Anybody still remember how to tune a carb?

[Joesmoe]

Wow, what a question. I got rid of my 1971 Jaguar E-Type Series III with its V-12 and triple carburetors I was unable to find anyone who knew what they were doing willing to work on it.

Kinda like now I'm STILL looking for a real tuner for the Rocket . . . somewhere accessible to Northern Virginia.

 

[R3Tex]

I have no problem tweaking the tune once I get it running, but getting it to fire off has so far eluded me after the last re-jet. The longer I think about it the more I've convinced myself that one of my fat fingers moved one or both of the floats out of spec. I sorta knew it was going to involve some fiddling around to get it right in all throttle positions, but if I can get it mostly right for now I will be satisfied until I can find more time to get it 100%. You guys have given me some ideas to try so hopefully this weekend will be a success and the bike will make its debut in Leaky next weekend. Thanks

 

[Triple Trouble]

This bike has a fuel pump and so I would suspect the floats first. This article should help.
http://www.vstar1100.com/1100jetting.pdf

 

[R3Tex]

And the prize goes to @TO rocket . Floats were way out. Something I should have looked at first but its been a long time since I jacked with an carb. After some careful consideration over a cold beer it looks like somebody put a rebuild kit it it and never set the floats. The tang that operates the float valve was perfectly flat. Thanks for the help guys

 

[rocketjohn]

I hauled my Intruder out the other day....it has been sitting while I fiddle with one thing and another. It ran on one cylinder.....the common fix for that is to run it up as fast as it will go in third gear and chop the throttle, using compression braking to suck whatever was clogging up the dead cylinder out.....voila....it sprang to life. That should remind me to use fuel treatment more often!

 

[Joesmoe]

I have decided (YRMV) that ANY machine that will sit for an extended period MUST be drained of fuel. Treatments have their use, but in my experience, they only delay the inevitable: lighter hydrocarbon fractions evaporate leaving ever heavier elements and varnish. Snowblower, lawn equipment, that precious old bike with a carb and drum brakes -- if it sits, I drain it.

 

[Steel]

I hauled my Intruder out the other day....it has been sitting while I fiddle with one thing and another. It ran on one cylinder.....the common fix for that is to run it up as fast as it will go in third gear and chop the throttle, using compression braking to suck whatever was clogging up the dead cylinder out.....voila....it sprang to life. That should remind me to use fuel treatment more often!

What size Intruder? I still have my dad's old 1400 in the shed.

 

[rocketjohn]

1400.....96 model.

 

[Bernard Vinet]

Not Rocket related but here goes...this is on a 2004 Yamaha Vstar 1100 Custom with 1500 miles on it that I am trying to get back together. Long story but it just happened to be sitting in my shop when we were slinging paint so it got disassembled and shot with a custom marble paint job and I'm trying to get it back together and out the door. There have been multiple wrench turners involved from the inception and the carbs have indicators that they have been fooled with before...like there is no brass plug over the pilot mixture screws. In my experience Mikuni carbs all have the PMS sealed under a brass plug after being set at the factory. Anyway here is where I'm at now. The bike has dual Mikuni constant velocity carbs on it and a set of free flowing curb burner type exhaust pipes installed and all of the intake plumbing taken off in favor of individual K&N pods on each carb. I have installed a jet kit to compensate (152.5 mains with the needles raised by one 0.020" washer and #20 pilots). The pilot mixture screws have been backed out 3 1/2 turns per the instructions that came with the kit. The problem is that the bike will not start...at all...won't even sound like it is trying to fire.

I initially had fatter jets in it but the first test ride showed me it was running way too rich so I rode it back into the shop, put it back on the lift and dropped down to the jets that are in it now and the b!tch won't start. I have checked for fire...fine on both cylinders. It seems to me that there is a problem in the idle circuit. The bike seems to flood immediately when the key is turned on. So here's what I'm thinking...either the floats need to be adjusted or there is a pilot air jet plugged.

Thoughts? Anyone? Beller? @TO rocket you jack around with old carbureted bikes....a little help?


I'm about ready to set fire to the POS and tell the girl that is supposed to ride it to Leaky in a week that she will have to become ballast on a Rocket

Do you have vacuum,very important with cv carbs! Check see if spark plugs are wet or not.

 

[R3Tex]

I need to update this...bike is running pretty well. One issue left...after cruising it wont come back down to idle when you come ro a stop unless you force it by lugging the engine in a higher gear and pulling the clutch in. Still have a ways to go but it seems to be doing a lot better