yet another Bayou 300 prob...

[jacslx]

hi, Sorry for the long post.. but It explains all I have thought of or tried to hammer out the bugs in my Bayou 300 (Cliffs at the bottom)

I have a Bayou 300 and its being a very temperamental beast right now.
I have been searching and reading the forums last several days looking for some advice or help.

Its a 95 300 4x2. Got it from my father several weeks ago. He had it several years and had the engine rebuilt about a year ago. It has run fine since. About 6months ago it started to act up. It did sit a lot and has sat since. I got a hold of it and brought it home. I have since rebuilt the carb witch included a sitting overnight in chem dip. I checked the rubber vacuum thing and it looked good. I checked the rubber intake boot and it too was good. (like i said been reading the forums) I changed the fuel filters. I have cleaned the Fuel tank several times with alcohol. I have also cleaned the petcock valve. Put in a new plug, new battery and fresh oil. At first the spark was orange color. I discovered that the boot was dry cracked and came right off the plug wire. I have it now a ring terminal crimped on to the exposed bare plug wire and screwed on to the spark plug. It now has a more bluish-slightly orange spark but not totally blue spark. Oh I also set the gap at .028. I checked cam/crank timing to best eyball ability and seems spot on. One thought of it running rough was maybe chain slipped a tooth. Compression I checked on my comp gauge was 98psi. I dont know whats normal.

After rebuilding the carb and putting back on the engine, I set the adj screw to seat and then backed it out 2 turns as I read here on the forums. I sometimes have to squeeze the intake to get it to fire. Sounds like its not getting enough fuel. Speaking of fuel, for some odd reason, the fuel filter will not fill up. It fills up about 1/4 way (just enough to flow into the output side towards the carb). Is the filter supposed to be full or atleast 3/4 full? It did once fill up, it started and then ran semi-ok until it was emptied. It popped sputtered and was very cranky. At idle it would have a guess a miss fire of some sire and almost stop running but it would catch itself and stay running at idle. Died several times, was a pain in the arse to fire back up when it did it popped and backfired. Been messing with he screw adjustment and the idle screw adj. It will start, run for a bit.. die... very hard to start back up, come back in 15min and it will crank up...

Now I seem to have the idle hammered out. It is still a pain to start some times, even with the choke on and squeezing the boot. It will catch, then I take the choke off and it will start (sometimes). So I took it for a ride down the driveway and back. Worked great! Eased on the gas and went through few gears, no hitch! I thought I was finished, then putt putt.. it died! DOH!! hit the starter and few revolutions and BANG! back fired though the tailpipe. hmm.. So I finally get it back started and drive back to the house. drove just fine. Now its acting up again... seems back to square one...


Seems like once I get a prob fixed another comes up.

Questions/Cliff:
Is the fuel filter supposed to be full or at least 3/4 at all times?
What should the compression read.. mine reads 98psi?
Seems like it either getting too much fuel or not enough...?
Seems like it runs the fuel bowl dry, then takes time to fill back up. I checked the flow through the filter it drained the tank just fine...

thoughts suggestions... thanks in advance...

[MrGiggles]

Originally Posted by jacslx

hi, Sorry for the long post.. but It explains all I have thought of or tried to hammer out the bugs in my Bayou 300 (Cliffs at the bottom)

I have a Bayou 300 and its being a very temperamental beast right now.
I have been searching and reading the forums last several days looking for some advice or help.

Its a 95 300 4x2. Got it from my father several weeks ago. He had it several years and had the engine rebuilt about a year ago. It has run fine since. About 6months ago it started to act up. It did sit a lot and has sat since. I got a hold of it and brought it home. I have since rebuilt the carb witch included a sitting overnight in chem dip. I checked the rubber vacuum thing and it looked good. I checked the rubber intake boot and it too was good. (like i said been reading the forums) I changed the fuel filters. I have cleaned the Fuel tank several times with alcohol. I have also cleaned the petcock valve. Put in a new plug, new battery and fresh oil. At first the spark was orange color. I discovered that the boot was dry cracked and came right off the plug wire. I have it now a ring terminal crimped on to the exposed bare plug wire and screwed on to the spark plug. It now has a more bluish-slightly orange spark but not totally blue spark. Oh I also set the gap at .028. I checked cam/crank timing to best eyball ability and seems spot on. One thought of it running rough was maybe chain slipped a tooth. Compression I checked on my comp gauge was 98psi. I dont know whats normal.

After rebuilding the carb and putting back on the engine, I set the adj screw to seat and then backed it out 2 turns as I read here on the forums. I sometimes have to squeeze the intake to get it to fire. Sounds like its not getting enough fuel. Speaking of fuel, for some odd reason, the fuel filter will not fill up. It fills up about 1/4 way (just enough to flow into the output side towards the carb). Is the filter supposed to be full or atleast 3/4 full? It did once fill up, it started and then ran semi-ok until it was emptied. It popped sputtered and was very cranky. At idle it would have a guess a miss fire of some sire and almost stop running but it would catch itself and stay running at idle. Died several times, was a pain in the arse to fire back up when it did it popped and backfired. Been messing with he screw adjustment and the idle screw adj. It will start, run for a bit.. die... very hard to start back up, come back in 15min and it will crank up...

Now I seem to have the idle hammered out. It is still a pain to start some times, even with the choke on and squeezing the boot. It will catch, then I take the choke off and it will start (sometimes). So I took it for a ride down the driveway and back. Worked great! Eased on the gas and went through few gears, no hitch! I thought I was finished, then putt putt.. it died! DOH!! hit the starter and few revolutions and BANG! back fired though the tailpipe. hmm.. So I finally get it back started and drive back to the house. drove just fine. Now its acting up again... seems back to square one...


Seems like once I get a prob fixed another comes up.

Questions/Cliff:
Is the fuel filter supposed to be full or at least 3/4 at all times?
What should the compression read.. mine reads 98psi?
Seems like it either getting too much fuel or not enough...?
Seems like it runs the fuel bowl dry, then takes time to fill back up. I checked the flow through the filter it drained the tank just fine...

thoughts suggestions... thanks in advance...

I would just remove the fuel filter altogether until you get it running. See if that helps.

98 PSI is pretty low for these engines. They need at least 100 to run well and have 150 new. Set the valve lash and see if gets any better. If it doesn't pour some oil in the cylinder and see if it gets better. If it does the rings are bad.

The plug will be wet if it's getting too much fuel and will have black smoke coming out of the exhaust.

[86klf300guy]

first thing id do is replace that wire boot.any moisture will cause a miss fire.

if it sat for a while id bet the rings are stickin in there lands.once you get her to idle and run it may free up and comp wil come up

my bayou had 165 psi of comp after 4 yrs of ridein new rings etc it was 195psi.

for the fuel issue on that float needle look at the tip of it close for they will corrode under the neopren tip and swell it up cause it to hang up in the float seat and not let fuel in .or even stop the flow of fuel into the carb.

also did you replace the oring on the choke pludger?and te little oring on the air fuel mix screw?air flow screw shold be like this ,,,,screw then spring little washer then oring.basically oring washer spring screw.if you didnt notice the oring when you pulled the screw out then it got stuck in the carb and now its mush due to the chem dip ate her up and causein a leak of air.

and no the filter doesnt have to fill up at all times it will pull fuel when needed.when the float opens itll pull the fuel in and when it closes the fuel will stop and a little air bubble is in the filter.no worries all will be good there.

try those out first keep us posted -corey-

[TJ-Bill]

you had 195psi Corey? geesshh.. I'm going to have to check my valves. I think I had 110psi when I checked this week.

[jacslx]

Well I just got around to putting a spoon of oil in the cyl. The compression test came back at 170. Bad rings?

When I rebuilt the carb, I made sure that I used every part in the kit. I did pull out the tiny o ring and replaced it. I also replaced the choke o ring too.

Now I cant even get it to start anymore.

[MrGiggles]

Check the valve lash.

[jacslx]

Ok little update,

So I took the carb back off and once again, cleaned it. When I took it off, the inside was wet with fuel. As if I sprayed fuel in the intake tube? It was full of fuel so I suppose there is fuel getting to the carb, but when I unscrew the bowl drain screw nothing comes out, ?? I inspected the fuel float needle seat and it looked ok. Re assembled and gave hit the start button. I had to cover the hole where the air cleaner attaches to to get it to start. It finally tried to start. Puffing smoke out.. Which I assume is the oil burning off that I poured into the cyl. So it started, to my surprise. I let it idle and warm up for about a min. then I very gently moved the thumb throttle. It backfired and barely came up in RPMs when it died. Hit start button again and it started, let idle again for a min. Gently moved the throttle and same thing. After that, it wont start any more.

Question, what is the top plastic nipple that is angled up? What is that for? When I turned the carb upside down fuel poured out. When disassembled it seems to have a direct path into the float/bowl area... whats it for? Is there supposed to be anything on it? Seems like it would allow dirt and crap to get into the carb.

I have a buddy who is skilled in the ATV building world to come look at it. May do a re-ring on the piston if the compression is truly low and have him check the valve lash.

[86klf300guy]

that 90 degree elbow is a vaen and is supposed to have a hose attached to it that runs down over the back side of the engine.if it is open then yes it can get dirt into it.as for the carb i think you have a pilot circuit plugged.

when you pulled the carb down did you get both of the jets out of the machine?one is a pain to get into you need a small width flat blade driver to get into it.because it sets down into the carb.that is your air jet.and it has a buch of pin holes in it that plug easy.the only way to clean that circuit well is to remove that jet and clen that jet well and the cicuit.

but then again a bad set of rings can do that also not able to pull a good strong vaccuum.


tj .....yeap i had 195 when the motor was freshly rebuilt.i checked it before i sold it (that was a sellin point) it was 165.i had put in a high compression piston and gapped the rings a little differently than "by the book"plus a good valve job was done new vavle springs etc.if i rebuild an engine i do everything to it.not just replace what is wrong like a piston.if the piston is shot and being it was a 86 i thought id better just do it. so i dont have any issues on the trails.-corey-

[jacslx]

I talked to the guy who rebuilt the engine currently in the bike (for reference this is referred as engine A). Says one of the head bolts broke off.
@#$@# would explain the low compression. Nice to known that before all this messing around!! Thing is it broke off in the block. again @#$#@$#@!!! So I have acquired another bayou 300 assembled engine cheap (for reference this will be called engine b) with a bad clutch. Thing is about that, is that has been sitting out under a porch for about a year. guy said it ran good when it was in another bike, he planned to transplant the engine on a go kart, but that never happened.. soo it was left sitting on the porch. I have pulled the head and cyl out and find out is has a .050 stamped on the piston. So I have to use Piston B and cyl B. Piston cleaned up really good. piston fits in cyl tight and the walls probably could use a good hone. Engine valves on A look better than valves on engine B So my plans are:

1) Pull engine block A out. Put in engine block B, pull Clutch A and put on engine B.
2) Use cyl B and head A. Now I have 7 used head bolts. Are they re-usable or shall i order new ones?
3) Get new ring set for piston and gasket set
4) Put it all back together!

I checked the rotating assembly on Engine B and it spins fine with out any roughness or any other noise. Drained the oil on engine B and it was black, but no Water.. thats good. It was fully sealed when I got it, except the spark plug.

[99prairie400]

They always say "stretch bolts" but it's been my experience, unless you are building a drag engine, stick those old bolts right back in and rock out. Make sure that you run the bolts in and out of their holes a handful of times with penetrating oil on them before wiping and installing. Make sure that the new threaded holes aren't going to break one of the new bolts off clean.

The plan sounds, well, sound. Let us know how it goes.

[86klf300guy]

my self i would take the engine out and use a easy out to remove said bolt from engine a and chase the threads out with a flat bottom tap. or took it to a engine shop and had them do it at least you knew what your bottom end was like.and prolly a lot cheapper to repair said bolt than r&r engine parts.

a broken head bolt huh thats a new one.it must have rotted from sittin?and when they took the bolt loose it snapped?when you put the new bolts in the head use a little engine oil and coat them on the smooth part of the bolt not on the theads.do not put oil in the threads or on them for oil in the thread hole will givve a bad torque readin when you go to torque them down and they will walk out on you or damage the head due to incorrect torque values.
leave them holes alone use a flat bottom tap to chase the threads clean and use air to blow out the holes of any trash left from cleanin the threads up.
good luck on your repairs keep us posted -corey-

[jacslx]

Corey,

You do have a point. To not interchange any parts and just take the base block to a shop to pull the broke end of the head bolt out. He said it snapped when he was tightening it. About an inch of the threaded part is still in the block.

I mis read the stamping on the piston. It reads 0.50 not 0.050
is it really 50 thousandths over?

To clear up, if im looking for piston rings... I found on this site here

A piston ring set for .50 part number 13025... thats the one i need right?

[99prairie400]

That's .5 mm which is .020"

Corey, I can see your point about "the devils at least you know" but I'm not sure if I'd rather mess with the old block or a new block with new potential devils. It really depends on why the old block snapped a stud off in the first place.

If block A sat outside for a year uncovered prior to it being rebuilt and the stud holes are rusted all up, I'd take my chances with a block B (and keep block A in the shed for bottom end parts just in case ).

If the stud broke off on block A because the guys torque wrench messed up, an easy out and a thread chaser later you're golden, I'd keep block B in the shed as a backup.

EDIT: So why are you going to use piston/cylinder B again? Is the one you had on there before messed up? Now that you've cracked the cylinder you're going to have to replace the rings anyway. I'd use whichever piston/cylinder looked the best (that may be B but I couldn't find where you said A was messed up so I'm wondering what bore A is)

If you do use piston/cylinder B the part number 13025-1093 is the ring set for the .5 mm OS set.

[jacslx]

Thanks, I just popped the jug of engine A to look at the broke head bolt. Looks like he fugggged it up good. The hole it about twice the dia of the bolt it self when he tried to drill it out and he tried to helicoil it too. That poped out super easy too. So that goes back to having to use engine block B. I looked at the piston A and it looks good, just caked with carbon on top. The cyl bore A doesnt look to bad, probably could use a slight hone and new rings.

Revised plan:
Use CYL jug A, head A, Piston A, clutch A and just Engine block B... I ordered a complete gasket set and Ill just re-use piston A and get new STD ring set. Hone the bore and then put it all back together!

pic of fuggged up head bolt hole:

[99prairie400]

Oh that looks like tee-total garbage. Who was this you had rebuilding that engine?

Check cylinder A for bore size to piston clearance. There's a spec but I'm not sure exactly what it is although I can tell you, essentially, if the cylinder looks good and the piston doesn't fall straight through it from one to the other, it's good.

Definitely a hone to knock the glaze off and a new set of rings and you're probably good to go.

There really isn't an advantage to using a .5mm oversize set or not using that oversize set. I would definitely hold onto the other one for a backup but whichever is easier to use (probably the oversize which is still on the little end of the rod) buy rings to fit and go with it. I was just curious if there was a reason why you weren't using piston/jug A.

[jacslx]

After further inspection on Jug A, there were some scratches that can be felt with fingernail. On the skirts of the piston too.

So ill use Jug B and piston B.

[86klf300guy]

boy i tell ya some people shouldnt be doin engine work after seeing that pic.
that 1 why to kill a good block fast.but a machine shop can repair that easy
with a heli coil that will not come out.

send (b) to a machine shop an have it looked at and measured by them to make sure your getting the correct ring set for cylinder(b) and have em hone it while there,and set ring end gap for you(if you do not have a ring file) and have em put the rings on the piston for also.for if they break the ring puttin it on they will have to pay for another set

while your at it have the head boiled clean at the shop and a valve lappin done and replace the valve seals. its easyier to do it now and save headaches down the road.a little more money now will save you more in the long run.also gives you a piece of mind that the top end is fresh new for when other issues pop up down the road-corey-oh yea also have the head checked for warpage after seeing that bolt it may have warped it,have em check it and mill if needed.i can bet that head bolt was not tightened to specs -

[jacslx]

Excellent ideas... Yeah I was planning on refreshing top end.

[86klf300guy]

ahh heck if you want to make a little more bottom end power have the head milled any ways. itll boost up the compression.the stock comp ratio i think was like 8.5-1. my bayou had 12.0-1 cause i had the head milled and a piston custom made for my machine and bored it way out (cant tell all my secerts) but it made mad low end power.but just millin the head a few thousants will bummp the ratio to like 9 to 9.5 depending on what the cylinder bore specs out at when done.

good luck on your project keep usposted with pics if possiable -corey-

[jacslx]

Any Idea what piston this is? This is the .020 overbore piston. I was looking for rings and some said wont work on a weisco... I guess i just need to know if this is a weisco or not. thanks



Hmm mill the head a few thousands... I like it!