Thinking about grinding headers? Read this

[00426ex]

Some people are looking at my name and thinking, "Oh, this guy is a noob. Don't listen to anything he says. He needs to have 1000 posts before someone should listen to him. Blah Blah Blah" Well, just because I am new to the forum DOES NOT mean I lack information and knowledge. Some people may say, "Oh, well he is only 16, HE MUST NOT know ANYTHING about an engine." Well, I must say, I do not fully understand every component to the engine, but I know a good bit just from taking it apart. My dad has been around engines since he was younger than me, and he is helping me with everything I do and giving my advice and tips on the engine. By now, you're probably wondering where I am going with this. Well, being new to the forum, I have been looking around a ton. I have found many threads on ways to improve your performance. One often suggested way is to grind down the welds on the headers. Many people think this helps, some are confused, and some even think it makes it worse.

FINAL ANSWER: GRIND OR DON"T GRIND AND HOW?

An expert on motors once told my dad, "The faster you get air in and out of the engine, the more horsepower you have." Don't think this guy was dumb. He has decades of experience working on engines (he IS a professional). This applies to whether to grind the headers or not. As soon as I asked my dad if I should, he said yes straight up. He knew that this was not debatable and needed to be done if you wanted to get more air out of the engine. With the welds, they decrease flow to the exhaust. When you remove the welds and make it a smooth transition, the air flow is better, which in turn will result in better engine performance. It is a very simple mod, took me maybe 30 minutes (and a few tips from my dad) and it was all done. I have not got to ride it yet, but later on or tomorrow I can update you on how well it works.

STILL CONFUSED?

I know when I first started looking at engines and their parts, I was very confused on what went where, how, why it was there, etc. Follow these instructions and it will be super easy to get more performance out of your engine.

1. I find it easy to remove the silencer first. (Done by removing the small allen key bolt running through a bracket where the silencer connects to the exhaust pipe and where the silencer bolts on to the frame.)

2. Remove the headers from the engine by taking out the bolts that run through the mounting brackets into the engine.

3. I find it best to go ahead and clean off the headers now so you aren't getting everything dirty while your doing this, and so they look nicer =) I even painted mine with High Temp Grill Paint.

4. I used a Dremel to do this, but you can use any rotary tool you have. Get a bit that is a sanding stone bit. (See below for reference picture)

5. Feel inside the ends of the headers where it connects to the engine. You should feel a bump. This is the thing you will need to grind down.

6. Take your rotary tool (while using goggles because small shards of metal will fly all over the place) and turn it up to maximum speed (If variable speed). Start Grinding away the bump.

7. Intermittently check on the bump. You want to sand down this bump until it is gone. If it feels smooth, move on to the next area around the header and keep going. It is fairly simple and easy to do.

8. If you feel like you want to make it nicer, you can take a finer sanding bit and sand down the inside. I don't think it is necessary, but some people may want to do it so it is "cleaner".



Picture of the Dremel bit I used:

http://i117.photobucket.com/albums/o58/K1lLer_2006/dremel_bit.png


Pictures of what the header should look like before grinding:
P.S. Didn't have camera available before grinding so props to hornetgod13 for the picture:

http://i117.photobucket.com/albums/o58/K1lLer_2006/stock_header.jpg

http://i117.photobucket.com/albums/o58/K1lLer_2006/stock_header2.jpg


Pictures of what the header should look like after grinding:

http://i117.photobucket.com/albums/o58/K1lLer_2006/100_0997.jpg

http://i117.photobucket.com/albums/o58/K1lLer_2006/100_0998.jpg

[00426ex]

Any constructive criticism and input is welcome. Tell me how it is and if it helped any of you =)

[slightlybent47]

Nice write up, though there are many threads on the same subject, there is bound to be someone looking to do that mod.
I polished the inside of my header after I ground the welds down, I have port work so it just made since to polish the header as well. It’s just a very small increase in air flow but every little bit helps.

[vaget22]

X2. Nice post.

[IRISH-RACER-14]

Im like yourself. im also 16 and I too am being judged by my age. Great to see another young member.

[00426ex]

Thanks for the positive feedback from everyone =) This is a small mod, but yes, every little bit helps.

[Ian400ex]

I'd like to know, is this mod noticeable or is it one of the small mods that with another small mod you get something out of it?

[CJM]

Its a small gain but it is noticeable.

I did it a long time ago, combined with a good slip on I think it works great.

[Ian400ex]

Originally posted by CJM
Its a small gain but it is noticeable.

I did it a long time ago, combined with a good slip on I think it works great. Would it require any f/a screw adjustment? I need to adjust mine soon anyways.

[CJM]

Originally posted by Ian400ex
Would it require any f/a screw adjustment? I need to adjust mine soon anyways.

Nope, not that I know of.

[slightlybent47]

I have my doubts that anyone could tell if it had been done by just riding it, because it’s such a small increase in air flow. But with small motors there is not a lot of HP to begin with, so any gain you can get no mater how small will be helpful.

[Ian400ex]

Originally posted by CJM
Nope, not that I know of.
Alright, I didn't figure it was enough air to mess with the carb.

Initially I felt the same, slightlybent. I'll do this mod sometime soon I guess. :o

[tri5ron]

I have no doubt that it enhances the airflow. Especially when combined with a good slip-on, uni/K&N.

I think it would be interesting to see it dyno tested BEFORE grinding,..
Then again, after grinding,...
then again with slip-on & filter, (rejetted at this point)...
then again with airbox opened up and re jetted again.

This would give some true numbers for accurate comparisons, and would either support or disprove the varying claims.

Similar to the "shootout" I did with the dyno-tuned 400ex carb vs. the dyno-tuned 450r carb.
Data is good!

[Ian400ex]

Originally posted by tri5ron
I have no doubt that it enhances the airflow. Especially when combined with a good slip-on, uni/K&N.

I think it would be interesting to see it dyno tested before grinding,..
Then after grinding,...
then with slip-on,filter, (rejetted at this point)...
then airbox opened up and re jetted again.

This would give some true numbers for accurate comparisons, and would either support or disprove the varying claims.

Similar to the "shootout" I did with the dyno-tuned 400ex carb vs. the dyno-tuned 450r carb.
Data is good!

Good idea! Go buy us a dyno! You can be this forum section's dyno man. :D

+10 grand bye bye :(

[tri5ron]

Originally posted by Ian400ex
Good idea! Go buy us a dyno! You can be this forum section's dyno man. :D

+10 grand bye bye :(
Haha, yeah, I wish I could,
but I already did the "carb shootout" on my own dime, and provided all the data, for everyone here to use/take, at their own discretion.

Time for somebody else to take a turn and step up to the plate.

[fearlessfred]

Originally posted by 00426ex
Any constructive criticism and input is welcome. Tell me how it is and if it helped any of you =)
google anti reversion headers the lip that u ground out was prob. there for a reason i do believe there is always room for improvement on any part that is mass produced

[slightlybent47]

Originally posted by fearlessfred
google anti reversion headers the lip that u ground out was prob. there for a reason i do believe there is always room for improvement on any part that is mass produced

Yeah it was left there because Honda was too lazy and cheap to do it themselves. lol!!!

[sc400ex_rider]

Originally posted by tri5ron
Haha, yeah, I wish I could,
but I already did the "carb shootout" on my own dime, and provided all the data, for everyone here to use/take, at their own discretion.

Time for somebody else to take a turn and step up to the plate.

Same dribble, different day.


ZING!!!

[MidnightBlade]

i have one side ground and my dremel died on me on the other side almost as soon as i started. so i have one half way ground and one just nicked, gonna move to a drill with a dremel bit in it, i know it wont burn up.

[trailrider894]

Being respectful will get you much further in this forum than sarcasm ever will.

I am the son of a 25yr GM Master Tech who ranks top in the nation of the GM Mark of Excellence Testing, i rebuilt my first car from the ground up at 17. I know exactly what it is like to be doubted because of your age. Just own up and blow people away when you answer question like a pro.

Anyhow, Welcome to the forums. If you have any questions you can PM me or a-lot of other people on here. Finally, search is your friend. Again, Welcome. :devil:

[tri5ron]

Originally posted by sc400ex_rider
Same dribble, different day.


ZING!!!
^^^ :confused: I'm not sure that I follow how this applies here :confused: ^^^


and to the OP,
I forgot to say, Welcome to the forums.
There are alot of good folks here, and ALOT of good info is available on ways to improve performance on your machine. Everything from suspension, engines, mods, and accessories.
You can go from mild mannered stock, to healthy strong trail, to respectable XC, to all out full blown wild/radical. It's all here.
That's the time proven beauty of the 400EX.
It's nearly bullet-proof when properly cared for.

Feel free to PM me anytime, and again, Welcome to the forums.

[00426ex]

Thanks for the welcome =) I just got done changing the oil and filer. One thing sucks though. When I was tightening the long bolt on the oil filter case, the end of it snapped off. My dad will get an ez-out and hopefully get it out of there. Then I guess we are gonna get another bolt. One problem after another just keeps coming up =) I guess that's just life... Anyways, thanks for all the help from you guys and hope I can return some back =)

[tri5ron]

Originally posted by 00426ex
When I was tightening the long bolt on the oil filter case, the end of it snapped off. My dad will get an ez-out and hopefully get it out of there. Then I guess we are gonna get another bolt.
This is a fairly common occurance with that particular bolt.

Be very careful when drilling the bolt to stay on center. Remember that while you drilling, you will be applying clockwise pressure, that will try to tighten the bolt shaft even more.
Left handed drill bits DO exist, and help to prevent this.
Be very careful, take your time, and make sure you do not break the drill bit or ez-out off in the bolt shaft.

Another possibility might be, if you can remove the oil filter cover, and have some of the boltshaft sticking out from the side case,
trying a "Bolt extractor". If you need a pic of one, I will be happy to post it for you.
OR,...
you might be able to file a couple of "Flats" on the boltshaft, just enough to get a good bite with some vise grips.

be sure , before you try ANYTHING, to squirt some PB Blaster, or similar grade of penetrating oil, in around the boltshaft.
(WD40, or Liquid Wrench, is not the best, when it comes to penetrating oils)

You can actually make a superior penetrating oil, simply by mixing a 50/50 mix of Acetone and ATF.
(it actually rates/performs BETTER than PB Blaster).

I have an old comparison chart somewhere, that did a Lab controlled test on the rust dissolving properties, and tension/torque measurements, required to break free corroded/stuck bolts, using the various popular brands of penetrating oils.
The 50/50 mix beat out ALL the store bought stuff.

naturally be very careful, as it is highly flammable.
have your dad help you, and take your time.

good luck.

[00426ex]

Thanks for the advice. I'll try a couple things and will definitely be careful.

[CJM]

Using an easy you will not end well, they usually end up breaking off and then you got even more problems removing the EZ out.

Try removing the oil filter cover, maybe you have some of it left sticking out.

I personally would remove the case cover (super easy) and see if you got anything to grab there. Or you could drill the sucker out (gotta remove the case cover) and retap it.

[slightlybent47]

This seems like a common problem so I’m going to use some never size on mine and I hope I never encounter this problem. If you cant find a left hand drill bit you can make one but you need to know what you are doing. When I was in school shop my teacher showed us how to sharpen drill bits and it sure has paid off over the years.

[togup]

first i would like to say welcome to the forum, I really enjoy a technical post with good pics even though that subject has been beat to death here but I dont mind the repetition this forum moves very fast so whats on the first page today will be gone tomorrow. I also do not know a persons age or experience so i do not judge, what you post will usually give you away. Make no mistake these guys here know their exs better than the dealers mechanic.
one more thing concerning the header grinding, after doing a mod and there is no need to change carb settings did you do any thing at all?

[MidnightBlade]

you can just buy a reverse drill bit. but i wouldnt use an easy out, NEVER ends well.

[CJM]

Originally posted by MidnightBlade
you can just buy a reverse drill bit. but i wouldnt use an easy out, NEVER ends well.

I agree, its cause they break..

[sc400ex_rider]

Originally posted by tri5ron
^^^ :confused: I'm not sure that I follow how this applies here :confused: ^^^

I guess you wouldn't. LOL !!? Thats what you said to the drag racers in the locked "when we post" thread. Im glad were subject to your opinion and censorship. Removing peoples post is lame. I see people posting 4 sale items all time in the ex section. :rolleyes:

[JOHNDOE83]

X2!!!!

Also for some odd reason, Im one of the only two being censored?

[Foxhound013]

Welcome to the forums man, i'm glad to see i'm not the only teenager hangin around here in these forums lol. I'm 15 lol. As tri5ron said theres a lot of good people and info here, tri5ron and Steve (I think his username is honda400ex2003, or somethin like that lol) are two really good guys on here that I see a lot of good info come from.

[tri5ron]

Originally posted by sc400ex_rider
I guess you wouldn't. LOL !!? Thats what you said to the drag racers in the locked "when we post" thread. Im glad were subject to your opinion and censorship. Removing peoples post is lame. I see people posting 4 sale items all time in the ex section. :rolleyes: Wow ! you have certainly got me pegged !
Apparently you have found a need to misconstrue and miscomprehend a quote of mine in a different thread, directed towards a different member, on a completely different subject, to justify your own misconcieved desire to retaliate here.

So just to set the record straight,
I am not, nor have I ever been, a moderator.
I have no powers to move, lock down, remove, or censor anybodys thread.
If you have an issue with that, take it up with the Moderators.

Rather than getting into a debate with you over why you feel you are right, and/or have the need to compensate, I'll simply ask you this...

Do you have anything worthwhile to contribute ?, or are you just trying to hijack this thread ?

Ron

[250ex_dan]

will it wrk on 250ex too.?

[00426ex]

I guess if the headers have the huge welds and you have the time. But on a 250ex, I wouldn't waste my time. It wouldn't affect a 250 near as much but if you want to, it is your bike =)

[00426ex]

I guess if the headers have the huge welds and you have the time. But on a 250ex, I wouldn't waste my time. It wouldn't affect a 250 near as much but if you want to, it is your bike =)

[00426ex]

Sorry for double post =/