Turbo GpZ550 Ignition misfires starting above 10 lbs boost

Not sure I mentioned but I stopped using the CVK32 after installing the Turbo.
Using the oem TK carbs. They have better pilot and choke circuits. Better fuel metering and atomization.

See links for first start on TK carbs and for a special choke lock I had to make to prevent boost from blowing the choke plungers open.

First start. photos.app.goo.gl/h8Ryx8JCkkLFA2Ut9

Choke lock bracket. photos.app.goo.gl/RqinuQfQacNBtQf56

Nice choke hold!

Update.
Head gasket leak developed under high boost.
Once warm and idling #4 cylinder was missing and backfiring and I could see leaking through the head gasket.
Oil was also spraying from the head gasket at the oil passage O ring.

While re-torquing the head nuts I discovered they were below where they should be so I pulled the head.
I'm using a copper head gasket which is good for up to 16:1 compression on a normally aspirated engine.
Higher pressures require Stainless O rings to help seal each cylinder.
I had the grooves cut for the O rings but never needed to install them. I just used copper wire to fill the grooves.

I really should have installed Stainless wire before running high boost.
Here's what happened to the copper gasket without them. It's subtle but visible and it is definitely NOT acceptable
I've ordered a new copper gasket and will use Stainless wire rings.

A few shots of the gasket and one of the O ring grooves cut into the cylinder block.
Gasket has permanent deformation

Wow, sorry to hear. Hope there wasn't any other damage... warpage etc.

loudhvx wrote: Wow, sorry to hear. Hope there wasn't any other damage... warpage etc.

Other than the head gasket all is good.
No overheating so the head is still flat.

You just can't run high cylinder pressure without a copper gasket AND the head or block O-ringed.
Copper alone can handle up to 16:1 compression but with the 12-13 lbs boost, pressure was higher than a Naturally aspirated 16:1.engine would see.

It was handling 10 lbs without a problem but after I fixed the ignition miss, it made more boost.
I have a replacement Cometic copper gasket being made and delivered in a week or so.
Between now and then I need to cut and fit stainless wire O-rings to the cylinder block. They have to fit with perfect filed ends butted together.

Waiting for new copper head gasket but new wire O-rings are in the cylinder block.

You can also see a new square cross section Viton oil seal.

My copper head gasket finally arrived this week and the head is back on the bike. Took longer than expected to get it made and delivered but Cometic may have been in partial shutdown. I've advanced the exhaust cam 6 degrees to more quickly spool the turbo but I won't be able to test ride for at least another day. 1 heat cycle followed by re-torquing the head is needed. I have high strength studs so the nuts get torqued to 24 ft-lbs using ARP lubricant. Lots of clamping force.

The waste gate actuator has been installed and set for 10 lbs boost so there won't be anymore 13 lb boost spikes.

First test ride with the advanced exhaust cam timing.
The turbine spools sooner BUT too much low end was lost.
I actually stalled the bike a couple times pulling from a dead stop and it runs lazy in the 3k to 4k range.
I'm setting it back to where I started.
Cams timed at 104/104.
Suggested timing for these cams is 106/108 but I found 104/104 much better on the street with or without the turbo.
Waste gate woks well. I bench set it to crack open at 10lbs and that's the exact maximum I see in the intake pipe after the intercooler.

Done test riding until I get the cam timing changed. Not today

garylbishop wrote: First test ride with the advanced exhaust cam timing.
The turbine spools sooner BUT too much low end was lost.
I actually stalled the bike a couple times pulling from a dead stop and it runs lazy in the 3k to 4k range.
I'm setting it back to where I started.
Cams timed at 104/104.
Suggested timing for these cams is 106/108 but I found 104/104 much better on the street with or without the turbo.
Waste gate woks well. I bench set it to crack open at 10lbs and that's the exact maximum I see in the intake pipe after the intercooler.

Done test riding until I get the cam timing changed. Not today

Cam s set back to 104/104 and test rides complete.
Amazing how much better that timing is. Not at all subtle.

With the waste gate operational I was able to push it very hard.
It's making way too much power for the stock clutch so replacing it is the next step.
My stock clutch has good friction and steel plates, heavier springs, and each is shimmed for additional clamping force.
All in all the clutch is in excellent shape but can't do the job under full boost.

I have a used 2013 636 clutch on the way that is slipper/gripper. It only uses 3 clutch springs so clutch lever force is light but the internal ramps on the pressure plate increases clamping pressure. Clamping pressure increases with engine torque. The "slipper" feature is not really needed but that's what it has.
My plan is to marry the 636 outer basket section to the stock 550 basket. The outer ring of the 550 basket (fingers) will get removed then replaced with the outer ring section of the 636 basket. A hybrid basket that retains the 550 gear and cushion system but uses the 636 clutch pack, hub, and pressure plate.
Lathe work and tig welding.

That's the plan

Note to self... "don't use 636 clutch for bumpstart-only bike".

whoa , were gonna needs pics documenting the process. very cool.

loudhvx wrote: Note to self... "don't use 636 clutch for bumpstart-only bike".

Good point.
I've had my battery go dead and had to bump start on more than one occasion.

It may be easy to remove the slipper feature. Just need to prevent rotation in one direction to nullify the ramps that lift the pressure plate and leave the "grabber" function intact.

I'll have the clutch on Thursday so I can start design this weekend.