[SamUK]

This is mainly for those who've been following my threads and answering my many questions.. (thank you to all who have helped me)

I got the timing sorted and it's set as close as I can get it, tensioner works fine, I'll fit a new change when I fit a new piston.
I've been back through a few threads and shady had written that the service manual states the compression should be 176 to 206psi for 1995-2000 models, mines a 98.
Take a look at the pics, lowest pressure is cold, highest is at normal running temperature!

Just to add, I didn't fit the big red cam, those pressures are with the stock cam.

 

[rodp]

Is this with throttle wide open and spinning over on starter ? If it is son, then unfortunately you have some work to do. Drop some engine oil down the plug hole to isolate piston from valves, may need quite a few squirts, enough to flood rings. If compression shoots up then it's piston, if it stays the same then it's valves.

Something doesn't seem right though, wouldn't have expected it to fire at those pressures. Test the tester with a tyre gauge if you can, hold one against the other and see if they both read the same.

 

[SamUK]

Just got into the house, I'll go back down and try again before I get in the shower.

Since I got rid of that flat spot/bog by tweeking the air/fuel mixture it hasn't wanted to start at all, it used to start without fail first press of the button within a second.

I'll report back within the hour.

 

[mac102004]

That motor is hurtin' if that's all your getting out of it.

 

[SamUK]

Is this with throttle wide open and spinning over on starter ? If it is son, then unfortunately you have some work to do. Drop some engine oil down the plug hole to isolate piston from valves, may need quite a few squirts, enough to flood rings. If compression shoots up then it's piston, if it stays the same then it's valves.

Something doesn't seem right though, wouldn't have expected it to fire at those pressures. Test the tester with a tyre gauge if you can, hold one against the other and see if they both read the same.

Okay, so I've made myself look a right wolly! :laugh:

I checked the hose on the compression tester to see if there were any obstructions, guess what, there was! One of those clear plastic plugs to keep the dirt out!

Here's the correct reading at full throttle off the starter with a fully charged battery.

 

[mac102004]

lol That's better, so that's with the OEM cam correct?

 

[SamUK]

In my defence the compression tester is new, I never thought to look lol.

I'm now a little confused as to why it won't spin 24x10 tyres in 2nd gear?!

 

[SamUK]

lol That's better, so that's with the OEM cam correct?

Yes, that's with the stock OEM cam, it's in good shape too with no signs of damage or wear.

 

[Manny]

I'm now a little confused as to why it won't spin 24x10 tyres in 2nd gear?!

that's because its only 300cc. these are not going to have high torque.

 

[misterclean59]

In my defence the compression tester is new, I never thought to look lol.

I'm now a little confused as to why it won't spin 24x10 tyres in 2nd gear?!

A marginal lean or rich condition can give low power without major symptoms. A clutch that slips just a little or brakes that drag come to mind.

 

[SamUK]

I'm not convinced Manny, I think there is an issue elsewhere. Blocked/rotten exhaust maybe, possibly carb jetted wrong, I don't know as yet. I'm going to eliminate things one by one and see what outcome I get.
My Dads 300 is snappy and feels alive, I've no doubt I could wheelie it with ease, mine is sluggish and lethargic, to wheelie I really have to pull up on the bars and drop down in the seat.
Easiest way to describe it... It's like jumping off a 450 dirt bike and getting onto a 250.

 

[SamUK]

In my defence the compression tester is new, I never thought to look lol.

I'm now a little confused as to why it won't spin 24x10 tyres in 2nd gear?!

A marginal lean or rich condition can give low power without major symptoms. A clutch that slips just a little or brakes that drag come to mind.

Brakes can be safely dismissed from the equation haha.. the fronts don't work at all and the rear is rebuilt, I have checked though and there all free.
I did have a flat spot/bog at about quarter throttle and tweaked the carb a while ago, had to richen the mixture slightly, there was noticeable difference though apart from the 'bog' disappearing.
I did wonder about clutch, if I'm in a mud hole and try to pull second gear all I get is the 'bog/induction' noise and no power to the wheels but the engine won't rev past that bog. It doesn't seem like the clutch is slipping but.... I'm no expert. I've never worked on ATV's this in depth before.

 

[fishfiles]

What year is your Dad's 300 , the one you are comparing your to ? ---------- 88-90 was a peppier engine ----- the wife's 90 engine screamed compared to my 95 , but as soon as break in time is over for me , I hope to out shine her

 

[Manny]

I just don't see it. ive literally bought over 40 fourtrax 300's. rebuilt quite a few, darn neart every year.

to date, I have never had one that had enough power to wheelie.

then again, I just don't see the need.

 

[fishfiles]

I don't really know your riding habits Manny but from reading your post over the years , I doubt your the kind of guy to do what it takes to get a wheelie on a 300 = from neutral , pull the foot shifter up with your foot as far as it will go and hold it there , rev the engine to the max and while leaning back , let your foot down fast

 

[mac102004]

Knee on the seat and foot on the rack, significant body english and wheelies are no problem even on my 94 running 18% GR and 28's. Sitting on the seat you can forget about doing wheelies.

 

[SamUK]

Maybe I'm just expecting to much then, bit of a bummer because it doesn't do what I want it to, Good job I fitted a winch!
My dads Is the same year, 1998 except his is mint, one owner from new and a sensible owner at that.
As a matter of course I'm going to rebuild the carb and bung the big red cam in and see where that takes me.

 

[SamUK]

I just don't see it. ive literally bought over 40 fourtrax 300's. rebuilt quite a few, darn neart every year.

to date, I have never had one that had enough power to wheelie.

then again, I just don't see the need.

Wheelies were just an example to describe the power, if I'm honest I s**t bricks if I wheelie the damn thing as the rear brake isn't good enough to control it when in the air!

Looks like I'm expecting to much from my 300, shame really as it's no longer very useful to me being gutless lol.

 

[shadetree]

I just don't see it. ive literally bought over 40 fourtrax 300's. rebuilt quite a few, darn neart every year.

to date, I have never had one that had enough power to wheelie.

then again, I just don't see the need.

Wheelies were just an example to describe the power, if I'm honest I s**t bricks if I wheelie the damn thing as the rear brake isn't good enough to control it when in the air!

Looks like I'm expecting to much from my 300, shame really as it's no longer very useful to me being gutless lol.

would you rather be gutless ?, or cashless ?..lol. wheelies do nothing but tear parts up. your atv, your cash, our time !..lol.

 

[SamUK]

Like I say, I'm not the biggest fan of wheelies on an ATV, if it goes wrong it hurts, BIGTIME! Lol. What I want is the power to spin the tyres ive just bought, kind of bummed that I've bought them and the damn thing won't pull second gear to spin them.
Going to fit my big red cam tonight, hopefully that will have some affect, will It be worthwhile fitting a hotshot cdi? Will I gain anything or is it a maybe or a waste of cash?