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Discussion Starter · #1 ·
First, this is my first tech post, would like to start by saying this is a very informative forum and thanks to all over the years, despite me being a new guy I did a lot of searching with very old posts and is motivating me to doing some cool things to our "new to us" 2004 660. I have been building high end street car engines for years, and continue to be current with modern electronics, engine building, and old classic carb work etc, but this old girl has me stumped. Lots of info below and I have a Yamaha manual, but it isn't giving me the detail I need to test some things.

1 - The engine will run great for about 5-10 minutes, then start missing and then eventually die and not start again until it cools.

2 - It was not charging when I got it (1 month ago), so after some testing, replaced the stator with a Yamaha unit. I was confident that was this issue but it was not It now charges but still dies, no change at all

3 - I believe it is not fuel related, but the previous owner had the orginal fuel pump and a new replacement in the gove box,, and an electric one installed. It had the return to prevent excessive pressure, but I still could not get the needle and seat to hold the pump pressure (1.5 - 2 psi on my gauge) so I put the new stock style pump back on. It seems to be working fine, and the bowl had fuel in it when it died. It picks up fuel quickly, even when I drained everything to pull the tank to get inside for the stator swap. I have been inside the carb and it was clean, although I do intend to put a kit in it sometime after I figure this out

4 - At this point, it has the orginal 2004 CDI unit, which I pulled, and don't see any wiring or burn marks externally, but it is one option I am considering. Maybe it's getting hot and dropping spark, certainly sounds like it is a possibility. Thoughts, likelihood?

5 - Because it happens hot, and I start to hear some puffing and popping, I was wondering if it could have a tight valve too. Have you guys seen any issues with tight vs loose valves that could be holding a valve off the seat when hot? I haven't taken a compression test yet, but it runs so nice until 10 min in or so, that I seem to want to blame ignition. Also, generally in the automotive world valves loosen with wear not tighten, but I do not know if someone has "supertuned" this in the past

6 - Last, just this AM, I saw that some people have had issues with the resistor in the plug wire boot. I haven't checked that but will today, as well as take a compression test. I suppose it could be a coil, but seems odd as it is in a cool place and I haven't read about a lot of coil failures

So sorry for the long run but my plan unless omething jumps out to you guys is

1 - Check the plug wire assembly
2 - Compression check for anything odd
3 - Swap out the CDI and see if it does anything (hate to throw parts at it, but seems logical if nothing else

Again, runs beautiful for about 10 minutes, every time, then starts dropping or missing, continues to get worse, and eventually dies. Seems like spark related, but looking for experience of someone who may have dealt with this

You could eat off this Rhino, it was bought by an older gentleman to use on his prperty and not a scratch on the skid plates, wiring is nice and clean, it's not molested and bone stock, so worth a bit of care to get it happy again

Thanks so much, hoping to get into some real Hot Rod Rhino stuff once I can keep it running!
 

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Had the same issue when I got my 2005. A thermal breaker delete took care of it. Procedure in the video below. His symptom was different but it worked for mine (run for 10-15 minutes and die, let cool, start back up). I was at the end of my rope and willing to try anything.

On the 04's the breaker is taped up in the harness under the dash by the ignition switch. I'm not saying it will solve your problem but it's worth a try.

 

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Discussion Starter · #5 ·
Had the same issue when I got my 2005. A thermal breaker delete took care of it. Procedure in the video below. His symptom was different but it worked for mine (run for 10-15 minutes and die, let cool, start back up). I was at the end of my rope and willing to try anything.

On the 04's the breaker is taped up in the harness under the dash by the ignition switch. I'm not saying it will solve your problem but it's worth a try.

I didn't think to see if the engine was overheating, are you thinking it gets so hot it vapor locks, or is that somehow tied to the ignition?
 

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Discussion Starter · #6 ·
Very interesting results today. I removed and cleaned the resistor and screw out of the plug wire and it ran long enough that I thought it was fixed. Probably 30 minutes and didn't die harshly but it was coming

Fan stayed running, temps stayed at the 175-180 range near the bleeder screw, 160-ish at the radiator. Whole time it was charging 14.08-14.20

I am wondering if it is indeed the coil as cleaning connections maybe loweered resistance letting it hang in there, it still started missing, but ran longer than I ever had it run by a wide margin

Shot the coil and it was reading 90 degrees, in a 75 degree shop, although I have never done that to a running coil, so may be normal, but it was generating heat
 

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Discussion Starter · #7 ·
More troubleshooting, and ordered parts. Cheap Chinese parts, but hoping it's going to fix it and then I can spend better money

- Cleaned the resistor and it ran much better, as I said before, so I buttoned it up to see what it did for 15 - 20 minutes of playing. It didn't like any real load and seemed to drop spark.

- So I cleaned all the connections at the coil and CDI, (CDI was clean), nothing had burn marks or odd look. Then swapped a plug for a non-iridium resistor that was new in the glove box. Man it didn't like that, barely ran and popped back. As far as I can figure it didn't like the added resistance

- That drove me to the coil. I pulled it off and attempted to take the resistor out of the boot and replace with a piece of steel for an experiment. Depsite being put together with a small screwdriver, the metal ferrule was not coming out. In fact, I broke it with the screw driver trying to unscrew it.

- I took the spark plug wire end off and attempted to check resistance, it shows an open circuit at all settings of the meter. So at this point I wonder if the plug wire end has a burn internally and the coil was fighting to make it jump the break? No real way of knowing but the end doesn't conduct electricity and something made it not want to come apart one day later

- I ordered a cheapo Ebay coil and wire assembly, and a cheapo CDI. So cheap it's silly and may add to more problems, but we'll see. I consider them throw away for troubleshooting and if I can keep it running will buy good stuff. FYI coil and CDI seem to be 2004 original

More to come next weekend!
 

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Discussion Starter · #13 ·
Thanks guys

Update on the Rhino, I swapped the coil and wire assembly with the Chinese Ebay cheapo and it fired on a 1/4 turn, I could definitely tell immediately. This coil and wire is very crappy, but for 14 bucks it was worth a shot, I then tried the cheap CDI and it also ran great, but was certainly the coil.

I think I am likely going to buy a new factory coil and wire assembly, leave the cheap CDI in it and get some miles on it, then swap the CDI and see how different it acts

The unfortunate thing is this is the first time I drove it, brakes are NOISY, dripping oil from somewhere, but it runs and runs good!
 

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Discussion Starter · #14 ·
Sunday update - sometimes you get lucky, sometimes you are a moron who screws up. In this case BOTH. The oil leak was that I left the small timing access plug loose when I changed the stator. I thought I had a bad case/crank seal, took it down expecting a bad seal and started it without the pass side fan and watched and saw it running out of the plastic plug. :rolleyes:

Grabbed a quarter out of the ash tray of my truck and it wasn't slightly loose, it took about 3-4 turns, ran it for a while and all is good. What a dope LOL

Got about 2 hrs on it today, runs like a dream. Picked up the manual, next week I am going to start from the back, check every adjustment that can be adjusted, grease every point that can be greased, check all the levels, do a cleaner install of the winch, and maybe mount the hour meter permanently, replce the exhaust pipe to muffler gasket/ and do all 3 sets of brake pads. Pretty happy so far!

Likely will get into the belt/clutch soon, but banging around the property is fun so far
 

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Don't know what all you did, but since this is new to you, be sure to burp the radiator to get it 100% full... front end high in the air and check run and fill twice.
 

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Thanks for the backup, I did burp it. Amazing how much it drops with what seems to be so little air.
be sure to burp it at both places. There is also a screw on the water pump that MUST be done to let air out of the water pump.

Thanks for the backup, I did burp it. Amazing how much it drops with what seems to be so little air.
 
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