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Post by cwazywazy on Dec 14, 2015 16:33:54 GMT -5
Around 2-3% of stroke would be a minimum clearance. 41.4mm x 0.025 = 1.035mm or ~0.041". 0.035" is about the lowest I've heard, and that is for racing. For street 0.040-0.050" or about 1-1.3mm would be safer for minimums. The piston to head or squish clearance could be a bit tighter because there's more to worry about with moving valves, but not much. I still wouldn't aim for much less than 1mm there. So if I increased the compression by removing the gasket would it increase enough to require using a higher grade fuel? What kind of gains would be expected? In other news, yesterday I ordered sets of main and pilot jets. I also cut out the raised areas of the CVT cover above the variator and clutch bell since it was cracked causing the kickstarter to not work anyway. I did try using JB weld to repair it but I got it to start once by being very careful with the lever and it was cracked again. When I cut it the piece came off in halves. I've been laying on a few coats of black spray paint onto the cover. ($1 Walmart cans are what I use for everything.) I used a rusty old hacksaw so don't expect anything perfect. |
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Post by 90GTVert on Dec 15, 2015 6:37:12 GMT -5
This is why you need to do a bunch of measurements and find your compression ratio or at least know cranking compression. It could be that you have high compression now and it will be too much with any increase and you'd need higher octane fuel or less spark lead. It could be that you have low compression and you'll pick up power without the need for higher octane fuels. It's not gonna be worth pushing it to the point that you need anything beyond premium pump gas. If you are currently low on compression (not related to ring seal), as some big bore/big valve setups are out of the box, then you may get nice gains out of figuring out how to boost compression.
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Post by cwazywazy on Dec 15, 2015 15:43:22 GMT -5
This is why you need to do a bunch of measurements and find your compression ratio or at least know cranking compression. It could be that you have high compression now and it will be too much with any increase and you'd need higher octane fuel or less spark lead. It could be that you have low compression and you'll pick up power without the need for higher octane fuels. It's not gonna be worth pushing it to the point that you need anything beyond premium pump gas. If you are currently low on compression (not related to ring seal), as some big bore/big valve setups are out of the box, then you may get nice gains out of figuring out how to boost compression. I think my dad has a compression tester somewhere... And as for the electric start, my battery seems to get down to that "vwomp vwomp" state a lot quicker now, even after a full charge. I'm sure this won't be as much an issue after my jets get here and my carb will actually give the engine enough gas, but would a bigger battery be a decent idea? I could always use the drill on the flywheel nut now that my CVT cover is more hole than cover.. |
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Post by 90GTVert on Dec 15, 2015 16:40:52 GMT -5
If you've got the little 4 series stock, you can fit a larger battery pretty easily in many of these Sunny style scoots. 7A-BS is often what fits. Never hurts to check measurements to be sure before you get one though.
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Post by cwazywazy on Dec 15, 2015 17:05:57 GMT -5
If you've got the little 4 series stock, you can fit a larger battery pretty easily in many of these Sunny style scoots. 7A-BS is often what fits. Never hurts to check measurements to be sure before you get one though. All right, I'll get one of those sometime. I have the cooling fan and shroud off right now and I was wondering if I could put a ratchet or something on the flywheel nut to lock it in place would I be able to get the variator nut off or would that just take the flywheel nut off and/or break the crank in half? EDIT: CVT pic  I just realized that I forgot to put in the new CVT gasket that came with my BBK. The original gasket disintegrated the first time I took the cover off. Oh well, it works. |
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Post by 90GTVert on Dec 15, 2015 23:04:01 GMT -5
That's not really a good way to tighten or remove nuts. You're better off holding the flywheel itself or the vari.
CVT cover gasket is only gonna matter for spacing and keeping the CVT cover from rattling. If the starter works well and you don't have a rattle, you don't really need to use the CVT cover gasket.
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Post by spaz12 on Dec 16, 2015 0:51:16 GMT -5
That's not really a good way to tighten or remove nuts. You're better off holding the flywheel itself or the vari. CVT cover gasket is only gonna matter for spacing and keeping the CVT cover from rattling. If the starter works well and you don't have a rattle, you don't really need to use the CVT cover gasket. Damn, I just learned something new. I've always thrown them gaskets away. |
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Post by cwazywazy on Dec 16, 2015 9:02:16 GMT -5
That's not really a good way to tighten or remove nuts. You're better off holding the flywheel itself or the vari. CVT cover gasket is only gonna matter for spacing and keeping the CVT cover from rattling. If the starter works well and you don't have a rattle, you don't really need to use the CVT cover gasket. Damn, I just learned something new. I've always thrown them gaskets away. Yeah, before I cut the cover I had the starter gear thingamajigger get stuck a couple times which required kicking the side of the CVT to get it to go. |
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Post by cwazywazy on Dec 17, 2015 16:57:00 GMT -5
Got my pilot jets. Threw in a 42 and I just can't get it to idle right. AFR screw all the way out gives the highest idle, but it's so high that with the idle screw all the way out its still "idling" with the wheel spinning. I tried adjusting it as best but the closest I got was where the speed would come down but it would die. Do I go bigger or smaller next?
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Post by 90GTVert on Dec 17, 2015 21:39:02 GMT -5
42 is a big pilot. Usually when the idle mixture screw on these carbs is turned out it's letting as much fuel as possible past so it means you need a larger jet. I don't think that's the issue here. I'd guess it's allowing air in while it's all the way out. Try a smaller jet. The common range for pilot jets is about 32-38.
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Post by cwazywazy on Dec 17, 2015 21:46:03 GMT -5
42 is a big pilot. Usually when the idle mixture screw on these carbs is turned out it's letting as much fuel as possible past so it means you need a larger jet. I don't think that's the issue here. I'd guess it's allowing air in while it's all the way out. Try a smaller jet. The common range for pilot jets is about 32-38. All right. Also when I put my intake studs in when installing the BBK I kinda stripped one.. Stupid Chineseum. It seems to stay on there well enough, but is it possible this would cause a vacuum leak? |
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Post by 90GTVert on Dec 17, 2015 22:09:32 GMT -5
Could be. Investigate leaks before you worry about tuning. You can mist water, use an unlit propane torch, or spray carb cleaner to find vacuum leaks. Engine operation should change when any of those things are very near an intake leak. Of course be careful with the flammable stuff.
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Post by cwazywazy on Dec 18, 2015 16:11:26 GMT -5
Could be. Investigate leaks before you worry about tuning. You can mist water, use an unlit propane torch, or spray carb cleaner to find vacuum leaks. Engine operation should change when any of those things are very near an intake leak. Of course be careful with the flammable stuff. Took intake manifold off, flipped over the stud so longer threads were on the bottom, applied a really light coating of silicone gasket sealant crap on both sides of the thick rubber gasket thingy, and put it all back together. I also cleaned the parts of the bowl and carb that seal to each other, same for the accelerator pump. Idles great and the carb leak is gone. (I don't know if I ever mentioned that here. It was a slow leak from the carb that dripped onto the engine when the bowl had fuel in it.) The accelerator pump sprays a tiny bit of fuel up into the air when I rev it.. Either that's not supposed to happen or the little rubber boot thingy that I lost is supposed to stop that. New problem, I was using the seat/bucket as a chair to sit on while working on the engine. Broke off one of the leg thingies that goes down to the mount. (It was already cracked around it.) Currently has JB weld drying on it to try and fix it. I should find a cheap broken scooter for parts or something.. |
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Post by cwazywazy on Dec 18, 2015 16:19:02 GMT -5
Did a better job cutting the fan shroud and painted the fan itself:  |
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Post by cwazywazy on Dec 21, 2015 15:27:36 GMT -5
So the battery is at 12.55v and still it's just vwomp vwomp. Tried taking out the battery completely and starting it with the battery on the lawnmower (starts the 13.5 Briggs no problem) and same thing. The mower battery was at lower voltage though. (12.4x) Do I still need a new battery or is there something else I can look into? It did start on the battery before repeatedly discharging and recharging with an 8amp peak charger... (It's only a 5ah battery.)
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