Fuel Mixture fuel mixture

[gone_fishin]

i double checked & tried 2nd from top again. about the same as pianoman, except i get good top-end on 3, so i went back to 3rd from top.

i think better performance is gonna involve going to 32:1, tho...get things a little more oily, like blaze says.

 

[chieflets]

for extra 1km or 2km in top speed its not worth using leaner fuel I rather keep it at 25.1 and keep it safe.

Chieflets

 

[bamabikeguy]

I'm trying something new on my personal engine. I had been using Stihl brand at 50:1, but my bikeshop guy, who also is the small engine expert in Decatur, gave me a few packets of Sten Mix synthetic, saying the muffler would stay cleaner longer.

Very noticable difference, less smoke coming out of the exhaust.

The thing I didn't like was how I had to drain the plastic packs into a bottle for on the road use, the packs are 1.8 fl.oz., and when I have to fill up on the road, I use the cap of the oil bottle as my measuring devise, 1 cap equals 3-4 cc.

On the outskirts of Bayou La Batre, a guy gave me a nearly full bottle of what he called "the best synthetic", AMS Saber Professional 100:1 Pre-Mix.

https://www.amsoil.com/

5 guys were gathered around my bike when he gave me the bottle, these guys are gulf fishermen. What they were saying was once the rings are seated, it didn't matter what mixture you used, 50/80 or 100 to one, synthetic simply took less to do more.

That personal engine has over 5,000 miles now, has had the cylinder inspected by two small engine mechanics who both say the rings are in perfect shape, so I'm going to take the advise and stick with synthetics.

 

[Guest]

Amsoil 100:1 run at 100:1 will hurt your engine. It is a great oil but the reason we need richer oil concentrations isn't for piston ring lubrication, its that darn connecting rod bushing. If you are going to use Amsoil 100:1 you should run it at a 50:1 ratio.

 

[bamabikeguy]

Thanx drew, I never DID go 100:1.

GEBE has a 22 oz plastic tank, on the road, I divide it in quarters, add 1 capful (3cc) per quarter, which works out 50:1

Last summer I went ahead and did precise measuring, with measuring cup, hypodermic needle and marking pen, to be sure to be able to measure 50:1 on the roadtrips.

 

[jaker]

ahh cool thats a slick idea marking the tank


a little off topic but has anyone else here ever tried Sea Foam to remove carbon deposits and clean carburator?

its recommended for all engines and i have personally used it on my drag raced 1986 thunderbird and when i put new heads on the 302 the cyl's were unmarked u could still see the factory crosshatchign all the way down and there was hardly any carbon buildup at all anywhere.

as far as use on 2 strokes its more often used by ppl with 2strokes and my pal uses it all the time in his 110hp boat just add to the fuel as recommended.

 

[Guest]

Seafoam is a great product but best used to do a cleaning not as a preventative added to each tank (gets expensive).

These engines are so easy to work on that pulling the head to clean the carbon off of the pistons is the cheapest and best route. You'll definitely know the extent of carbon buildup if you do this once a year or more depending on how much you ride your motor bike.

I personally want more carbon buildup on my piston. I'll take any bit of help to up the compression ratio on our 6.6:1 engines

 

[chieflets]

Drew,

Shim the head slightly if there is room clearence

Chieflets

 

[jaker]

if u mean decking the cyl you had better clay it first to make sure u have enough room.

i am not sure about this next bit of info but my logic tells me this..
because of the way a 2stroke works the compression of the engine is limited to how efficiently it can pump air into itself
based the fact that 4 strokes are better air compressers.. meaning to increas the compression on a 2stroke u have to tune intake port heads tuned pipe etc where as on a 4 stroke the mest effective way is to reduce chamber size.

the reason a 4 stroke has more compression is because of the valve timing and having an extra stroke for intake etc....
2 strokes rely on port location and becaue of this cannot fill the chamber as efficiently as a 4stroke

reducing chamber size may help on a 2stroke but i imagine the chamber is pretty close to as small as it can be
i have heard of some mod where they got a flap on the crank that forces the air into the port faster and increases compression