Running correctly? No reference

bdento59 · Post by **bdento59** » Tue May 26, 2009 11:59 am

I have to say that overall, I'm fairly satisfied with how the X is running as of late. After working through carburetion troubleshooting/adjustments since last July, I finally determined that the vast majority of my issues stemmed from pilot jets that were either drilled out or damaged during the last 30 years of PO's cleanings. I replaced them with new #35's. The rest of the '80 carb setup is also stock, except for the mixture screws, which are 2.5 TO. The exhaust is OEM, and the air cleaner is an OEM style K&N in the stock airbox. Now that the pilots have been replaced, the bike starts, idles and (when well twisted) accelerates hard to redline. I've also been getting ~32 mpg over the last three tankfuls. So, you may ask, "then what's the problem?". Well, there are two, actually.

1) The bike needs partial choke to run well for almost 10-20 minutes during 70 degree weather. If I try to run it w/o choke during light throttle, it has a (very) flat spot from off idle right up to about 4500rpm.

2) Even when fully warmed, the bike "feels" like it's running lean in the lower rpms, hunting and surging enough to be noticeable. AFAICT, it's not misfiring, but when I compare it to a well carbureted example (like my '96 GPz1100), it just doesn't seem as "willing" to accelerate immediately upon first movement of the throttle.

So, these are the symptoms... are they normal? I've no reference point, since my CBX is the only one I've ever ridden or worked on. What I do know is that before I changed out the oversize pilots, the bike seemed much more willing to "go" between off-idle and 4K rpm, but the plugs kept fouling, so what's the sense in that... Any input would be appreciated. TIA

alimey4u2 · Post by **alimey4u2** » Tue May 26, 2009 12:24 pm

No that is not normal, although it is a large mass engine & does take a time to get to working temperature, this is excessive. Check for air leaks around the rubbers by carefully squirting starting fluid around the area. If the revs pick up, you have an air leak. Do not do this in an enclosed space/area. I'm sure the other guys will give more advice as Keihins are not my area of expertise'....