Turbo studder

[Busatroop]

Recently returned from Iraq and had the bike in paint..took the opportunity to change oil/replace plugs/flushed coolant...the painter of course had the tank off but other than that there was nothing touched...when he put it all together and we fired it up ran awesome but the fuel pressure is pretty high close to 55 (stays somewhat steady there )...runs obviously rich due to the smoke out the exhaust...while running it rides great besides the light amount of smoke at idle...when coming into boost it runs up nice but when you hammer it it seems to stumble or studder in boost its kind of intermediate...bike was pretty muc not riddin from jan 07- present due to deployment and then in paint what can a novice as myself due to trouble shoot this or can anyone recommend a shop near Killeen,TX and once I arrive early next wek I can get in touch and make something happen....sorry for the long write up and thanks for helpin!


Bike is outfitted with a Motorhead kit its a 2006 Bike stock internals tuned by Rays Suzuki in Sumter,SC...again thanks!!

 

[cdhoroho]

too rich
needs to have the fuel pressure set around 38-42


johnny cheese is the man in texas to take it to

 

[twotonevert]

Since it has sat for about 18 months, have you cleaned the throttle bodies. Something may be hung up, gas will turn to varnish in that time and it may just take some time to clean itself out. You could try some fuel additive/cleaner. We used to use seafoam on my mustangs, but not sure about using it on our bikes.

 

[dave3.4]

I'd check your fuel line and see if it got pinched.The fuel pressure should drop at boost if the line is pinched

 

[Busatroop]

ok guys good info..when we replaced the tank we did realize there was a angle in the fuel line we didnt like but it wasnt pinched it was more or less creased and we already addressed that issue(new line will be going in saturday)I have a fresh tank of gas with octane booster in it but will look into the seafoam... Should I attempt to adjust the pressure myself of should it go to a expert...if I do it myself Im thinking with the bike running I adjust the screw until desired pressure or do I have it all wrong? could you guys revisit the spark pug type and gap with me cause I may have fockerd that up with the new plug ... again guy thanks for the replies...also johnny cheese is this the same guy in Austin TX? I think I saw a thread that mentioned him...

lastley when my tuner tuned the bike he did a mix of 93/116 and said just to run the 93 and I will be fine if thats the case why not jsut tune it wit 93 why the mix....again thanks I appreciate the help!! many thanks!

 

[cdhoroho]

you can adjust the FP with the bike off just turning it on and off to prime the system
or while running (doesnt matter that much except being down a pound or 2 when running)

he should have tuned it on just the pump but you should be fine if not runnimg it im top end type of riding

the plugs should be ngk cr9e gapped to .018-.020

 

[Busatroop]

thanks CD I'll dig into on saturday let you guys know

 

[rocketgeezer]

If you bike has sat for a year and a half its most likely got fuel deposits somewhere tank, filter, injectors, I would start with a fresh fuel filter, new plugs and tank of fresh gas (pump 93) it will run better on the street with pump in it anyhow, also your FMU could be gummed up may just need dis, and clean up, if shim is bent, rebuild kit from bell is about $30 I think,.... also do you have a restrictor or a check valve in the boost line to the FMU?

 

[Busatroop]

ok guys I have replaced the plugs,inline fuel filter, fresh gas and everything with no luck still getting some studder and the fuel pressure bounces around cant keep it steady, also not to mention now I have some over heating issues(damn its hot here in texas) now the painter had the bike apart Im wondering if a vacum line or something got over looked and didnt get hooked up and unfortuneatly do not know what line should go where etc..I know I did the intial install a few years ago took it to a tuner had him look it over tune etc with no issues but now Im at the point of blowing it up..

anyway anyone have a detail instuction on this set up so maybe I can see if there is something wrong...other wise I take it to Johnny Cheese as soon as I get ahold of him..

 

[Mr Bogus]

fuel pressure is unstable? what kind of regulator is on it? if the pressure is always good and surging to "too high" then regulator is likely hung up.. if it is "below normal" it could be the regulator or a pump..

If the regulator is sticking shut, it could as easily get stuck in the "open" mode... much worse..

 

[Busatroop]

brother I wish I new I bought the kit used a few years ago and went with it. I know the fmu is silver and from my recolection there is no writting on it...man this is getting to be a headache..lol

weird thing is before I went to Iraq other then some over heating this thing ran just fine wasnt until I got back that I started having issues,,,

 

[cdhoroho]

sounds as though the fmu is causing you problems
if you can afford it id upgrade to secondaries
if not then a new thicker shim would help the issue a bit (that and a retune)
the overheating issue is possibly due to needing a different mixture of coolant (that and a possible fan switch relocator)
do you have an intercooler? if so then that will cause it to have the overheating issue

 

[02spool]

Did you check the adjustment on the fmu(pressure),the thumbnail adjuster? Mine was knocked full shut by my tuner,had same problem. Should be adjusted between a half turn to one turn out from closed. Mine is around a half turn out from closed but also depends where it was when it was tuned. All the way closed is max pressure, you want it at 41to43 psi at idle goodluck

 

[Busatroop]

thanks for that I'll give it a go..

 

[Busatroop]

sounds as though the fmu is causing you problems
if you can afford it id upgrade to secondaries
if not then a new thicker shim would help the issue a bit (that and a retune)
the overheating issue is possibly due to needing a different mixture of coolant (that and a possible fan switch relocator)
do you have an intercooler? if so then that will cause it to have the overheating issue

no intercooler...and Im begining to agree that the fmu is my issue ..I think its out of wack for sure....