Help! Siezed Air Sol cylinder

[Pelone]

I recently seized an Air Sol 70cc cylinder that had been broken in with only 600 miles on it. I've read that Air Sol's have a propensity to seize and can be not so reliable. I'm running a 110 main jet, and from looking at the plug, I was obviously running rich(maybe a bit too rich as the plug was a bit gummed up and black). I have since installed a Malossi 70 cc kit and certainly don't want this to happen again. I was running some octane boost to bring it up to around 100 octane. I had been running it wide open, but for only about 1 or 2 minutes when it began to sieze. Is 110 too big, and will rich make you seize? I have removed the snorkel and dremmeled out the air box to its rectangular size. If too rich, should I just drill a hole in the main box for more air, and since its oil injected, will more air and a larger jet mean less oil in combustion and thus cause a seize? I'm a bit dumbfounded as to why I seized while running rich and don't want to ruin my new Malossi kit.   

[JJJoseph]

It's REALLY EASY to blow up a 2-stroke!  Little things like drilling out the airbox can make them run lean and everything seizes up (overheats) within minutes when running WOT.  Some 50mm BBKs are designed for racing with wicked port timing.  These ones especially are easy to incinerate. I suggest installing a mild BBK (like a standard 60-70cc Malossi), but leave everything else stock while running it in.  and don't run it at WOT until you're sure it's set up right.  Don't worry, this is what setting 2-strokes is like.  Racing jugs are cheap and designed to last one race, then replace.  The Malossi will have a much better service lifespan.

[LoveMyKymco]

All 50 mm kits have very tame porting, exceptionally far from aggressive or "racing". A malossi sport kit has more aggressive porting than a HK 50mm kit. The HK 50mm which is one of the best for port timing and sizes. VAST majority of 50mm kits MUST be re ported (by you or someone qualified) to have exhaust timing perfect. Go ahead and check it for yourself, when the piston crown is at BDC count how many MM you can see on the side of the piston. Ive had the 50MM cylinders be off by 5mm on BDC and under by 4mm at TDC. The timing on 75% of 50MM kits out there off by 10-30 degrees. Thats an insane amount volumetric efficiency just tossed out the window. Now if you get into the MHR and MHR replica range you will have near 90% VE and need near no porting to make it perfect.
Im only speaking from 20 years of experience with these engines and various kits. The bigger the cylinder does not mean the bigger the HP, anyone who builds 2 strokes will tell you porting is everything. Made in china and tai bores dont last long because of the poor quality of the materials used, not because they are "race" cylinders. Ill put one of my Corsa or MHR kitted engines vs any 50mm kitted anything and kill it every time.
Airsal cylinders are ok mid of the road, they can take a few seizes due to nikasil coating but once the nik is damaged the cylinder has to be relined or its junk. You cant hone them. If youre using the stock carb I would suggest to immediately stop. You really need a bigger carb so that the proper amount of air can reach your cylinder. Only so much air can flow through that tiny little carb venturi. Also you should be doing a premix and not using the stock pump. Just for reference, when I ran a stock carb with a 50mm kit I only used a 95 jet. If you still needed more fuel I would look into an air leak somewhere.
Here is a set up I did just to show how poor the 50mm and stock carb vs a 24mm kitted 50mm set up would do. This will give you an idea about jetting.
Kymco SC10AS engine with ported intake windows
HK 50MM kit ported exhaust, transfers, and boost port
Polini CF reeds in stock unported reed block
Stock kymco carb with 95 jet and needle clip in 4th from top slot
Stock agility airbox modified same as you did
stock sc10as intake
PhonGear V8 exhaust
Blue "racing" cdi
Orange KOSO coil and NGK HT lead
NGK br8hs plug
10,600 RPM max
330-350F degree F continuously on CHT@WOT
32:1 pre mix with oil pump blocked off

I did run this set up how ever I do not recommend the stock carb ever on BBK.

[91cavgt]

What octane booster were you running?  The ones that say they raise the octane by 3 or 4 or 5 points are just that, points.  So if you're running 93 octane and then put in an octane booster that claims a 6 point increase in octane, you will end up with 93.6 octane, not 99 octane.   Torco octane booster is the only real octane booster I have found, but it is hard to find and expensive but it works.

[LoveMyKymco]

50/50 93 octane pump gas and VP110 is the only way I feel is safely effective. Octane boosters like Cav said are useless. Ive never tried the one he suggested.

[91cavgt]

50/50 93 octane pump gas and VP110 is the only way I feel is safely effective. Octane boosters like Cav said are useless. Ive never tried the one he suggested.

http://www.torcousa.com/torco_product/un_acce.html


Here it is.  It costs $21 for a 32 ounce bottle, but shipping is expensive on it. 



I have used it in my old SRT-4.  With running one 32 ounce can of this to 10 gallons of 93 octane, it would effectively raise the octane up to 104 octane.  I had an OBDII computer connected to the diagnostic port and could monitor ignition timing.  With running a full 32 ounce can of Torco in the tank, I would see an additional about 10-13 degrees of ignition timing while at full boost.  This tells me that it was working because the ignition increase was not an aftermarket program, it was the factory computer advancing the timing because of lack of knock.  So at 19 psi of boost, the car was running about 32 degrees of timing advance with the Torco in the tank!! 

[LoveMyKymco]

I have seen the torco before actually now that I see the site. Ive heard of claims of it turning your plugs a funny color. Aside from that everyone seemed to like it. You can use toluene and xylene also, all 3 are equally harmful for you to breath in after and before combustion. For that matter leaded race gas is horrible for you to breath in.

[91cavgt]

I have seen the torco before actually now that I see the site. Ive heard of claims of it turning your plugs a funny color. Aside from that everyone seemed to like it. You can use toluene and xylene also, all 3 are equally harmful for you to breath in after and before combustion. For that matter leaded race gas is horrible for you to breath in.

Yes, when you run it your plugs will turn an orange, brownish kind of color.

[JJJoseph]

Lots of good racing feedback, but it doesn't sound like you're going racing.  Never mind all the talk about octane boosters, etc.  Your Malossi won't have particularly high compression, but it can overheat and seize when running too lean. Otherwise it's a good, well-made assembly.  The stock carb is just fine with a BBK, just needs rejetting to about #95.  Some 50mm kits like Ruima are nice streetable setups.  Others can be real screamers, but not so streetable. It's easy to blow up a BBK with a big carb and tuned exhaust because the BBK is inherently out of balance due to the bigger piston (which in most cases is about 10gm heavier than a stock piston), and they can wind up over 11,000rpm.  So take it slow with the new BBK and tune it carefully.  Try to keep it below 9000rpm at all times.

[LoveMyKymco]

Your malossi will have 130 psi when finished, how do I know this? Because I actually have owned that cylinder, and also the 50mm Ruima cylinder. This guy JJ is full of something and its not knowledge. A big bore kit is NOT inherently out of balance. If it were even slightly off balance the crank would walk and the piston would seize.
JJ you have no clue what youre talking about and just talking to talk. Heres a pic of parts for my next build. 55MM ruima cylinder, 52.6MM stroker crank, 30MM carb, etc. I have a little know how on building these engines.

[JJJoseph]

Your malossi will have 130 psi when finished, how do I know this? Because I actually have owned that cylinder, and also the 50mm Ruima cylinder. This guy JJ is full of something and its not knowledge.

Well, obviously you're just uploading photos & pretending to be an expert.  I on the other hand have built and raced scores of 2-strokes, not like yourself who seems to be totally clueless about reliable 2-stroke performance engines.  If you don't know what you're talking about, you shouldn't be giving advice to others.  I'm curious: how do you feel when you go about recklessly bad-mouthing other contributors?  How does it feel to have your manure tossed back at you?

[LoveMyKymco]

JJ post one picture of an engine you have right now. One that is currently running. Youve only built 50mm kits that blow up because you dont know how to tune or build a simple 2 stroke. Simple post some proof, or your a worthless. I live in the show me state, so show me youre not a liar.
Problem is youre a troll with no experience. I have 20 videos of the bikes Ive built all you have to do is go to my photobucket or youtube page. I dont lie and day dream about fixing scooters like you do JJ. Ive owned a mechanic shop for going on a year solid on top of my real job.
Also if youd like to read more about what Ive accomplished you can always check out hondaspree.net
This site is dedicated to kymcos or Id post the million other pictures of my built scooters.
JJ just post one picture of something you actually have and that is running and not just talk.