High Idle

[Superjet]

Good day! I am having a problem with a hanging idle. Seems when started all is ok. Upon stoping with clutch pulled in revs are high but drop off under load by releasing the clutch. It did not do this before when i had the carb holders installed without the metal carb holder covers. Since putting them on having high idle issues. New carb holder gaskets (thick ones) and new carb holders. I have pushed the metal holder cover split fins flush against the holder and have the band clamps tightened until they touch as mentioned on this site. Other than this issues my bike runs good. New lubed throttle cable routed without sharp bends and newly rebuilt carbs with inline filter. Any thoughts?

 

[TwoManyXS1Bs]

Try a forum search on "manifold leak", lots of tips/tricks...

 

[gggGary]

Spray some carb cleaner around the carb fronts while engine is idling listen for speed changes.
If this bike has an ignition advance rod, weights/springs; a hanging advance can cause high idle.
Carb synch known correct?

 

[Superjet]

I will spray after work to see. Carb sync has not been done. All was working ok and carb band clamps were not tight to touching before just recently and now high idle. Was wondering if tightening them up all the way created the leak. But have read thru a few old threads and will go thru the checkouts. I have to figure iut how to build a manometer

 

[MikeC23]

I had the same issue. It was the aftermarket carb boots.

 

[Superjet]

I have 2 sets of stock ones. I will check to see where the leaks are located then decide. I will install a fuel line between both sync ports like suggested by one of the guys here.

 

[Jim]

Just received these.....

TourMax makes parts to OEM standards.... in Japan, not China. They've been making rubber parts since 1972 and actually made some of the OEM parts for the big 4 Japanese manufactures.
Edit: ARS made OEM parts not TourMax. My bad.
Quality of these two pieces is outstanding!
40 bucks delivered. Dark Horse Motorcycle Parts store on Ebay.

 

[Superjet]

Hey guys just checked with carb cleaner and the manifolds are fine. Jimd54 my carb manifolds are xs650direct (mikes xs in Canada). I should of got the ones from Sirius Consolidated when I got some parts as they are the same ones you have shown in the pic above. The problem is the throttle shaft seals. As soon as I spray them idle drops down. Any links to a good thread to replace the seals? I will be doing my best to get it back up and going.

 

[Jim]

Any links to a good thread to replace the seals?

Look in the Tech section. Download the PDF "carb guide."

 

[Superjet]

JimD54 do you use the gaskets that come with those intake boots? I have a set but used the thicker ones that came with the Athena gasket kit.

 

[Jim]

I use the thicker Athena gaskets.

 

[TwoManyXS1Bs]

Something you may want to consider, is to trim/file/smooth any casting flash found on the carb spigots.

Those imperfections can cause permanent deformities in the rubber boots, possibly leading to leaks, especially if the carbs are reinstalled slightly misoriented to existing dents...

 

[Superjet]

Thanks Twomany I will take a look once carbs are removed. I was just reading thru the thread about replacing the seals. Gonna go with OEM seals rather than xs 650 direct rubber garbage. Seems all that I have purchased from them that have any slight quantity of rubber in it automatically takes a nose dive in the garbage can shortly after it gets out of its package. Just wont go down that road any longer with their parts. Gotta look for a good source of the butterfly plate bolts here in Canada. Sometimes tough to get stuff out here on the east coast.

 

[robinc]

Superjet, if you have trouble finding those butterfly screws, PM me and I'll mail you some, got a bunch.

I get them from a specialty hardware shop here in London.

http://www.faccafasteners.com/

 

[Superjet]

Thanks Robinc. I will look thru the thread again for the screw specs. Would like to find the allen head ones....but will be a tough find for sure!

 

[robinc]

NP Superjet. I've got Allens. Gimmee a shout if you need em.

I think they're M3 x 8mm

 

[Superjet]

Robinc PM sent

 

[Superjet]

Was able to backoff all 4 screws on the butterflies from my spare carbs. Haven't tried on the set on my bike yet. Gonna be next week before I can get to it cause seals are on order from Yamaha.

 

[Superjet]

Guys I am about to tackle the shaft seal replacement and final cleaning. When pulling apart the carbs, have some had any issues with the T fuel connection upon re-assembly? Seals leak? Mine do not leak now but was wondering if any removal wouldnt seal properly. I do have a new spare (not xs 650 direct) on hand. Or have you guys only rotate the carbs to allow access if possible to remove the butterfly shafts? Just want to make sure I do it right.

From what I understand the process is on my BS34's:
1- remove carbs from bike
2- split carbs from angle, top holder, sync link and choke shaft.
3- remove top cover, spring and slide
4- "crack" 4-butterfly bolts and fully remove. Some have suggested applying grease to the ends of the threads to avoid shavings falling.
5- remove nuts and springs
6- slide shafts out and remove seals.
7- install seals with lip facing outwards and spray with silicone lube. ]carb[
8- reinstall all back together with suggestions noted on the thread in the tech section.
9- final butterfly assembly once carbs all together with angle with snapping of throttle to center butterfly.
10- bench sync with idle nut backed off showing a space from throttle shaft arm and adjusting to have small even gap at bottom of butterfly valve.

Does this sound right guys? Just want to make sure I understand it all.

 

[5twins]

You've pretty much got it except for the last step, #10. With the idle speed screw backed off, you won't see any gap at the bottom of the butterfly plates, they will both be closed completely once synced. Then you re-set the idle speed adjustment screw and then you will get the small gap on each butterfly plate.