almost deadly throttle/idle Kaw kz750 csr m1

[xj11john]

My bro-in-law has this bike and the other day he was in his yard putting around tring to get it to run right when all of the sudden it took off WOT! before he could stop it he had to lay it down in a brush pile!

I was on the way down to help him look at it, and had to go to the ER to see him, anyway got back and looked at it the next day, throttle cable was not hung, closed all the way??

When we started it up with throttle closed after idleing for a sec. it idle up like it was WOT, and the throttle was closed!!??

It wouldnt hit right on one cyl for awhile then started running good after messing with idle mixture screws, then WOT again with throttle and buttleflys completely closed??

Any idea? any input would be welcome as he has not gotten to ride almost any this season, thanks in advance

[xj11john]

I was thinking it could be something to do with vacuum diaphram lifting the needles too soon, but not that familular with the carbs or mine to know if this could happen.

I guess its off to the kawasaki shop for him , Unless there is someone out there that can help.

[randy]

I would venture to say that the carbs are way out of synch. Maybe one (or more) carbs have open butterflys.

[Geezer]

I'd take the throttle cable off and see if it slides up and down in the housing OK. One strand can unravel from the cable and cause all sorts of problems.

Geezer

[xj11john]

Randy, Geezer,

The carbs were pre-synched, but suppose they will be properly synched this time (prob at a shop .)

The throttle cable was fine, the cable inside had alittle slack from the hosing to the butterflies, but I took that out with the adj. on the handlebars, it was working just as it should, when throttle closed butterflies closed, spring on butterflies doing their job.

so it was puzzling to say the least, any other ideas welcome.

[dorkpunch]

i had a similar problem on an xs- i took the carbs off, cleaned em, and installed, and it would do the same thing you said, idle for a sec and rev up. turns out the cable some how "shrunk". looking in the carbs it looked okay. try disconnecting the cable at the carbs and see if it does the same thing. i actually ended up triming the twist grip so it could turn farther back in the housing.

[xj11john]

Thanks for the reply DP,

I'll get him to take off the cable next time I talk to him (bro-in-law), and see what happens.

Geezer,

I'll also let him know about the strands in the cable that can unravel and cause probs,

Thanks guys.