[mike dawson]

hello all i pulled the seat off my sons 01 xr100 to remove the plug in the air box but no plug the bike has never been touched since new it has a two hole rubber snorkle do i rip this out or just cut a big hole in the top of the box and then rejet please advise

[PGer555]

If that snorkle is removeable then rip that right out and make sure you rejet..

[WillCRF]

Mike,

I am in the process of doing the same to both of my boys '02 XR100s. Just ordered bigger main (102) and pilot (38) jets from our Honda dealer so waiting for those to come in before I start the project.

You can also purchase here at CRFsOnly those little round breather inserts which include a filter material. I think you drill about a 1 inch hole and pop them in. They are sold 4 to a pack. Was thinking of adding these to the top of the box in as well as removing the snorkel. It has been awhile since I had one of their seats off so I will have to first look at the box to see if there are reasonable areas to install these inserts.

Not really expecting much of an improvement with this mod a small bore bike. Regardless, I am sure the boys will think they are faster if it just sounds different. Maybe I will be surprised.

Will

[WillCRF]

Somehow an icon was inserted on the previous post instead of an 8. That was a 38 pilot I ordered.

Will

[mike dawson]

will what needle are you going to put in those 100s there is no power up kit so i dont know i'm putting a 40 pilot and going to try a 115 main 102 might be to lean did you gut the exhaust and put a hipo air filter we did i did this to my 150 and i went up 17 on the main and plug looks perfect i hope it works the same for the 100 any guess on the needle let me know

[PGer555]

I was helping out my friends lil bro with his xr100 jetting and we talked to the honda dealer. I was doing some reader on another site about what jet to use and they said they were using 102's and 105's. The honda dealer recommended even lower (obviously). So we were going to go with the 105 but we ran out of time in the summer. A 115 would be way over rich on an xr100. They use 115's in crf150's. Try a lower main and ajust the needle as needed.

[WillCRF]

Mike,

We started with a 105 main, 38 pilot, stock needle lowering the clip one position (richer) and placed 4 round air vents in the top of the airbox. After adjusting the fuel screw in, it was running very crisp for a XR100. We did a side-by-side with our other XR100 and you could tell a difference.

The next day we ran a Poker Enduro and the bike was stalling now and then. The temps that day shot back up 70 degrees. I think it was a rich bog / stall. Turned the fuel screw in some more and it ran fine.

I have not checked the plug to see what is going on. Might still be on the rich side with the needle and main adjustment. If it is, I will let you know.

Will

[mike dawson]

will what screw are you guys turning the idle screw or the one in the bottom (i was told to leave that alone)also they told me to take the bike out and run it wide open then pull the clutch and push the kill switch and coast back and this is how you check the plug is this right ?????? let me know thanks

[WillCRF]

Mike,

You are correct on how to check the plug by using the kill switch at different throttle positions. As far as the screw on the bottom, that is the fuel screw. The screw on the side of the carb addresses the idle.

If you add a larger pilot jet, you will have to adjust the fuel screw on the bottom. The pilot jet and fuel screw work in tandem to control fuel from zero to about 1/4 of the trottle travel. By adding a larger pilot, you need to reduce the amount being provided by the fuel screw. This is done by turning the screw in or clockwise. I kept turning mine in little by little after adding the new pilot until I got good crisp throttle response off idle.

Overall the modifications I made to my younger son's bike (pilot, main and airbox) has made the trottle response much better. There is a lot less hesitation or throttle lag. Now my other son is on my case to bring his XR100 up to par with these modifications.

Let me know if you have any additional questions. Good luck.

Will

[mike dawson]

hey will did you gut the pipe also what main jet did you use did you change the air filter last ? do you think that a 40 pilot is to much thanks for the help let me know mike

[WillCRF]

Mike,

I modified the pipe by simply adding a Powroll Exhaust Chamber. I bought it here on CRFsOnly. The main I installed was a 105. I also bought a 102 if this turns out to be too rich. The pilot jet installed was a 38.

I also installed 4 airbox round vents to open up more air. Those are also available here on CRFsOnly. I still have not done a plug check to see if I am a little on the rich side. If so, I will drop back down to a 102 on the main.

I think you will be happy with these cheap modifications. The carb work definately makes the throttle response better. Not really sure if the Powroll chamber adds any additional performance since I did everyting at once. It does make it sound faster which is probably more important to my son than throttle response.

Will