missing on top end

[RagunCajun]

Well, my shee has been missing on the top after i run it very hard for a while. I checked the plugs and it looked a tad bit lean. I thought my filters were too dirty so when i came home from riding yesterday, i use the recharger kit from k&N to clean them. They were filthy but that wasnt the problem. So today I bumped up the mains from 340 to 350 an hour or so ago.

 

I went take a test ride. All is well. It pulled great on top even after multiple speed runs. I thought i finaly had it. Then i started to do some donuts, 2nd gear wheelie practice etc. Sort of things that are hard on the engine because the rpms are kinda high and the bike isnt moving fast(no much airflow). Well after a while, i went for some speed runs to cool her off and she started bogging real bad. I drive her under my carport and took the plugs out.

 

They looked like this:

http://www.2sly4.us/rc/codys_stuff/MyBansh...s1%208-5-07.JPG

http://www.2sly4.us/rc/codys_stuff/MyBansh...s2%208-5-07.JPG

 

With that said, i will discard those plugs. I will do a plug chop then post picture because i dont understand how to read plug chops.

 

Seems to me the plugs like picture are fine. There's a nice cardboard color. I dont think the bike is overheating(i dont have a coolant tank, i disguarded it).

 

There doesnt seem to be a leak. I didnt a compression test when i had the 320 mains in. Both were over 130psi(great!). At that time, it did this as well but quicker.

 

I dont have any out of the ordinary mods. 350mains, 27.5 pilot, needle clip in the middle i think. There seems to be less low end than there was before but im not sure. I noticed this while trying to balance a wheelie out of the powerband(low low rpms). This could be due to a loosely fitted choke tube which i will secure, no biggie. But if that's not end, whatever it screwing up my top end power when it gets heated up could be causing that.

 

I just dont get it, it pulls like HARD then after a while it will miss on the top end. And from all the reading i do, my problem area is a main jet sort of thing because it controls how much fuel it gets all around cept around idle i think.

 

Any pointers fellas? ::

 

BTW mods that effects the engine are the fallowing:

ported job

20cc domes w/ noss head

t5 pipes

vf3 reeds

+4 timing

k&n pods w/ outer wear

 

edit* i did not ride it after i changed the plugs like 30 min ago. for all i know it could be two partialy fouled pluggs which in tern would make me look like an idiot posting this long post.

Edited August 6, 2007 by RagunCajun

[kb247]

It may have had a miss on top end yesterday but it still beat a YFZ 450! :biggrin:

[RagunCajun]

amen to that Keith!

 

I still need practice though. My drags were far from consistent.

[RagunCajun]

i did a plug chop on one plug:

 

http://www.2sly4.us/rc/codys_stuff/MyBansh...1%208-05-07.JPG

 

http://www.2sly4.us/rc/codys_stuff/MyBansh...2%208-05-07.JPG

 

http://www.2sly4.us/rc/codys_stuff/MyBansh...3%208-05-07.JPG

[jmd0346]

i did a plug chop on one plug:

 

http://www.2sly4.us/rc/codys_stuff/MyBansh...1%208-05-07.JPG

 

http://www.2sly4.us/rc/codys_stuff/MyBansh...2%208-05-07.JPG

 

http://www.2sly4.us/rc/codys_stuff/MyBansh...3%208-05-07.JPG

 

 

 

Sounds electrical to me. Do you have buddy with a Banshee? Try switching stators and see what happens. Sounds like it only happens after you heat things up a bit. Which sounds like and electrical break down somwhere.

[RagunCajun]

Naa im the only one around with a shee for the most part. Do i have to get a new stator or maybe CDI and replace them to see if one of those is the problem? Sounds pricey.

Edited August 6, 2007 by RagunCajun

[shee4speed]

How's the fuel flow? Cock screens clean? Maybe pull the petcock off and check it out.

[RagunCajun]

The fuel flow seems a little rough getting to the carbs but it doesnt seem like a problem. You could be on to something though. Here's an engine shot from the other day.

 

http://www.2sly4.us/rc/codys_stuff/MyBansh...0shot7-1-07.JPG

 

You can see it goes under the boost bottle and it has to climb back up to "t" then off into the carbs. Ill have to check this out. Ill get it really hot again then look at the fuel lines to see if i see it's getting fuel.

 

As for the petcock, it just unscrews off?

Edited August 6, 2007 by RagunCajun

[stovepipe]

Interesting mine is doing about the same thing. Do you notice if you putt around slow and let the engine coolant cool down that it pulls good for about two runs and then it starts to miss again? I feel that mine may be overheating somewhat . If I ever figure mine out i will pm you. Do the same if you figure yours out first. I posted mine on 7-20-07 with no solid conclusions as of yet. I just parked it in the corner for the time being tired of screwing with it.

 

The bike ran fine until i did the listed mods ( I should have left it stock )

 

The only mods to mine are

T-5 pipes

FMF tourqe reeds on stock block

K&N in stock air box

290 mains

needle one clip richer

stock pilot

comp 115-118

[RagunCajun]

Sounds good.

 

I'm gonna drop down my mains to about a 330, and richen(one closer to the point) my needle clip one notch. It might be loading up from getting too much fuel. Althought that would mean i needa lean out the needle. Ah well, ill do what i was told and see. With that said, i dont know why it only starts to miss on top when it gets warm. Like you said, when it cools down, i can make a couple passes before it does it again. Makes sense if it was over heating but hell, i got my mains up so high plus im at 40:1. And people ride their shees much much much harder than i do mine and they are fine so that rules out over heating. Unless my impeller is shot, ill check that as soon as i get my shift kit stuff in, ill take off the clutch cover. Which reminds me, i needa go buy some more engine ice. Hell, ima just get some regular antifreeze and use that till i figure this out, that way i dont keep wasting engine ice. $$$

 

I really dont see how i could be overheating because im running such a big main. I'll let you know when i figure it out because i wont give up. Im going home right after work tomarrow and mess with the carbs then beat on it so it heats up super quick haha.

Edited August 7, 2007 by RagunCajun

[jet mech]

do you think you could be running the carbs dry? just a thought but you may start out with full bowls and you run for awhile and you don't get enough fuel to the carbs to begin with and it just never catches up. someone I now had this problem and bought a better petcock and bigger fuel lines and problem with the bowls running dry stop and said his shee ran great after that but drove him nuts 4-ever :shrug: give it a shot

[jeepman380]

By your plugs it looks like you are a bit rich. Did you do a WOT plug chop with new plugs? If it's rich it could be loading up and fouling plugs while you are lugging it around and doing wheelies and stuff.

[RagunCajun]

jeep man, I dont foul plugs. Never fouled one since i done all the engine work.

 

As for lack of fuel, it's a possibiliy for sure. I thought if id let the bike sit for a while even with it turns off for a few min, wouldnt the bowls fill back up? I did that and it still misses. But like ya said jet mech, it could be my lines and pet cock.

 

I will be going through everything said one by one. That way i rule out all possibilies.

 

BTW as for the running rich on the plug pictures....the bike seemed to be lacking a tad bit of power on the top when it wasnt cutting out. Definently way too rich.

[RagunCajun]

Well i put the 330 mains and moved the needle clip one notch closed to the pointed end. the bike ran much much strong and better. The plugs look a hell of a lot better too. The idle was too low but a little adjusting of the air screw and idle screw and shee have a very reliable low idle.

 

Everything was going good, i went rip for about 10 min. But it killed on me. I looked in the tank, i was very low. I switched tovreserve. I could see the lines starving for fuel. I ended up having to be towed back to my house after walking a mile to get my dad.

 

My bike misses like a son of a bitch like it's out of fuel. It will rev fine but only with the clutch in. Any load and it misses again likes it out of fuel. Plugs still look awesome though. Better than yesterday!

 

I'm very certain i have trash in my tank or something. I was told there's a mesh screen by the petcock so i bet it's full of trash.

 

I'll remove my tank and clean everything and see what shee does.

Edited August 8, 2007 by RagunCajun

[hotrodbanshee]

Get an ohm meter and check your sparkplug caps. Mine would miss and pop like hitting a rev limiter at 3/4 to WOT and found out that my plug caps were bad. I thought it was jetting problem all along.