07 Blubbers at 1/4-mid throttle ??


17 replies to this topic
  • yam314

Posted July 17, 2009 - 01:18 PM

#1

I live in Houston-Sea level and around 100 deg F and I have an 07 450 that used to run perfect. Now it will blubber,as if it is rich, at 1/4 to mid throttle.
I have owned this bike for a couple of years,and I am using the same jetting
that I normally use for this time of year.

Main-160 (I went down from my winter jetting of 165-170)
Pilot-40 ( I had a 45,then a 42 in it previously)
Dropped my needle from 4'th clip from the top to 2'nd clip from the top.
Adj fuel screw has been tried at all positions.

Everything else is stock w/ Pro Curcuit pipe (I also tried the stock pipe as well)
No matter what I try, it doesn't seem to make much difference. I am going to try and disconnect the TPS and see if that makes a difference. I also have an 08 450 that runs great with the aforementioned jetting.Any ideas?
And YES, I have looked at all of the sticky threads on jetting,and they are all pretty much the same as what I am running.The carb has been gone thru twice,filter is clean,and there is no leaks in the exhaust.
The wierd thing is,that since I no longer ride this bike,my Son does,it has developed this problem.When I had it,the thing ran perfect!

Thanks,
Jeff

  • mjw1

Posted July 17, 2009 - 02:27 PM

#2

Does it do it more when it is cold or hot if it does it more when cold than hot than you are to lean move the clip on the needle to the 3rd groove from the top.

  • yam314

Posted July 17, 2009 - 02:51 PM

#3

It has been running great over the winter with the 168 main,45 pilot,4'th clip on needle,and fuel screw 2 turns. Now the weather is 100 degrees,it is running bad.

I just removed the TPS,and I think that made it better. The neighbors are starting to get annoyed,and it's fixing to rain(thank goodness!),so I will try it out some more tomorrow.

  • grayracer513

Posted July 17, 2009 - 03:22 PM

#4

How's your air filter?

  • yam314

Posted July 17, 2009 - 04:52 PM

#5

Perfectly clean Uni

  • grayracer513

Posted July 17, 2009 - 06:48 PM

#6

Did it start this on its own. or did you have the carb apart before it started acting up?

  • Troutman

Posted July 17, 2009 - 07:40 PM

#7

It has been running great over the winter with the 168 main,45 pilot,4'th clip on needle,and fuel screw 2 turns. Now the weather is 100 degrees,it is running bad.

I just removed the TPS,and I think that made it better. The neighbors are starting to get annoyed,and it's fixing to rain(thank goodness!),so I will try it out some more tomorrow.


This may be dumb question but where and how do you disconnect the TPS?

  • SC_Spode

Posted July 17, 2009 - 07:48 PM

#8

This may be dumb question but where and how do you disconnect the TPS?


Where - at the plug on the end of the pigtail coming from the carb.

How - you disconnect the pigtail from the the connector.

Look for the wire coming off the left side of the carb.

If you have a manual it will make it clear.

:worthy:

  • Troutman

Posted July 17, 2009 - 07:52 PM

#9

Where - at the plug on the end of the pigtail coming from the carb.

How - you disconnect the pigtail from the the connector.

Look for the wire coming off the left side of the carb.

If you have a manual it will make it clear.

:worthy:


Thank you, mine runs great but if I am going real slow it will blubber. I am going to try to disconnect the TPS to see if this helps.

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  • yam314

Posted July 18, 2009 - 05:30 AM

#10

Did it start this on its own. or did you have the carb apart before it started acting up?


I'm not really sure Gray.It pretty much began on it's own.I don't really ride the bike anymore since I gave it to my 14 yr old son-he just rides it.I noticed it running rough at a recent race he was in.As long as he was on the gas,it was ok.But coming out of corners,and when he was going slow thru the pits,was when it started running bad.

I adjusted the fuel screw at the track,but it did not make that much of a difference.When I got it home,I tore the carb down,replaced the pilot 45-42,and dropped the needle one clip.I have always had the TPS connected on both bikes,but I suppose it could have gone bad?

  • grayracer513

Posted July 18, 2009 - 07:44 AM

#11

There's limited reason to be suspicious of it in this case, but check the plate on the engine side of the slide. It should be in with the square side with the hole near the edge down, and there should be no cracks or pieces missing. Might as well look at it.

  • bigred455

Posted July 18, 2009 - 10:51 AM

#12

Also put the needle back to the 4th clip position Stock,even at sea level and warm temps the needle on the 07 works good. Your main could stand to come down to a 158,but that is not your problem.I have a 07 also,I live in South Jersey, very humid, sea level. The needle in the 4th clip is the ticket ,I have moved up and down just to see,and stock clip pos is best.That is a stock needle correct? How old is the gas also? I 2nd that. Make sure your slide is in the correct way!

Keith

  • yam314

Posted July 26, 2009 - 12:25 PM

#13

We went riding yesterday. Around 100 degrees,and the bike ran great since I disconnected the TPS! I suppose that somehow the TPS went whacko,but I don't really see any need to fix it or reconnect it now.

I don't really understand the slide issue. How could the carb function at all if the slide was installed incorrectly?

  • SC_Spode

Posted July 27, 2009 - 04:43 PM

#14

I don't really understand the slide issue. How could the carb function at all if the slide was installed incorrectly?


It's not the entire slide assembly - look at a fiche, I believe it's part #10 on the 2007 model. The piece gray is talking about can be installed upside-down and will cause some headaches for you until you figure out what is wrong.:banana:

It will run with it installed incorrectly... just not properly.

:worthy:

  • grayracer513

Posted July 27, 2009 - 07:18 PM

#15

Inverting the spring plate on the slide affects the "cut away" of the slide assembly. If you've had round slide carbs open before, you'll remember seeing that the (atmosphere) side of the slide is cut out a bit. The amount of this cutout affects the way air flows over the main fuel discharge nozzle while the slide is opened less than about 1/4 throttle. If the plate on an FCR gets flipped over, it causes an excessively rich condition from off idle to around a quarter, which will then clear up at heavier throttle openings, as if there were nothing wrong.

  • ben_suhard

Posted July 27, 2009 - 08:05 PM

#16

Maybe not worth mentioning, but just thought I'd ask about the hot start lever, cable, and plunger; it's not letting extra air in? I assume it's working properly seeing that you've had the carb apart and cleaned already.

  • yam314

Posted July 28, 2009 - 07:14 AM

#17

I never took the slide all the way out-just the needle.The HotStart was working fine.
It runs great now w/ the TPS dis-connected.(But it used to run great in the past w/ it connected).
I have had this bike for 2 yrs now.

  • mjw1

Posted July 28, 2009 - 02:31 PM

#18

My TPS went out on my bike about 4 years ago and it wouldn't run good at low rpms but would at high rpms so i diconnected the TPS and have not had a problem yet.





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