Engine dies as throttle applied...ideas?

Like the title says, heres the situation: I start her up, and she idles a little high and I can even rev when in neutral (at least to 5 or 7k rpms, haven't tested past yet). When I get it in gear and apply throttle, it dies pretty fast. Definitely doesn't get past 3k rpms after it is hooked up to the rear wheel. I'm thinking it may be with the carb. For a spectre it only has a needle jet and a pilot jet, and according to what I have it set as, it should be getting more fuel than before I muddled with everything because I upped the jet size to compensate for pods. I'm also using a stage 2 jet kit so the needle is changed and I put the jet size to 116. Pilot jet is the same, 35.

My guesses are that it's not getting enough fuel and too much air, or valve train timing is wrong, or something. Ideas?

Set up for 1983 kz750 spectre (n2) is:
116 needle jet size (upped from 100)
different needle (it's a bit skinnier)
pods (crappy ones for sure, but I wouldn't have *this* bad of on effect...)


Heres a video:

What kind of exhaust pipe have you got?

donthaveakawman wrote: What kind of exhaust pipe have you got?

its a 4 in 1

so it is the dynojet stage 2 jet kit, 4-1 exhaust and pods. the stage one is the 116 jets, you need the 122's for the spectre.

You have pods on CV carbs. You will find tuning them to run well throughout the rpm range a challenge. Ed

donthaveakawman wrote: so it is the dynojet stage 2 jet kit, 4-1 exhaust and pods. the stage one is the 116 jets, you need the 122's for the spectre.

No you're right I think I did stage 1 instead. My bad. Thanks for the comment.

650ed wrote: You have pods on CV carbs. You will find tuning them to run well throughout the rpm range a challenge. Ed

But not even able to get a basic run? Thanks for the comment

try the stage 3

There is an obvious problem that is bigger than just jet sizes. I don't care if you have 110's or 180's, it should run far better than that.
Make sure the carbs are clean and everything is working like it should. It sounds like it's not getting any fuel other than what is coming out of the pilot jets. I would say take the tops off the carbs and swap the needles back to the stock ones with the stock clip setting and see if that helps.

Spenzher wrote: ...I start her up...can even rev when in neutral (at least to 5 or 7k rpms, haven't tested past yet). When I get it in gear and apply throttle, it dies pretty fast. Definitely doesn't get past 3k rpms after it is hooked up to the rear wheel....

Would consider possibility of a sticking or frozen timing advancer that's staying in the retarded idle position.

The advancer may require lubing, or both cleaning and lubing, or inspection and repair or replacement.

This condition will manifest the symptoms described.

Operation of the advancer may be viewed under a strobe-type timing light.

Good Fortune!

CrazyDuck wrote: There is an obvious problem that is bigger than just jet sizes. I don't care if you have 110's or 180's, it should run far better than that.
Make sure the carbs are clean and everything is working like it should. It sounds like it's not getting any fuel other than what is coming out of the pilot jets. I would say take the tops off the carbs and swap the needles back to the stock ones with the stock clip setting and see if that helps.

Ah okay thanks for the comment!

Patton wrote:

Spenzher wrote: ...I start her up...can even rev when in neutral (at least to 5 or 7k rpms, haven't tested past yet). When I get it in gear and apply throttle, it dies pretty fast. Definitely doesn't get past 3k rpms after it is hooked up to the rear wheel....

Would consider possibility of a sticking or frozen timing advancer that's staying in the retarded idle position.

The advancer may require lubing, or both cleaning and lubing, or inspection and repair or replacement.

This condition will manifest the symptoms described.

Operation of the advancer may be viewed under a strobe-type timing light.

Good Fortune!

Okay thanks for the suggestion I will check that today!

First off DO NOT listen to anything donthaveakawman has to say. Has it always done this or did it just come on after working on it?

baldy110 wrote: First off DO NOT listen to anything donthaveakawman has to say. Has it always done this or did it just come on after working on it?

haha okay. And no, this is happening after I've done a valve clearance check. It worked before I touched anything.


I also took off the magnetic timer on the side so I could better see the crankshaft position (and put back on of course). I checked and was able to rev to redline almost when parked and in neutral. As soon as I engage any gear it just puttses out like none of the cylinders are really affecting the rear wheel. Very strange.

Some notes: I'm able to start every time with the throttle open, but not when closed, however when it starts it idles around 1.5k. It almost seems sporadic in its response.