loss of power and spittering n sputtering while cruising??

i couldnt get my seca 750 started at first so i replaced the cheapest thing to start..the plugs...it fired right up but i have a few issues hopefully someone can help me with...first of all the bike will not stay running inless its in the PRI position on the petcock...i dunno whyit sdoes this can you help?...second while im riding the bike is spitting n sputtering pretty bad while im just cruising along but when i hit the throttle it goes pretty good....and now the bike isnt spitting and sputtering while im riding but it sounds alot different and i lost a good bit of power definetly...what should i do ??? do you know whats wrong ???

 

Re: loss of power and spittering n sputtering while cruising

I'm having exactly the same problem and so I thought i'd dredge up this old post in the hope that someone who knows what they're talking about could offer some advice???

anyone....?

 

With your petcock on PRI you are going to have a big loss of power especially if the vacuum line is still attached. Sounds like a fuel delivery issue. Chances are you need to have your carburetors cleaned (possibly rebuilt) and have them synced. After that you should have a smooth running bike. I'm not an expert but that is about the most common and usual culprit in a funky running bike. Dirty carbs. And just because they are clean on the outside doesn't mean fuel and air are moving through those teeny tiny passages properly. There are a lot of threads on here on cleaning carbs and a lot of people with a lot of advice, tips, and suggestions. Give the bike a carb cleaning.

 

If it only runs in Pri then there is a problem with the vacuum operated fuel petcock on the gas tank. If your still running crappy in pri then you have to clean your carbs. There is no short cut. You do it completely or you will be wasting your time.

 

Check/change the oil,if you have left it in the prime position the crankcase will fill with fuel. Clean the carbs!!!!

 

Check the vac hose from petcock to intake manifold
for cracks.
Any air getting in the hose will interuped the vac flow and
prevent the diaphram from operating properly.

 

Thanks for the tips guys.

The timing is good also as today she wont start at all! it turns over but won't catch.

And that's after going to the mechanics yesterday when they replaced the seals and gaskets on the carbs.

The thing I noticed this morning though, was that it was left in Pri. Would that fill the carbs and stop it starting?

What are some likely problems?

 

If you left it on PRI over night, read this thread.
http://www.xjbikes.com/Forums/viewtopic/t=24116.html

 

The mechanics left it on prime?
If so and the fuel is now in your crankcase, that
shop owes you an apology along with a new oil change!