Look to your Service Manual under Engine page 3.3 and it will give you the proper line up of the gears.

But as it notes, do this at Top Dead Center of piston on the compression stroke.

Should be able to see the valve rockers and know when you're at the compression stroke of the front cylinder.

Pirate

 

I checked and double checked the timing when I put it back together and the engine wont start. There's air, spark, fuel pressure and breaking at the injector and there's oil pressure, but still no go. I'm getting a lower compression pressure in the cylinders, very low as in 65,but prior to the removing of the engine to this it was in the mid 100's. I didn't do anything with the cylinders but I haven't touched the engine in almost a year so is it possible that the rings are 'stuck'? I really don't want to remove the head and check the piston's that way with oil or anything at the moment because I know how slow polaris is here at getting parts as I would need a head gasket to check it out. Maybe I would be better going there and ordering it right now but if there's any way I can do a sensible fix without the motor being worked on again. Would adding oil to the top of the pistons and cranking the engine over help move the rings or will I have to break down the engine again and try and fix the issue with new rings? sorry for all of the questions but i'm just throwing it out there for some input.

 

squirting a lil oil in the cylinders would help a bit. I'm no expert on these but it sounds as if the cam timing is off a bit.

 

Been a while since I did this but I can tell you one thing, until you time the cam shaft there is no compression stroke or exhaust stroke, just top dead center.

The crank turns one turn to the cams two turns so the crank at top dead center is in the same place, once you put the cam in or cam gear on then it is either tdc on exhaust or intake. So lets say we had two gears with alignment marks, one on the crank and one on the cam gear. We start with the crank on TDC and does not matter what stroke because the camshaft defines that.

As I recall, one of the cyl is the #1 so when you are lining up the gears that cylinder has to be at TDC, also one of those gears is spring loaded and you have a tool to hold them in alignment when installing.

Like I said been a while so I can't remember but I do recall the 800 engine was the easiest I ever built, Kawi V twin is fun

Hope this helps

Todd

 

Very good thoughts Todd!!

But with the RZR 800 motor...I believe...you need to make sure the cam is in the right position to be a firing on TDC.

The injectors are electronic, so if the #2 cylinder is on the compression stroke but the came is 180 degrees out, the #1 injector will open. So you're not getting fuel when you need it.

And the motor will never start.

So, to my mind, you need to remove the front cover on the motor and the valve cover.

I'd also suggest removing the rocker arms to make it much easier to turn the motor.

This way you can check the alignment of the timing marks on the cam and crank. And you can watch the pushrods moving and know which cylinder is on the compression stroke. Reading through the Service Manual, getting the alignment marks correctly lined up should have the cam timing matched to the fuel injection timing.

Now, having experienced it once on a start-up...the bolt holding the CPS, Crank Position Sensor, is tight...right? I was amazed to have the bolt holding the CPS in place was finger tight, but it would vibrate and get too far from the crank flywheel gear and wouldn't fire. Or fire very intermittently. PITA to get in there and tighten the bolt...but got er dun...and the motor fired and ran just great!

Just some thoughts...

Pirate

 

Very good thoughts Todd!!

But with the RZR 800 motor...I believe...you need to make sure the cam is in the right position to be a firing on TDC.

The injectors are electronic, so if the #2 cylinder is on the compression stroke but the came is 180 degrees out, the #1 injector will open. So you're not getting fuel when you need it.

And the motor will never start.


Pirate

That is what I said, read this again

"As I recall, one of the cyl is the #1 so when you are lining up the gears that cylinder has to be at TDC, also one of those gears is spring loaded and you have a tool to hold them in alignment when installing."

So after the right cyl is at TDC and cam is in right it is right.

The point I was making was, the crank does not have a compression stroke, it has no idea what stroke it is on, the cam determines that.

Example, lets say we have the rear cylinder on TDC and put cam in correctly for that cylinder and everything is timed up right and it runs. Now, take gear off crank, turn the crank one complete turn and do it again, still right because the crank turns once to the cams twice

So when putting cams in or cam gears in you don't have to know the stroke of the crank just the correct cylinder is at TDC when timing to cam.

Todd

 

Hi Guys,
Thanks for the quick replies. I'm hoping this will help me out but I do have another question before I pull the engine again. Its not a big job by no means but its a PITA for sure. From I can tell of the cam gears and crank gear with regards to alignment, they can only go on the shafts one way only. I never removed the crank gear at all during. Just the other two to remove the oil pump to remove the dowel. The other shaft is keyed in, so that can only go on one way. Also, the cam shaft with the dual gear with the springs can only go on its shaft one way. Just line up the timing marks and they 'should' be in time. So in my case I may be out 180 degrees. I really hope this is the case to be honest because it is a big pain for sure to not be able to operate my machine, especially with moose hunting coming up next weekend.lol.
So when I remove the engine and cover and cam cover, which cylinder would be considered #1 and #2. When I put it together the last time. The cylinder with the clutch (forward) had the valves closed and the other cylinder had the valves open as they were pushed down by the rockerarms.
So would my plan of action be to remove the cam gear, remove the counterbalance gear, rotate the counterbalance shaft one turn to line up with the crankshaft timing mark and then replace the counterbalance gear and then put the cam gear on as per usual. I know I might sound like an idiot here but i'm just trying to look at a good plan of action here. I really appreciate your help.

 

For one thing, you can remove the bed, the CVT complete, and the front engine cover with the motor in the chassis.

DUH...I can't remember which cylinder is #1...but for some reason I seem to recall the cylinder closest to the rear bumper is #1. But if you get them timed by the marks...it makes no difference.

I don't think the plan should be to remove the timing gears first. Remove the front cover and the spark plugs (be danged sure to clean the spark plug pockets thoroughly so nothing goes into the cylinders)

Now you can turn the motor pretty easily by hand.

Now turn the motor until the alignment marks either align or don't. I do not think you can put the gear on the cam incorrectly. Looking at the Service Manual, the cam has a flat side on the gear mounting face, and is engraved "this side out", so if you have the engraving out, you can't put the cam gear on 180 degrees out.

Follow the Service Manual instructions and check to see that all the gear alignment marks are aligned correctly. If they are, good. If they aren't, then you need to remove the gears and get things aligned correctly.

Let us know as you get started and include pics so we can see what you're seeing.

Pirate

 

Very true. But only for a motor like this with both cylinders coming to TDC at the same time.

The cam gear can only go on the cam in one position...so that assures that the correct valve timing matches up with the CPS signal to the ECU for injector timing.

Make sense?

Pirate

 

True, then any TDC on the piston is good as long as the gear marks line up

I did forget both pistons move together on the 800, so TDC is TDC on the crank then get cam right and you are good.

 

Are you guys saying that on the 800 motor both pistons travel together to top dead, both on compression stroke or is one 180 off?
Both injectors fire at the same time?

 

I have a question that I have posted previously but got no answer. With all of the knowledge in here hopefully one of you guys can give me some insight. I picked up a 2010 rzr 800. Idols and runs great. Been on a few rides with no issues. Decided to check why the engine light was on. Code says 651 4. So I check the pig tales on the injectors and the rear was unplugged. Plugged it in and the bike shut off. Unplugged it and cranked right up. From what I can see without removing the bed,which j will do this weekend, that the rear injector has 1 red wire spliced into the front injector pig tale. WHT the he'll is going on. Please help

 

The 800 is an even-firing parallel twin. Both pistons go up & down at the same time. Prior to 2011 (no cam sensor), Both injectors & both plugs fired together. The injectors squirt HALF of the amount needed for each combustion cycle on the intake & power strokes. This means when the MAG cylinder is squirting on the intake stroke, the PTO cylinder is squirting on the power stroke on the back of a closed valve. The fuel waits there until the intake stroke. The plugs both fire at the same time. One on the compression stroke, the other on the exhaust stroke. It's known as a wasted spark. In 2011 when the cam sensor was added, the injectors then shot all their fuel on the intake stroke. The plugs fired on the compression stroke. The marks on the cam, counter-balance & crankshaft only line up one way. The outer mark on the cam aligns with the inner mark on the counter-balance. The outer mark on the counter-balance aligns with the mark on the crank gear. That's it.

 

Thanks for the info deron. It is nice to have access to guys that are full of knowledge and willing to help with the issue at hand. Can you see any reason why the previous owner of my rzr would have had to wire the Injectors this way? Or how to go about trouble shooting the issue?

 

Just a guess without the machine in front of me, sounds like he was bypassing a broken wire. I would test all 4 injector wires back to the ECM. If you start to see signs that he or someone else was messing around inside the harness, I'd just replace it. There are plenty of them around, especially on eBay. They provide good pictures & guarantee them to work. I've done it before on an '08 RZR with a butchered harness. The used harness was about $100 with free shipping & fixed all the gremlins.

 

Deron,

Interesting information...thanks!!

I was re-reading my Service Manual.

Got any idea what MAG and PTO stand for?

Thanks,

Pirate

 

From a sledder forum:

MAG= magneto side of the engine (usually also houses the recoil starter)

PTO= Drive clutch side of the engine

Not sure how they relate on RZR

 

This is correct on a RZR too

 

Geoff,

That would make sense, MAG - rear cylinder, PTO - CVT/clutch end.

The 2011 Service manual says the MAG and PTO connectors are different and thus can't be switched. But you sure can get them confused at the coils.

Wasn't aware that both injectors fired and spark plugs fired on both cylinders at the same time. Gonna look at my old Holz Stage III cam and see if the lobes are aligned to open both intake an both exhaust valves at the same time. Hmmm...

Thanks for the info!!!

Pirate

 

Yep, just remember 2011 & newer 800s are sequentially injected vs. the 2010 & earlier twins. If you reverse the injector connectors on it (2011 & newer), it won't run right.

 

Getting them confused at the injectors is next to impossible as well. They used some sort of factory silicone/glue on the connectors and they are next to impossible to remove at least on the 11+ models with my experience. The plugs are different lengths below the coil pack as well, one is grey and one is black, again this is on the 11+ models.