TOPIC:

Long-
I think that I did to many things at once and now I don't know which mod is causing which problems.
I feel somewhat overwhelmed at the moment and I don't even know what to do next. Maybe someone here has some ideas.

The Bike is an 1981 KZ650H1 Here is a gallary pic
I replaced the carbs with my '81 KZ1000 BS34's (see this Thread from last September)

I installed #140 main jets and #40 pilot jets and added K&N filters and a MAC 4x1 header. The bike would start but it would go stright to 6600RPM and stay there. I read in several posts here that this is a sign of leaking manifolds so I used my handheld gas torch to check for leaks. I did not get any drops in RPMs what so ever so I tried WD40 and got the same results. So I may be wrong but I don't think that there is a leak.

I discovered that the idle screws were not set remotely close to what the (KZ1000) manual said that they should be which is 1 1/4 turns out from a light seat.
when I set those things got a little better. The RPMs dropped some which allowed me to let the bike run long enough to discover that it was only firing on 1 & 4.

Since this seems like a coil or electrical problem let me side step here and list the electrical mods.
3 ohm green Dyna coils, Dyna wires, Dyna S ignition, NGK B8ES Spark Plugs and the coil mod that many are now doing.
I check for spark on all of the plugs and the spark is big and blue and you can hear it snap. In fact once I had the loose plug wire in my hand while it was running and the spark actually jumped over to the engine several inches.

So since it has spark on all 4 I started looking at float levels as the cause for some cyl's not firing and discovered that in 3 of the 4 carbs the fuel levels in the tube were above the gasket by about 3=5mil. and 1 was a little low but not bad. I set the float levels a total of 3 times and each time I put the carbs back on the bike a different cyl would be out. I have the levels close now and it is down to #3 not firing and idle is still up around 3500.

Here are the rest of the problems:
On the cyl's that are firing the pipes are so hot that they smoke. (black MAC pipes) I know that they get pretty toasty but this seems like they are much hotter than normal.
Grey smoke out the back of the pipe.
Some backfiring although it is less now.
Plugs are black (rich right?)
Here is the kicker: When I turn off the bike using the off switch the bike dies as it should but then a few seconds later when I turn the key off, the bike backfires real good and sounds like the whole thing is gonna blow.

I am starting to worry that summer 07 is going to come and go with out me riding at all. Any ideas on how I can dial this setup in some and get it stable?

Michael:kiss:

Id suggest double checking the wiring on the coil mod relay. It sounds like you just might have one (or more) of the terminals wired incorrectly.

I'll try to address few issues here. When you power up the Dyna coils this popping is the same as on my bike. I was told by a veteran bike mechanic this is normal for these coils and it has never caused me any problems. Mine sound like someone popping a balloon.

Adjust your float levels and have your carbs synched with mercury sticks to double check that everything is at the correct level.

Your mains are waaaaaaay to big. I am going to guess that you have Mikuni 24's. I had the 700 Wiseco kit with a pipe, filter and some porting to head and the biggest main jet I had in the carbs was a 122.5 and this was too much.

Other members will chime in here with their thoughts.

Cheers-Colin Firth-Ontario Canada

i'm guessing your pilots are too big as well .your pluds are black .that meens rich that meens toooo big .you probalble have not run on anything but the pilots yet.they suply fuel up to 1/4 throttle.then the needle kicks in up to 3/4 throttle then the mains.u say 1 cyl is not fireing,could it be flooding?float needle sticking of float level still too high?I use 122.5 pilots in my 33mm carbs on an 1135cc motor.that sounds like a lot of carb for a 650cc.Your bike looks nice ,by the way.

Post edited by: mark1122, at: 2007/06/25 04:08

Post edited by: mark1122, at: 2007/06/25 04:13

The pilot jets and mains are correct for this application. Folks using VM carbs shouldn't assume that VM tuning rules apply to constant velocity carbs... they use FAR larger main jets when you go to pods and aftermarket pipes than they would with a VM series carb.

The big POP is not normal when you shut it off isn't normal as far as I know. I convert all my bikes to Dyna S ignition, coils and wires when I redo them and have never heard a pop like that. The high rpm problem can be quite a few things; generally, it is a throttle cable or a sync mechanism is contacting a carb holder clamp screw... it can also be from a throttle butterfly binding and staying a bit ajar. The throttle butterflies on a BS34 are open only a very small bit to idle and 6K idle means they can be open just a bit more... Last, if your vacuum ports are uncapped, this can cause a high idle.

I suspect an electrical issue of some sort but would not rule out carb issues. Drag your bike down one Saturday and let me look at it... would be glad to help out. If that is too much trouble, Zabors is a good shop, although a little hard to get into due to their work load... there aren't too many shops in the Austin area that are competent and will work on a vintage bike.

I forgot to ask... have you adjusted your valves? If so, is there a dim possibility that the cams were installed incorrectly? What type ignition do you have and how did you time it?

Post edited by: wiredgeorge, at: 2007/06/25 09:52

Id suggest double checking the wiring on the coil mod relay. It sounds like you just might have one (or more) of the terminals wired incorrectly.

I think that you are right. I just don't know where to begin! I know I am close to having it wired correctly but I need to just undo everything and check it again.

Post edited by: nosxiH, at: 2007/06/27 20:32

reborn650 wrote:

I'll try to address few issues here. When you power up the Dyna coils this popping is the same as on my bike. I was told by a veteran bike mechanic this is normal for these coils and it has never caused me any problems. Mine sound like someone popping a balloon.

Adjust your float levels and have your carbs synched with mercury sticks to double check that everything is at the correct level.

Your mains are waaaaaaay to big. I am going to guess that you have Mikuni 24's. I had the 700 Wiseco kit with a pipe, filter and some porting to head and the biggest main jet I had in the carbs was a 122.5 and this was too much.

Other members will chime in here with their thoughts.

Cheers-Colin Firth-Ontario Canada

The pop comes when I turn the key off after it was running. It sounds like some one shoved a firecracker in the muffler. I have not sync'd the carbs yet. I need to make or buy a carb sync tool. Which causes me to ask a question that has been on my mind..after connecting the vacuum ports to the sync tool what the heck do you adjust? I have a single screw for setting the idle??

You know the float levels are really close. How much is close enough when it comes to this? 1 mm or so one way or the other should not really affect the carb or could it?

I chose the mains and pilots based on an earlier posting. I know *jack* about carbs and how the are affected by different changes like jets. I am at the complete mercy of what I read when it come to carbs.(Although I am getting good at tearing one down and putting it back together) heheh

Thanks for your advice!

mark1122 wrote:

i'm guessing your pilots are too big as well .your pluds are black .that meens rich that meens toooo big .you probalble have not run on anything but the pilots yet.they suply fuel up to 1/4 throttle.then the needle kicks in up to 3/4 throttle then the mains.u say 1 cyl is not fireing,could it be flooding?float needle sticking of float level still too high?I use 122.5 pilots in my 33mm carbs on an 1135cc motor.that sounds like a lot of carb for a 650cc.Your bike looks nice ,by the way.

Post edited by: mark1122, at: 2007/06/25 04:08<br><br>Post edited by: mark1122, at: 2007/06/25 04:13

You are right. I have not had it even on the road in front of the dagum house since I began this project. The plug is wet on whatever cyl is not firing so I do suspect flooding but no matter how much I adjust one or more of the cyls will not run. I took out the 122.5 to replace with the jets that are in there now.
Thanks for the comp! helps out to get a complement when you start to wonder why you started this project.

wiredgeorge wrote:

The pilot jets and mains are correct for this application. Folks using VM carbs shouldn't assume that VM tuning rules apply to constant velocity carbs... they use FAR larger main jets when you go to pods and aftermarket pipes than they would with a VM series carb.

The big POP is not normal when you shut it off isn't normal as far as I know. I convert all my bikes to Dyna S ignition, coils and wires when I redo them and have never heard a pop like that. The high rpm problem can be quite a few things; generally, it is a throttle cable or a sync mechanism is contacting a carb holder clamp screw... it can also be from a throttle butterfly binding and staying a bit ajar. The throttle butterflies on a BS34 are open only a very small bit to idle and 6K idle means they can be open just a bit more... Last, if your vacuum ports are uncapped, this can cause a high idle.

I suspect an electrical issue of some sort but would not rule out carb issues. Drag your bike down one Saturday and let me look at it... would be glad to help out. If that is too much trouble, Zabors is a good shop, although a little hard to get into due to their work load... there aren't too many shops in the Austin area that are competent and will work on a vintage bike.

I forgot to ask... have you adjusted your valves? If so, is there a dim possibility that the cams were installed incorrectly? What type ignition do you have and how did you time it?<br><br>Post edited by: wiredgeorge, at: 2007/06/25 09:52

I have not adjusted the valves on this bike. I have only done external changes so far. I have the dyna s electronic ig. on it. I timed it based on a combination of the instructions that cam with the dyna s and the clymer manual. I had a timing light but it croaked while I was trying to set the timing on the bike so I had to go with a static time from that point. May not be exact but I think it is close.
THe butterflys are closing pretty tight because I have the throttle idle screw backed off all the way since it is already idling so high.

You know, I think that I may contact you in Aug. about bringing this your way. Thanks for your comments!

Just a note: Zabors won't work on old bikes before the 1990's. I tried to take my 1980 kz750 over for a carb checkup and he told me that they wouldn't touch it cause it is so hard to find parts. No knock on Zabors from me, just don't want you to waste your time going over there.

Thanks. I have not been over there in years myself. I used to have them do all my work in the late 80's.

This post originally posted by Pyxen in a double thread.

And you've done the standard stuff - checking compression, valves, etc?

Are you sure the idle adjust knob is out far enough? If the idle is staying up high, that might be the problem on that one.. yeah, black=rich. How black is it though?

There's a great page online that shows plug pics: Verrill Plug Chart. This might help ya out a bit.

If they're *really* black, it could be oil..are they oil fouled, and not just gas? I guess it wouldn't be firing if it were..but the grey smoke out the exhaust says burning oil to me.. Tim A., Ottawa, On., Canada

And Here's NoSxiH's response:

The idle knob is out as far as it will go. I see daylight between the end of the screw and the throttle linkage where it usually hits. The plugs that are hitting get a very dry sooty black. looks like powder not oily. They are not fouled in the sense that they stop firing or have buildup but just very black. Thanks for the web site too.

I forgot to mention that the compression on all four cyl's is at 145 per my harbor freight compression tester.

Post edited by: nosxiH, at: 2007/06/27 21:25

Post edited by: KZCSI, at: 2007/06/28 09:15