still going

[Joe Breaux]

just an update on my MSU 500 . For all the misery it caused me the first 2 yrs, and the combination of some quality YAMAHA parts, it has now become a reliable ,useful UTV without the constant fear of having to push or tow it back from trails. I have not had a single issue pop up in a very long time.. FINALLY!....and as a side note, I just bought  a C FORCE 600 ATV to replace an old and well used  Honda that finally after 18 yrs gave up a rod bearing.  So far the new one has really impressed me .. I like the new Power Steering and  this CVT Auto Trans is new to me on an ATV .. I m used to constant shifting on my Hondas .  It also has something I have never seen. Its EBS  engine brake system, as soon as you let go of throttle, it engine brakes you to a stop rather quickly.. its great idea for the grandkids safety . Takes a little getting used to tho.. All in all, I like it. We shall see how durable it is after break-in.. I do "RIDE" them! .....and they honor their warrenty! and the dealer is 15 minutes away.. 

[T-boss 410]

That's good to hear, Joe. I hope you didn't just jinx yourself 😎. I haven't had to contact Massimo, so I don't know if they really did improve their customer relations.

There was a post here a while back that a guy had discovered that the battery cables were undersized, and he was working with the manufacturer to correct it. I never heard from him again. I can make my own cables, but I don't know what size to use. I'm assuming you don't have any issues with starting your UTV, but with mine it occasionally doesn't want to turn over. If I turn it off, then hit the starter again, it will start. I thought that maybe it was because of the undersized cables.

Anyway, even though I have ribbed you about your Massimo, I'm glad that you're enjoying it.

[Joe Breaux]

never had issues with starting it.. always started right up..and in 5-10 minutes overheated! lol .. All is good now. But it was a nightmare from day one when I had to be towed back to Camp after 15 minutes of driving! Maybe your battery is aging or might not be large enough ? I had a 350CCA battery in mine new.. When it crapped out, I put a Marine Starting 600CCA battery under driver seat and ran new larger and longer cables.  used #6 AWG wires 

[T-boss 410]

Mine came with a 300cca, which just wasn't doing the job. So I bought a 350cca, which seemed to do the job, but it doesn't seem like it's still turning over fast enough. I remember a post from a member who was aware of the problem and was working on a fix. I could fix it myself, but I don't know what wire guage to go with.

[Ben1098]

decompression release problems will give the "stall" and require multiple hits to get it to finally crank over.  Valve adjustment (exhaust) is critical to the decomp pin opening the valve.  Other problem is the actual decomp assy worn or a groove chipped out in the cam follower where the pin rubs at low RPM.  See older post of mine on the decomp assy in the cam....interchangeable with Rhino....identical down to the welds and flyweight interference problem.

[T-boss 410]

Are you referring to the 2017 Kymko 450i post?

[T-boss 410]

2 hours ago, Ben1098 said:

decompression release problems will give the "stall" and require multiple hits to get it to finally crank over.  Valve adjustment (exhaust) is critical to the decomp pin opening the valve.  Other problem is the actual decomp assy worn or a groove chipped out in the cam follower where the pin rubs at low RPM.  See older post of mine on the decomp assy in the cam....interchangeable with Rhino....identical down to the welds and flyweight interference problem.

Does this particular engine (Linhai 352cc engine) actually have a decompression release? I have a copy of the service manual, and I can't locate anything in the manual about a decompression release. Can you possibly show me where it is located? I'm trying to do as you advised, but I'm jot having any luck locating it.

The issue of hitting the starter a few times isn't a common occurence. This happens about 50% of the time that I start it when cold, especially after it's sat for a few days.

Thanks much!

[Joe Breaux]

My 500 engine has no decompression release , but it spins easily and has always started easily.. that was never an issue..  blown head and head gaskets were the plague that fell upon mine from 1st day I bought it.. for which Massimo refused any warranty reimbursement from first day break down on 

[T-boss 410]

I'm still thinking it's the battery cables. Until I can find out what the stock guage is, I can't go forward with replacements. I don't have any kind of tools that I could use to measure it.

[Ben1098]

I cannot find the post....it was for the Massimo (HiSun) 500.  The decompression release is built into the valve train cam.  Remove cam gear round cover and notice the flyweights and stamped timing dots.  The pined disc rotates and the attached rod in the center bore of the valve cam and pushes up a button pin with a cam "flat" on the inside center rod cam in a cam....which hits the exhaust valve follower.  At higher RPM, the flyweights sling out, rotates the cam inside the valve cam, and then the button pin retracts below the cam profile.....full compression.  Yamaha Rhino had same build error as Massimo.....the sets were identical down the the welds and machining tool marks....SAME VENDOR?????  Die grinder work required to obtain the full travel of the flyweights.  One of my HiSun reworked cam/decomp assys was "borrowed" to fix a Rhino.....never to return.

The post covered the rework of flyweights, the wear gouge the button pin takes out of the cam follower, the small rod cam edge that wears round (less button pin lift), the error of adjusting the exhaust valve clearance with the decomp pin raised (up at low RPM thus need to manually rotate flyweights to lower pin button for adjustment OR turn the cam to be sure you are OFF the button...watch the follower for the "jump" coming off the pin).