Rhino 660 rebuild options - suggestions

[Projectjunkie]

I bought a pair of 2006 660 rhinos, one with a hole in the bottom end, the other with low compression

I believe they each have about 3500 miles

Realistically what is the easiest/ cheapest/ best bang for the buck path to get the low compression one running?
Buy a wiseco piston and ring and have jug honed?
Buy an Amazon or eBay jug kit?
Tear it apart?

I've never actually rebuilt a motorcycle engine

I'm not looking to make it new, just to make it run, put a few hours on it and trade it off

what say Irate?

 

[martyfowler]

First thing will be to find out why it has low compression. Check for a stuck valve or valve lash too tight. If thats not the problem then tear it down and measure/inspect the piston and bore for wear. It could be as simple as a stuck ring or rings that have been overheated and lost their tension.

Im no expert and i have never worked on a Rhino, but thats where i would start.

 

[Projectjunkie]

First thing will be to find out why it has low compression. Check for a stuck valve or valve lash too tight. If thats not the problem then tear it down and measure/inspect the piston and bore for wear. It could be as simple as a stuck ring or rings that have been overheated and lost their tension.

Im no expert and i have never worked on a Rhino, but thats where i would start.

It seems to have come on gradually, and was ridden regularly, thinking that would rule out the most of the valve train issues?

the rings being stuck or sprung is interesting, I'll do some diag when I pick it up

 

[TRINDU]

1. Throw a cheap cylinder kit on it and send it. They look to be $150 on amazon. Make the best out of the two.

2. Post the parts rhino up for however much it cost to fix the good one.

3. ???

4. Profit.

 

[martyfowler]

Id still check the valves before you tear in to it too deep. Valve/seat wear could come on gradually, as well as carbon buildup that might keep the valve from fully seating. Keep us posted. Id be interested to hear what the actual cause is. Hopefully its something simple and cheap.

 

[Projectjunkie]

1. Throw a cheap cylinder kit on it and send it. They look to be $150 on amazon. Make the best out of the two.

2. Post the parts rhino up for however much it cost to fix the good one.

3. ???

4. Profit.

I'm looking, seeing mostly big bore kits, seems nobody wants a stock rebuild, I'm ok either way, according to the reviews, the big bore requires extra tear down, or packing the case with rags and clearancing the case with a grinder to make it fit, I'll opt for stock if I can find it, trying to prevent the snowball effect

Id still check the valves before you tear in to it too deep. Valve/seat wear could come on gradually, as well as carbon buildup that might keep the valve from fully seating. Keep us posted. Id be interested to hear what the actual cause is. Hopefully its something simple and cheap.

Will do, good info. At this point in time is be happy to make run and sell it, I've got a family crawler to build

 

[86zukwilly42]

You should buy my 06. 686 rhino.. fresh motor. fully built.... on the real. I would just buy one of the cheap jug kits. an see what happens. new engines are money. I spent just over 4k on mine. An now im over the whole sxs thing an want to sell it..

 

[Projectjunkie]

Here we go

yesterday I set up a swamp cooler in the garage, cleaned out enough space to get this thing in, pulled the cage and rolled it in

watching some u tube vids now

I need to put a jumper on it and read the miles/ hours, I'm thinking I'll do more or less diag depending on hours, either looking for specific failure or assuming it's just worn out and start ordering parts

thoughts?

PO pulled the spark plug, and did minor tear down, he took the belt and stuff apart, thinking that was his low power issue, so when it's done, I'll need to go after that too

 

[Projectjunkie]

 

[Projectjunkie]

3100 miles

375 hours, but the meter rolls with key on, machine has stereo might be lower hours, need to do some diag, shit

 

[Projectjunkie]

Little update

I looked up some other machines, these aren't necessarily spent by these hours/ miles

Seller seemed to maintain his fleet of offroad toys, the pcv system was dry, I'm not writing off this engine without diag, ordered a 12mm adaptor for my compression tester and leak down tester.

Seller did mention he had 50psi on a compression test, but if the carb wasn't open, battery weak, etc, it could be a bad result

Also, any input on the decompression mechanism?

It seems that the cam gear retards timing, and uses inertia once started to advance it?

thoughts?

 

[Projectjunkie]

.

.

..

Tagging y'all for some knowledge

it's got 105-110psi compression, it gives me 45-50psi on 1st puff, then builds to full on about 4 spins

I squirted some oil in it and it didn't change my reading at all, but, I only spun it fur 30 seconds ahs the piston is at a 45deg, but, with the clan pcv system, I'm thinking the rings are decent, I also found the spark plug, zero fouling

Now, is this enough compression factoring in the de compression mechanism?

When I inspected the rockers, it has 2 exhaust valves, one got tight a few degrees before the other, but then both had comparable lash (by finger, not gauges)

thoughts?

 

[Fredycruger]

Tagging y'all for some knowledge

it's got 105-110psi compression, it gives me 45-50psi on 1st puff, then builds to full on about 4 spins

I squirted some oil in it and it didn't change my reading at all, but, I only spun it fur 30 seconds ahs the piston is at a 45deg, but, with the clan pcv system, I'm thinking the rings are decent, I also found the spark plug, zero fouling

Now, is this enough compression factoring in the de compression mechanism?

When I inspected the rockers, it has 2 exhaust valves, one got tight a few degrees before the other, but then both had comparable lash (by finger, not gauges)

thoughts?

adjust the valves and go from there.

i had 660 raptor i put new piston and rings and it started right up and ran pretty good
went to get some bolts and it but would not fire up later

after week of fucking with everything possible i checked the valves and they were tight AF made adjustment and started right up again

pull carb and go trough it.

got spark?

 

[martyfowler]

adjust the valves and go from there.




I agree. Set valves to spec and see how it runs. Should be able to find compression specs somewhere too. I would guess 105-110 should be enough.

 

[Projectjunkie]

?

.

Ok, backed off all valves, no noticeable leakage, and none in coolant reservoir

I am getting substantial leakage from valve cover and crankcase

this is with piston at bdc

It is a surprising amount of air versus what seemed an almost acceptable comp test and clean pcv, any insight on the compression release? Does it vent compression into the crank case?

or is my jug just wallowed out at the bottom?

 

[Projectjunkie]

I dug out a nice USA leak down tester, I've never used, and didn't come with instructions

I can manipulate the inlet regulator to get any reading I want, the more air you put in, the less % leakage you have

according to all this, my leakage looks minimal

I'm thinking next move is to adjust all valves and comp test, then soak the rings with oil and comp test again

 

[martyfowler]

I'm thinking next move is to adjust all valves and comp test, then soak the rings with oil and comp test again

Sounds like a good plan to me.

 

[martyfowler]

I just read where someone said the compression should read 163.5 min and 210.5 max. I also saw it mentioned that the compression release will affect the readings, but I never saw anything about how to disable it for testing. Sounds like yours is definitely way low. Since you saw blow by into the crank case it might be best to go ahead and tear it down far enough to measure/ inspect the bore.

 

[Projectjunkie]

I just read where someone said the compression should read 163.5 min and 210.5 max. I also saw it mentioned that the compression release will affect the readings, but I never saw anything about how to disable it for testing. Sounds like yours is definitely way low. Since you saw blow by into the crank case it might be best to go ahead and tear it down far enough to measure/ inspect the bore.

I loosened up an exhaust valve, and got about 120psi, then put oil in the hole and got 130psi

I threw it back together and tried to start it

I noticed more oil in the air filter than I'd previously thought

It ran on ether for a while, but never really picked up gas, it's been sitting since November, probably gummed up. The other rhino died 2 weeks ago,
I may swap the carbs and try again.

I found those numbers a couple times, but, like you, couldn't find the info on decomp

also found people saying 130psi was acceptable WTF

 

[jhama78]

FWIW, this is the piston and jug that came out of my rhino 660, burned oil like a bitch but fired up and ran without any noise at all... pulled it apart to swap just and piston thinking it was rings but it was obviously way more than rings..

 

[Fredycruger]

I loosened up an exhaust valve, and got about 120psi, then put oil in the hole and got 130psi

I threw it back together and tried to start it

I noticed more oil in the air filter than I'd previously thought

It ran on ether for a while, but never really picked up gas, it's been sitting since November, probably gummed up. The other rhino died 2 weeks ago,
I may swap the carbs and try again.

I found those numbers a couple times, but, like you, couldn't find the info on decomp

also found people saying 130psi was acceptable WTF

so it runs on ether?
clean out the carb
.
130 is acceptable. it might have washed out cylinder

on raptors auto decompresser is built into the cam, it is controlled by rpm (centrifugal force),under 700 rpm there is a pin that protrudes from the cam and opens a valve, after 700 rpm that pin retracts and operates normally.

 

[Projectjunkie]

I

so

Aight, while running it on ether it backfired and sheared the key on the flywheel so I had to pull the passenger side of the engine down, that coupled with the air leakage into the crankcase, i figured I'd pull the jug. It had a scratch, I water tested the head for leakage, it was probably mid life ok, but i took the jug and head to a motorcycle machine shop, they were ok with a hone, but sold me a valve job with new valves, I ordered factory rings, side cover gasket and woodruff key. I cleaned out the carb somewhat and pumped the fuel tank out while waiting on parts

tonight I got it running, but I think it needs the carb cleaned out more, it didn't went to run without the choke, even once warmed up.

I go to put the clutch shit together, the P.O. thought it was a weak clutch before condemning the engine with a comp test.

I find what I'm calling the primary fixed sheave stripped out, which I'm assuming was the problem all along, and then I think I'm missing the tin cover and hardware from the clutch. I love buying shit in pieces

soooooo...

recommendations? What exactly do i need to buy here? Brands to look for, or avoid?

 

[Projectjunkie]

jhama78

 

[jhama78]

I'd talk with Hunterworks, let them know how you are going to drive use the rhino and have them recommend a clutching setup for you. https://hunterworks.com/yamaha_rhino__accessories



They are pretty much the last company making lots of parts for the Rhino and seem to have their shit together. Looks like you are gonna have to buy a whole new sheave anyway so you might as well improve on it since its broken.

 

[Projectjunkie]

I'd talk with Hunterworks, let them know how you are going to drive use the rhino and have them recommend a clutching setup for you. https://hunterworks.com/yamaha_rhino__accessories



They are pretty much the last company making lots of parts for the Rhino and seem to have their shit together. Looks like you are gonna have to buy a whole new sheave anyway so you might as well improve on it since its broken.

I'll call them, thanks

 

[Projectjunkie]

Update

so while I had to decide between patching it together and buying an upgraded clutch, my good friend made me a pretty fair offer and it's on his garage now

 

[rocketron]

For clutch, run Hunter Works OD weights (if it doesn't already have, it looks like it might as the sliders are not stock) and a EPI purple spring in secondary. Don't need outer tin piece if you are running greaseless weights. For a bit more bottom end you can put a shim behind drive plate (can't remember yamaha part number but will look though my notes to see if i can find it).