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Post by katt on Oct 10, 2018 20:47:02 GMT -5
Did another 20 miles on a new spark plug #115 main jet.
It misfire on WOT one time throughout the trip so i assume its still bit too rich, i felt detonations though and temp were getting to 100*C when i hold it in 7500-8000 RPM zone for few minutes straight.
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Post by gsx600racer on Oct 10, 2018 21:29:31 GMT -5
This is going to be a silly question. You have two vacuum taps off the intake manifold. The one I highlighted RED I assume is going to the fuel petcock. The one I highlighted YELLOW is going to where ?
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Post by katt on Oct 10, 2018 21:37:04 GMT -5
This is going to be a silly question. You have two vacuum taps off the intake manifold. The one I highlighted RED I assume is going to the fuel petcock. The one I highlighted YELLOW is going to where ? Pic was taken in the middle of me setting up carb, that orange hose goes into the carb itself, on 24mm they have a vacuum hose port its on the opposite side of the electric choke. If you disconnect any hose from intake manifold engine dies instantly would not start or idle too much air being sucked in. I appreciate the effort though.
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Post by diynuke on Oct 11, 2018 16:04:38 GMT -5
Alright ive been thinking.
what if your compression is too high. due to a wrong head or something. that would explain why it gets so hot and why it could misfire/knock.
but did you try what I asked you to do?
And I still don't think its alright that your spark plug is so white at the top.. it should be browner. because my stock Kymco agility 50 spark plug bone stock was coffee brown at the top and black at the base of the insulator and everything was pretty clean so that was fine..
I have to say its pretty weird whats happening with your scoot. I guess it could be a problem with the head since it already should run fine with the 18mm carb
But in a few weeks I can comment a bit more since I probably will fire up my engine. a 52.4mm bbk ncy with a Chinese head which is ported pretty big with an 24mm carb ill have a look how it goes.
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Post by katt on Oct 12, 2018 1:42:45 GMT -5
what if your compression is too high. due to a wrong head or something. that would explain why it gets so hot and why it could misfire/knock. but did you try what I asked you to do? What did you ask me to do besides buying a new tune kit? Do you mean move the filter further back from the carb on some hose?
My compression measured like 170 last time i checked with gauge, i will try again.
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Post by 2010vip on Oct 13, 2018 15:13:47 GMT -5
Vacuum supposed to only matter on idle speeds, higher RPM produce more suction and higher vacuum, currently i have low vacuum from having A9 cam shaft installed have problems starting. My goal behind buying 24mm is to save money and also if i decide to swap later to 150cc engine i will need one anyway, since they come without carb. The 24mm will start harder because of no accelerator pump. If it starts hard now it will be harder to start with the 24mm. If you decide to go with the bigger carb naraku carb is a good one, 80 for the carb, 40 for the intake and you have to modify the throttle cable. It is an awesome carb, but its jetted for 125 to 150cc.
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Post by katt on Oct 15, 2018 17:37:14 GMT -5
Took apart the block after 850 miles putting 50mm BBK here's whats inside.
How bad is the scuffing inside the block? It looks bad, but not deep mostly smooth feels slightly with the nail, my old 47mm block is the same except it has vertical scuffs.
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ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Oct 15, 2018 17:53:22 GMT -5
Inside the block is not that bad, but the head and piston are about useless. Also the top of the jug should have a nice clean sharp right angle. It also looks like you might have blown the head gasket, or that could just be oil that leaked out when you took it apart.
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Post by katt on Oct 15, 2018 18:42:34 GMT -5
Looks like carbon buildup to me i had same on the old 47mm bbk when i took it apart, i did clean piston, but not the head that time, actually i scraped it off for now. And only after like hour of scraping i remembered that i could have used an oven cleaner for $5 ffs. Also took out the valves and the mounting shoes shoot out into garden took another hour to find them among all the leaves and other mess. I scraped the head a little, but it should not matter i guess?
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Post by scooterpimp on Oct 15, 2018 18:49:29 GMT -5
Wow , that piston looks like the bottom of a Styrofoam cup. , when i did my recent bbk on zummer it was way carboned up on stock everything with only 300 miles , looked like i was running leaded gas for 10 years it was so carboned up...ethonal related???
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Post by katt on Oct 15, 2018 19:35:30 GMT -5
I used oven cleaner on aluminum and i sprayed all over too inside out its oxidized aluminum surface now i have to scrape it off, its been a while i messed up like this last time i used household bleach though. I should have known and bought Air Conditioner coil cleaner spray it is not oxidative (i think) yet just as tough as oven cleaner. Wow , that piston looks like the bottom of a Styrofoam cup. , when i did my recent bbk on zummer it was way carboned up on stock everything with only 300 miles , looked like i was running leaded gas for 10 years it was so carboned up...ethonal related??? carbon builds from running lean.
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Post by gsx600racer on Oct 16, 2018 0:11:06 GMT -5
Well...... I will have to admit I was not expecting to see that for only 300 miles. I was expecting to see it a lot cleaner and sunken piston dome or a hole starting to form from the detonation and overheating you described in previous post. I would like to see pictures of the wrist pin, wrist pin bearing, small end of the connecting rod, and the underside of the piston. That will tell me how hot that engine really got. As for , gonna disagree with you there. Not sure where your getting that info from. Taken from here. "Carbon build-up looks like a thin layer of black soot, and is a naturally occurring by-product of a combustion engine and is especially prevalent in direct injection systems. This build-up can result in stalling, lack of power, poor acceleration, lowered gas mileage, excessive emissions, and hesitation Check Engine Lights and even bent valves if left long enough. These things occur because the carbon build-up coats the sensors of the vehicle and the back of the intake valves which makes it so the computer cannot control the air/fuel mixture properly. This all can, ironically, lead to even more carbon build-up. There are a handful of things that can lead to excessive carbon build-up on your vehicle’s engine. Things such as: Proper running GDI engines, call if you aren’t sure if you have one Contaminates in low-grade gasoline Internal Oil leaks An air/fuel mixture that is too rich Many short driving trips Excessive idling A bad PCV valve" Here are some pics from one of my builds after a season of riding.(34 hours and guessing 1300-1500 miles)
Keep in mind, this was running 32:1 oil premix (normally its 40:1)so it was oil heavy. There was very little carbon build up.
Build thread here.My thoughts: I think that's way too much carbon build up for only 300 miles. To me that looks like excessive oil being burned. So either the ring gaps were not staggered or the oil rings have prematurally wore out. From the looks of the top of the piston after it was cleaned looks like this kit was a cheaper one. Usually the higher quality kits the top of the piston is machined 100%(smother)Carbon will tend to form quicker on casted surfaces(unfinished). You could also have an issue with crankcase ventilation or pressure build up inside forcing oil past the rings. Maybe a gasket(base or head) failure where oil was getting into the cylinder. Could also be leaking oil around the valves/valve guide seals. Was hard to see the valve area after you removed the valves. Not sure what your oil consumption was. Bad or low quality fuel. As for the marks on the cylinder wall. I would check the ring groves for carbon build up or burned/baked oil. This will eventually force the rings out towards the cylinder causing premature ring wear, loss of power, and excessive oil consumption.
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Post by scooterpimp on Oct 16, 2018 8:48:59 GMT -5
I used oven cleaner on aluminum and i sprayed all over too inside out its oxidized aluminum surface now i have to scrape it off, its been a while i messed up like this last time i used household bleach though. I should have known and bought Air Conditioner coil cleaner spray it is not oxidative (i think) yet just as tough as oven cleaner. Wow , that piston looks like the bottom of a Styrofoam cup. , when i did my recent bbk on zummer it was way carboned up on stock everything with only 300 miles , looked like i was running leaded gas for 10 years it was so carboned up...ethonal related??? carbon builds from running lean. whut???
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Post by katt on Oct 16, 2018 17:10:32 GMT -5
Its okay i put it all together and works good.
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Post by katt on Oct 17, 2018 13:34:38 GMT -5
Except that the vibration that i thought was detonations is still there, dunno how i can tell if it comes from engine or drive train or suspension?
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