Non GS: 88 XT600 Want to clean out carbs but YDIS in way

[VermontNewbie]

My buddy Jared who works at a Harley dealership picked up another buddy of mine, Phil, a XT600 that was traded in, got it for 500 dollars. We got it running last night by pushstart and we road it around a couple times. It had alot of carb pops and wouldn't run very well. Today I set out at undoing the carb and cleaning her out for phil, who has never ridden before. Well I take a look at it, One carb, one big ol Tube labled YDIS next to the carbs, two exhaust pipes. I start thinking its a twin but only one plug wire. After me and my good friend google found out it was Yamaha Dual Intake system, does anyone know and procedure about removal and cleaning? I'm about to just take it off and go for it. I've done tons of carb cleanings on inline fours, but this other thing isn't a carb, just has lots of hose running around.

Question, what does dual intake into one cylinder do for you?

Oh and the funny part, I was trying to solve carburetion issues on my bike, but because of YICS, yamaha intake control system, I couldn't synk the damn things without a special tool. Crazy yamaha engineers.

[jimcor]

I'm not familiar with that engine but I say it's a four valve head and there are two intake valves and Yamaha chose to run the fuel/air mix to each valve seperately. Gimmick, ? Same for the exhaust. Honda did their big 500cc four stroke enduro bike the same way. Well at least the exhaust side of it.

Yamaha Digital Ignition System, Yam Dual Intake System, could go on for days or take all the fun out of it and google it. 8)

[focus frenzy]

the XT350 I had, had the same system, it is a real good set up.
it is a two barrel carb, you have the left, main carb that is controlled by the throttle cable, and a second slave carb that gets its gas from the main carb and is opened by intake vacuum when the throttle is open beyond a set point.

the YDIS system allows the engine to just suck from one side at low RPM, it keeps the vacuum level up and you get a spin to the intake charge as it is drawn in only one of the intake valves.
the benefit is great low RPM torque and response.

yet as the RPM rises the secondary opens up and it revs out good for the best top end power.

the right side has no idle or low speed circuit, it just has the main jet and needle, with a small rubber line that connects to the left side so it has no float or float valve to mess with.
you clean them pretty much like a single carb that has a extra CV diaphragm and main jet on the side.
make sure the intake boots are good, the Yamaha intakes are just as much prone to coming loose from the mounting ring as the ones on out GS's.

[VermontNewbie]

Thanks much for the info, very interesting setup indeed. Pics later!

[cloudbreakmd]

http://www.xjowners.com/

[focus frenzy]

http://www.xjowners.com/

wrong bike.

[cloudbreakmd]

Re: Non GS: 88 XT600 Want to clean out carbs but YDIS in way

Oh and the funny part, I was trying to solve carburetion issues on my bike, but because of YICS, yamaha intake control system, I couldn't synk the damn things without a special tool. Crazy yamaha engineers.

I included a link to the XJ page to help him with the Maxim (I've had two of them).