P700 Help diagnosing problem

[skinsone]

I work on a big ranch and we have a lot of hondas. 1000's and 700's. In the winter I've taken to helping fix issues with them as we have been keeping our local dealer in business and we're trying to cut a little cost. I've taken apart a 1000 subtransmission and replaced the reverse gear (with a service manual) and swapped stators on a 700 so I'm getting braver about diving in and trying to repair some of this stuff. Certainly not a mechanic but not afraid to try.

Picked up a 2016 700 from another unit on the ranch the other day to work on. It has just shy of 17k miles. (They're used daily around here). Apparently it had some starting issues last summer so the starter and ecm were replaced. It ran well for a short time then went back to same problem and also wouldnt shift so it was parked. The first thing I did when I got it here was check the oil. Of course it was low so I filled to correct level and took it for a spin and voila, it shifted like it was supposed to. I drove it for about a half hour and it misfired and just died. Like turning off the key. I hit the starter and it fired right up but when i got to about half throttle it began missing and backfiring all the way back to shop. Bout a half mile. Sounded like a rev limiter was working too.

Today I took all the plastic off, pressure washed it and adjusted the valves. Exhaust were fine, intakes were loose so I tightended them to spec. I took it for about an hour ride and I cannot get it to duplicate what it did the other day. Took it up some steep hills and it seemed to have plenty of power. It starts every time, but it's loud. The exhaust is tight. I can hear a pretty apparent tick or slap that sounds like it's coming from deeper in the motor than the valves. Idles fine, revs up fine. I have a 700 service manual on the way and am preparing to pull the cam. Thought I'd ask here to see if I'm on the right track or if I'm looking in the wrong area. Thanks

 

[Admin]

 

[HondaTech]

In neutral does the engine rev up like it should? Or is it hitting a sort of early rev limit?

 

[skinsone]

In neutral does the engine rev up like it should? Or is it hitting a sort of early rev limit?

Yes it revs like it should. after driving for a while I let it run in the shop and worked the throttle and it wrapped up and idled down.

 

[skinsone]

Update: Tore the top end down and installed a new cylinder and piston. I was expecting to find a worn cam but the lobes were still in spec, decompressor on cam seemed to be working as it should although I didn't have a new one on hand to compare it to. Buttoned it back together, crossed my fingers and hit the starter and it fired right up. Still ran a little loud though. Used a stethoscope (2' piece of all thread) to listen to cam and timing chain and it sounded pretty good.

Drove it around for about an hour and everything seemed to be fine. Plenty of power. Pulled it back into the shop and was just about to start putting all the plastic back on and I decided to start it again for good measure and thwack! Metal on metal somewhere. Thinking the worst I took everything I had done down to the piston expecting to find metal everywhere and nothing. All was well.

Took stator cover off and removed torque limiter and small starter gear and hit the key and starter sounded great and teeth aren't wore. (It's pretty new) After reviewing manual I'm beginning to think one way bearing on starter clutch is shot. I can rotate the engine with a ratchet while watching starter gear behind flywheel and every once in a while it won't spin with the flywheel. Not all the time, it'll make several revolutions with it but if I adjust the speed of my ratcheting sometimes the gear will hang up. Does this sound right? This is with just the cylinder on, when the whole top end is on there's a spot where i have to put more effort than before to turn it. When I got the machine, the guys said they had replaced the starter and it worked great for about 10 starts then started acting up again. Makes me think it had been failing then finally gave up the ghost with me?

After reading the info on this site I'm thinking of going in and replacing cam and starter clutch. Is there a way to get the flywheel off without the special tool? Does the front driveshaft have to come off to perform this? Would have been nice if Honda could have made the stator cover about a 1/2" bigger so you could get flywheel off without taking the crankcase cover off.

 

[skinsone]

Update.
New cam, starter clutch and one way bearing, torque limiter, starter. The entire starting system is new. Followed service manual, put correct torque on everything. Had a witness with me when I got it back together and started the machine. It started and ran fine for about 15 starts then it started acting up again. Starter started banging and can’t crank engine over. Sounds awful.
When I crank engine by hand there’s a spot where it’s pretty hard to turn with a ratchet and if I don’t hold the socket while ratcheting the engine will spin backwards. I initially thought this was caused by good compression as it’s a new piston and cylinder. this is the point in the revolution where the starter doesn’t have enough torque to overcome it and where the godawful sound comes from.
When I had cylinder off, I inspected timing chain and everything I could see in the crankcase from the top as I didn’t split the case. Crank seemed to spin fine, no metal, clean. Chain seems ok and on the sprocket on crankshaft. Nothing seemed abnormal. Put just the cylinder back on and spun motor by hand and watched the piston and it operated properly. I’ve taken apart valves and cleaned. I double and triple checked the timing on the cam sprocket at top dead center when I reinstalled cam chain making sure cam lobes were facing down.
I’m wondering if it’s possible to install cam off 180 degrees? Does is matter which stroke you’re on at TDC? What could be causing so much pressure on piston or timing chain that if I’m ratcheting it’ll freewheel counterclockwise for a 1/4 turn or so?
at this point I’m about to just pull this motor and get into crankcase. One good thing about this is I’m getting a lot faster and taking them apart. Ha