Yamaha Rhino Forum

Mikuni hsr 45 runs terrible at cruise speed

This is a discussion on Mikuni hsr 45 runs terrible at cruise speed within the Engine forums, part of the Technical category; Anyone know where to adjust, 686 +1 valves stage two cam Have af guage jetting is good throughout, out of the box sudco carb bigger ...


Go Back   Yamaha Rhino Forum - Rhino Forums.net > Technical > Engine


Engine For discussion of engine performance, and maintenance

Reply
 
LinkBack Thread Tools Display Modes
  #1 (permalink)  
Old 08-12-2011, 11:30 AM
dlytlesh1's Avatar
Member
 
First Name: Dave
My Rhino: 2007 sport
Join Date: Dec 2007
Location: Ca.
Posts: 114
View dlytlesh1's Photo Gallery(0)
Mikuni hsr 45 runs terrible at cruise speed

Anyone know where to adjust, 686 +1 valves stage two cam

Have af guage jetting is good throughout, out of the box sudco carb bigger main, adjusted stock needle and stock pilot things just wont run at cruise speed like 1/4 throttle, is it a accelerator pump adjustment, need for a change in needle or pilot jet

As long as Im moving the throttle works good just can not cruise
__________________
sh1
Reply With Quote
Sponsored Links
RhinoForums.net is the premier Yamaha Rhino UTV/ATV Forum on the internet. Registered Users do not see these ads. Please Register - It's Free!
  #2 (permalink)  
Old 08-12-2011, 02:56 PM
dlytlesh1's Avatar
Member
 
First Name: Dave
My Rhino: 2007 sport
Join Date: Dec 2007
Location: Ca.
Posts: 114
View dlytlesh1's Photo Gallery(0)
Anybody?
__________________
sh1
Reply With Quote
  #3 (permalink)  
Old 08-12-2011, 03:34 PM
nvs2none's Avatar
Motorboatin' Sum
 
First Name: Donnie
My Rhino: 2006 Rhintax
Join Date: Nov 2008
Location: Eugene, Oregon
Posts: 2,582
View nvs2none's Photo Gallery(39)
Needle/main jet.

Try dropping your need down/or raising it up and see what happens.......

If you think it is rich lower the needle by raising the clip, or if you think it is lean raise the needle by lowering the clip...........
__________________
Reply With Quote
  #4 (permalink)  
Old 08-12-2011, 05:01 PM
dlytlesh1's Avatar
Member
 
First Name: Dave
My Rhino: 2007 sport
Join Date: Dec 2007
Location: Ca.
Posts: 114
View dlytlesh1's Photo Gallery(0)
Ifit was a 2 stroke, Id have this dialed in in a second, these rhinos with the 45 carb is a pain..ive ran the needle up and down no change..Im thinking it might be the size of needle that came with it. But Im guessing...
__________________
sh1
Reply With Quote
  #5 (permalink)  
Old 08-12-2011, 09:45 PM
Site Supporter
Premium Member
 
First Name: Court
My Rhino: 06/SE x 2
Join Date: Feb 2007
Location: Anthem, AZ
Posts: 3,698
View AZCourt's Photo Gallery(0)
What does the air fuel meter say when its running crappy at cruise?
Reply With Quote
  #6 (permalink)  
Old 08-12-2011, 10:49 PM
nvs2none's Avatar
Motorboatin' Sum
 
First Name: Donnie
My Rhino: 2006 Rhintax
Join Date: Nov 2008
Location: Eugene, Oregon
Posts: 2,582
View nvs2none's Photo Gallery(39)
It may need a different tapor needle. Call Chris at benchmark........I have been down this road with a hsr48. The first part of the tapor on the need is too large causing it to run lean in thatt throttle position. The best way to get it dialed is get a wideband......
__________________
Reply With Quote
  #7 (permalink)  
Old 08-12-2011, 11:56 PM
dlytlesh1's Avatar
Member
 
First Name: Dave
My Rhino: 2007 sport
Join Date: Dec 2007
Location: Ca.
Posts: 114
View dlytlesh1's Photo Gallery(0)
Azcourt it reads fairly steady around 13

Nvs2none as far as the needle I read the tuning guide, found on this forum, and it mentio ed the size of the taper on the needle..when it sits slightly up, at part throtal, the biggining of the taper is just at the throat of the jet, but the manual says performance set ups ussually need a leaner needle..just seems backwards to me

Maybe ill call chris, I was just hopeing someone knew what setups are standard changes on a mikuni. Its fairly typical mods for a 686

The car works ok it just sucks if you want to cruise
__________________
sh1
Reply With Quote
  #8 (permalink)  
Old 08-13-2011, 09:02 AM
nvs2none's Avatar
Motorboatin' Sum
 
First Name: Donnie
My Rhino: 2006 Rhintax
Join Date: Nov 2008
Location: Eugene, Oregon
Posts: 2,582
View nvs2none's Photo Gallery(39)
Strange that your AFR reads around 13.................mine would go way lean at cruising and if I raised it up to help it would be fat at WOT. So I went to a smaller tapor.....but my AFR reflected that as well...............you may have a stator/ignition issue.
__________________
Reply With Quote
  #9 (permalink)  
Old 08-13-2011, 09:36 AM
rhinonut's Avatar
Camshaw is a giant Q-tip!!!
 
First Name: Jimmy
My Rhino: 07 4 seat SR1
Join Date: May 2008
Location: Flagstaff, AZ.
Posts: 6,839
View rhinonut's Photo Gallery(23)
Get the leanest needle, get the leanest accelerator pump nozzle and run it around 10.5-11 on A/F at idle with the a/f screw. Running it rich at idle will help make up for it running lean in mid range. Adjust your start scfrew on the accel pump so it activates at 1/4 throttle and stop screw at adjusted at 3/4-7/8 throttle. Start from idle and work your way up to the main jet with your adjustments. This is how I ran mine and ran perfect.
__________________
Reply With Quote
  #10 (permalink)  
Old 08-13-2011, 04:23 PM
dlytlesh1's Avatar
Member
 
First Name: Dave
My Rhino: 2007 sport
Join Date: Dec 2007
Location: Ca.
Posts: 114
View dlytlesh1's Photo Gallery(0)
Thanks thats what the guide said leaner needle, but I had no idea with all the accelerator pump adjustment etc...Ill try it..Im in the middle of going through the front end for Worcs in washington..I should have time at the race to tweak it
__________________
sh1
Reply With Quote
  #11 (permalink)  
Old 08-22-2011, 09:43 PM
Site Supporter
Premium Member
 
First Name: Court
My Rhino: 06/SE x 2
Join Date: Feb 2007
Location: Anthem, AZ
Posts: 3,698
View AZCourt's Photo Gallery(0)
I had to run the leanest needle with the 660, but with 686 and 693 motors I had to go back to the stock needle. I'll see if I can find my notes on the 45 and 686 combo.
Reply With Quote
  #12 (permalink)  
Old 08-23-2011, 12:08 AM
Member
 
Join Date: Aug 2011
Posts: 2
View computeruse20.0's Photo Gallery(0)
Ifit was a 2 stroke, Id have this dialed in in a second, these rhinos with the 45 carb is a pain..ive ran the needle up and down no change..Im thinking it might be the size of needle that came with it. But Im guessing...
__________________
rims
Reply With Quote
  #13 (permalink)  
Old 08-23-2011, 09:34 AM
dlytlesh1's Avatar
Member
 
First Name: Dave
My Rhino: 2007 sport
Join Date: Dec 2007
Location: Ca.
Posts: 114
View dlytlesh1's Photo Gallery(0)
Just got back from washington for thw Worcs race at 100-300 feet, my home is around 1200. I adjusted the fuel pump start and stop like rhinonut said and it ran the best itever had. Dont know if itwas the adjustment or the low altitude, I will run ithere at home and see if it goes to crapagain..

Court I would be interested to hear what you had
__________________
sh1
Reply With Quote
  #14 (permalink)  
Old 08-23-2011, 03:32 PM
rhinonut's Avatar
Camshaw is a giant Q-tip!!!
 
First Name: Jimmy
My Rhino: 07 4 seat SR1
Join Date: May 2008
Location: Flagstaff, AZ.
Posts: 6,839
View rhinonut's Photo Gallery(23)
Quote: Originally Posted by dlytlesh1 View Post
Just got back from washington for thw Worcs race at 100-300 feet, my home is around 1200. I adjusted the fuel pump start and stop like rhinonut said and it ran the best itever had. Dont know if itwas the adjustment or the low altitude, I will run ithere at home and see if it goes to crapagain..

Court I would be interested to hear what you had
Glad it sounds like it worked. Did you get the lean accel pump nozzle as well?
__________________
Reply With Quote
Reply

Lower Navigation
Go Back   Yamaha Rhino Forum - Rhino Forums.net > Technical > Engine


Search tags for this page

686 hsr carb

,

686 rhino hsr45 jet sizes

,
how to tune a 45mm hsr on a 686 rhino
,
makuni hsr 45 on rhino
,
max cruising speed on 2007 rhino
,

mikuni 45 tuning

,

mikuni hsr 45 pilot jet

,
mikuni hsr 45 se stage 1
,
mikuni hsr carb on a 2stroke
,

mikuni hsr running rich at idle

,

mikuni hsr45 manual

,

mikuni hsr45 performance

,

mukini hsr 45 main jet for rhino

,
need air filter for mikuni 45mm hsr on a rhino
,

rhino mikuni 45

Click on a term to search our sites for related topics.

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -7. The time now is 04:06 AM.


Copyright 2008 BrianSquared LLC