Valve cover bolts...

[junior636]

Has anyone drilled and tapped the head to accept a larger or corse thread bolt? A lot of my bolts are stripped, broken off, orjust keep backing themselves out. One of my cam chain tensioner bolts pulled the threads too, all on its own.... Are you guys using any loc-tite? I'm frustrated!

[on the rocks]

most peope use heli coils to replace stock threase so you dont have a bunch of differnet bolts on your motor. the heli coil will actualy be stronger compared to just rethreading the aluminum due to the bolt and thread contact being steel on steel, not steel aginst solft aluminum.

[junior636]

Can I get the head off with out pulling the motor?

[on the rocks]

yes you can.

[CJM]

Tap to 1/4" or 7mm. Whatever strikes your fancy.

Then make DAMN sure you torque them to 7 foot pounds. I use a 1/4 ratchet and make them hand tight myself.

[junior636]

Well took the head off only to find my piston is missing a few pieces.....might be time to go hybrid crf 450, I'm really tired of this 400.

[CJM]

That does suck. But the better question is why did it happen-your fault for lack of maintenance or whomever you bought it from.

[junior636]

Im not sure, I only have a few hours on it, all I have done is work on this thing since I bought it. Its running quite rich so it wasnt lean. Its just missing a small piece on top on the edge so the ring is exposed. I will upload a pic when I get a chance. It was running great, I just wanted to fix the oil leak and noticed it.

[junior636]

If I buy a wiseco piston kit and go 12.5:1 would I need to run race fuel? Is wiseco the best to go with? Any thing else I need to know when replacing the piston?

[chronicsmoke]

Originally posted by junior636
If I buy a wiseco piston kit and go 12.5:1 would I need to run race fuel? Is wiseco the best to go with? Any thing else I need to know when replacing the piston? .

Never any problems with Wiseco in my 400.. You'll need race fuel with that piston.. Not to worry, people will be more apt to follow you for the sweet smell of the fuel burning :D

I went trailing Wednesday for the first time in like 3 years and that's what they were saying behind me, haha.

Are you boring they cylinder? If so, have them bore the cylinder to match the piston and hone afterwards.

[junior636]

Im not sure, there are no marks on the cylinder, probably need to measure to see if it needs bored?

[CJM]

Highest you can run on pump 93 gas is 11:1. As stated by chronic, 12:1 or higher means 100+ octane.

Wisecos fine, I used them a few times. The pistons are heavier tho and vibrate a tad, CP or Je is slightly better since they are lighter.

[junior636]

Whats the best? Anything better than the Je?

[Stickman400]

CP is the best but is insanely expensive
Wiseco is next in line with reliability and a nice price
JE would be the next option, but a few on here have said they melt, but idk
Namura is the worst of the bunch, DON'T BUY THEM, they are almost guranteed to melt.
Anything else I wouldn't trust.