Building a 416. Need help!

[Johnb427]

So I have seen several other threads but I wanted to make sure that everything that I have will work well together. I bought the quad last year and was told that it had a stg 2 hot cam and high compression piston. I found out last week when I tore it down that it didnt have the piston but did have a stg 1 hotcam. Since I had it apart I decided to try to get some more power out of it. I got a good deal on a new cylinder already bored to a 416. I have the stg 1 cam, +3 timing key, aftremarket air box and hmf slip on. Basically all I need now is a piston and gasket kit. I cant decide on a 10.1 0r 11.1 piston. Can someone give me some more info and advantages and disadvantages of each. Also will I have to rejet after going with the bigger bore and higher compression? I mostly trail ride with a few wide open areas if that matters.

[iSavage504]

If you really want a reliable & ScReAmInG 416 read my sig...
but for what u have so for i would definitely go with @ least 12:1 JE or 13:1 unless you dont mind running race fuel (105+ octane)
If you do go with either setup i do not only suggest but i PROMOTE C&D head porrt & polish along with Kibblewhite's HD valve kit. Also get you a header & CDI box with that slip on (not much but hey, theres a difference after head work)
The degree key is a major PLUS. i have a +3,4 & 6 & never had problems with heat.
To seal it all up, make sure your carb is tuned correctly, great air intake (k&n no lid) & consider a HD cam chain & a 06+ trx 450r carb from ebay would be a wonderful delight :D

[Johnb427]

Thanks for the advice. Do you have oversized head studs in yours? I also forgot to mention that I am on a budget. I don't want to put much more into it at the moment but I do want some more power. I was thinking 11.1 wiseco and be done for now.

[supertrooper90]

More compression = more power

In all of my research 11:1 comp. ratio is as high as you can go with out having to run race gas.

It sounds to me with your key and cam choice you'd be best off with running a 10:1 piston. I don't think you can run pump gas with the +3 key with an 11:1 piston. I know you said your cylinder was bored, but when you get your piston it needs to be finish honed to the proper clearances that the piston manufacturer recommends.

I have an 10.8:1 JE piston. I did the gt thunder head studs. In my opinion while everything's apart its just better to do it for minimal cost. But I think they bore it after the install of the studs to make sure the cylinder is true.

yes you will have to rejet.

If your looking for budget friendly, I'd do the 10:1 and keep the stock head studs and be done with it. I used the an xr400 head gasket on mine to keep the comp ratio where it should be.

[ish416]

If you are going to be running the +3 key stick to 10:1 or maybe 10.5:1 otherwise you will be needing to run somewhere close to 100 octane.

If you remove the key, you should be good up to 11:1 on premium pump fuel.

Since the engine is air/oil cooled most won't venture past 12:1 because of the need to run 100+ octane. If the engine was liquid cooled then 12 or 13:1 would be fine for pump gas. It comes down the temps being hot enough to ignite the fuel before the plug fires. That is a very bad thing.

A header is not really needed. It would be a waste of money for the gain you would get.

I would look into an 04-05 450R carb as they are about the best bang for the buck mod on an EX. The 06+ 450R carbs are FCRs which are one of the best types of carbs you can get but I am unsure if they will bolt on without an adapter. The 04-05 carb works perfectly and there are several write ups about them in the stickies section.

A CDI box is completely worthless IMO and most other members agree. The EX engines have long stopped making power where the stock limiter is. Unless you have an extremely well built EX they are simply not worth the money.

Also, get HD head studs.

So my list for you would look like this;
11:1 or 10/10.5:1 with +3 key
04-05 450R carb or rejet stock carb
HD head studs
CRF timing chain

You will need a jet kit either way you go with the carb.

supertrooper90 nailed it with the gaskets as well, XR400R gaskets.

[CJM]

Id suggest a 10:1 piston, you cannot use the timing key with the 11:1 (well you can but imho your borderline unsafe b/c of the heat the key will generate plus the comp ratio of the piston. Some have no issues, Id rather play it safe). With that setup you can run 93 octane no problem.

Ish and supertrooper are also giving solid advice. Head studs imho are worth it-heat generated b/c its an aircooled engine will cause the exhaust side studs to eventually come out-HD studs fix that.

I currently run:
11:1, 416, stg 2 hot cam, open airbox, my lexx/homemade exhaust setup, uni filter and Im quite happy. Its quite fast and while its not a 450, its got plenty of power vs a stock machine. Only thing left for me is the 450 carb-which is well worth it. An FCR carbs worth it but requires a bit more adapting than the 04-05 450r keihin carbs.

[supertrooper90]

I couldn't get my 450r carb to work during the break in period, so i used the stock 400 carb. It was quick, but I was a little disappointed with the 416 that I had built. Once I got the 450r carb figured out, it was like a whole new bike!!! The 450 carb really compliments everything extremely well. It truly does everything I want/need it to do.

[Johnb427]

Thanks everyone for the advice.

I will be getting the hd head studs since my cylinder is new and doesn't have studs at the moment. I don't mine running a race gas mix and I ordered a spal puller fan so I am thinking about 10.8:1 wiseco. So to sum it up my build would go like this.

416 with 10.8:1 cr
Stg 1 hotcam
Hd head studs
+3 timing key
Hmf slip on
Aftermarket airbox
Spal fan
And running race gas mix or straight 100?

[iSavage504]

Originally posted by Johnb427
Thanks everyone for the advice.

I will be getting the hd head studs since my cylinder is new and doesn't have studs at the moment. I don't mine running a race gas mix and I ordered a spal puller fan so I am thinking about 10.8:1 wiseco. So to sum it up my build would go like this.

416 with 10.8:1 cr
Stg 1 hotcam
Hd head studs
+3 timing key
Hmf slip on
Aftermarket airbox
Spal fan
And running race gas mix or straight 100?
OH YEAH! IM PROUD FOR YOU & YOUR EX!
I was actually typing a reply but just made few changes now that i've noticed you will be running race fuel :D
My suggestion of setup for you & budget:
VP C12 (108) DONT MIX - BURN STRAIGHT
JE 11:1 (87mm)
+3 Degree Key
(06') R carb
K&N (no lid OR JUST REMOVE COMPLETE AIRBOX & HEAD 2 YOUR LOCAL HARDWARE STORE & CREATE YOUR ON INTAKE BRACE TO HOLD FILTER STEADY & WRAP IT WITH AN OUTWEARS)
CRF or any other EX HD timing chain
XR Gasket (I AGREE WITH THIS AS WELL)
Full HMF exhaust if have few extra $$$
Thunder's studs - Will be needed in your EX's future of success & reliability
BUDGET COOLING MODS (A MAJOR PLUS 4 FUTURE SUCCESS)
Air shrouds $40-45
2nd Inlined EX cooler or universal trans cooler $25-35
SPAL fan (puller not pusher) $20-30
Larger capacity oil tank $70-80
OIL TEMP GUAGE $10-20

A CDI box is worthless on a stock/mild rebuild. I really didnt notice a difference in mines until my last build (sig) and then when i tried different degree keys i invested into a programmable CDI made by MSD ignitions ---> NOW WITH MY SETUP THERE WAS/IS A MUCH NOTICEABLE DIFFERENCE MAINLY IN REVS & ENGINE SPEEDS. Must know what you are doing with those programmable or else it's suicidal to your EX

GOOD LUCK & KEEP IN TOUCH ON YOUR BUILD

[Johnb427]

Well I keep leaving little things out. It already has air shrouds and a bigger oil cooler.

[iSavage504]

OH YEAH - Seems that you are on a good track for a great rebuild.
***DONT FORGET 2 TAKE PICS OF REBUILDING PROCESS***
We all on here would very appreciate the "high" from seeing not only ours but others progress with their EX :D

[supertrooper90]

If you leave the +3 key out you shouldnt need the added expense of race gas. Cam2 (100 octane) is $8.25 a gallon at the pump in nj. And the c12 is like $65 for a 5 gallon jug And if your running race gas I would do a 12:1 piston and get more power.

[Johnb427]

Im not 100% on the race gas but if I can get it for a fair price I don't mind paying a little more for extra power / reliability. I don't ride that often and even when i do I only go through about a tank of gas.

Here is a picture of what it looks like before I started tearing it down.

[Johnb427]

For some reason I could not get a picture to upload.

[ish416]

If you plan on going with a build that may require race gas, I would look to run E85 if it is available in your area.

You will need to jet 15-20% richer but it is the best "race fuel" for the price.

Nice looking quad btw.

[400MXer]

Are different head studs really necessary? I have a 416, with 11:1 or 12:1 piston, sparks cam, ported and polished, all the bells and whistles from Fischer Cycle but no head studs, and I have never had a problem with my head gasket. It has 4 hard seasons on it, before it became my backup and was still ridden a lot then. He said he is on a budget, and if there is no reason to get them, then what's the point. Save your money and put it somewhere else.

[Johnb427]

The main reason I am going to get the studs is simply the fact that I have a new cylinder that doesn't have any studs at all. I have to buy studs anyway so why not get the hd studs.

Also I have thought about E85 and it is available at lots of gas stations in my area but I just don't know much about it. Can someone give me some more info on it?

[Johnb427]

No major updates but I did send my cylinder to GT thunder today to have the hd head studs installed. Im trying to find the best price on a 87mm 11:1 piston before I make any more purchases. Any suggestions? And any info on e85?

[Johnb427]

Got some parts today. Im just waiting on my gasket kit and jets.

[426kidz]

where did you get tha spal fan? and how much was it?

[Johnb427]

Originally posted by 426kidz
where did you get tha spal fan? and how much was it?

Ebay. It was around $40 shipped

[426kidz]

cool...what size is it? remember who you got it off of?

[Johnb427]

Originally posted by 426kidz
cool...what size is it? remember who you got it off of?

4 inch puller. Sellers username was "Troygaud"

[Johnb427]

Got the fan wired and brackets made up. Just waiting on the paint to dry to mount the fan.

Also can anyone give any advice in jetting? It has a 160 main and a 38 pilot jet. Looking at the plug that came out of it it was running rich. With the mods I have already listed and wanting to run e85 can anyone give me a ballpark area to start?

[426kidz]

POST SOME PICS OF THE FAN SET-UP!!

[Johnb427]

I should have all my parts here by tomorrow other than the jets.
I need someone that can help me get in the ballpark on the jetting, because I dont have a clue. Anyone?

[ridehonda400ex]

Try getting it running where you want it with normal gasoline. Then up your jetting by around 20% across everything. That should get you pretty close to where you need to be. Then just fine tune it till its all good!

[Black450ER]

Took a little searching to get to the thread I remembered reading about E85, but I found it, lol! I want to try to use it as well. http://www.exriders.com/vbb/showthread.php?s=&threadid=460999&highlight=*e85

[Johnb427]

After working on it most of the weekend and doing things several times to get it right, I finally got to fire it up. It started right up but it does have a pretty bad oil leak and the valves are in serious need of adjustment. Hopefully I can get these small things worked out tomorrow and take it for the first ride next weekend.

[Johnb427]

Well its been a couple of weeks I have been busy (got married and went on my honeymoon) but I did get to take it out for a ride and I am very impressed by the added low end power that it makes now, but it is time for a new clutch. It pulls hard in first and second but third gear sucks unless you just roll into it. I might try to get a clutch in it before the weekend but either way I will be riding at a place called dirty turtle where Fischers ATV world will be this weekend.