EXUP Worldwide

<br>Hey all!<br><br>I am presently trying to locate 20 missing horses from my 89 EXUP.<br>I removed the L\H side panel <br>at the weekend while working on another problem. I started the engine, warmed it and the observed the movement of the servo as I revved the engine. It looks like the servo moves in stages as opposed to one smooth movement. Is is meant to rotate in different stages according to RPM or should it rotate smoothly?<br>I also whipped the airbox off and checked how the floats return to their original position. 1,2 & 3 return at exactly the same time but number 4 takes ever so slightly longer (milliseconds.) Could this difference seriously affect performance? It would appear that the diaphragms are OK so my mate suggested just stretching the spring a little in that carb. Is this OK do you think?<br><br>Jason<br> <p></p><i></i>

Hi Hiras<br> Whether or not your EXUP valve moving in stages is normal or not I'm not too sure, but it sounds just the same as mine, and I've never encountered a problem with it (apart from the squeak).<br> I assume that you are talking about the slides in the carb and not the floats, and one moving at a slightly different speed isn't anything to worry about, as long as it moves freely it's O K, I wouldn't recommend trying to bend the spring, but you could put a small washer above the e-clip on the needle to try to remedy the problem, but this will also make the slide open slower and may compound your problem.<br> 20 horsepower is quite alot and a compression check might point you in the right direction. chris <p></p><i></i>

placing a washer under the clip on the needle will have no effect on how fast the slide raises or falls...it will richen that cyl and have no effect on the vacuume signal to that slide. The size of the two holes beside the needle hole in the slide controles the vacuume signal along with the spring. lightening the spring will increase the slide velocity. making the two holes SLIGHTLY larger will I believe add to that effect.<br>But that in all likelyhood ain't where yur 20 horsepower are hiding. I would take the bike to a reputable dyno room and let them do their thing.<br>Here are my reasons....<br> What ever changes you make to the jetting, You have no way to quantify. <br> You are most likely making more than one change at a time, so you won't know which thing you changed did what.....<br>you don't have an exhaust gas anylizer so if you DO stumble onto the perfect setup....You'll never know it, cause you have no way to quantify it!<br>Heck....you won't even know which direction to move in<br>I used to race fuel bikes and the BIG joke among people that built and raced them was "Is it rich or lean?" Sounds silly till you realize that fuel has 40% more oxygen that gas so as you increase fuel....you increase oxygen also. It can get very confusing unless you have the proper tools<br>The other thing is how much money will this cost you? A lot less than you're going to spend in time doing it without the proper tools<br>Food for thought...<br>Jim <p></p><i></i>

dragracer1951<br> Surely, by placing a washer ABOVE the e-clip you are "tightening" the spring thereby making the slide return to the closed position faster, no? <p></p><i></i>

Jeez....I HATE it when I miss a little tiny word like ABOVE.......<br>I would imagine that it would have to be a fairly thick washer though, but you are certainly correct, it would make the slide close faster<br>Sorry for my confusion<br>Jim<!--EZCODE EMOTICON START :cheers --><img src=http://img.photobucket.com/albums/v209/ ... Cheers.gif ALT=":cheers"><!--EZCODE EMOTICON END--> <br> <p></p><i></i>

Hello Hiras<br><br>If not mistaken the EXUP should move smoothly. If yours do not, try and check the wire which operate the EXUP. If they "squeak" they are dry as a desert, frequently oiling due to the temperature, improves movement. Check if it has started to break, in that case renew them. It is not a big deal to install.<br><br>Regards<br>Lemmy <p></p><i></i>

Missing HP usually is a sign of low compression. How many miles on your bike? Last valve adj? and last carb Sync? These bikes aren't Italian, but do require specs to be met to have true 5 valve harmony.<br><br>CHUCK D. <p></p><i></i>