<
 
 
 
 
>
hide You are viewing an archived web page collected at the request of Road Star Clinic using Archive-It. This page was captured on 05:48:25 Feb 24, 2018, and is part of the Road Star Clinic Closure collection. The information on this web page may be out of date. See All versions of this archived page. Loading media information

This is an archived version of the Road Star Clinic. The Road Star Clinic can now be found at www.roadstarclinic.com. Please join us there!

Road Star Forum
Welcome, Guest
Please Login or Register.    Lost Password?
Re:coughing just off idle
Go to bottom Post Reply Favoured: 0
TOPIC: Re:coughing just off idle
#850143
Curt (Moderator)
Never to old to ride!
Moderator
Posts: 22378
graph
User Offline Click here to see the profile of this user
Gender: Male curt.switzer@outlook.com Location: The Colony, Texas Birthdate: 1943-11-24
Re:coughing just off idle 3 Years, 1 Month ago  
Click my site link and then select the "Projects Button" on the second page is a picture of how I set my float level on my stock carb before I went to the HSR.
 
Logged Logged  
 
  The administrator has disabled public write access.
#850149
davej (User)
Platinum Boarder
Posts: 18167
graphgraph
User Offline Click here to see the profile of this user
Gender: Male Location: Toledo Ohio Birthdate: 1957-00-00
Re:coughing just off idle 3 Years, 1 Month ago  
Here is a link from another thread discussion going on right now. It is just another way to set the float. I did mine like in this link with the ruler and it has worked great for me. Curts way also works well. BTW I seen where you said the correct size of your main jet is 67.5??? I don't think that is possible it is a 167.5 unless it is some brand that none of us have ever heard of.


http://roadstarclinic.com/component/option,com_fireboard/Itemid,187/func,view/id,41213/catid,12/#41140
 
Logged Logged  
 
dave
  The administrator has disabled public write access.
#850153
LuckyDon (User)
Platinum Boarder
Posts: 2127
graphgraph
User Offline Click here to see the profile of this user
Gender: Male Location: Guerneville, CA
Re:coughing just off idle 3 Years, 1 Month ago  
What elevation are you at? Very important.

Colorado???
 
Logged Logged  
  The administrator has disabled public write access.
#850156
SKWEARpeg (User)
Platinum Boarder
Posts: 12885
graphgraph
User Offline Click here to see the profile of this user
Gender: Male Location: Milton, Florida Birthdate: 1958-00-00
Re:coughing just off idle 3 Years, 1 Month ago  
LuckyDon wrote:
What elevation are you at? Very important.

Colorado???


Elevation, is not a problem for the stock CV carbs. It'll work as well at sea level, as it does a mile high. The slide, works off the pressure differential, between outside atmosphere, and the venturi in the throat.
Yamaha jets them all the same, regardless of where they're sold.

Now, if you go to an HSR, then you have to start messing with the jetting, depending on elevation.
 
Logged Logged  
 
Last Edit: 2015/01/16 11:39 By SKWEARpeg.
 
  The administrator has disabled public write access.
#850157
Agpilot (User)
Platinum Boarder
Posts: 1568
graphgraph
User Offline Click here to see the profile of this user
Re:coughing just off idle 3 Years, 1 Month ago  
LuckyDon wrote:
What elevation are you at? Very important.

Colorado???
Really?? I thought you all knew by now that you don't jet a CV carb for elevation?
 
Logged Logged  
  The administrator has disabled public write access.
#850158
Tykes_Place (User)
Platinum Boarder
Posts: 3341
graphgraph
User Offline Click here to see the profile of this user
Gender: Male tykesplace Tykesplace Location: Helena, MT
Re:coughing just off idle 3 Years, 1 Month ago  
One thing that I was experiencing was roughness and grit between the accelerator pump and the cam. When I rolled the throttle the cam wasn't sliding freely to push the plunger down. So it acted like the pump was stuck. I took it apart and cleaned it really well. Polished the cam and plunger tip with my Dremel and plastic polish. Then coated with a bit of lithium grease. The cam moves smoothly now.
 
Logged Logged  
 
  The administrator has disabled public write access.
#850164
Rocketman (User)
Fresh Boarder
Posts: 9
graphgraph
User Offline Click here to see the profile of this user
Gender: Male Location: Fort Worth Texas Birthdate: 1958-12-03
Re:coughing just off idle 3 Years, 1 Month ago  
yes sorry keep screwing that up it's 167.5 Thank you.
 
Logged Logged  
  The administrator has disabled public write access.
#850165
Rocketman (User)
Fresh Boarder
Posts: 9
graphgraph
User Offline Click here to see the profile of this user
Gender: Male Location: Fort Worth Texas Birthdate: 1958-12-03
Re:coughing just off idle 3 Years, 1 Month ago  
Texas Fort Worth
 
Logged Logged  
  The administrator has disabled public write access.
#850175
scottw (User)
Platinum Boarder
Posts: 2590
graphgraph
User Offline Click here to see the profile of this user
aRe:coughing just off idle 3 Years, 1 Month ago  
Rocketman wrote:
Hello guys; I have a 2006 Road Star 1700 that I put exhaust on and a BAK, Dyna 3000, ported intake, Barons jet kit with 67.5 main jet, a Dyno Jet 37.5 pilot needle, PMS 1 turn, idle at 910, Barons needle on the 4th groove. The bike runs 100% better than before I did all the performance mods, and it is perfect with one hiccup or cough so to speak. When I come to a 90 degree turn (like a city street corner) and make the turn and get back on the gas the bike will cough. Or sometime when I am starting from a dead stop it will cough. This is intermittent doesn't do it every time and usually only after is full y warmed up. There is no popping through the exhaust at all, and other than this the bike is running great. When I blip the throttle it does not cough, and I have looked at the squirt when I blip the throttle and it looks like it is squirting when the throttle blade starts to open, but it is kind of hard to tell when the bike is running, can this be checked when the motor is off? My question is do you think it might the accelerator pump timing and or duration? or maybe the needle needs to be moved up a groove (3rd)? if it's the pump I haven't seen how to adjust the timing screw. I have seen that most people swap the nut on the Duration screw to the bottom side of the bracket and adjust the screw all the way down to get the least amount of duration they can. But I haven't seen anything on the timing screw. Thank you for any advise or input you guys might give.
====================

GUYS,1ST THINGS 1ST!!!!! /LOL!!!!!!

The OP said the motors running fine accept for having a pop back thru carb once in a while when applying throttle coming off idle or when hitting throttle at low speed and thats it.

So with that in mind when having an off idle carb cough/pop back thru carb coming off idle you " should not go into changing pilot jets " etc right off the bat before 1st ensuring the following are working and or adjusted properly which were specifically designed to reduce or stop off idle stumble when applying throttle!

* ENSURE ACCELL PUMP IS WORKING WHEN YOU MOVE THROTTLE & FIX IF NOT WORKING.

* ENSURE THE ACCELL PUMP STARTS TO SQUIRT FUEL THE SAME EXACT MOMENT THE THROTTLE PLATE
STARTS MOVING WHERE YOU TWIST THE THROTTLE AND IF NOT ADJ TO OBTAIN THAT.

* ALSO MUST ENSURE IDLE SPEED 900-950RPM PER YAMAHA SPEC WHICH MANY GUYS HAVE SET TOO LOW WHICH
IS AN ISSUE FOR A LRG CARB'D V-TWIN COMING OFF IDLE ADDING TO POPPING BACK THRU CARB ISSUE TOO.

* WITH MOTOR WARMED UP AT PROPER 900-950RPM IDLE SPEED ADJ PMS SCREW FOR BEST HIGHEST/SMOOTHEST IDLE SPEED.

* ENSURE PLUGS ARE IN GOOD COND & GAPED PROPERLY TOO.

* ENSURE THE PLASTIC END CAPS ON PLUG WIRES ARE ALL TIGHT WHICH IS AN ISSUE AT TIMES ON R*.

* ENSURE AIR AND FUEL FILTERS ARE BOTH CLEAN & IN GOOD COND NOT NEEDING TO BE CHANGED.

Its only after you ensure all the above is done as i suggested that if the motor still spits back fairly often when coming off idle when applying throttle at lower engine speed thats when you should get into recalibrating carb via pilot jet,etc and not the 1st thing you.

Yes you can fatten up lower end more with dif pilot ETC to fix off idle stumble but doing that feeds the motor with additional fuel all the time WHICH it may not need .

Doing that over time/miles equates to more fuel used that's maybe not required costing more if the off idle stumble is really caused by improper acceL pump adj or if its not working along with too low of an idle speed & too lean pms setting etc.

And another thing to keep in mind even when you have the carb dialed in properly that these lrg carbed v-twin motors will still spit back at you once in a while so if your chasing a A couple spit backs thru the carb in a 6-8hr day of riding i'd say that's not bad at all and to no go nuts trying to chase that down.

Scott
 
Logged Logged  
 
Last Edit: 2015/01/16 12:39 By scottw.
  The administrator has disabled public write access.
#850177
davej (User)
Platinum Boarder
Posts: 18167
graphgraph
User Offline Click here to see the profile of this user
Gender: Male Location: Toledo Ohio Birthdate: 1957-00-00
Re:coughing just off idle 3 Years, 1 Month ago  
Scott first things first, I believe he said he has checked the squirt on the acc pump and it appeared good. 2nd as we all know he has the wrong main jet in it for a 1700!!! He also said the idle is at 910. I don't understand your theory of trying to fix something else knowing that the main jet is wrong to start with. With that he will be running lean as the needle lifts regardless of the things you mentioned. So why not get to the proper main jet size "first" and then work on any remaining issues if one is still present???? I can also say that if mine give a couple of spit backs in a days ride I would be in the carb to find out what is wrong. See mine don't do that. I can even blip mine all day long and unless I blip it about 15-20 times in a row in about 30 seconds time it won't spit at all.


With that I believe the advice given prior to your post is solid proper advice.
 
Logged Logged  
 
Last Edit: 2015/01/16 13:27 By davej.
 
dave
  The administrator has disabled public write access.
Go to top Post Reply
Powered by FireBoardget the latest posts directly to your desktop
...................................................................... ...................................................................... ...................................................................... ...................................................................... ...................................................................... ...................................................................... ...................................................................... ...................................................................... ...................................................................... -->
New Forum Posts


The Road Star Clinic is a collaborative community of riders who archive and publish user contributed technical data about Yamaha Road Star motorcycles.

Copyright 2003-2007 Road Star Clinic and its respective authors.
<-- -->