Wildcat80 racing engine

[Wyvern]

While Permatex does say it's fuel resistant, they don't say it can be used on head gaskets

Keep us posted

The only thing I know that can is copper gasket spray.

 

[Wrench]

The only thing I know that can is copper gasket spray.

Yep, that's a head gasket coating

 

[Wrench]

Use Permatex GREY Fuel Resistant. It's also resistant to oil. I used it to seal the cylinder head with gaskets,

Permatex gasket maker on the head gasket is gonna restrict heat transfer
Heat from the cylinder want's to escape thru the cyl head cooling fins

 

[sherron82]

Use Permatex GREY Fuel Resistant. It's also resistant to oil. I used it to seal the cylinder head with gaskets, and also the alllt he connecting and contacting areas on the reed valve. No issues with air leaks whatsoever. The exhaust is bound to leak during break in. I used Right stuff RTV red silicone there instead.https://youtu.be/8OegyqrxsSI?si=E7FD6eJszIONgD4y

Word of suggestion on head bolts. Invest into a torque wrench. I torque my headbolts at 14ft lbs. No Issues. I periodically check their tightness after riding. ONLY do this after the engine has completely cooled down. I'm using a NGK BR8HS with an additional washer for the spark plug and haven't tried the BR5HS yet.

Do not full throttle until you've reached about 320 miles. Advice from the seller of California Motorbikes directly:

20:1 break in fuel oil
32:1 after.

I destroyed my previous ported wildcat due to breaking in with 40:1. It's too lean for this motor and believe me the piston WILL SHATTER.

Heat cycling is important. If your engine is getting really hot. Keep in mind this is normal. I'm on my 4th 2.5L tank and heating is called "seasoning the enternal gaskets. Remember these engines aren't watercooled so they can only FAIL if you drive the throttle too hard.


As for tuning the PZ16mm Carb. Here's what works for me. 2 full turns and 1/8th on the air/fuel screw. 3 full turns on the speed screw with the projected spring. I ideally call this the rpm screw. I had a lot of trouble getting the carb to set the first few tanks. Lift your carb needle up one notch from the center. Believe me running rich IS better than lean. These engines will blow pistons on too lean of settings. Remember higher is richer, lower is leaner. I had to study tuning carbs like crazy. Even then sometimes the PZ16s are trash out of the box. I know this because the second Ported kit he sent me the carb was complete trash and untunable. I just cleaned the old carb from the blow engine.

Thanks so much for the info, really helpful..

I finally got the wc80 engine only with reed valve, windowed piston and 16mm carb on the bike. Also got a cdh67 exhaust. Im really liking it. Runs better than I thought. This is the first ride and I know the idle is too high, possibly a leak somehere. Other than that it's great.

 

[sherron82]

Use Permatex GREY Fuel Resistant. It's also resistant to oil. I used it to seal the cylinder head with gaskets, and also the alllt he connecting and contacting areas on the reed valve. No issues with air leaks whatsoever. The exhaust is bound to leak during break in. I used Right stuff RTV red silicone there instead.

Word of suggestion on head bolts. Invest into a torque wrench. I torque my headbolts at 14ft lbs. No Issues. I periodically check their tightness after riding. ONLY do this after the engine has completely cooled down. I'm using a NGK BR8HS with an additional washer for the spark plug and haven't tried the BR5HS yet.

Do not full throttle until you've reached about 320 miles. Advice from the seller of California Motorbikes directly:

20:1 break in fuel oil
32:1 after.

I destroyed my previous ported wildcat due to breaking in with 40:1. It's too lean for this motor and believe me the piston WILL SHATTER.

Heat cycling is important. If your engine is getting really hot. Keep in mind this is normal. I'm on my 4th 2.5L tank and heating is called "seasoning the enternal gaskets. Remember these engines aren't watercooled so they can only FAIL if you drive the throttle too hard.


As for tuning the PZ16mm Carb. Here's what works for me. 2 full turns and 1/8th on the air/fuel screw. 3 full turns on the speed screw with the projected spring. I ideally call this the rpm screw. I had a lot of trouble getting the carb to set the first few tanks. Lift your carb needle up one notch from the center. Believe me running rich IS better than lean. These engines will blow pistons on too lean of settings. Remember higher is richer, lower is leaner. I had to study tuning carbs like crazy. Even then sometimes the PZ16s are trash out of the box. I know this because the second Ported kit he sent me the carb was complete trash and untunable. I just cleaned the old carb from the blow engine.

So you do mean with both screws all the way out then do as you said with the turns, correct? Thanks

 

[Deleted member 35519]

So you do mean with both screws all the way out then do as you said with the turns, correct? Thanks

Permatex gasket maker on the head gasket is gonna restrict heat transfer
Heat from the cylinder want's to escape thru the cyl head cooling fins

Thanks for the proper advice. I'm still learning

 

[Deleted member 35519]

So you do mean with both screws all the way out then do as you said with the turns, correct? Thanks

Air/ Fuel screw closest to the Air filter. Turn all the way in gently. Then this:

1/4 TURN is a quarter of a half moon?
1/2 TURN IS clockwise of the screw head once.
1 FULL TURN IS clockwise of the screw head twice

It is recommend factory setting your air fuel screw 2 and half turns out to 3 full turns.

Speed screw is the projected screw with the exterior spring center of the PZ16. It is regularly recommended to turn in all the way gently then 3 full turns out. HOWEVER. With this carb it's the opposite it seems just for this screw. Screw the IDLE/RPM screw all the way out until it's not threaded. Then gently seat it. now try 3 full turns in.

Hold your clutch in idle at a full stop. Now breifly rev your engine from yoru throttle grip half way. Very brief full revs are ok but be mindful this engine isn't fully broken in! Habbit to use full revs only on cold starts not driving. Adjust your rpm screw as necessary. For a very detailed and educated guide to carb tuning check out these two videos.





These are of two people who are highly educated and experienced.

 

[Deleted member 35519]

Permatex gasket maker on the head gasket is gonna restrict heat transfer
Heat from the cylinder want's to escape thru the cyl head cooling fins

Sorry i meant the gaskets seating the cylinder between the crank case. My bad i was very tired when i wrote this and there are some wrong steps.

ONLY USE COPPER HEAD GASKET sealant on the head gasket, I use none with the aliminum gasket provided. However if it was a copper gasket i may heat on the oven for 5 minutes? Then coat the gasket with copper head gasket sealant. Some advice somewhere... Haven't tried it. I just use the aliminum one and make due the contacting surfaces of the top cylinder head is atleast 600 grit sanded. or clyinder head. Sand on the most flat surface.


And yes I had the jet needle advice backwards. Higher is leaner. Lower is richer. IT IS ALWAYS BETTER TO RUN RICHER? Mines set right now too 2nd up from the very bottom.. It seems to be the only needle setting I get to tune the carb strongly as I suggested above... Keep in mind this may vary where you live. I am 1k-1,500 above sea level.


Also This engine by default is 5 horse power. Much more that a regular china factors 2-3hp. So keep in mind it idles higher than most motors. I have tried everything to decrease the rpm on idle without bogging out the engine. Find the perfect area it won't bog. It's a challange on such a cheaply made carb... again it's a 5-15 dollar carb. Not much better.. I had to get this out of head that I'm not tuning a $100 dollar carb on a 3-10 thousand dollar bike. I have read some places of people trying other carbs and loving the improvement from what they used prior. These issues vary as it depends on the quality of the carb. Granted it's cromed inside. The other internal compenent aren't I am intrested in trying a nibbi 16-17mm. From my understanding and research. egines that don't rev pas 5.5k rpm only need 16mm carb like this egnine. However other sources point that as long as the carb manifold is between 16-19mm. You can add a bigger carb between these range. Of course the air passage way of the carb is larger..

 

[Deleted member 35519]

Also I haven't endeavoured this yet. But I'm having trouble finding pilot jets, slow jets and main jets for this carb. If you find out let me know. PZ16 main jet is a m4 hex. That's all i've found for sale online thus far.

PZ20-27 point to KEIHIN PZ SERIES and the main manufacture. However I'm not positive these jets would be compatiable with the PZ16 by any means.

Seems like the PZ20 prejetted from factory would be an ideal start as these don't exceed over 70-72 on the main jet.
PZ19 has a main jet of 75.

These should be easy to work with. I do know... that most Chinadolls only need a main jet between 60-70.

KEIHIN PZ SERIES CARBURETOR CARB - Jets R Us

 

[Deleted member 35519]

Thanks so much for the info, really helpful..

CDHPOWER CDH88 is what i just put on today and it's amazing! I was originally going to try the Wildcat MZ65 clone. However I have this setup on a Scwhinn Stingray OCC chopper it required me to use extended cranks and pedals. I also had to torch and bend mine today! I'll keep you posted with photos soon. Right now I'm ceramic silica high temp coating the leg area of the exhuast heat baking it then using fiberglass heatwrap. and heatshield. I'm also going to rip the motor and paint rest of the frame black... This is an old beat up schwinn i bought off a tweaker for 160 usd lol​