banshe blew up right piston on second ride

[rappy660]

just rebuilt, bored .20 over, t-5s, 20cc domes, ported, advanced +4 timing, v-force 3's and K&N pods. Stock carbs with 310 mains. Took it out saturday to break in, everything went well, plugs were good color. On sunday went hill climbing. It idled fine so i do not think there was any air leaks. The hill climb was about a 20 second long climb at full throttle. 3 or 4 time it would fall out of powerband near the top. Not thinking anything at the time, i thought i was running out of power, but now i believe i was running out of gas on the right cylinder, causeing it to die out, and after 4 times of this happening it burnt a hole in the piston. Here is a video of it doing it. Im the yellow banshee around 1:30 that dies out.

http://www.hillclimbersforum.com/showthread.php?p=58633#post58633

 

Let me no if anyone has any idea what can be causing it to runout of gas. The floats seem fine as well

[rappy660]

just rebuilt, bored .20 over, t-5s, 20cc domes, ported, advanced +4 timing, v-force 3's and K&N pods. Stock carbs with 310 mains. Took it out saturday to break in, everything went well, plugs were good color. On sunday went hill climbing. It idled fine so i do not think there was any air leaks. The hill climb was about a 20 second long climb at full throttle. 3 or 4 time it would fall out of powerband near the top. Not thinking anything at the time, i thought i was running out of power, but now i believe i was running out of gas on the right cylinder, causeing it to die out, and after 4 times of this happening it burnt a hole in the piston. Here is a video of it doing it. Im the yellow banshee around 1:30 that dies out.

http://www.hillclimbersforum.com/showthread.php?p=58633#post58633

 

Let me no if anyone has any idea what can be causing it to runout of gas. The floats seem fine as well

 

think i figured it out. i never took the little plastic things out of the carb. could they have restricted the fuel flow?

[Jereme6655]

think i figured it out. i never took the little plastic things out of the carb. could they have restricted the fuel flow?

 

nope....they don't restrict fuel...they are a splash-guard which should be left in. did you properly break the engine in after you fully assembled the motor?

[Rodneya]

Break in has nothing to do with a hole in a piston.You can run a new top end as hard as you want to as soon as it is warmed up and not have issues.

 

Check your fuel cap breather is not blocked, and take the fuel petcock out and clean the screen. When you rebuild, do a leakdown test and check the intakes with carb cleaner to rule out leaks.

[jbooker82]

Gut and drill out your fuel cap for the hell of it. If your running one of those little breather cap hoses (aluminum valve on 1-2 inches of hose) throw that in the trash.

 

Take the petcock out of the tank to make sure it is clean and not full of crap. It has a fine screen just like a fuel filter. I would go a head and clean the tank out while you have it drained, off and fuel valve out. When I cleaned mine there was sand about half way up the reserve tube.

 

Maybe consider getting a dual pingnel. It flows way more fuel than the stock one and has a fuel line for each carb. Down side is that there is no reserve.

 

[sleeper06]

310 mains on a ported,podded shee sounds lean

[rappy660]

310 mains on a ported,podded shee sounds lean

 

the other side plug was fine, running a little rich if anything.

[J-Madd]

Way lean = deto and burn a hole in the piston. You're motor requires more fuel hillclimbing (especially at the top) due to the load on the engine. If you just randomly checked the plugs, you didn't get a reading of what was going on at the top of the climb regarding the jetting. You also could have had an air leak.

[J-Madd]

the other side plug was fine, running a little rich if anything.

 

 

Well, I vote for air leak then. Just missed your post!

[GrMeyer]

Iagree that ur lean. U should be in the 330's and deff 27.5 pilots. If one side is fine and the other isn't. Then I would look for an air leak. If ur running stock carbs then the stock petcock is fine. Deff pull it out and clean two screens. What is ur float hight set at? Did u check compression as for what gas to run?

[rappy660]

Iagree that ur lean. U should be in the 330's and deff 27.5 pilots. If one side is fine and the other isn't. Then I would look for an air leak. If ur running stock carbs then the stock petcock is fine. Deff pull it out and clean two screens. What is ur float hight set at? Did u check compression as for what gas to run?

 

the compression was 150PSI. The float height was at what the manual says it should . Like i said the other plug was burning perfect with the 310's after checking it after climbing.

[sleeper06]

You need to do a chop at upper rpms,as sonn as you idle it for a lil it will turn black,you must use new plugs

[shawn941]

Iagree that ur lean. U should be in the 330's and deff 27.5 pilots. If one side is fine and the other isn't. Then I would look for an air leak. If ur running stock carbs then the stock petcock is fine. Deff pull it out and clean two screens. What is ur float hight set at? Did u check compression as for what gas to run?

exactly what i was thinking,,,,hes running 20 cc domes,,,may need to run race fuel depending on what his comp is

[06specialedition]

If your running lean, that means I'm running lean too. I have a ported Shee with 320's, but I've only ridden it a few hours and I'm at 5,000 feet... You got me thinkin now

[sx_v1s10n]

Similar thing happened to me but I didnt blow a hole it in but she deff burnt up. This was actually a friend of mines quad.. and he rebuilt top end and then shortly after in top end the piston burnt out lost compression and died. Just pulled the head off tonight since he gave me the quad cuz he dont have the time to work on it and owed me money and this is what I see. I hope its just a top end rebuild and not something more because I got it for a steal... I will check for air leaks once I put it all back together maybe that was the problem since when he did the rebuild he added a new 2-1 carb and pipes.