390 carb on 212 hemi predator seems to be working, or is it?

#42
Hey just wanted to drop in real quick and let you know that I haven’t gone anywhere or quit, just been busy with work, birthday parties, holidays, and all kinds of other stuff the last few weeks.
I just finally got the temp sensor mounted last night. I saw a lot of comments about not bending them or they’ll break, but I had to bend mine just a hair. (I could have taken a burr grinder to the cooling fin but I didn’t feel like getting it out.) I used some skinny pliers and made sure to not bend the part where the temp element is, I don’t see why it wouldn’t work but we’ll see this afternoon. I’m anxious to see how hot I’m running, hopefully it’s not something crazy high.
 
#43
Hey just wanted to drop in real quick and let you know that I haven’t gone anywhere or quit, just been busy with work, birthday parties, holidays, and all kinds of other stuff the last few weeks.
I just finally got the temp sensor mounted last night. I saw a lot of comments about not bending them or they’ll break, but I had to bend mine just a hair. (I could have taken a burr grinder to the cooling fin but I didn’t feel like getting it out.) I used some skinny pliers and made sure to not bend the part where the temp element is, I don’t see why it wouldn’t work but we’ll see this afternoon. I’m anxious to see how hot I’m running, hopefully it’s not something crazy high.
I was wondering what happened to you.

You will find, they run cooler then what most think.

It's gonna take a good 20 min. hard ride to get oil up to temp, before getting a good cylinder head temp reading.

I have found this way works good for setting ignition timing with cylinder head temp.
After you are very close with the carb jets and tuning try this.

With no tape on blower intake side, and oil is up to temp, run the snot out of it for another good 5-10 mins, pull over and watch temps drop while idling, you wanna see a 225-250 degrees steady, idling, it won't take long to get back down there, while idling. I have my idle set around 2000 rpm, to keep oil slinging, I run 3000+ stall springs.

If you see below 225 after this test, you need LESS ignition timing. Drop 2 degrees at a time, and keep testing.
If you see more then 250, you need MORE ignition timing, add 2 degrees at a time and test more.

When reading a sparkplug, look at the ground strap, you will distinctly see a color change in the bend of the ground strap. This is dam near perfect timing and the lil engine will be happy. If there is black soot, and you cannot see the color change in the bend, it is overly rich, loosing power, and needs some carb tuning.

For max cylinder head temp, you can control this with tape over the blower fresh air intake. The max temp is your preference. Add or remove tape to your liking. I run mine hard riding, 300-350 on a hot day. It always drops down to 225-250 at idle. Gokart engine builders recommend 400-420, during a race. And a rebuild halfway thur a season if that gives you an idea how hot they can run and live.

Mine is 3/4 taped up. I DO NOT RECOMMEND ANY TAPE ON AIR INTAKE, if you do not have a cylinder head temp gauge to keep an eye on it.
 

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SAS289

Well-Known Member
#44
I was a bit surprised how cool these run after checking oil temps just after rides. One of my bikes is pretty much just a yard rider that gets 5-7 minutes rides here and there that includes brief full throttle runs. I'm getting 110 degree oil from that which is nothing. The oil never thins out all the way. On my bike that gets longer rides I've never seen an oil temp higher than 155.

Seeing those temps I see no need to run anything thicker than 5W30. Last year my yard rider ran with 5W20 that I had left over from oil changes on my car.
 
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