[SOLVED]Engine break-in....stalling...overheating?

I agree with Larry, your cam woes are not the source of the idling issue.

I would bet the farm that you're having intermittant spark once the coils/wires get scorching hot. Use a timing light on the bike once its hot and starts doing the idling trouble. You should see a timing light flash EVERY revolution of the crank on any plug wire - regardless if that cylinder fires or not! If theere is so much as a blip of inconsistant light at idle - your ignition system is the culprit!

5 minutes of continuous full throttle operation on a fresh motor isn't the best method of breaking it in. You might have started to seize the cylinders.

No no no 10 secs pull hard then cool down for 5 minutes (engine was very warmed up before doing that)

I've read alot about engine break in... this guy seems very well trained about that...

www.mototuneusa.com/break_in_secrets.htm

I meant spark timing.

How do i do that i don't have points ignition...it's the transistor version i have...bracket is fixed no rotating seems possible...

I would bet the farm that you're having intermittant spark once the coils/wires get scorching hot

Replace with new dyna coils and wire ? Or coil are simply not heat resistant and i must shield them from heat?

I will buy a timing light to check this and a IR sensor today...

Yesterday i was looking for dyna coil on z1enterprises but i don't know if they are compatible with stock igniter... primary winding resistance on my coil now are 2.6 ohms!

EDIT: is this good ? z1enterprises.com/Dyna-Dual-Output-30-Oh...s-pair-DC11-210.aspx with those wire z1enterprises.com/Dyna-Ignition-Wires--7...-core-black-208.aspx

Also do i really need the crimping tool ? Never changed spark plug wire

also i think i need solid copper wire (not supressor one) because i have a resistor in my spark plug (BR8EIX iridium)

Plug "Ground Strap" seems excessively running HOT where should be 50/50 on the strap for correct temperature range of operation... I'm possibly just not seeing this correctly due to camera flash or something...

Just in case, Maybe this will help...
Reading Sparkies...

What kind of filter element? Paper car filter?

They will get blocked after some time on a hot day. I had the same symptom, ran fine, then died after highway ride then stop-and-go traffic. The filter just stopped flowing. I think the new gasoline is melting the glue inside the filter, then the glue gets depositied on the filter element. My paper filters would always look empty after a little riding.

I went to scintered brass filters and all those probs went away. I also am using a metal screen filter in a clear case. That filter stays full all the time, and works great.

Here's a vid I made showing the paper filter does not flow until I pressurize the tank. Then the filter flows.

vid

Also, in the future, if it stalls immediately after riding on the highway, that is the first symptom of low valve lash clearance. But as Larry said, your clearances are not that bad yet. The scrapes on the heel of the cam lobe are puzzling. Maybe someone before you let the lash get way too small.

What kind of filter element? Paper car filter?

Air filter K&N...and no fuel filter ... only petcock filtering...

Yes carbs are clean freshly rebuilt!

Plug "Ground Strap" seems excessively running HOT where should be 50/50 on the strap for correct temperature range of operation...

Should i switch to a colder plug ? NGK temp range 8 is what they refer in the manual as being stock plug temp.

thank you very much!

EDIT:

quote from NGK website

An unaltered engine will run within the optimum operating range straight from the manufacturer, but if you make modifications such as a turbo, supercharger, increase compression, timing changes, use of alternate racing fuels, or sustained use of nitrous oxide, these can alter the plug tip temperature and may necessitate a colder plug. A rule of thumb is, one heat range colder per modification or one heat range colder for every 75–100hp you increase. In identical spark plug types, the difference from one full heat range to the next is the ability to remove 70°C to 100°C from the combustion chamber.

I can buy BR9EIX (1 range colder)

With a timing light/or static if you must, retard your ignition timing 2 degrees and try that.

I've bought the timing light (Equus 3551) www.amazon.com/Equus-3551-Xenon-Inductive-Timing/dp/B000EVYH72

Now what to check with the timing light... see if spark plug are working correctly?

And what about adjusting spark timing any procedure with a fixed transistored ignition system?


I will buy colder plug tomorrow (BR9EIX) and post temp results too!

thank you guys for your very nice help

regards,
laurent

changed to colder plug ...i don't see an improvement still stalling at idle....me thinks overheating...

running around 300F-400F on the head

regards,
laurent

Oops another thing...

When started to rattle badly and want to die... if i increase the idle it will be stable for few mins then start to rattle and die again ... why is the idle stays at 1100-1200 rpm each time it turn it!?? unless i make full turns now it start to increase....i'm guessing that 1100 rpm hot means 1800 rpm cold next time i will start it right ???

OMG !!! check this out





After 10 miles run (with new colder spark plug)... look at the spark plug looks like never had been used ! No black base ring ...still shiny wtf and white insulator!!!!!

Why would be my old spark plug ok and now waaaaaayyyy tooo lean ?


EDIT:Swapped my gas cap with my 83 kz550 which didn't have any problems.... still same thing.

However i'm starting to think about fuel delivery problem i always have a big bubble in my gas line...think my petcock is clogged maybe...

regards,
laurent

Last EDIT:
Petcock is okay ...lots of flow...at least we know this is out of the question...

Gonna check my carb float level...

Out of KAWI Manual, says it all....

NOTE: This is for the KZ900, different then yours but concept is the same.
Confirm in your manual for specifications/recommendations...

ELCouz wrote: ...Swapped my gas cap with my 83 kz550 which didn't have any problems.... still same thing.
However i'm starting to think about fuel delivery problem i always have a big bubble in my gas line...think my petcock is clogged maybe....

Fuel starvation due to whatever reason (and there are several different reasons, including but not limited to improper fuel level), may result in over-heated engine operation because of a too lean fuel mixture, even with otherwise perfect carbs.

The bubble inside a fuel line is normal and usually not an issue, and occurs where fuel starvation isn't present.

Good Fortune!

Fuel starvation due to whatever reason (and there are several different reasons, including but not limited to improper fuel level), may result in over-heated engine operation because of a too lean fuel mixture, even with otherwise perfect carbs.

BTW, is that normal to have 80C (176F) on the carbs float ? I'm worried that the big engine heat around the carbs is playing with the fuel mixture...

Did a 60 miles run today run very very well and smooth on highway no traffic (temp today is 99F) but when air flow is restricted (running idle...stops, red lights) it start to rattle badly and stall...

out of luck!

regards,
laurent

Coincidentally this looks like the same problem from last year!

kzrider.com/forum/2-engine/384186-very-v...roblem-with-my-kz750

I'm thinking throwing the Mikuni BS34 carbs through the windows... i'm sure it's fuel related...everything else has been rebuilt (engine side) and valve lash more than triple checked! Carbs has been rebuilt and vacuum synced too more than twice!