are HD head studs needed???

[trx400EXtreme]

if i bump my 400ex up to a 426 are heavy duty head studs really needed? whats the chances of the stock studs failing over the HD studs?

[m36indiana]

i run a 426 on mine without hd studs, only time you need them is if you go 11-1 compression or higher

[trx400EXtreme]

it says in your sig that you run 11:1.:confused:

[Honda#4]

I'd just run them so your safe no questions asked

[tar]

Originally posted by Honda#4
I'd just run them so your safe no questions asked

I would too..it's cheaper to do it the first time

[Honda#4]

^^^^ he's right

[trx400EXtreme]

alright, thanks

[Grant Casey]

but if i got a 440ex witha 11.1 or higher piston get the studs

[AZ440ex]

I have run my 440 with 11:1 for 4 years now with stock studs. I have had the head come lose once but I did not use a TQ wrench to put it on that time. Every other time I have and no problems.
If you have the money and the motor is already apart its not a bad idea. I think I have been lucky. It seems more people than not do have problems.

[400exrider707]

I think they are a good idea personally. I ran a stock bore 11:1 with stock studs. Any more compression, or a larger bore and I would have put studs in. I would rather have it there and not have to worry about it. Also over 11:1 I would also highly recommend a heavy duty rod. They have been known to bust with 12:1 and higher.

[lawdog800]

Do you need anything higher than premium pump gas with 11:1 or does it need a race gas mix or straight 110 race gas????

[trx400EXtreme]

you dont need to run 110 with 11:1. you can just run the regular pump gas, but it wouid prob. be better to run the premium.

[Honda#4]

You can get away with using 93 for 11:1

[lawdog800]

Thanx...

Trying to plan ahead. We are rebuilding the boys 2000 400ex. We just got it used and it is a little rough, so winter project is to completely rebuild top to bottom end to end. Ive been gathering parts slowly..New 450 shocks, Pro Circuit T4 exhaust on the way both from fellow members here. Ordered some ASV levers from EvilBay (Spend way too much time and $$$ looking for deals there...)

We know nothing of what if anything is done with the engine so it too will be stripped, measured and re-built accordingly....He already has some colors picked out for powder coat, still has to decide on 2000 plastics or newer 2005-2007 plastics.....got a brand new seat from e-bay for about $70.00 shipped from Hidy Honda.

This stuff is addicting..................We stripped and rebuilt both of our kids race snowmobiles with new PC chassis over the summer.......

[Ruby Soho]

get the studs. better safe than sorry

[DAVE14]

Ive pulled mine with 11-1 , i had the upgraded studs but a damaged cyl. with a helicoil . my next ( good cyl.) with more studs gave me no problem at all

[F-16Guy]

Sounds like it's getting done right. I agree on the studs; they are a must-have for reliability. I would also get a CRF450R timing chain (same as 400ex but thicker and stronger)and have the valves and valve seals done. If you're worried about having to run race fuel, you can always run the OEM 400ex head gasket. I think most of the pistons out there are designed for the xr400r, which uses a thinner head gasket, so that's what the compression ratios go by. If you use the 400ex gaskets with a Wiseco 11:1 piston, it should knock the compression ratio down a little. I have an 11:1 416cc in mine and I can almost always get by on super unleaded. I usually mix a little race fuel with it if I'm going to Dumont or Glamis because it runs hotter there.
I know there's a lot of debate on here about the 450r shocks, but I'm about 205 lbs and I have mine on +2 a-arms and they feel really good. I raced a couple WORCS races and placed 2nd and 3rd in Production B with the shocks completely stock. I think +2 arms would be good, or you could buy a spring kit and turn the compression and rebound lighter if you're keeping the stock arms.

[lawdog800]

SInce I am new to Quads, Where do you get different studs for the quad engines?????

Also, I see recommended here to use 450 timing chain...Does it use same gears and length?????

Thanx

[trx400EXtreme]

Originally posted by lawdog800
SInce I am new to Quads, Where do you get different studs for the quad engines?????

Also, I see recommended here to use 450 timing chain...Does it use same gears and length?????

Thanx GT thunder makes HD head studs. the crf450 timing chain is the same length as the stock 400ex timing chain. its just way stronger because it has thicker links.

[F-16Guy]

Originally posted by trx400EXtreme
GT thunder makes HD head studs. the crf450 timing chain is the same length as the stock 400ex timing chain. its just way stronger because it has thicker links.
Sorry about hijacking your thread. The GT Thunder studs are slightly larger in diameter with a few more threads. I would say that the installation is at least as important, if not more important, than the studs themselves. If you send your cylinder to them, you know that it will come back perfect. If you're having the cylinder bored, why not send the new piston with the cylinder and have them bore and hone the sleeve while it's there for the studs? It will be a bolt together project once you get it back. They do some of the best work out there, so you won't have to worry about whether the bore is straight or within specs like you might with a local shop, and their prices are pretty reasonable.
The CRF450R timing chain is stronger than the 400ex, and it's also a lot cheaper. I think it's about $28 from Service Honda.