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View Full Version : i desperately need help with my 416!!



rhandw69
09-04-2001, 05:57 PM
Recently i installed a Je piston, 416 kit.
This past weekend i took it to the sand dunes for the first time since the upgrade or downgrade!!
I have noticed a great increase of bottom end to mid. However from mid to top i virtually have none. In a 300 yard drag, i was getting past by scramblers, stock 400exs and anything else that tried. I could jump out on everybody by about 2-3 bike lengths. But once im there, i have no pulling power to top end speed.
Last year i was able to consistently beat the same bikes that are beating me now.
Who out there has a 416 that can ofer me some help on this, what is your carb settings at??
I left the cam stock as well as the carb, i do have a WB e series and K&N.
So where do i go from here???
Rhan

nakomis0
09-04-2001, 06:30 PM
Sounds like you could use some jetting.

rhino99
09-04-2001, 07:14 PM
Jetting sounds like the problem to me as well. I had a 300ex that I put a pipe on and the top end sucked. I finally jetted it right and the top end was 100 times better!

NVR2L8
09-04-2001, 10:25 PM
Did you do any jetting changes after the motor work? What kind of jetting are you running now--pilot, needle, and main? Just as a starting point due to the increased displacement, I would think you would need a larger pilot jet, maybe lower the clip to richen up the midrange, as well as run a larger main. Of course, each setting depends on how the motor responds at the different throttle positions. Lastly, are you running quality unleaded premium that is at least 92 octane?

rhandw69
09-05-2001, 09:43 AM
Well i had this buddy of mine working on my jetting so much that im not sure what im running now, i believe that i have a 148 pilot jet. A 162 main, and the clip in the last position to richen it up. All weekend long i was having a problem with it being really really lean. In fact dangerously lean. We turned my air/fuel mixture out 3 .5 turns.
Im beginning to think that i just need a bigger carb or something!!! Or a cam, because there is no way a bone stock 400ex should walk rite by me easily when 5 months ago, the same 400ex was basking in my sand roost by about 3-4 bike lengths. Needless to say it was a very frustrating weekend because of this. So i gave up on the 400 and rode the Banshee the rest of the time. Sorry!!
Rhan

MJNOVA
09-05-2001, 10:31 AM
It sounds like something is amiss. For what your running a 50 Pilot and 162-165 should be OK maybe a little less depending on alt. If your still lean your sucking air somewhere or something is put together wrong. A 416 with a cam will ALWAYS outrun a stock bike.

rhino99
09-05-2001, 10:40 AM
I think that you maybe have an air leak somewhere. You shouldnt need a bigger carb, just bigger jets to richen it up. I am not sure how you would go about checking for an air leak. Is your plug still lean? If so, HOW lean, is it real bad, or jut a little bit leaner than you would like?

I agree that a 416 shouldnt get beat by a stock bike under any circumstance besides rider error. Even without a cam you should stil be faster because you have a high compression piston. Actually, what compression are you running? Maybe you need race gas?

09-05-2001, 11:03 AM
I'd get on the horn and call somebody that really knows what there doing before you need a new motor installed to fix the one that's soon to be blown up.. Call curtis sparks, tc racing, gt thunder, rocky ridge racing,,,somebody with the knowledge of what should be happening with that motor...Be smart and patiant with it,,,good luck..:D

MJNOVA
09-05-2001, 11:45 AM
Just to clear things up: RACE FUEL does not give you horsepower. A basic rule that is most times true is: Use racing fuel for two reasons----A> If you increase comp. to the point that you are getting detonation--use a higher octane rated fuel. B>If you are trying to control engine temp. it is also a good idea. Race or High octane fuels burn slower and more controled, that's all in general. Most engines will produce more power on cheaper-lower octane fuels-----They may blow up, but lower octane fuels burn hotter... The way to use race fuel is to burn it and advance the ignition---Best of all worlds... If you go beyond 10.5 or so to one on a EX it's best to run it.

rhino99
09-05-2001, 12:02 PM
I wasnt talking about using it to make HP, I just meant that maybe if he was running a high comp. piston, that not using it would cause it to heat up and not run as fast top end? I was told when I had my 300ex that excess heat sucked hp, so I thought that could be a problem?

MJNOVA
09-05-2001, 12:24 PM
SORRY---I am always reading about people wondering how much faster their bike-quad will run or has run stock with race fuels.
I ran my quad through 10 pulls and lost about 1 to 1.5 horspower as it strated to get hot. I let it cool and the numbers came right back. 400's hate the heat...

My questions is---Why bore to a 416 and do no other work. Without a cam or headwork or carb the differences will be small.

rhandw69
09-05-2001, 12:56 PM
Ok heres some answeres to some points made,
i am running pretty much at sea level here. Sometimes we may be at aroun 700 ft, but thats about it.
I couldnt afford the cam and the carb, im just taking it step by step as my funds get bigger.
If my bottom to mid is good, than what jettings change or alter the mid to top?
I had a guy ride it who knows alot about these things and from what he said, he loved to low end torque it gives, but what he noticed was that it wants more fuel. He said when he dragged it, and hit 3rd, the motor shut off as far as giving more speed and power. He thought that all it needed was to get more fuel.
So what do i do to accomplish this???
RHan

papaw
09-05-2001, 07:40 PM
this might be a long shot but do you know the vent hose that goes from in between the intake and carb to the heat shield try plugging it up.i know sounds pretty crazy but when i put my 416 together i had problems with my carb needing more fuel also.just pull your plastic and start it up and stick your finger over the hose and see what it does.for mine it was sucking extra air directly into the motor.plus don't be afraid to go big on the jet.i'm at 800 ft.and i can run a 210 main with no problems depending on the temp.but i also have a couple of extra mods than you right now.

NVR2L8
09-06-2001, 12:12 AM
For just a 416 overbore with no other mods the stock carb is just fine, and is capable of providing enough fuel for the engine. In fact, there are a lot of people who have built 416's, 426's, 440's, and have included cams, head work, and other intake and exhaust mods, and the stock carb works fine with these engines. Although an FCR helps more heavily modded engines you don't necessarily need one, so you don't need a larger carb to fix your problem.

If I were you I'd check the intake system for any leaks, especially since you probably had everything off during the rebuild. Get some spray starter fluid, and while the engine is idling spray a little bit of it at each point where there is a connection. If the engine rpm speeds up a bit when spraying the starter fluid, you've found an area where air is getting in and affecting your jetting.

The needle and main jet affect the jetting and alter the mid to top end. Since you've increased the displacement though, you need to rejet starting from the bottom up. My guess is you need anywhere from a 48 to 52 pilot jet. Install whichever size gives the best performance when starting it cold, and after warming up doesn't hesitate when you slightly wick the throttle. With the pilot jet your fuel screw should be near the standard setting of 2.5 turns out. If you have to adjust more than 1.5-2 turns out then go to the next size larger pilot...conversely, more than 1.5-2 turns in then go to the next size smaller pilot jet. Then work on the midrange by adjusting the needle. Although I doubt you'll need to adjust it from the 3rd notch, try lowering the clip to richen it up a bit. See how it performs from 1/4 to 3/4 throttle, and raise/lower the clip accordingly. For the main, I always install a larger main jet than necessary, and then work down. For your mods and elevation my guess is you need around a 165-170 main jet, so start with a few sizes larger than that. Make sure you're doing a chop to check the plug throughout the 3 main throttle ranges. Also keep in mind that a lot of brands of pump gas tend to burn really clean, often resulting in a white deposit on the plug even though your jetting is correct. You might try running a blend of premium and unleaded race gas in order to get a good plug reading. FYI...here in CA there are some many additives in the gas, that my plug reads white even when correctly jetted. When running a 50/50 mix of race gas though, my plug is nice and brown.

Lastly, if you still have a power problem and can't get it jetted, then there might be an internal problem. Are you sure that you got the index marks lined up correctly when installing the timing chain and cam sprocket? I don't have my service manual handy and can't remember the exact procedure for aligning the marks, but were the timing marks lined up and on the correct stroke?

rhandw69
09-06-2001, 11:17 AM
One thing i did notice was that according to the manual, the timing mark has to be on the "T" so that the bolts on the cam sprocket are perfectly horizontal to the cylinder. Well, we tried, but the best i got it was about 1 tooth off. One bolt is on the line and the other is slightly below the cylinder. Now we are wondering if that has a huge affect on it.

What is the stock pilot jet on the 400 anyways??
I have a 48 in it now, we put that in to kind of experiment with it from a 42. We didnt have a 45.

Thanks for all the advice
Rhan

09-06-2001, 11:22 AM
stock pilot jet is 38...

Stunz
09-06-2001, 11:27 AM
[QUOTE]Originally posted by NVR2L8
[B]...For the main, I always install a larger main jet than necessary, and then work down. For your mods and elevation my guess is you need around a 165-170 main jet, so start with a few sizes larger than that.

I agree. Get a bigger main jet.

09-06-2001, 03:24 PM
Definately change your jetting. Look for air leaks, and if you really want to get something out of your 416 get a timing advancement key and have your flywheel cut. If you are to do this you will beat stock 400's by 3 and 4 bike lengths in 200ft. If you really want to get serious do a little head work and change your cam.

86atc250r
09-07-2001, 11:03 AM
Well...

The reason you had trouble lining up the cam timing was because your cam chain is worn.

As the cam chain wears, the tensioner takes up the slack and retards the cam timing which shifts the power into the top end.

One thing that could have happened is if it worn beyond the point that you can tell where the cam is supposed to really be timed to, you can accidentially advance it one tooth - advancing the cam will shift the power toward the bottom end of the powerband.

When I replaced my cam chain, it was so far retarded that after I replaced the chain (which put the timing back to stock), I actually lost a lot of top end and had to lean my jetting out. I have since slotted my gear and can alter my timing as I choose now - right now, I've decided to stick with stock timing.

I'd be checking that timing right away if your engine is struggling to pull the upper mid and top. As I said, if the chain is worn to the point that you can't properly line things up, go the direction of cam retard, not advance.