Carb question RE: Main jets

Hi guys,

I'm going to soon pick up my new-to-me 650 turbo and reading though the reams of technical material available on the 'net, I've found that it came from the factory with different jets on the inner two cylinders.

Has anyone here installed a single size main jet in all four carbs and what was the result?

My experience has been in building several other 4 cyl engines and many, many triples that ocassionally the factories would use different jets but it was only an attempt to lower overall emissions and had nothing to do with the actual run-ability of the engine.

What have you guys found?

I'm going to order parts soon and don't care to waste time ordering parts that I won't need.

Thanks for the help,

jeff

 

Might want to see what size they are. I suspect they could be larger to feed more fuel ointo the inner cylinders so they don't burn as hot as the outer. Remember lean is bad on normaly carbed engines but lean is lethal on turbo engines under boost mode.

MN

 

did the turbos come with oil coolers?

 

Hello JeffK.. that must be about 4 turbos signed in, in about th last 2 weeks you guys should talk...good luck with it. And you've got a nice bum..

 

MN-Maxims is right on the money. From the experts I've talked with all of them say that Yamaha put larger jets in the two middle cylinders to run them richer,this keeps the cylinde a little cooler. I re-jetted my XS1100 for a 4 to 1 exhaust and K&N filter and did not put different size jets in the middle cylinders, kep all 4 the same. Its been several years and plug have not shown any ill effects.

 

That's kind of what I had thought. They probably would have installed the larger jets on all four had they been able to keep the emissions down. Anyone use the larger jets across the board?

As a 2 smoker, I'm used to jetting rich then doing plug chops as I get them down to where they want to be so it looks like I'll be doing the same thing with this bike.

Thanks for the compliment Bushy but that isn't my bum.....lol Isn't she a sweet thing though?

Thanks guys...that helps a lot!

Hey snowwey66, check this out...saw you had a GT550, I finished one last yr.

http://www.youtube.com/watch?v=sxxS2CR1Lxc

jeff

 

Why yes they did, and are they ever nice to have...

 

Yes they came with oil coolers. I too just got a 82 Turbo a couple of weeks ago. It'd be nice to help each other out as we go. Mine hasn't run in about 6 months due to carb trouble I think. Got it from a mechanic who's a recent grad from one of those MC schools and is clueless on the old stuff.

 

That's the same bike I posted in the Classifieds. Looks like it was a good buy?? Good to hear someone on here got it

 

Any moron can go fast in a straight line. It's in the twisties that seperate the men from the boys.'

I love that line MCRW......my daily rider is a Vstrom1000, certianly no drag strip terror. This past summer I'm riding down the local hywy at a reasonable 60-65 and a squid pulss up on my rear tire on what looked to be a Busa or other screaming rocket. He follows me like this for 3/4 of a mile or so even though there is NO other traffic. He's not dangerously close but not far from it. My exit is a decreasing radius on to another little more major hywy so as I pull into the exist lane I see that my new friend does the same. Keep in mind that for the past 3/4 mile or so I've heard him pull the clutch in and rev his engine to the moon and back. I figure as we go around this long turn, he's going to pass. Well, ever since I roadraced back in the 70's, I really don't like being passed in a turn. I don't know, maybe it's because I'm a a**hole or maybe it's because I can still drag a knee on occasion. We'll, what ever the reason instead of backing off the throttle, I roll on a bit....not a terribly whole bunch but knowing the exit ramp as well as I do I take it up to 70 or so and ride the turn, speeding up just a tad more as it decreases, fully expecting Mr Racer to come flying by on the inside. I pull onto the hywy and start looking in my mirror since I can't see or hear Mr Racer......and looking.....and looking.....yes, and still looking.....heck, the thought crossed my mind that maybe he's crashed. I'm not kidding a bit when I say that I'm 1/2 mile or further on the "new" hywy when I finally see Mr Racer coming onto it. I'm now laughing so hard inside my helmet that tears are streaming down my face...turns out Mr Racer can't TURN!!!!

Needless to say, you all know exactly what he did now....yes, he twisted the throttle and blasted by me well into triple digits without even a glance......wow, he sure was cool......lol....all in fun, but if you're going to pretend that you can ride, better actually know HOW to ride.

jeff