Rincon 680 won’t go over 30

[Eelang 9]

2007 Honda Rincon 680 w only 500miles 200hours and looks like new that I bought off older neighbor, Very clean. started and seemed to run just fine then when I hit full throttle it was gutless. 
wont even go 30mph, it does seem to breakup ignition wise and bog. When driving down road it’ll barely hit 30 and runs rough. 
im a mechanic and I’ve checked these items
no codes no f1 light on 
New plug
Coil and wire look like new and I replaced which made no difference 
Ran w Air filter off and it looks very clean anyway 
Checked fuel pressure 52psi running 
Also checked fuel injector and seems fine 
Clean new fuel 
Tested 5v ref and return signal from TPS and it seems to Coincide with throttle movement. 
Pulled muffler rear spark arrestor piece off and looked clean 
Checked compression 135psi 
I check valve lash and reset but it was to spec, Also watched rocker arm movement and cam lobes seem fine. 
Trans shifts fine and it’s a very clean machine, engine oil looks perfect and has always ran synthetic. 
where do I go from here? it revs right up and does break up alittle free revving it and idles nice but has no power. Neighbor confirmed it’s not running like it should he said he’s had it over 60mph before.

Let me know if f you have any suggestions thanks 

Edited September 26, 2022 by Eelang

[shadetree 5,543]

1 hour ago, Eelang said:

2007 Honda Rincon 680 w only 500miles 200hours and looks like new that I bought off older neighbor, Very clean. started and seemed to run just fine then when I hit full throttle it was gutless. 
wont even go 30mph, it does seem to breakup ignition wise and bog. When driving down road it’ll barely hit 30 and runs rough. 
im a mechanic and I’ve checked these items
no codes no f1 light on 
New plug
Coil and wire look like new and I replaced which made no difference 
Ran w Air filter off and it looks very clean anyway 
Checked fuel pressure 52psi running 
Also checked fuel injector and seems fine 
Clean new fuel 
Tested 5v ref and return signal from TPS and it seems to Coincide with throttle movement. 
Pulled muffler rear spark arrestor piece off and looked clean 
Checked compression which is difficult due to the cam/comp decompression mechanism but seems to have good compression. 
I check valve lash and reset but it was to spec, Also watched rocker arm movement and cam lobes seem fine. 
Trans shifts fine and it’s a very clean machine, engine oil looks perfect and has always ran synthetic. 
where do I go from here? it revs right up and does break up alittle free revving it and idles nice but has no power. Neighbor confirmed it’s not running like it should he said he’s had it over 60mph before.

Let me know if f you have any suggestions thanks 

welcome. i read yer list, did you check the timing on it ?. what was the compression reading ?.

[Eelang 9]

Compression was around 70 cranking and I haven’t checked the timing. 
I keep looking for something simple because my neighbor is 72 and never beat on it or took it through mud. It’s always sat in his garage and he only used it for yard work. 
I’ll have to look into the process of checking timing 

[shadetree 5,543]

14 minutes ago, Eelang said:

Compression was around 70 cranking and I haven’t checked the timing. 
I keep looking for something simple because my neighbor is 72 and never beat on it or took it through mud. It’s always sat in his garage and he only used it for yard work. 
I’ll have to look into the process of checking timing 

70 psi is low, and yes..deff inspect the timing.

[Eelang 9]

I thought 70 psi was ok per the service manual due to the decompression cam mechanism used. 

[Eelang 9]

I rechecked compression and got 135psi 👍

[jeepwm69 7,223]

I'd guess fuel pump.  If it's that old with those few miles on it, probably sat for long periods, and E10/ ethanol gas will ruin a fuel pump if you let them sit with gas in them.

 

I know you posted fuel pressure, but I wonder if that's consistent.

 

Does it always do it or is it sporadic? 

[Eelang 9]

It always does it, I put a fuel gauge inline before injector and was getting 52psi running in park. but I’ve saw in the service manual it should only be 40-44psi but I’ve also saw elsewhere it say 50-55 so I don’t know. I do know that the new spark plug is black but it’s not smoking at all 

Edited September 26, 2022 by Eelang

[jeepwm69 7,223]

2 minutes ago, Eelang said:

It always does it, I put a fuel gauge inline before injector and was getting 52psi running in park. but I’ve saw in the service manual it should only be 40-44psi but I’ve also saw elsewhere it say 50-55 so I don’t know. I do know that the new spark plug is black but it’s not smoking at all 

 

Have you checked the IACV?  It's on top of the throttle body.  It's held in place with two tamper proof torx screws.  Use vice grips to remove those, and pull the IACV up and out.  Then, looking at it, turn the key on.  The IACV should screw in and out smoothly as it cycles.  You can lube it with some light oil (WD40, PB Blaster etc). 

 

Basically on the EFI machines, the IACV is the choke, and it it gets stuck/ hangs up, it's like you're riding with the choke on.

[toodeep 1,733]

I'll put my guess on the camshaft. They go bad fast when they go. You can take the top cover off and remove the followers to inspect it without removing the cylinder head. The rear bearing on the camshaft is another thing to go bad but that should have given you tight intake tappet clearance. They use metal gaskets on these so a little spray paint will give it a coating to make it seal again if you find nothing bad. There's no serious pressure on the top cover gasket.

[Eelang 9]

I pulled the iacv off, inspected and lubricated with no change in performance 

[jeepwm69 7,223]

1 hour ago, Eelang said:

I pulled the iacv off, inspected and lubricated with no change in performance 

Well crud.  I guess next is @toodeep’s suggestion….cam

 

I thought the cam problems were on the 650’s, and a worn cam on a machine with 500 miles on it?

[toodeep 1,733]

All the Rincons, Big Red, Pioneer and even the Rubicons (up to 2014) could have the cam problems. When they go, they go and they don't have to wear down much to start giving issues. I've seen them go bad with all different mileage on them, 200 - 20,000 miles.

 

My only other thought is nest in the intake system/air box snorkel blocking air flow.

 

A very, very uncommon problem would be the pulse generator/ pick up coil but those usually just gave a random issue.

[Misterclean 406]

Black spark plug. Intake obstruction in the snorkel? Have you run it with the air filter removed?

[Eelang 9]

Yes I have ran it with the air box removed. I’ve replaced every part replaceable with no change.  Just threw a throttle position sensor on today and it did nothing. New injector, new fuel filter, plug, wire and coil, clean and lubricated IACV, there’s no throttle after 1/4 is like there’s no power gain. Compression is 135psi and I relashed valves but they were already right on. Rockers look to be moving as they should. Takes right off decent but just doesn’t gain much at all after 10mph and peters out at 30 going 400 ft and then trans downshifts weird.  

[shadetree 5,543]

41 minutes ago, Eelang said:

Yes I have ran it with the air box removed. I’ve replaced every part replaceable with no change.  Just threw a throttle position sensor on today and it did nothing. New injector, new fuel filter, plug, wire and coil, clean and lubricated IACV, there’s no throttle after 1/4 is like there’s no power gain. Compression is 135psi and I relashed valves but they were already right on. Rockers look to be moving as they should. Takes right off decent but just doesn’t gain much at all after 10mph and peters out at 30 going 400 ft and then trans downshifts weird.  

does the c.d.i./ecu have a speed limiter made into them ?, if they do ?, maybe the speed sensor is bugging out ?, or the c.d.i./ecu is hitting the speed limiter built into it ?. just spit ball'n here !.

[Eelang 9]

The speedo seems to work but I’m not sure if there’s a seperate speed sensor for ecu. I’ll have to research the speed limiter operation 

[toodeep 1,733]

Unless I missed where you have done it already, take the time and inspect the cam followers (lifters). I bet your going to find one that has wear on it (if you can get it to pull out) and starting to wear the cam lobe down. I've done this rodeo a few times and that is what I would do. Actually I would plan on replacing the camshaft and do the inspection on the tear down just to confirm, but that's me.

 

The ECM does have a rev limiter built in but I have never seen one mess up to do this, online or in my shop.

[Misterclean 406]

13 hours ago, toodeep said:

Unless I missed where you have done it already, take the time and inspect the cam followers (lifters). I bet your going to find one that has wear on it (if you can get it to pull out) and starting to wear the cam lobe down. I've done this rodeo a few times and that is what I would do. Actually I would plan on replacing the camshaft and do the inspection on the tear down just to confirm, but that's me.

 

The ECM does have a rev limiter built in but I have never seen one mess up to do this, online or in my shop.

I thought I read something about the rev limiter for reverse being enabled in forward too. That would do it correct?

[toodeep 1,733]

3 hours ago, Misterclean said:

I thought I read something about the rev limiter for reverse being enabled in forward too. That would do it correct?

 

The start in gear switch not getting turned off because of a sticking brake lever is known but that start to spit and sputter right away when trying to ride it. The reverse limiter would do the same, kill the ignition making it spit and sputter way before the speed he is getting out of it. I haven't seen that issue but I suppose anything can happen.

[Melatv 774]

Check the shift solenoid connectors for corrosion -- you can also apply 12 VDC to each solenoid -- should hear a sound --- Black & Brown connectors

[Eelang 9]

It’s not a rev limiter issue it just plain has no balls and flattens out and doesn’t spit or sputter or go over 30 or have any throttle feel after 1/4 throttle. The engine revs up in neutral and sounds perfect🤔  I put a complete fuel pump in today and it didn’t change anything but what I noticed is in 3 gear when I have it floored going 25-28 it downshifts into second but only when I throttle to full if I leave throttle low then it stays in 3rd but as soon as I throttle down it drops to 2nd. 
 

[Fishfiles 19,716]

I am not a 680 guy , but let me throw some on the wall ,  seems I read somewhere about a situation that will cause dethrottling to protect the engine , kind of like Mr Clean was talking about in reverse , but it might have been involving the fan and a overheating problem ,   not exactly  like a rev limiter , call it a deaccelerator, no pop of miss , just a steady that's it -----  seen my Dodge diesel do it once of twice before getting castrated 

[ATC4ever 1,009]

Have you kept it in 2nd in ESP mode & revved it out to see if its good? 

[Misterclean 406]

^{Have you checked for tight valves? I had a four valve XR 250L years ago that did something like that. It would heat up and lift the exhaust valves a little to loose some compression.}