[Rednek12982]

Ok so a friend brought me his 98 fourtrax 300 4x4- says hey it was running, smoke came from front area(smells electrical). He rode for about 2 hours finishing what he was doing. Before this he was already having to kick start because it wasn’t keeping the battery charged. After the 2 hour ride it totally stoped working

I start to diagnose the prob, cdi has a melted hole in it, order it, the plug wire, the regulator/rectifier, plug, get that all installed and try to start, carb is acting funny now, easy fix right, carb rebuild kit, run to local Honda shop and pick one up. Now it idles but Boggs down/dies when throttle is applied.

So I have done the following(should eliminate to many question):
1-Rebuild carb
2 Installed carb with float bowl off to verify float valve is working and fuel is making to bowl
3 - checked and adjusted valves
4-5-Torn carb down for the 3rd time, carb cleaner and air compressor
6-gone step by step in repair manual thru electrical system
7 - here’s the one I think it is; Compression check- 120 psi- the manual says 178-206! Wow that’s high, my question is could I have caused this by adjusting the valves, this isn’t my first time doing it, and I’ve verified it 2 times, but if it’s been out of adjustment too long could the valves need to be left “out” of adjustment

 

[fishfiles]

....from what I have experienced 120psi and it will run but poorly -------- low compression could be because the timing chain is stretched out and the piston is not getting all the way up before the valve closes ---- also if the diaphragm on the slider in the carb has a hole or tear in it then it will run ok till mid throttle then fall on it's face ---- when you replaced the CDI etc , did you use Honda parts , the after market parts off e-bay are junk , also not all year 300 CDI are interchangeable as far as I know , it sounds like you might be fighting more than one demon

 

[Goober]

A couple of things for you to test; from the manual.

How new is battery? You can get hard starting and rough running when the battery is bad. Perform a load test.

Also the stator can get fried if you run it too long with a bad battery. Perform the diagnostics.

I don’t use compressed air; I use pipe cleaners and swabs

 

[Rednek12982]

Well it’ll run, and run good on 120psi, but get this, I didn’t drink enough beer!

See the other night I only drank 3, but after being 6 in

I decided to take the top off the carb, and manual lift the slide to see if that would change something, and bam, runs like a champ, so I went in and moved e-clip, I copied it as was, in the middle, but I’m guess the new nedle is a touch longer, so it wasn’t letting enough fuel into the motor.

Now it’s running like a champ!!

 

[fishfiles]

when you took that compression test did you hold the throttle wide open ? it will read low if not . if you are really at 120 right now , your not running as good as you could

 

[Goober]

LOL not that I’m trying to rule out the positive effects of alcohol ... #1 I’m glad your quad is running.

Perhaps the pilot screw or linkage not adjusted correctly and your new needle setting compensated for that.

When you rebuilt the carb did you also replace the needle seat? It wouldn’t be a good thing to replace the needle and not the needle seat, but I’ve done it. (The seat usually comes with the kit but the manual doesn’t really tell you how to remove it.)

So anyway it sounds like you’re motivating and that’s good. Check that spark plug every now and again—if it’s fouling consider you may have to readjust the pilot screw settings, throttle linkage and needle plunge.

 

[SamUK]

Regarding the compression test, did you perform this at wide open throttle? A low reading will be shown if the throttle isn’t open fully.

Glad you found your issue though.

 

[Rednek12982]

To those that ask, yes I did it at wide open throttle

 

[Rednek12982]

Yes I replaced the seat, I’m guessing someone has either installed the wrong pin or adjusted to conpensate something in the past, or replaced the pin and not the seat, who knows....

 

[shadetree]

the clip on the main jet needle is suppose to be set in the middle groove, this is stock setting from the factory. as goober said, if you did not replace the needle seat ?, this might be why it runs better when moved it.