Engine problems

Ive got a question for you knowledgable engine guys. My riding consists of riding through the glades hunting for the most part. I've got an 05 660 that has always run fine. I let it sit for the last year but decided to give it to a buddy of mine (not a mechanic but plenty of garage experience) to prep it for some riding I want to do this summer. He also has a 660. He cleaned the carbs and had it running fine it seemed. I bought a dynatech cdi and was planning on getting a sheave from James next. After putting in the cdi he noticed a lot of oil blowback into the air box. Probably a 1/4 quart after a 10 min ride. I went over to check it out and it took a while to get it started. When running it definitely blows a ton of oil out. After talking to another mechanic he said that it could be the rings. I made the decision to go ahead and break it down. When we got to the piston while pulling it out we had a round piece from the side of the piston between the rings fall out. About 3" long. Everything else looks great, almost brand new looking. Cylinder wall is perfect. I've decided that the only extra power I want is the cdi and James' sheave. I'm not a mechanic and won't have the time to get into working on it all the time if I go overboard. Is it possible that's the only issue i have or should i go farther? So if I stick to a stock piston should I stay with the oem or is there another piston and rings I should get? Is there anything else I should do since i have it broke down? I haven't had good experiences with the local dealers service dept. with my other bikes and don't want to deal with them other than buying parts. I'm definitely calling James tomorrow for advise and a siphon break. Gonna have to wait for the sheave now it seems depending on how much I spend on this repair. Any advice you guys could give would be a great help.

Wiseco / JP both are great products maybe bump your compression up a little
hone cylinder and make sure you get the ring end gap set per specs , also the cylinder/head studs are a added security not to have bolt stretch an a leaking head an or cylinder gasket
now the piece that fell out , is it part of piston or a broke ring, pic could help, make sure nothing got in the bottom end

I agree with Jeff, that's all sound advice. If your looking for someone to do it for you that wont screw you over, Im in N FL and Rhino's are my specialty. I have done work for some members on this site and have a good Rep, If you would like to talk about it feel free to call me. 850 259-1166 Mike.

It's part of the piston. Between the ring grooves. I've got a pic on my phone ill try to upload. I don't think anything got into the lower end. I was just looking at getting a 686 kit. Ill definitely stick with a quality brand verses saving a few bucks. Gonna try this one myself Mike but will keep you in mind in the future. I head to my lease in Ga quite a bit and could probably drop it by on the way up in the future. Thanks.

If it's just a small Alum piece of the ring grove, I dont think you have avything to worry about, It probly went out the exhaust when it broke off. That's what happens when you let your toy's sit around to long. lol

if your going with the 686 changing the cam would help it a lot, from what you said for type of riding you do the mud buster cam stage 1 would be good for you ,just my 2cents

I agree with Jeff agian, with the Cam, getting the heavy duty springs for the valves is also needed.

thanks Mike I forgot about the springs

Stuntmanmike wrote:

I agree with Jeff agian, with the Cam, getting the heavy duty springs for the valves is also needed.

Doesnt the mudbuster only require the center intake valve spring from a raptor and all other springs can be stock??

Not according to the cam manufactuer. And I wasnt about to take the chance and Go Cheap!

What you have explained sounds like detonation. A few things to keep in mind:

1. Cracked ring landings are generally an indicator of lack of timing or excess ignition timing.

2. The aftermarket CDI you are using has a linear increase in timing of approx 5 degrees past 2500rpm.

3. Adding a higher compression piston than stock with the added timing you have is just asking for a more major problem.

4. An 11.0:1 compression 686cc motor with 5 degrees advance will require around 110 octane fuel to keep detonation at bay.

5. Adding head studs to the above package with advanced timing will likely cause even more expensive damage. By removing the factory STRETCH bolts that allow the head to lift and "blow" the head gasket you will now pull the studs from the cylinder or the cases. This can damage cylinders and even crack the cases...

Hope that helps a few people out...

Nate
Alba Racing

Thanks for all the good advise guys. After talking to James and calling Alba I went ahead and ordered the 686 kit from Alba and shipped my jug out yesterday. I also just ordered a new JBS sheave. Now I'm second guessing myself after reading your post Nate. I don't have access to 110 octane fuel anywhere close to home. I'm gonna go ahead and order oem head bolts I guess. The last thing I want is to be working on the rhino all the time.

he is saying less timing would be better

We are changing to a 10.0:1 compression 686 piston so he does not have to be concerned.

Nate
Alba Racing

thanks nate!

Sheave got here yesterday. Thanks James!

Another thing to consider is a siphon break from JBS. When You put the CDI on it allows the engine to run much higher rpm's causing the breather to suck the oil out of the crankcase. A very common problem with Rhino's that have an aftermarket CDI. the siphon break will prevent the oil in the airbox.

I should have said that that, my syphon break and filter, 14g weights and my orange spring came in also.