Broken Carb Cast problem?

[Nate01]

After picking up my 03' RX this year...I pulled the carbs and cleaned jets/pilots but never pulled the tops apart....upon installing my ECP kit the other night....come to notice that #2 carb has a peice of the cast broken off on the backside where the little o-ring would originally be...that is completly missing so im guessing the the top would not seal properly....also found the #4 carb was missing the spring??? I installed the kit (filters/jets) and put all 4 spring in and adjusted as needed....sleds idles even better now and the throttle response is alot more crisp...thing is that it ran GREAT before and idle perfect after the cleaning...? WHen I cleaned the plugs they read perfect so it didnt seem to afect the sled at all....whoever had the carbs apart from the last ownership def dropped the rack and and forgot one spring...surprised I didnt have more problems...my question would be what it the purpose of the little o-ring and can I continue to run the sled the way it is...?

 

[LazyBastard]

The carb slide is vacuum activated. The o-ring seals the cap to the manifold vacuum allowing the slide to be lifted as the buterfly valve opens and as the engine speeds up (sucks harder). If is definitely required. You may be able to patch this using something like jb-weld, otherwise pull it apart and bring it to a welder.

 

[Nate01]

problem is that is completly broken off...there would be nothing to repair...I may need a new carb....why did it runs so good this far....there was not even a hiccup and I wouldnt have even noticed had I not pulled the tops off..?

 

[LazyBastard]

I have no idea why it would run "so good", except that maybe you're just not fully aware of how good it *could* run.

 

[Nate01]

so will i hurt the machine to run it this way...im guessing its been run this way for a while if the last owner had no idea....when I pull the plugs...they are perfect tan color..? should I or can I replace just the one carb or do I need the entire rack...may just be easier getting a used rack off here...? How is theory should the sled run with my situation..? What problems should be assosiated with missing the o-ring etc...?

 

[LazyBastard]

The theory *I think* (these CV carbs are funny animals) is that that slide won't open as much as it should, which means that less air is getting through that carb, which means less power. It should idle fine since the slides are all closed at idle, fuel flow is controlled by the needle valve, which is attached to the slide, so it is unlikely to run extremely rich or lean, which explains why the plug looks ok.

Individual carbs are available from dealer, part number 8FA-1490x-00-00 where x is the carb number (1 at oil tank side through 4 at clutch side). Description is "Carborator assembly X" -- its probably complete with slide, springs, rings, jets, etc. Probably cheaper to buy a used rack, but a good idea to check the dealer price just so you have something to compare with.

 

[Nate01]

Well thats helps alot...it prob will be cheaper to just get an entire rack and have my spare one for parts need be or sell what I have....running the way it is then will not do any harm other than im not seeing my full potentional of power?? Will the carbs then be able to be sync'd properly or will I have an issue there?

 

[RX1Jim]

Can you post a picture of the broken carb? The billet carb caps offered by STM do not use the small o-rings. Their instruction tell you to throw the o-rings away. The billet carb caps are used for turbo/super charged engines but also work with non-boosted engines. I put a set on my carbs since I love shiny stuff. Anyway, we may be able to answer your questions better by seeing a picture.

 

[Nate01]

Jim....ill try and snap a pic tommorow...I as well like shiny things too...how much for the set you picked up....what is the design being that the o-ring is scrapped?

 

[RX1Jim]

I bought a set from Ted Jannetty for about $180. He is in the advertiser's section, Turbo Addiction Parts (TAP). Ted is a great guy to deal with. The billet cap design makes a seal around the inside rim of the cap. There is no opening in the cap out to where the o-ring is located. The caps are made by STM. They had the STM logo engraved on the top of the caps. I didn't like the look with the logo so i polished it off in a lathe.

Post a pic and we'll figure out some options for you. I have see complete carb racks for sale by members such as LANEO for about as much as the billet carb caps. If you buy a set of used carbs, make sure all the jetting is right AND make sure they are clean, clean, clean!!!

Where are you located??

 

[Nate01]

Jim...
sounds good .....im pretty interested in these and I may shoot an email to Ted....I will prob swap all my jetting etc from my current setup to the new carb rack or just get the billet caps...I have the ECP kit....