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4 mil problem this weekend. Question for the gearheads!


phx450

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This past weekend brought my new 4mil to glamis. (already broken in).

 

Unload the bike out of the truck and warm it up. Race up the hill 3 times. Not racing anyone but certainly running it hard. On the 4th time up hit 5th gear pinned and it shuts off. Not a boom or any crunching metal but it clicked off. I coasted back down to the truck.

 

I proceed to check all the basics, Gas, gas on, has water, etc.

 

I sit at the truck and kick the shit out of it, it rumbles a little and i could get it started with both chokes on. Once i turn the chokes off and let it calm down it bogs and dies. We play with the CDI(stock) wiring, I even swapped out another CDI(Stock)

I got it running again and raced the hill a 5th time, same thing happened fith gear pinned and it dies, no noise this time just bogs and dies.

 

When i get back to the truck i try the same thing. However when you kick it now it feels as though it has zero compression.

 

 

My question is now what?

 

No compression and this problem. Could it be the reeds? Piston ring?

 

help.

 

I'm taking it apart this week and would like any feedback from you 4 mil pros!

 

If it helps i have a the trinity stage 4 heads, override, 38mm gas carbs.

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Spark plugs were okay, No metal shavings or anything. Believe me that was what i was worried about.

 

I never thought about running the bowls dry.

 

The gas tank does have a pingel.

 

I will check into that as well.

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He said gas...gas on...I thought the same thing.

The only reason I said run the bowls dry is because he was on a long 5th gear WOT run.

 

If not...could be in the ignition, I'd remove the stator side cover, check there, check for burned wires, check the pickup gap, etc....

 

If you got a pingel and are on gas...hmmm....could be...but probably not likely.

Still, wouldn't rule it out. Have you held it WOT in 5th for a long time before without issue?

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Here is the trick thing.

 

Last week at Gordons well i was breaking it in on flat ground, As well as racing flat ground. This is why i thought about the bowls being ran dry.

 

Up this hill it did have the problems.

 

 

I guess you could say up the hill I had it in 5th gear a ton more then on the flat drags.

 

 

The thing that scares me most is the lack of compression when you kick down on the kicker. I wonder if the bowls ran dry if i will have problems in the cylinder head. If so i will proceed to shoot myself in the head as this is a brand new build.

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Here is the trick thing.

 

Last week at Gordons well i was breaking it in on flat ground, As well as racing flat ground. This is why i thought about the bowls being ran dry.

 

Up this hill it did have the problems.

I guess you could say up the hill I had it in 5th gear a ton more then on the flat drags.

The thing that scares me most is the lack of compression when you kick down on the kicker. I wonder if the bowls ran dry if i will have problems in the cylinder head. If so i will proceed to shoot myself in the head as this is a brand new build.

 

 

If you ran it out in 5th pinned twice I would say it got hurt

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If it leaned out and smoked a piston, your cylinder head would be the least of your worries.

If you pulled out the pistons AFTER this last time and saw NO metal or aluminum on them...hmmm...a broken piston will leave some kind of deposit on the spark plug.

Get a compression gauge to confirm your thoughts...then, pull the head.

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If it leaned out and smoked a piston, your cylinder head would be the least of your worries.

If you pulled out the pistons AFTER this last time and saw NO metal or aluminum on them...hmmm...a broken piston will leave some kind of deposit on the spark plug.

Get a compression gauge to confirm your thoughts...then, pull the head.

 

 

Thats what i figured on the compression. If i did smoke a piston or ring for that matter wouldnt it smoke like crazy out of the corresponding pipe? I figure i would smell it and see all of the smoke?

 

VP 110 mixed with 91 pump gas. Running klotz.

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Thats what i figured on the compression. If i did smoke a piston or ring for that matter wouldnt it smoke like crazy out of the corresponding pipe? I figure i would smell it and see all of the smoke?

 

VP 110 mixed with 91 pump gas. Running klotz.

 

If you put a hole in a piston, it won't start....

Pull the plugs, then pull the head to double check.

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Thanks for the help,

 

My last question is if you put a hole in the piston, would it smoke out the pipe or give me any other easy sign?

 

Or am i just wishing?

 

Sounds like you ran it out of fuel one too many times. Probably started to seize and pulled alum off of the piston up onto the rings (hard to explain but you'll know when you see it) and I would imagine it has alum stuck to the cyl walls hence the loss of compression.

 

May not need to be bored but you'll difinitely need a new top end and the alum removed from cyls along with having them honed.

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Thanks for the help,

 

My last question is if you put a hole in the piston, would it smoke out the pipe or give me any other easy sign?

 

Or am i just wishing?

 

If you burned a hole in the piston, I highly doubt that it would smoke any more than normal. If anything it would smoke less out the side of the exhaust that has the respective hole in it.

 

If you ran your bowls dry and burned a hole in the piston I think you probably would experience the exact symptoms that your are having now. You need to do a compression check to start out with. I have burned up alot of pistons and the only real clue that i had was that the bike would hardly run and that I had low compression in one of the cylinders. The spark plug looked fairly normal and there was not any metal shavings to be found.

 

FYI: A Banshee will run without one cylinder firing if you fiddle with it enough. It won't run well, and it will seem like it is bogging and the only way to keep it running is choke it alot and keep the revs up. In all cases it will seem like it is down on power. :thumbsup:

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