Yamaha Grizzly ATV Forum banner
1 - 20 of 23 Posts

·
Registered
Joined
·
18 Posts
Discussion Starter · #1 ·
I have a 2009 grizzly with a 734cc 105.5mm trinity racing big bore kit coupled with a stage two cam and hot rods complete bottom end kit and an having major starting problems due to the engine having much higher compression. It will turn over and catch at tdc, stick there for about 3 seconds and come back around twice more before almost draining the battery and killing the solenoid. i have a bigger than stock agm battery but stock starter and idk if a higher torque starter will be enough to overcome the higher compression. I’ve been told you can get a longer decompression pin made but i’ve had trouble finding someone to do it and have been told it’s more expensive to get one fabricated than it is to buy one that comes with a cam but from my understanding most hot cams use the stock decompression. that may work for a stock bore with the cam but coupled with a big bore the stock decompression pin isn’t enough. i know this because me and my father fabricated a longer decompression pin from the end of a drill bit and installed it in the cam and it seemed to helped a tremendous amount to the point where it would actually turn over and start, however still with some trouble.. what other ways can i help with this high compression set up on my atv so it will crank easier?
 

·
Registered
Joined
·
18 Posts
Discussion Starter · #2 ·
Cmon guys i’m sure someone has some insight, this is my second time posting something about this and still no response, perhaps i may be posting on the wrong topic section, i’m not sure.
 

·
Registered
Joined
·
1,060 Posts
I have no knowledge regarding your question. There are a few guys that used to run engines similar to what you have with regard to performance but I haven't seen them around much lately. @wernerwilliam and @loudelectronics may be able to provide some insight. Hopefully this tag will bring them to your thread.
 

·
Premium Member
Joined
·
2,290 Posts
Can't speak for Grizzly engines but I've built high compression V8s and had good luck with high torque starters and high cca batteries.
 

·
Just wanna ride!!
Joined
·
5,542 Posts
Hang around. Somebody will be along to help you out. @dag1401 can you weight in on this?
 

·
Premium Member
Joined
·
12,854 Posts
As said above, the guy that did this in years past are not around much these days.
I would send Loud and Dag a P.M. to get their attention, they may have the e-mail notice on for P.M.'s.
 

·
Registered
Joined
·
201 Posts
Sounds to me that the decompression pin was either not reinstalled or somehow incorrectly done.
other than this?

hmm i had a weak battery on mine and it wouldn't start at all it tested ok but would not start the bike
I ended up getting a interstate jell-pack and it starts fine with that.

i guess a weak starter could do it too.
 

·
Registered
Joined
·
18 Posts
Discussion Starter · #8 ·
i think i’ll just try running a heavier gauge wire from the solenoid to the starter and see if that helps any if i does then i may go ahead and get me a higher torque starter like a ricks or something, if that doesn’t work then i’m at a loss cause valves are set correctly to the cam’s specs
 

·
Registered
Joined
·
5 Posts
Just a thought about if there was a recommended "squish" for head gaskets? I had similar issues with HD high compression motors and it was too little head gasket. That and I did also change my timing later. It was almost impossible to start even with extra current and a higher torque starter.
 

·
Registered
Joined
·
18 Posts
Discussion Starter · #10 ·
I put the correct size head gasket on there, it was a copper cometic head gasket for a 105.5 mm bored head. but i agree i almost feel as if a stronger started and heavier gauge wire will still not turn it over.. i still believe that the length of the decompression pin is the way to go as far as getting the starter to turn the engine over for it to crank..
 

·
Registered
Joined
·
839 Posts
I have an 843cc stroker,big cam, piston,ported , polished, etc. Stock decompression mech when installed correctly works great. Did have an issue with mine few years back. out of the blue when I shut off after 30 min ride wouldn't restart. could hear it fighting the starter at TDC. I kept trying to start and ended melting battery post,wires etc. Only time in 10 years the Grizz never made it home under it own power. Came home on trailer
Thought was starter, bought new starter, same issue. put heavier wires etc just for shit and giggles and still same issue


Pulled out cam and found decompression pin sheared off right where the flat spot is machined in it to catch the nipple from the rod that runs in centre of cam.
replaced new part and it was good to go again until what I believe broke a piston skirt. Bike is still in my garage with motor un touched


Bought an xp1000 POPO instead


Was lucky found the broken pin laying up top near the valve springs, Didn't drop down into crank case. if your mech is working correctly if you do a compression check at cranking speed it should be really low like 70-80 psi I believe.
If like me you have over 150psi at cranking speed you know the decompression mech not working correctly. Pin doesn't come out of cam very far, just enough to hold the rocker up and valve off seat to bleed compression off
 
  • Like
Reactions: reogem

·
Premium Member
Joined
·
9,514 Posts
Werner..I was hoping you would chime in on this. I thought the big bores worked fine with the stock pin but wasn't 100% sure. Thanks.
 

·
Registered
Joined
·
839 Posts
Werner..I was hoping you would chime in on this. I thought the big bores worked fine with the stock pin but wasn't 100% sure. Thanks.
Sorry don't get over here very often , just happened to pop in yesterday


Anyone every here from AZ 660 from Alaska I believe ? Hes the guy that bought the wet cutch delete from me. Curious how it held up for him. He posted a bunch of videos when he first installed but nothing since


Cheers
 

·
Premium Member
Joined
·
9,514 Posts
Werner do you mean this guy?
Has a WCD in his sig. Hasn't been on GC since 2016.
 

·
Registered
Joined
·
18 Posts
Discussion Starter · #15 ·
i’m positive it is installed correctly and it is also a brand new decompression assemble, lever assembly, pin, and the whole ordeal. the only thing i have been able to do for the engine to turn over and crank is create a longer decompression pin which worked wonders as far as releasing enough compression for the starter to turn over the motor. if my stock one was installed correctly and valves are set correctly ect, what other reason would my stock starter not be able to turn it over
 

·
Registered
Joined
·
839 Posts

·
Registered
Joined
·
839 Posts
i’m positive it is installed correctly and it is also a brand new decompression assemble, lever assembly, pin, and the whole ordeal. the only thing i have been able to do for the engine to turn over and crank is create a longer decompression pin which worked wonders as far as releasing enough compression for the starter to turn over the motor. if my stock one was installed correctly and valves are set correctly ect, what other reason would my stock starter not be able to turn it over
CHECK THE ROCKER ARM WHERE THE PIN RIDES AND SEE MAYBE IF ITS WORN OR GOUGED OUT
MINES CRANKS OVER JUST LIKE A STOCK ENGINE @ 10.75:1 COMPRESSION


IF YOU HOOKED UP A LEAK DOWN TESTER AND PUT AIR PRESSURE TO IT, AT TDC YOU SHOULD HEAR THE AIR LEAKING OUT EITHER THE INTAKE OR EXHAUST DEPENDING ON WHICH ROCKER TH E PIN IS HOLDING OPEN( I DONT REMEBER IF IT WAS AN EXHAUST VALVE OR INTAKE VALVE THAT GETS CRACKED OPEN
LIKE YOU I WAS THINK BIGGER CABLES ETC BUT BIKE RAN FOR 4 YEARS WITH SAME CABLES AND NEVER HAD AN ISSUE


BEFORE I FOUND BROKEN PIN AFTER FRUSTRATIONS TOOK TO DEALER. THEY SAID NEEDS STARTER


SAID GO AHEAD AND INSTALL, WENT TO PICKUP BIKE AFTER THEY SAID ITS GOOD TO GO AND WHEN I WENT TO PICK UP BIKE IT WOULDNT START SAME ISSUE. (IT WAS INTERMITTENT) DEPENDING ON WHERE BROKEN PIN WAS SITTING SOMETIMES DECOMPREESION WOULD WORK , SOMETIMES NOT. I TOOK BIKE HOME THAT NIGHT, STRIPPED OFF THE PLASTICS AND REMOVED THE CAMSHAFT ANDOUND BROKE PIN


IS YOUR BIE GOOD STARTING NOW WITH THE LONGER PIN ? WHAT DID YOU MAKE PIN OUT OF ?
SOMETHING GOOD AND HARD I HOPE. LIKE A GOOD DRILL BIT ?


CHEERS
 

·
Registered
Joined
·
18 Posts
Discussion Starter · #18 ·
@Werner
Yes it cracks over much easier with a longer decompression pin. Also, to answer your question, yes it was fashioned from a drill bit but nowhere near the strength of a stock, case hardened one as the pin is becoming mushroomed and is not smoothly domed anymore. the quad will turn over for quite sometime before it fires then will eventually kick over. Other times it will send a backfire out of the exhaust almost as loud as a gunshot. I’m wondering if my coil could be bad, i’ll have to check the resistance with my volt meter soon and see if that could be one of my issues as for it not firing up right away, i’m pretty sure it’s either that or just lack of cranking power at times. It doesn’t run very well but i’m pretty sure it’s because of all the mods that i haven’t tooned the quad for yet with my ehs bullet box.
 

·
Registered
Joined
·
22 Posts
@Werner
Yes it cracks over much easier with a longer decompression pin. Also, to answer your question, yes it was fashioned from a drill bit but nowhere near the strength of a stock, case hardened one as the pin is becoming mushroomed and is not smoothly domed anymore. the quad will turn over for quite sometime before it fires then will eventually kick over. Other times it will send a backfire out of the exhaust almost as loud as a gunshot. I’m wondering if my coil could be bad, i’ll have to check the resistance with my volt meter soon and see if that could be one of my issues as for it not firing up right away, i’m pretty sure it’s either that or just lack of cranking power at times. It doesn’t run very well but i’m pretty sure it’s because of all the mods that i haven’t tooned the quad for yet with my ehs bullet box.
Did this end up working? I'm looking at big bore kits to start running in hare Scrambles.
 

·
Registered
Joined
·
1 Posts
I have a 2009 grizzly with a 734cc 105.5mm trinity racing big bore kit coupled with a stage two cam and hot rods complete bottom end kit and an having major starting problems due to the engine having much higher compression. It will turn over and catch at tdc, stick there for about 3 seconds and come back around twice more before almost draining the battery and killing the solenoid. i have a bigger than stock agm battery but stock starter and idk if a higher torque starter will be enough to overcome the higher compression. I’ve been told you can get a longer decompression pin made but i’ve had trouble finding someone to do it and have been told it’s more expensive to get one fabricated than it is to buy one that comes with a cam but from my understanding most hot cams use the stock decompression. that may work for a stock bore with the cam but coupled with a big bore the stock decompression pin isn’t enough. i know this because me and my father fabricated a longer decompression pin from the end of a drill bit and installed it in the cam and it seemed to helped a tremendous amount to the point where it would actually turn over and start, however still with some trouble.. what other ways can i help with this high compression set up on my atv so it will crank easier?
the timing is off had same problem did the same kit
 
1 - 20 of 23 Posts
Top