rpm of the clutch once I get enough power to do so. Any thoughts?
 
5-7HEAVEN said:
moving the clutch to the jack shaft eliminates the 23t/10t combination.

So, divide your drive ratios by 2.3.
Click to expand...
I have already eliminated the 2.3 reduction, and now have a 3.0 reduction on the jackshaft kit. as explained in an earlier post. If I have a 1:1 ratio driving the jackshaft that came with the engine, thus driving the clutch, and the gears are 15t, there should be enough torque for the system to work. It will also give me space on the crankshaft to mount a pulley to drive an alternator.
 
I do have one little issue though. My engine will only run with the choke mostly on. It runs well around 90-85% choke. I doubt I have a vacuum leak, and I'm certain I don't have a clogged jet. However, my gas is about 4-5 months old, could that be the problem? I read that ethanol free gas has a shelf life of 6 months before losing it's combustibility. Could it be that the reduced volatility of my fuel is increasing the mixture needed for my engine to run?
 
I think I've figured out how to pump my oil through a filter without sucking the engine dry. If I use a peristaltic pump with a potentiometer, I can use an 8floz/min pump at a lower rate with 1/8in ID high temperature and pressure tubing. I can also use a smaller diameter high temperature food grade tubing from the filter to the crankcase, so I can see when the oil has reached it, meaning I can pump oil through the filter directly from the bottle before connecting it to the crankcase.
 
Alternatively, since it would be dangerous to run the engine while the pump is running, I can run the pump whenever I stop for gas or rest, and run it at max capacity. I'll run slightly more oil in the crankcase than normal though.
 
Well, big BIG problem. My freehub broke right after I left my park for the store. Cassette just spins, some resistance at one point. I'm hoping it's either the pawls or the splines that broke, and not the teeth the pawls engage. The wheel is a magnesium alloy, so I don't want any magnesium powder sparkin any fires.

I'll be pullin the wheel apart tomorrow to figure out what happened.
 
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