TOPIC:

<I'm cross posting this to Electrical subforum in case this is a result of replacing the electrical parts>

This is an 85 ZN700 LTD that would run for about 20-30 minutes before draining the battery. Recommendations were to start by replacing the R&R and possibly the stator.

I've replaced the R&R and fuse box (was melted) and can get the bike started and it stays on, however the engine races- it immediately goes up to about 4000rpm and stays there. The throttle is backed off at the handgrip, the choke is off.

I know the boots have to be replaced, I can see a big split on one- but the bike didn't race before the electrics got replaced. On the other hand, I had to disconnect so much stuff just to get to the regulator/rectifier that even with photographs it's possible I messed up while reconnecting the hoses to the gas tank.

It also looks like there might have been some vacumn hoses missing before I got into it but I can't be sure because the shop manual for this bike is really sketchy.

I was going to go through the Electrex testing diagram to see if the stator has to be replaced, but I have to figure out how to get the rpm down first.

Any ideas?

Thanks in advance,

ZN700Ltd-

PS- Thanks WiredGeorge for telling me about "Auction Sniper", I got the RR, Fusebox and wiring harness for $60 including shipping- And all the part are in really good shape!

It's definitely not an electrical problem so I deleted your post in the electrical forum.

Either your butterflies are not closing (stick throttle cable or idle adjustment) ot you have a serious air leak.

I don't have a manual for your bike, so I can't help you much with the hose routing.

Steell,
thanks for the reply.
The manual doesn't really show hose routing, because coverage on the bike is an addendum to the 84 KZ750 Shaft manual- I had to look at that and the parts diagram to get a sense of what goes where.

What I can't figure is why it wasnt racing before I replaced the electrics and it is now. I guess it's back to taking the gas tank off and trying to see if any other hoses got disconnected.

ZN700LTD

My thoughts would be that it doesn't have anything to do with the "new" electrical parts you just installed, but rather an air leak or incorrect vaccuum hose routing somewhere.

Is your bike a California (charcoal canister, fuel seperator, ect.) or a 49-state model (non emissions junk)?

I'll have to double-check my garage, but I'm pretty sure I have a "somewhat" complete photocopy of the factory hose routing diagram.

I found and scanned the hose routing diagram I have, which you'll (hopefully) see below.
If the diagram pic doesn't show up, shoot me a U2U (private message) with your email addy and I can email you it to you if you'd like.

This is for the California model. But the tank vent and return hose routings, as well as carb hose routings, should be the same as the 49-state model.

Ok, one more attempt at reposting the diagram pic after resizing it.

Post edited by: RetroRiceRocketRider, at: 2006/01/29 13:44

Post edited by: RetroRiceRocketRider, at: 2006/01/29 13:45

Ok, one more try after AGAIN resizing to the acceptable size.
Then I give up!

Three possible reasons why your bike may be "racing" when started:

1. MUST FIX!!! Replace intake manifolds if you see one cracked. Cold air being sucked in. A piston WILL hole soon - VERY EXPENSIVE to not replace the manifolds

2. Vacuum ports not plugged. If you have removed stuff where there is no place to terminate vacuum lines as they were from the factory, put vacuum caps on the the vacuum ports that are open or have unterminated hoses. See comment about holing piston in #1 comment

3. TIGHT THROTTLE CABLE... you have to install the throttle cable then loosen it so there is some slack in it else the throttle will hang open a bit. You install the cable and then adjust using the barrel adjuster under your right switchgear. Watch the cable end as it is installed into the carburetor so that it is VISIBILY slack as you are adjusting it. Don't forget to tighten the locknut on the barrel adjuster after adjusting the cable but do STEPS 1 & 2 FIRST!!!!!!!

Hi,

Would an air leak around the carb bowls cause this same kind of problem? I can blow into the carb vent tubes and see bubbles come out from between the bowls and carb bodies. This is obviously bad, but there isn't any gas coming out..guess I'm destined to get some carb kits from Z1, eh? Hrm..

I just got my bike going again, and now it starts but immediately red lines and only works on cylinders 2,3,4. It's really pissing me off.