same problem again

[edouble88h]

need some info. bike was sputtering pretty bad and had it taken to the shop. picked it up mech told me he replaced fuel related parts mapped my pc and all i needed was a dyno. it ran great for 2 days. yesterday rode to work and BAM started sputtered again. at a stop lights i had to rev to 6-7 grand just to take off. looked @ it this morning nothing seems to be loose, kinked or missing. any ideas?

latest work @ shop:
new fuel pump
new fuel filter
complete fuel system check (good compression and psi)

bike: 99 busa, two intake cams, i cut 6in off yosh exhaust, pc3, bmc air filter no other mods

 

[ajblbv]

Are the fuel lines new? Are any of them kinking? I had an issue with mine last year, after replacing much of the fuel system I cut new lines to replace the worn out ones on the bike, and unknowingly made one an inch too long. It would kink just enough that the bike would die intermittently. The stock has actually has a 90 degree curve to it. So I would start there.

Otherwise, is it a dealership you are taking it to? Are they willing to stand by their work? I would suspect that you would have a good issue with any shop manager if you replaced the fuel pump on their advice, and the problem is not solved.

Keep us in the loop.

 

[edouble88h]

not sure if the lines were replaced (mech didnt mention having to replace them). they have wiring around them to prevent kinks. it's not a "dealer" but a known shop in my area. he's coming to pick the bike up this afternoon. he has given me quite a deal on the hours that he's put into the bike since he had it for so long before i got it back. he has reassured me i won't get it back until he is 100% satified that i won't have to bring it back for the same issue.

 

[ajblbv]

Did he replace the fuel filter? Mine disintegrated, and the floating particulate occasionally clogged the fuel line, also 1999s have been known to get the injectors clogged due to a failed fuel filter. I ended up putting in an inline filter and leaving the area of the pump empty.

 

[edouble88h]

fuel filter was replaced. the only thing i could think of was injectors. he didn't mention doing anything with them.

 

[ajblbv]

There are a few older posts saying that when the filter disintegrated particulate got all the way to the injectors. I replaced all mine, but I did it at the same time as doing the inline filter, so I can't say for sure if I needed it or not, I just wanted to be safe after having reliability issues.

 

[edouble88h]

back to the drawing board .. funny thing i did mention to him something about taking them out and sending them somewhere to get "sonic cleaned"?

 

[delbert]

you say the filter was replaced , what about the fuel screens were they checked

 

[Blanca BusaLess]

Did they drain tank and replace with fresh gas ?
If not it could be as simple as water in your gas.
What it sounds like to me.

 

[edouble88h]

you say the filter was replaced , what about the fuel screens were they checked

yup that was done to

 

[edouble88h]

Did they drain tank and replace with fresh gas ?
If not it could be as simple as water in your gas.
What it sounds like to me.

i'll ask but when the derusting was done (by another shop) fresh gas was used. then i had the sputtering problem. so new mech went through the complete fuel system and put in new pump, filter/screens. compression was good and fuel pump was at the correct psi. could it have been the grade of fuel used? heard 87 is good enough. i usually put high grade in all my vehicles but if 87 works better....