If it stutters when you start to twist the throttle, and smooths out as the enginfe catches up, I think it is a fuel starvation issue. If the hoses are on good then you might have a carb issue.

I don't know if bike carbs have a small pump in them that squirts fuel when you open the throttle, but cars do. If that pump doesn't work properly then you can get what I think you are describing.

There could also be an intake leak.

 

I am a mechanic on off road equipment and cleaning spark plugs is old school , you can not clean plugs any more they short out internally , just change them , and if your gas cap was not sealing you would be splashing gas out also but maybe you are getting some of the electronics wet , why are you pressure washing it so much ? and watch adding to much ADDITIVES you can be making problems , if one treatment don't fix it it probably won't or that is not the problem

 

Thundermug....What is baffling me is that it's not just if i twist the throttle. If i'm stationary and rev the engine it seems fine, it's only when it's under load as i accelerate through the gears in mid range revs. Idle is ok, wide open throttle seems much better, but under normal riding it surges and backfires like a machine gun.

1st 96 Ultra......I was planning on using the additive for 2 tanks as thats what it recommends on the bottle and i'll be changing the spark plugs this weekend hopefully.

Simon.

 

that's good , the way it sounded I thought you had used a additive several times , it really sounds like the spark plugs are a good bet cause that is just what they will do is break up under a load like you described

 

Will post again after i try the new plugs on the weekend. Thanks everyone.

 

if you need any help just give a holler [ and a plane ticket ] would rather be there in the heat than here in Michigan in the cold and snow

 

Unfortunately i havn't been able to get much riding done so still on the first tank with the additive. Bought new spark plugs and will fit them in a few hours when the bike cools down. Still won't know if that fixes it until the next ride from dead cold though.

1st 96,
You wouldn't like the heat here, too hot for a jacket so i'm just riding in my sunglasses and my vest.

I took a friend of my wifes for a ride through the hills today. She adores Harleys and i suspect i might have to wash my pillion seat now.

 

Problem solved,
Thank you so much to everyone who contributed. In the end it was the spark plugs. I changed them tonight and there was not the slightest hint of surging or backfiring. She is running as smooth as silk and has got her old growl back when i give her a fist-full of throttle too.
I'm guessing i did originally get some bad fuel and that fouled the plugs but i don't know for sure. All i know is i'm a happy **** and have you guys to thank.

Spark plugs $11.00
Anti lock cream sachet $2.30
Getting my baby back to her old self....PRICELESS.

Simon.

 

What about washing the P pad????

Glad ya got it fixed...come to think of it, when my weadeater and edger do that ...it is the plugs...

 

I didn't realize the problem was solved.

Original message deleted.

Congrats!