Twin Cam 88 HSR42 issue
#1
Twin Cam 88 HSR42 issue
Hey,
So I have recently installed a HSR42 on my 04 wide glide. The issue I am having is that I can get it to run and idle rather easily (following the tuning guide).
The reason for my first post on this forum is that it feels like it stutters or coughs at cruising speeds. It isn't constant and not consistent.
I am mainly looking for a kind of check list or guidance on what I should do next.
HSR42 settings
Pilot: 25
Main: 160
Pilot air screw: 2.5 turns out from seated
So I have recently installed a HSR42 on my 04 wide glide. The issue I am having is that I can get it to run and idle rather easily (following the tuning guide).
The reason for my first post on this forum is that it feels like it stutters or coughs at cruising speeds. It isn't constant and not consistent.
I am mainly looking for a kind of check list or guidance on what I should do next.
HSR42 settings
Pilot: 25
Main: 160
Pilot air screw: 2.5 turns out from seated
#2
Is it a stock 88" or is there any performance mods done to the engine?
25 idle jet might be too big, I have 20 on my 95" Dyna and it does not run lean. Also the accelerator pump jet is usually too big, I changed from 70 to 50.
None of this should cause stuttering during constant speed though. Make sure there are no intake seal leaks, or exhaust leaks.
It could also be a clogged fuel filter, or even the tank ventilation. The latter one can be checked by opening the fuel cap while driving, if the stutter goes away you have a clogged tank vent.
25 idle jet might be too big, I have 20 on my 95" Dyna and it does not run lean. Also the accelerator pump jet is usually too big, I changed from 70 to 50.
None of this should cause stuttering during constant speed though. Make sure there are no intake seal leaks, or exhaust leaks.
It could also be a clogged fuel filter, or even the tank ventilation. The latter one can be checked by opening the fuel cap while driving, if the stutter goes away you have a clogged tank vent.
#4
So Checked my seals and gaskets and they aren't leaking at all. Checked tank ventilation system with the test ride below. Didn't change anything with cap open or not.
Finally got to test ride the bike and re-tune it as the weather has been dreadful as of late. I took my screwdrivers with me to adjust the fuel accelerator pump and air mixture screw. Got it to operating temp and pulled over. Adjusted the accelerator pump screw #1 to come on slightly sooner. Bike was running a lot better but not 110%. 2nd time pulling over I screwed the air mixture screw 1/4 of a turn in making it richer. PERFECT!
All I can say is.... read the tuning manual and bring your tools with you!
Thank you SwedishMeatball & TexasScooterTrash for the pointers!
Finally got to test ride the bike and re-tune it as the weather has been dreadful as of late. I took my screwdrivers with me to adjust the fuel accelerator pump and air mixture screw. Got it to operating temp and pulled over. Adjusted the accelerator pump screw #1 to come on slightly sooner. Bike was running a lot better but not 110%. 2nd time pulling over I screwed the air mixture screw 1/4 of a turn in making it richer. PERFECT!
All I can say is.... read the tuning manual and bring your tools with you!
Thank you SwedishMeatball & TexasScooterTrash for the pointers!
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TexasScooterTrash (06-10-2024)
#5
if it is neezing or coughing back through the carb at light throttle cruising, you have an issue with the needle in the slide. there are some things that can be done, go in throught the top pull out the needle and raise it one notch. once the needle is out you will see the eclip thatat sets it's position. you want to raise that position once installed, so place the clip on the next lower slot, then re-assemble and test ride. If that does not do it, you need to install the next richer neelde and try again. the needles have a number on them and the book descibes this process and the way to interpret what needle is what.
m
m
#6
Do one change at a time. Doing multiple "fixes" on carb work usually results in chasing your tail.
Not sure what altitude you are at but id say sea level to maybe 2000 feet elevation keep the default setting with the needle clip in the middle and confirm the needle size while there.
my suggestion is start with dropping that pilot jet to 20 or 22.5 as 25 is for sure too big for an 88
Not sure what altitude you are at but id say sea level to maybe 2000 feet elevation keep the default setting with the needle clip in the middle and confirm the needle size while there.
my suggestion is start with dropping that pilot jet to 20 or 22.5 as 25 is for sure too big for an 88
#7
Hey, sorry for not replying to this thread with an update as it as been too cold and wet to ride where I am. I haven't done anything with jets or needles as of yet. All I have done is adjust the idle and air fuel mixture screw. It is currently 1 1/4 turns out and idling correctly. Issue I have noticed is that it isn't warming up fast enough 1°c (34° F) and coughs. It is mostly me being impatient and wanting to ride.
I am going to adjust the needle clip as marcodarq first and give it a go. As it feels and sounds too lean.
It is also only 100 feet above sea level.
I am going to adjust the needle clip as marcodarq first and give it a go. As it feels and sounds too lean.
It is also only 100 feet above sea level.
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