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Interesting valves should have stopped the piston before it hit the plug did it do anything weird before it stopped running. I would probably pull the cover and inspect the timing chain first, maybe see if it will budge with a wrench on the cranknut, dont go crazy with it just move it back and fourth gently.

You need to keep posting till you can download the service manual; That tells you what work can be done with the engine in place. If you tell us the year and exactly what model it is, I or someone can check for you.. They come in chain or shaft drive, and with or without electric start, and I wouldn't be surprised if there were kick or pull start versions as well.. We need the suffix of the model number..

Has anyone had a suzuki 230 quad lock the engine up? Its a well maintained bike, it locked up when my son was riding it. Pulled the plug, it has connected with the piston. I'm thinking the con rod let go. I don't have a service manual. Does the engine need to come out to check further?

Ha.. That is a bummer.. That it's started to work ! I hate that too, all the more since I'm a mechanic. Perhaps now leave it idling and wriggle all the wires everywhere bit by bit hoping to find a short or broken wire that makes the motor die.. Wires mostly only break right where they go into the metal crimped terminal, and they break inside their insulation so you need to use long nosed pliers to gently tug on those ones, and the other place that used to be more common in the past when they used thick wires, was up near the steering head where they flex. Shorts to the frame of course.. anywhere. I'd also check the switches.. The kill in particular is prone to dirty or mud filled contacts. The mud not actually being a dirty contact problem, but when it gets wet it can short enough to cause problems. And thanks for the thanks. It's my pleasure.

Sorry for lack of response but have had little internet the last few days. I do want to thank you for all your help with this as I had a big learning curve. Not having good schematics didn't help either. It has started to work. I hate problems that just go away on their own. The fact that the pit bike CDI worked from the start leads me to believe that it is most likely one of the interlock inputs. I suspect that one of the interlock switches was flaky and when I checked it without any movement it would show good and when the motor was rotating it would come and go. If not that then a bad connection that when disconnected and reconnected. The fact that the pit bike CDI worked from the start leads me to believe that it is most likely one of the interlocks. I have not tested it by riding it as I want to go through the brakes and make sure they work good before I do as it has set so long. Stopping is always a good thing. Luckly this ATV will mostly be used on my property in Idaho and not on trails so when (not if) this problem appears again I won't be in some remote location. I also plan to take the older CDI that I purchased and that didn't work and cut the connectors off and wire up the pit bike one to have as an emergency spare. This will disable all the interlocks but should allow me to get it back to the garage easily.

Believe half of what you read and nothing of what you hear.

Wow! Thank you. So I must have a QuadRunner, has auto trans w/reverse and electric start. After the VIN is LT230E and then a stamped letter "H". Any idea what "H" is for? Mfr. Date is 06/86

Thanks. Guess I need to get sanding.

View File 2019-2024 Yamaha YFZ 50 Service Manual 2019-2024 Yamaha YFZ 50 Service Manual Submitter wanrep Submitted 05/04/2025 Category Yamaha ATV  

View File 2017-2018 Yamaha YFZ 50 Service Manual 2017-2018 Yamaha YFZ 50 Service Manual YFZ05YYXH YF05RH Submitter wanrep Submitted 05/04/2025 Category Yamaha ATV