I synched throttle bodies , checked fuel system and replaced whole pump and regulator had too much fuel pressure and corrected that . New injectors and spark plugs . Adjusted tps sensor bike still runs the same . Checked vacuum lines . At idle tachometer will go up and down a couple hundred rpms sparriticly nit theres i can tell it's doing it by listening only by watching gauge. Also replaced coils today . Only thing I havent done that the manual suggests is check valve clearance. Bike has 22,000 miles
Inconsistent idle and low idle stuttering
- Thread starter Sparky405
- Start date
Berlin Germany
Registered
what model?
stuttering? a feel of accelerating and slowering in seconds when rolling at one/same speed?
at all models:
did you check the sprocket drum in the rear wheel if it is loosened or tight? loosen? 2-3 mm turnable when sticked into wheel? replace dampers.
did you give 3-5 mm space in the throttle cable? none or less than 3mm it is too tight - same feeling.
_______________
and how ever
pls check valves - you are in a real hurry with that
usually every ~15,000 mi
stuttering? a feel of accelerating and slowering in seconds when rolling at one/same speed?
at all models:
did you check the sprocket drum in the rear wheel if it is loosened or tight? loosen? 2-3 mm turnable when sticked into wheel? replace dampers.
did you give 3-5 mm space in the throttle cable? none or less than 3mm it is too tight - same feeling.
_______________
and how ever
pls check valves - you are in a real hurry with that
usually every ~15,000 mi
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I've got a 2005 (12,000km) with the same symptoms. I'm going to assume you have a Gen 1 too. Given my bike's getting old, I've replaced a whole bunch of stuff (vac lines, fuel pump, filter, injectors, boost/MAP, and more recently the CKP/Stator). I also replaced the TPS and set it correctly. Despite all this, and even after throttle body sync, the idle/low RPM running remains lumpy. After reading a bunch of threads on the issue, it actually seems pretty normal for a lot of these Gen 1 bikes, some of which are more than two decades old. So my advice is to not worry about it. Gen 1's are old school, raw bikes and they seem to run lumpy under 3000rpm. Keep putting good quality oil and fuel in it, and from time to time let it have an Italian tune.
EDIT: Oh, as for valves - I've learnt over the years to not worry about them. Sure, it's good for that glowing piece of mind of "gee, they're in spec", which on big Suzuki's they invariably are 99% of the time. But it's your call.
EDIT: Oh, as for valves - I've learnt over the years to not worry about them. Sure, it's good for that glowing piece of mind of "gee, they're in spec", which on big Suzuki's they invariably are 99% of the time. But it's your call.
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Kiwi Rider
Registered
I'm pretty sure the issue is at idle rpm, is what he's attempting to correct, not while its under load in gear, at speed.
Yes had injectors cleaned and tested ultrasonic
Gen 2's are definitely smoother. They have more advanced electrics, primary and secondary injectors, primary and secondary throttle bodies, etc. Gen 1's are raw, unbridled, even quite basic by today's standards. They're long in the tooth and most examples I've seen are as rough as guts. I love 'em.
I raise the rpm or let it idle the needle isn't steady. Today I re synched throttle bodies as close as I can with my cheap vacuum gauges and it seems like it helped a little
Vanishing Point
Registered
My first Q exact year from your busa
Yup, behaves EXACTLY the same as mine. I even have a spare ECU that I swapped and it made no difference. I know my vacuum is good, so it's not a leak. One thing I'm checking on mine today is the TPS connection (where it fits against the throttle body). I have heard that it can get loose from wear and tear and move around causing the TPS signal to waiver, which causes idle to move around and influence low RPM running, including rev hang. Once I look into that I'll post my findings.
Same here I replaced vacuum hoses
Berlin Germany
Registered
loooooooooong hmmmmmmmmmmmmmmmm
you remember that the busa is no V8 /10 /12 ?
the two sounds i heard seem to me as normal and usual - for a genI.
genII´s exact sound i don´t remember in this moment - sorry. ;-)
yes at the genI the iddle jumps/varies a very little bit in a (feeled) dimension of i guess ~50 rpm´s or so - I personally never cared about it - I always accepted it as normal.
valve clearance set to max
throttles synchronized as fine as possible
and i have built the most precise synchronizer - completely from parts from the hardware store around the corner.
even the most expensive measuring instruments cannot be more precise,
because the physics alone works on my equipment.
the instruments in the purchased ones always have springs and therefore inevitable tolerances .
the only problem will rise if you have put the throttle-group into thousands pieces.
to synchronize after reassembling you need the "clock" instruments to achieve a basic setting , because my "big thing" gets rid of its fluid (motor oil) to one cylinder faster than youn stop the motor by the red switch.
so only ! use my tool after this basic setting !
I cannot say how the Carbtune will react to massively unsynchronized throttle valves - sorry - never used them before.
see this pic of my ~35" long "big thing"
and if you want you can get the carbtune as the alternative to my big thing
vantage - small in size and by that really easy to transport
it works on the same physical basis as mine above.
what i´m thinking about is to replace the X-screws by alen-screws
their advantage i guess should be that you need zero downforce to turn them contrary to the X-screws - ergo you have not to put any pressure onto for grip with your X-screwdriver (Philips).
even if you use this (highly recommended) "Vessel" X-screwdrivers who are built for the "JIS" - standard screws.
next time i have to syncho i will replace the screws (x to alen) before - promised ;-)
you remember that the busa is no V8 /10 /12 ?
the two sounds i heard seem to me as normal and usual - for a genI.
genII´s exact sound i don´t remember in this moment - sorry. ;-)
yes at the genI the iddle jumps/varies a very little bit in a (feeled) dimension of i guess ~50 rpm´s or so - I personally never cared about it - I always accepted it as normal.
valve clearance set to max
throttles synchronized as fine as possible
and i have built the most precise synchronizer - completely from parts from the hardware store around the corner.
even the most expensive measuring instruments cannot be more precise,
because the physics alone works on my equipment.
the instruments in the purchased ones always have springs and therefore inevitable tolerances .
the only problem will rise if you have put the throttle-group into thousands pieces.
to synchronize after reassembling you need the "clock" instruments to achieve a basic setting , because my "big thing" gets rid of its fluid (motor oil) to one cylinder faster than youn stop the motor by the red switch.
so only ! use my tool after this basic setting !
I cannot say how the Carbtune will react to massively unsynchronized throttle valves - sorry - never used them before.
see this pic of my ~35" long "big thing"
and if you want you can get the carbtune as the alternative to my big thing
vantage - small in size and by that really easy to transport
it works on the same physical basis as mine above.
what i´m thinking about is to replace the X-screws by alen-screws
their advantage i guess should be that you need zero downforce to turn them contrary to the X-screws - ergo you have not to put any pressure onto for grip with your X-screwdriver (Philips).
even if you use this (highly recommended) "Vessel" X-screwdrivers who are built for the "JIS" - standard screws.
next time i have to syncho i will replace the screws (x to alen) before - promised ;-)
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