Hey everyone-

I just thought I'd pass down the tips I was given to increase the performance of my 04' Predator 50. As recommended by many on this forum I contacted Billy Holt from WRH Racing.

Here is what was said:


>Hi Billy-
>
>>From what I read on the net, you are the guru of mini quads.
>
>My 2004 Predator 50 needs some help. It continues to foul plugs and I need
a little more power out of it. I am considering a hi rev CDI. My thoughts
are that that will let the engine clear itself and burn the plugs clean. I
don't want to mod this for racing, but I want to make a reliable trail quad
for my 2 young daughters. My questions are,
>1. CDI yes? Which one? Will it work with the stock kill switch? How much?
>
>2. Do you recommend drilling the stock exhaust baffle?
>
>3. Your thoughts on lowering the needle in the carb one position to lean
it out a bit.
>
>4. Any other advice you may have.
>
>Thanks in advance, If sucessfull, I'll post the results on the atving forums.
>
>Mud_Runner


>============================================== ==
Billy's response was as follows-



I recommend leaning the needle 1 time, and drilling the baffle out with a
bit the size of the existing exhaust hole at the end of ther pipe. Also get
some boysen reeds for it. The cdi thing is up in the air right now as eton
changed their design, it is a no worky cdi now. Try the 2002 polaris cdi
for the 90.
Billy Holt


I did all the above and am very happy with the results. The atv starts much easier, doesn't foul plugs as easy, and is quite a bit quicker. I would have to say that the most improvement came from the new boyesen power reeds. These were the least expensive directly from boyesen.
Click here for Boyesen power reeds

They only took a couple days to get and were simple to install. Once apart and able to compare them to the stock ones, it's easy to see why they make such an overall increase in performance.

As far as drilling the stock exhaust baffle, it's quite a bit louder. I was surprised at the increase in noise. More so that being louder, it changes the exhaust note to a much snappier sound. After cutting of the exhaust tip and drilling the baffle, I played around a bit with the sound. I found that by holding the cut off piece back up to the pipe the sound was cut in half. It still seemed to rev the same but with a much improved sound. I welded the piece back on and am very happy with the result. For grins, I slipped a deep socket over it to see what difference a longer end piece would make. It was alot quieter. I settled for the OEM look.

My daughter seems much happier on it now. The above mods totaled less than $30 bucks and made much needed increase in performance.

Just thought that I would share.

Mud

 

Sounds like something I would like to do for my daughters 50. One question I have is what do you mean by leaning the needle one time-doesn't make sence to me sorry.

 

Did you try the 02 cdi? Did it work on the 04 pred? Thanks

 

Yeah it sounds a little odd the way it was written.

What he means by it is adjusting the hieght of the needle in the throttle slide assembly, you can effectively change the amount of fuel allowed to mix with the incoming air to the engine.

If you remove the air box assembly, you can look in the throat of the carb. You'll see the slide. If you press the throttle, you'll see it go up and down. The long vertical needle on the slide goes down in the float bowl and into the main jet.

By repositioning the needle, (or lowering it) the slide allows more air in while obstructing the amount of fuel allowed to come up through the main jet. This will lean the air/fuel mixture.

If you remove the carb and pull the throttle cable slide assembly out from the top of carb, you can take the needle off. It is suspended by a circlip that is in one of 5 or six grooves. If you move the clip to a higher groove, the needle will sit lower.

That is what is meant by "leaning the needle one time".

Sorry for the long winded answer. Hope this answers your question.

Mud

 

Nope - I have not yet tried a new cdi.

I am fairly content with the mods I've made so far. I have two girls and when the older one needs more, I'll buy another quad. I don't want to pass down a starter quad that will be to much for the littlest one.

If anyone else tries it, please post your results.
Thanks,

Mud

 

I'm going to do the mods listed above but I have a concern.

1) I bought the reeds from Boyesen and they say that there reeds will lean the mixture alittle.
2) when I move the clip on the needle one notch it will lean it out alittle.
3) I heard that if I drill the muffler baffle it will lean out alittle.

It seems that these mods may lean it out to much.
Is this true?
Will I need to do anything to richen it up alittle?

[img]i/expressions/face-icon-small-confused.gif[/img]

 

I would do a plug check after the mods. Might have to go up on the main jet.

If the plug looks good and power feels good and smooth your in busness.

 

hmm...wonder if there is a list of good tips for the 90 pred?

 

the performance parts list for the pred 90 is unlimited. you can get almost anything you want for them, motor parts, suspension, aftermarket shocks. almost anything

Mark

 

Drilling out the exhaust??? I've read other forums about this...Am I reading this correct,
1. cut-off the exhaust TIP
2. Drill out the hole with a similar size drill bit to take restrictor out??

You didn't cut off the entire end of the pipe...?