New Carbs and a problem....

[IceCold4x4]

Just put these larger cvk40's on the bike in place of the stock cvk36's along with a prototype jet kit that's produced good results on 4 other bikes.

Looks like the slides aren't lifting completely to me. The springs included are stiffer than stock.

Anyone know what the result of going back to the weaker stock springs might be? Or for that matter what would cause the slides to not lift all the way because everything else idle / part throttle and what not seems damn close to perfect and it's making ALOT more power at part throttle just not at WOT.

[01YZF6]

Are there adjustable slots on the needles to move the clip on?

[kdtrull]

I'm no expert but that looks fairly normal to me.  It will only open against the spring pressure proportionally to the vacuum produced by the engine (and allowed to pass to the top of the diaphragm).

At any rate, the last 10% of a valve(slide) opening is almost negligible with respect to flow.  In very general terms, when a valve (slide) is 25% open, the percentage of maximum flow for a given differential pressure is already at 50%.  This is more true for non-compressible fluids, like water.  There's more considerations for compressible air but the relationship  between max flow vs. %open of the valve is still roughly true.

You could play around with weakening the spring (cut a turn or two out of it)....or put a weaker spring in....but I'd be surprised if it made much of a difference.

Where you might realize a significant difference is in the time it takes the slide to reach its position for a given applied vacuum....throttle response.

You can even drill addition ports to allow the vacuum to be applied to the top of the diaphragm even faster....this method worked great on my DR50 as it had a slight hesitation at mid RPM when you would yank open the throttle.  One little extra hole eliminated the hesitation.

Experiment....have fun.

[IceCold4x4]

there are adjustable slots yes.

After talking with the creator of the jet kit. He is almost positive that there is dirt or debris in the main jet circut restricting fuel flow. (he says thats the only reason why 3 difference main jet sizes would ever act almost identically.) So back to square one and will be soaking these guys for a while and then some careful reassembly just to make sure.

[kdtrull]

[IceCold4x4]

hrmm. dumped in a can of seafoam and went and made some sustained pulls at WOT on the freeway. bike seemed to act better so I'm gonna let it sit and cool and rinse and  repeat but I think he was right and there is some debris stuck in there somewhere. . .

Now it's snapping the front end up in first like it used to. and scaring me on the top end. (i know the speedo is about 12 percent off on reading high) but it seems to want to actually pull all the way to redline in 5th now at something over 160... (way too fast for the streets for more testing of that theory)

Also dropped in the largest jets he sent for the pilot and main and now seems to be acting rich at times so I'll probably have to drop back down a few jet sizes once it passes all this junk...

Going to give it another shot tomorrow with some piddling and see how close i can get it, then hand it off to landers at tech 46 for some dyno tuning.

[IceCold4x4]

hrmm. dumped in a can of seafoam and went and made some sustained pulls at WOT on the freeway. bike seemed to act better so I'm gonna let it sit and cool and rinse and  repeat but I think he was right and there is some debris stuck in there somewhere. . .

Now it's snapping the front end up in first like it used to. and scaring me on the top end. (i know the speedo is about 12 percent off on reading high) but it seems to want to actually pull all the way to redline in 5th now at something over 160... (way too fast for the streets for more testing of that theory but common sense says that is probably about 148ish)

Also dropped in the largest jets he sent for the pilot and main and now seems to be acting rich at times so I'll probably have to drop back down a few jet sizes once it passes all this junk...

Going to give it another shot tomorrow with some piddling and see how close i can get it, then hand it off to landers at tech 46 for some dyno tuning.