[dydot]

Hello everyone,

I am new to this forum and new to working on ATV's. My fiance has a 1998 300ex that I recently got running. However, at 3/4 throttle and after the quad will bog down. I have put a new carb from amazon on the atv and it runs good other than the 3/4 throttle issue. I thought it was due to a bad exhaust pipe because it was cracked right after it connects to the motor. I replaced the piping and now does not leak. Since then I have put a new spark plug and fuel filter on it. I have messed with idle screw and another screw on the carb and neither have helped. Any help would be greatly appreciated. The carb is a Caltric Caltric Carburetor.

Link: https://www.amazon.com/Caltric-Carburetor-TRX300-FOURTRAX-1988-2000/dp/B0083W18IU

Anyone know how to properly tune this carb?

 

[j.dalton0309]

Hello everyone,

I am new to this forum and new to working on ATV's. My fiance has a 1998 300ex that I recently got running. However, at 3/4 throttle and after the quad will bog down. I have put a new carb from amazon on the atv and it runs good other than the 3/4 throttle issue. I thought it was due to a bad exhaust pipe because it was cracked right after it connects to the motor. I replaced the piping and now does not leak. Since then I have put a new spark plug and fuel filter on it. I have messed with idle screw and another screw on the carb and neither have helped. Any help would be greatly appreciated. The carb is a Caltric Caltric Carburetor.

Link: https://www.amazon.com/Caltric-Carburetor-TRX300-FOURTRAX-1988-2000/dp/B0083W18IU

Anyone know how to properly tune this carb?

Welcome to the forums from East Texas! Your issue is the jetting in the carburetor. Does it have a snorkel or anything? I would recommend a dynojet jet kit. They have derections to tell you what altitude and what jets to use.

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[SlammedRanger]

China junk carb. Mostlikely will never be 100% right no matter what you do. Did you keep the oem one? Hopefully you did because you will be cleaning it and using it in the end. The china carb i bought is used as a paper weight in my shop. Holds down papers really well. Dosnt make a good boat anchor though lol. Welcome to the forums!

 

[dydot]

Would the Dyno Jet kit work in this carb? I am in southeast ohio so I believe 800 ft above sea level. The quad actually came with a carb just like this. I am assuming the previous owner did the same. I bought a used carb on ebay and it came in pieces missing a one part. Ill pull it back out today and take a picture of the piece I am missing.

If you look at the reviews of this carb they sound very promising. However, my situation is not lol. Do you guys think there could be any other issue besides the carb causing this? Since it is at the 3/4 throttle mark, that means that it is the main jet causing the issue?

 

[dydot]

I have attached a picture of the part i am missing.

 

[dydot]

Thanks for the help guys. I really appreciate it. What do you think about this Carb?

Honda TRX 300 EX TRX300EX Carb/Carburetor 1993-1997 NEW | eBay

 

[j.dalton0309]

Sold? Anyway yea you need that spacer, anything used is always a bad idea (no offense) I've just never had good luck out of used stuff, I'd go to the nearest Honda dealership and order a new carburetor from Honda, you may also check spark plug

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[dydot]

Yeah I did replace the spark plug yesterday. There are more like that carb. It says that it is NEW rather than used. I have had bad luck with used aswell.

 

[SlammedRanger]

That piece you are missing is a baffle to keep the fuel from sloshing passed the main jet. If that is missing you will get a bog on sometimes when hitting bumps or jumps. I have actually had very good luck with used parts. I always buy on ebay and if its not as described i get my money back. Really hassle free. My experiance with china carbs of any kind is the floats dont work for crap. They either stick open or closed. I would bet thats your issue. Your probably running the bowl down faster then the float can re fill it and thats why your bogging 3/4 on up.

 

[dydot]

Yeah that makes sense! This china Carb does not have the baffle either. What do you think about this Carb on ebay? I think I will order it, if you guys think its a good idea. I was not able to find a replacement baffel.

Thanks again guys for the information.

 

[SlammedRanger]

I dont like that the brand says O. Thats got china written all over it. I wouldnt purchase any oem carb that isnt keihin. Or mikuni. Personally.

 

[dydot]

Okay, I don't think ill buy that then. With my stock 300ex carb I have a rebuild kit. Would the quad run good without that baffle then? I cant seem to find a baffle.

 

[SlammedRanger]

It would as long as your not racing or jumping big jumps. I wouldnt trust it to hold consistant power of the lip of a jump at all. For safety reasons. You may notice alittle hesitation in trails on big bumps or g-outs also.

 

[dydot]

Great I will give that a try. She will not be doing anything crazy. Just doing some donuts in the yard lol. Thanks for the help. Ill continue to look for another baffle.

 

[TRX2fiveO]

I probably have one.... But honestly remove the air filter box lid abd see if the bog goes away?... I would most likely change the main to a 130 and the slow to a 40 but pull the lid first and run it.

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