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Messages - sparky_ppl

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1
People 50 / Re: Help with Airsal BBK on 2003 People 50 2T
« on: August 07, 2013, 12:35:02 AM »
Just to let you guys know and give a follow up to this post:

The kit has been installed and been running amazing since the last posts. I ended up shaving off 0.030" off the top of the jug. The guy who did it runs a performance dirt bike shop and was impressed with the overall quality of the Airsal kit. He was able to sand down the very top of the coating after milling which prevented any chipping (had the cylinder apart recently to replace the head bolts with studs and everything look great). If i remember right, the squish gap measured at about 0.82mm after milling.

Once again, you guys are awesome and hopefully someone who finds this with the same problem now has a solution.


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People 50 / Re: Help with Airsal BBK on 2003 People 50 2T
« on: July 26, 2012, 04:51:08 PM »
Bad tuning killed the Malossi, I'll post pics of the deceased later  :'(   

The stock carb had some shims to raise the factory needle. I have a 21mm Arreche carb and am waiting on a 20mm intake manifold.

The scoot is just a weekend warrior, not a daily driver. I don't want to race it but I'd like to squeeze every bit of performance from it without splitting the crankcase.
I bolted the kit on as is and it had nothing for power, that's what caused me to come here and learn about the squish gap (out of the box the kit didn't touch 0.062" solder when checking).

I chose the Airsal due to aluminum construction and the 3x thermal conductivity compared to iron (live in florida).

Will machining the top of the Airsal cylinder ruin it? The ports looked like they were where they need to be @BDC.

If I machine the head down then machine the combustion chamber edges back in, wouldn't that put me right back where I started as far as the squish gap is concerned? I know I would gain compression from this.

Thanks to all of you for the information, this is insanely helpful. scooterinvasion.com is also amazing in terms of information.

3
People 50 / Re: Help with Airsal BBK on 2003 People 50 2T
« on: July 24, 2012, 10:27:34 PM »
The only reason ZX50 was mentioned was when I first found the difference in bolt length and saw the ZX50 head bolts were 5mm shorter which led me to think I got the wrong Airsal head and that isn't the case.

My fear with machining the head that there is no lip around the combustion chamber to remove material. If it is shaved down, I will lose some of the angled portion of the combustion chamber (see illustrations: http://imgur.com/a/YITW5). This would create a wedge shape opening outward away from the center. Any thoughts on this?

I can pull the head then bottom out the head bolts in the crankcase to ensure the are not bottoming out while being torqued down, haven't done that. I do like the studs though, going to order those tonight.

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People 50 / Re: Help with Airsal BBK on 2003 People 50 2T
« on: July 22, 2012, 07:30:00 PM »
Update #2

Pictures for reference: http://imgur.com/a/QKXJs

Did some measurements for port timings and checked for ports being open @ BDC. With the piston at BDC all ports were fully open with the exception of the 12o'clock port (assuming exhaust is 6o'clock from top view). I measured from the top of cylinder to 12o'clock port @ 1.847" (46.91mm) and top of head to 10o,clock port @1.686" (42.82mm). Difference is 0.161" (4.09mm) and the distance from the top edge of the piston ring to the top corner of the piston is 0.10" (2.54mm) which tells me at best the piston ring is only beginning to touch the bottom edge of the 12o'clock port. These were all taken with the thinner gasket (0.020" thick) installed.

The distance from the top of the cylinder to the top of the exhaust port is 0.955" (24.3mm) and top of cylinder to transfer ports is 1.305" (33.15mm) so those are within spec.

Question here is does this 12 o'clock port need to be fully exposed like the others? Stacking gaskets could fix this but with the squish gap already so large and the rest of the cylinder within spec, I'd have to mill the head so much that the edges of the combustion chamber portion would be flat. Won't that defeat the purpose of the squish band?

Another option is the Malossi head I have. It could be milled down but the edges of the combustion chamber would still be flat. The groove in that head for the o ring is 0.050" deep and the slight lip that surrounds the combustion chamber is 0.015" so whatever it is milled down wuold have to be in addition to that. The advantage of the Malossi head is that the spark plug sits a little farther from the piston than the Airsal head. The distance from the head surface to the spark plug ground strip is 0.173" on the Malossi head vs 0.097" on the Airsal. The piston protrudes past the head gasket approx 0.01 to 0.02" @TDC so if I were to remove 0.050" from the Airsal head that would leave a 0.02" to 0.03" gap from piston to spark plug.

Seems to me the error is more in the piston than anything else. if the distance from wrist pin to top of piston were greater, all problems would go away.

5
People 50 / Re: Help with Airsal BBK on 2003 People 50 2T
« on: July 21, 2012, 02:46:44 AM »
Update:

I checked the squish gap with the thicker gasket (0.030" thick) and the head gasket (0.020" thick) using 0.062" solder. With these gaskets installed, it didn't even touch the solder. I swapped the base gasket for the thinner one (0.020" thick), torqued the head and found that the solder would just barely get touched maybe 0.060" thick. Removed the head gasket and got about 0.047" thick solder. Removed the base gasket too and got 0.041" thick solder (1.05mm).

It appears now that the Airsal kits aren't machined as precise as needed and some material needs to be removed. The question now is where this material should be removed from: top of the cylinder or the bottom of the head? From the measurements above, I probably need to remove 50 to 60 thousandths. Thank you Airsal!

I did take it for a drive with no gaskets and it felt like a 70cc scooter should but still needs some carb tuning so that's encouraging. It appears to be just a matter of getting this squish band correct to get back on the road.

6
People 50 / Help with Airsal BBK on 2003 People 50 2T
« on: July 18, 2012, 09:38:22 PM »
So I ordered an Airsal BBK for a 2003 People 50 2T and went to install and noticed the head bolts were too long with this kit. I've had a Malossi kit on this scooter with the same head bolts (People has M7x1x100mm bolts whereas ZX50 has M6x?x95mm bolts). The cylinder (jug) is the same height as the Malossi and stock plus the exhaust flange matches the People (different from ZX50) so I'm pretty sure the cylinder is correct. Measuring the thickness of the head where the head bolts pass through, the Airsal head is 5mm thinner than factory and Malossi. When trying to install, the bolts bottom out before making contact with the head.

I've searched high and low and haven't read of anyone needing to shorten the bolts to make the kit work but I went ahead and did it anyways. Threaded the bolts an extra 8-10mm and chopped off 5mm from the end and the head can be torqued down no problem.

The engine idles great but part throttle is pretty horrible: sputtering and inconsistent power. Wide open is hit or miss with performance. I haven't done any jetting as the scooter ran great with the Malossi kit and everything else the same setup (info below).

More Info:
Spark plugs are BR8HSA (new & properly gapped)
Tecnigas pipe NextR
K&N cone filter
Factory carb w/factory pilot & 95 main
Factory reed (good condition)

So my questions are:

Anyone else have to modify the bolts to make the head fit? I'm wondering if I have the correct head.
Does anyone know if the Airsal heads are different from ZX50 to People 50?
There are two base gaskets provided: thick and thin. Which should be used (or both)? I currently have the thicker one only.

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