Oh yes! It was definitely worth it! She’s a great machine to this day, I’ll be getting POV footage on it right away here, we got some snow now so will be a good test for her as it had no issues in the mud, very strong machines they are!
@@tanmansbikebuilds931 So happy you like your new toy! l offered a parts 2006 Poliar 2 stroke 450 4x4 with a rod through the bottom, looks very clean. Do you know anything about this beast?
You are right, it is piston/ring issues, l poured 2 spoonful oil into spark hole, compression shot up to 181 lbs from 66 lbs, so good valves seals confirmed.
Before top end renewed, l put some lucas and engine restore, managed to bring compression to 80lbs, the idle is not dying anymore. If l horn the cylinder, if there are no deep scores, ring gap 10-15 mil is acceptable. l just re ringed a 99 Merc 90 hp, the gap on new rings are 20-25 mil, still getting 120 lbs compressions (2T motor). no complain.
It really is a simple procedure I was quite intimidated when first looking into it and also assumed I would have to pull the whole motor but with the cylinder studs out the top end can be removed without pulling the motor, major plus! Just be sure to be at top dead centre before you start tearing it apart, and be sure to not let the timing chain drop in the bottom end zip tie or use a wire to keep the timing chain up tie it up the the frame. But overall was quite a simple process so don’t be intimidate! Good luck! If you run into issues let me know and I’ll see if I can help you👍
l got 66 -68 psi on my smoker Bigbear, too low for 114 psi spec. min. Is it bad rings or bad valves? Was flying around neighborhood in light snow ground, still has lot of power😀
Sounds like the piston to me, I thought valves or even valve seals aswell but you’ll be surprised how bullet proof these quads are, so they will still run with a blowen up top end so definitely pull your cylinder off and take a look, if the piston looks good measure the ring gap and be sure there in spec but definitely check out the top end, valves on these quads are a bit of a task but can be done with the proper tools, but it ended up being my top end anyway, let me know your results!
So does the whole cam come out of the head when you take the chain off or just the sprocket? And if it’s just a sprocket, is there a key way on the cam?
Chances are if you can smell gas when you dump the , that is why it’s smoking. The carb is leaking fuel into the engine causing it to over full. Fix the leaky carb and that bikes ready to go.
The carb has never leaked, if you watched the video you would see it was just my piston was rubbing the cylinder walls because the rings were shot, I put a new piston and rings and honed the cylinder and has never smoked since and I’ve been riding it for almost a year since then, it’s never leaked fuel, it does leak oil from the transfer case tho, so I constantly have to top oil up every hour of riding so that will be the next major fix!
You and your Grandpa had so much mud fun, it worth all the time and smart work put into restoring the Bigbear!
Oh yes! It was definitely worth it! She’s a great machine to this day, I’ll be getting POV footage on it right away here, we got some snow now so will be a good test for her as it had no issues in the mud, very strong machines they are!
@@tanmansbikebuilds931 So happy you like your new toy! l offered a parts 2006 Poliar 2 stroke 450 4x4 with a rod through the bottom, looks very clean. Do you know anything about this beast?
@@osbornebay944 tbh I’ve actually never even Rode one myself but would love to get my hands on one, they look Absolutely monstrous!
Thanks for the vid. Very helpful. Cheers from Australia.
Eh no worries brother, glad I could help🔥🔥
Good video. And from start to finish in one video. Not a 28 part mini series.
@@d.l.horton2093 thank you I appreciate that!
You are right, it is piston/ring issues, l poured 2 spoonful oil into spark hole, compression shot up to 181 lbs from 66 lbs, so good valves seals confirmed.
Great to hear brotha! Quick top end Rebuild and she’ll be a whole new beast!!
Before top end renewed, l put some lucas and engine restore, managed to bring compression to 80lbs, the idle is not dying anymore. If l horn the cylinder, if there are no deep scores, ring gap 10-15 mil is acceptable.
l just re ringed a 99 Merc 90 hp, the gap on new rings are 20-25 mil, still getting 120 lbs compressions (2T motor). no complain.
Right, yah true that! Tbh yah no doubt that would be your best bet, see what happens amd let me know
Nice job!
Thanks Man!
@@tanmansbikebuilds931 👍🏻
Nice job 👍
Wow man, you saved my life! My 94 Bigbear smokes just like yours. Any particular points l need to pay attentions when disassemble the top?
It really is a simple procedure I was quite intimidated when first looking into it and also assumed I would have to pull the whole motor but with the cylinder studs out the top end can be removed without pulling the motor, major plus! Just be sure to be at top dead centre before you start tearing it apart, and be sure to not let the timing chain drop in the bottom end zip tie or use a wire to keep the timing chain up tie it up the the frame. But overall was quite a simple process so don’t be intimidate! Good luck! If you run into issues let me know and I’ll see if I can help you👍
@@tanmansbikebuilds931 Super, l ordered a piston kit with all the gaskets, l ll horn the cylinder for the new piston.
@@osbornebay944 yah definitely hone it out! She’ll be a beast for yah
Chrome Molly or Carbon Rings...?
Tbh I’m not to sure I bought OEM replacements from Yamaha.
l got 66 -68 psi on my smoker Bigbear, too low for 114 psi spec. min. Is it bad rings or bad valves? Was flying around neighborhood in light snow ground, still has lot of power😀
Sounds like the piston to me, I thought valves or even valve seals aswell but you’ll be surprised how bullet proof these quads are, so they will still run with a blowen up top end so definitely pull your cylinder off and take a look, if the piston looks good measure the ring gap and be sure there in spec but definitely check out the top end, valves on these quads are a bit of a task but can be done with the proper tools, but it ended up being my top end anyway, let me know your results!
Is the cylinder to block gasket metal? I believe the head gasket is so it would be reusable, correct?
No it’s i high heat gasket paper from the case to the cylinder
The head gasket is tho yah
Ok thanks!
So does the whole cam come out of the head when you take the chain off or just the sprocket? And if it’s just a sprocket, is there a key way on the cam?
No not the whole cam, and just the sprocket will come off and yah there is a key way, will only go one the one way.
Chances are if you can smell gas when you dump the , that is why it’s smoking. The carb is leaking fuel into the engine causing it to over full. Fix the leaky carb and that bikes ready to go.
The carb has never leaked, if you watched the video you would see it was just my piston was rubbing the cylinder walls because the rings were shot, I put a new piston and rings and honed the cylinder and has never smoked since and I’ve been riding it for almost a year since then, it’s never leaked fuel, it does leak oil from the transfer case tho, so I constantly have to top oil up every hour of riding so that will be the next major fix!
Which makes me think the owner before me ran it out of oil and it still had just enough compression to still run.
Hi. You dont change a valve seal?
No, i ended up not having the proper tool to do it, ended up being a bad piston anyway
@@tanmansbikebuilds931 ok thanks. Regards from Poland.you do IT. Now is ok.