Technical Discussion Topics related to Technical Issues

carb issues, maybe its in my head

Thread Tools
 
Search this Thread
 
Old 08-16-2010, 08:12 AM
  #1  
Senior Member
SuperBike
Thread Starter
 
uchi's Avatar
 
Join Date: Aug 2009
Location: thorold ontario
Posts: 1,978
uchi is on a distinguished road
carb issues, maybe its in my head

i went riding with some people the other week, and one of them is an older guy who used to do alot of racing, built motors, and knows carbs better than anyone ive met. ive asked people about him and everyone praises his work and his knowledge so we got to talking. i knew my bike was running a little off and after he took it for a ride and then rode behind me he knew she was running rich. the gurgling and occasional hesitation showed her to be running too fat and he said behind me all he could smell was gas. so he offered to help me out by taking a look at her and syncing the carbs. now i was under the impression my carbs were synced by my buddy who had been messing with them for me. turns out they werent. they needed a full turn on the sync screw to run right. on top of that we yanked the plugs and both were black and looked wet. so we ended up taking out the needles and removed the shims. all 5 of them. left the clip in the 5th position for now.

now the bike runs 100 times smoother. i only rode it last night put about 50 km on it, but shes noticeably smoother and even sounds better, not as deep and gurgly but more angry and happy to be abused kind of sound. i cant describe it, but its different and sounds like its running better. the thing runs so much smoother now, it doesnt seem to want to surge at all at lower rpms, but again i havent tested it for more than an evening so maybe im getting ahead of myself on it. but it seems to me as if shes lacking a little power over 8000 rpm. she felt slower to hit redline in 4th gear than usual. when i talked to the guy about it he said its possible that things were so carboned up in the motor that she was just cleaning herself out. hell the carbs had carbon in them that we wiped out carefully when we had them off. also i was thinking it may be carboned up from the track day, i found after each session she wouldnt idle and would stall when i i let off the throttle and clutched in. likely from running too rich as the plugs showed. so the point of this post, well there is no point, i think its just in a my head and once i give her a good day of hard running she'll clear up and get back on pace, but im looking for other opinions on this matter?

also im not sure why my buddy had put 5 fuken shims on the needles. the only thing i noticed is that with the shims out she pops a little when i close the throttle but when i get back on it again theres no hesitation at all. so im thinking maybe he didnt sync the carbs and was compensating for that with extra fuel thinking it was running lean
uchi is offline  
Old 08-16-2010, 08:21 AM
  #2  
Out of my mind, back in 5
MotoGP
 
Tweety's Avatar
 
Join Date: Nov 2006
Location: Skurup, Sweden
Posts: 6,109
Tweety is on a distinguished road
That sounds like IL4 guy vs V-twin guy (or allround at the very least)... Classic difference...

And the less noticable "hit" up top is most likely the deceptive way the VTR makes power if it's running right or close to right... There is just as much power, it's just that the fat midrange masks it...

On the other hand... It might be that once you have cleared out the carbon deposits, you might end up putting one of those shims back... But no effin way is there supposed to be five in there... Then you are definetly compensating for something else, and should start over to get the whole chain right to begin with...
Tweety is offline  
Old 08-16-2010, 08:52 AM
  #3  
Remember stock is BAD!
SuperSport
SuperSport
 
divingindaytona's Avatar
 
Join Date: Jun 2004
Location: Jacksonville FL
Posts: 760
divingindaytona is an unknown quantity at this point
Not good. I would say keep your friend far away from you bike.

Buy a service manual and do it yourself thats the only way to make sure it was done correctly.
divingindaytona is offline  
Old 08-16-2010, 10:29 AM
  #4  
Banned
MotoGP
 
8541Hawk's Avatar
 
Join Date: Aug 2007
Location: Lake View Terrace, CA
Posts: 5,942
8541Hawk will become famous soon enough
5 shims, really was that on each needle or all together? Then again I do think most folks run these bikes a bit too rich on the top.
8541Hawk is offline  
Old 08-16-2010, 11:15 AM
  #5  
Senior Member
MotoGP
 
VTRsurfer's Avatar
 
Join Date: May 2008
Location: San Clemente, CA
Posts: 3,451
VTRsurfer is on a distinguished road
Originally Posted by 8541Hawk
5 shims, really was that on each needle or all together? Then again I do think most folks run these bikes a bit too rich on the top.
It seems at that point the needles wouldn't even be functioning, since they'd probably be lifted just about all the way out of the jets.

I argee with Daytona.
VTRsurfer is offline  
Old 08-16-2010, 11:28 AM
  #6  
Senior Member
SuperBike
Thread Starter
 
uchi's Avatar
 
Join Date: Aug 2009
Location: thorold ontario
Posts: 1,978
uchi is on a distinguished road
yeah 5 shims per needle. the guy who just synced the carbs, bill, has made the bike run better than its ever run. when the jet kit was put in originally it ran crappy but the guy wasnt a carb guy, then my other buddy korry set them up 3 times, each time we ran into a snag, the proper pilots werent in my jet kit so we had to order them, and then we had other issues. and now this is the 5th time the carbs have been touched and the bike runs alot better. i need to run it in the daytime to be sure and really get a good ride in on it but last night it felt better than before. maybe it picked up a little mid range and the top end feels like its lost a bit of power as tweety said. i remember reading on here somewhere that you cant really trust the spark plugs too much for an accurate assessment of how the bike is running, any truth to that? or can we safely rely on plugs when i yank them again in a couple days to check their color?
uchi is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
quillinsmat
Technical Discussion
11
09-12-2014 09:01 PM
Renderw
Technical Discussion
17
07-01-2013 08:03 PM
eersfanpilot
Technical Discussion
17
05-18-2012 06:26 PM
MisfitToy
RANT!
2
06-30-2008 12:27 PM
Scumbag
General Discussion
15
09-26-2007 07:27 PM



Quick Reply: carb issues, maybe its in my head



All times are GMT -7. The time now is 06:59 AM.