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Post by repherence2 on Oct 21, 2021 12:39:05 GMT -5
Temp gauge helps with tuning when using powerjet carb. In my experience, the main jet takes care of the 3/4 throttle region. The powerjet comes online after that. Tuning can be finicky but once you figure it out, peace of mind at WOT.
There are videos of power jet carbs in action. I think the guy was in the Philippines. He mounted the camera so that you can see how/when the fuel is pulled from the bottom of the bowl and up to the power jet. I seems to be a function of vacuum and throttle position.
Once you get it in tune, it should be lovely.
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Post by repherence2 on Oct 22, 2021 20:54:04 GMT -5
if you do not want to have to tune around the power jet, i have read that people simply disable it by inserting a BB into the power jet hose to seal it off. then it acts like a normal PWK once you do that. ...options.
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Post by nelson on Oct 22, 2021 21:34:56 GMT -5
I assembled the motor today. I ended up using two paper base gaskets the some Motoseal to seal up the stacked gaskets. The bike came with a Sunworld PWK 28mm carb. It has a power jet and some ports im not familiar with. I think they are overflow ports but im not sure. Im also not familiar with powerjets either. Im not sure what they are really for, is it just to add more fuel WOT outside of the main jet? Here are those strange ports.  When I cranked over the motor it idles very high. Im not sure if its just a small main jet or I have an airleak. Ill put the pressure tester on it tomorrow to check it. It turns out the motor is also an AF16E and not the AF18E. Normally I wouldnt mind but its a problem in this case. There is no vacuum port on the cases to operate the fuel pump. So to solve the problem I am going to modify the oil pump plug to have a nipple for some vacuum tube. Ill post the results tomorrow.  Yes, those are vents. Man, por15 goes hard. I did some floor pans 20 years ago. Can beat with a hammer won't chip. Anywho, that's a nice ride going to be a good time! |
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Post by hippo008 on Oct 23, 2021 20:07:27 GMT -5
I mounted up the motor and wheels to make a roller. The bike starts up fine but is pretty easy to kick and smokes a LOT. I put the compression tester on it and got 90psi. The bore looked good and the piston also seemed good so I am not sure if the rings are clapped out or what. My gauge is a cheapo AutoZone brand gauge so that may be why the lower number. It could also be my squish is set way out, I still have yet to measure. I run 92 octane pump gas but I am not sure what to set my squish at. Ive seen .8mm as a good target before but I dont know if thats on all setups for pump gas.
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Post by hippo008 on Oct 24, 2021 19:20:04 GMT -5
Heres the first start of the AF27 with the AF16. Its making an odd noise let me know if you can identify it.
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Post by hippo008 on Oct 25, 2021 15:31:37 GMT -5
I started up the motor again today and the ticking\clicking noise got worse. I checked my squish and im at 1mm which im sure is safe. The noises concerned me enough that I decided to breakdown the motor and investigate. Here are my observations. The cylinder and piston dont show any major scoring or wear however the hatching on the cylinder walls is gone. Upon closer inspection however I noticed the piston skirt is cracked and slightly chipped. The wrist pin was seriously stuck inside the piston. I needed to use a C clamp and socket to press the wrist pin out of the piston. The wrist pin bearing seemed to be fine. The piston can move around inside the bore. With the piston at TDC I gently tried to move the piston around the bore and it did so freely and without any effort. This was exasperated as the piston moved closer to BDC. The crank isnt a PG crank at all. Its the ScooterTuning mini-stroker crank. Its branded 2AB, I assume thats the company that produces them. It has a stroke of 43.2mm etched on one of its journals. The crank bearings are OEM Honda and in seemingly OK shape. However with the cases already broken down I would rather just spend the money and replace them than roll those dice. With all that in mind here is my current plan. I think the Polini Corsa on this thing is just too far gone. The cracked piston, the piston slap, the stuck wrist pin and poor setup of the motor makes me think this thing was abused. The cases, crank, carb, intake, gears and ignition are all good however. I plan to purchase the 50mm (or similar) bore that is meant for a mini stroker crank. If I really feel the need I could always increase the exhaust duration to get some more juice out of it. Im also going to purchase some fresh bearings and seals. Im already inside the motor I may as well do a complete job and do it right. I like having that peace of mind.    |
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Post by aeroxbud on Oct 25, 2021 16:23:42 GMT -5
Good idea. That piston doesn't look good. And whoever built the motor should of used new bearings.
Better to be safe than sorry.
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Post by 808ministroke on Oct 27, 2021 2:46:20 GMT -5
So that clicking noise that clicking noise is one that I've gotten several times on a few different bikes Here are some things that caused it for me maybe one of these is the issue of your clicking. 1st off I would check The fan and and make sure the propellers aren't hitting a shroud or a bolt Also could be like the urbandics for your electric starter on the variator side Or could even be that heat shield on your exhaust rattling. After you tore it down the 2nd thought could have been piston slap is that what your determining it was?*¿◇¿☆?
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Post by hippo008 on Nov 3, 2021 9:22:05 GMT -5
So that clicking noise that clicking noise is one that I've gotten several times on a few different bikes Here are some things that caused it for me maybe one of these is the issue of your clicking. 1st off I would check The fan and and make sure the propellers aren't hitting a shroud or a bolt Also could be like the urbandics for your electric starter on the variator side Or could even be that heat shield on your exhaust rattling. After you tore it down the 2nd thought could have been piston slap is that what your determining it was?*¿◇¿☆? Im fairly certain it was piston slap. I took the fan shroud, fan and small side cover off and had the same results. Even if it wasnt piston slap the piston it came with was cracked anyways. It would cost about $100 for a new Polini Corsa piston kit or about $130 for a whole new 50mm top end. Even though the Corsa is a great platform id rather save myself the potential headaches and get new parts. |
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Sum-azn-kid
Scoot Enthusiast
Posts: 183
Location: Hawaii
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Post by Sum-azn-kid on Nov 10, 2021 1:58:03 GMT -5
Yes a 50mm topend will be cheaper. But sometimes the quality of those kits and performance is lacking. I prefer to spend the extra for a quality bore kit like a polini corsa. Ive seen some people luck out with those cheap kits and others end up going Italian after wasting $$$ on the cheaper alternatives first...
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Post by 190mech on Nov 10, 2021 5:36:49 GMT -5
I agree!Oldgeek got a 50 kit that looked nice,so I ordered the same one for my build,the transfer ports were terribly mismatched and took me hours of time on the porting bench to clear it up,almost like the core shifted during casting and QC just boxed it up...  |
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Post by hippo008 on May 5, 2022 20:16:56 GMT -5
THE TIME HAS COME A gentleman in my area let me know he's importing a couple rare Jog 90s from Japan. You know I'm interested in a Jog 90, so that means it's time to slap together this hunk of junk and get it sold! I have entered full scavenger mode to get this thing completed with as few dollars as possible.  I put in the cheap mini stroker AF16 I just completed in this frame. I want to keep my Baja totally JDM and a filthy AF16 doesn't fit the bill. Plus I got all of the parts on a deep discount! I removed all the nice overrange CVT stuff and slapped in some old stock Honda AF18 CVT to get it rolling. I also put on the greatest most ghetto air shroud this world has ever seen, it's fantastic.   I temporarily have a Polini PWK 24 mounted on this thing. That's way too nice a carb for this bike so I plan on buying the cheapest OKO I can get my grubby fingers on and using that. It started right up and sounds pretty good!  |
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Post by 65grendel on May 7, 2022 17:22:33 GMT -5
You know where the rims came from? They’re nice looking. I hope your trade works out
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Post by hippo008 on May 20, 2022 19:06:28 GMT -5
I'm having a hell of a time getting the 28mm SunWorldRacing PWK in tune on this thing. I've tried main smaller main jets like 128 and huge main jets like 165 and not had much of a difference. I put in a 155 and the bike ran OK with a little sputtering but when I went down to a 152 the bike was making that lean WAAAAA sound.
I'm running a rumia mini stroker crank and 50mm mini stroker bore. I'm wondering if the 28mm carb is simply too large for this setup and I should jump back to a 24. I'm really scratching my head here
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