I got this posted over in the Uforce Section But I think it applies to the Z Force as well


Picked up a 2014 UFoce 800 side here on the East Coast of Canada. It is a basket case and in need of repair and rebuild as it has engine issues. It came with a disassembled engine with a broken crankcase, a replacement good crank case that is split in half and a box of parts (some used, some broken, some new). I know I will need to buy a few parts as all are not there to complete the engine rebuild. I have done rebuilds in the past (Artic cat Wildcat 1000, Motorcycles etc) so the rebuilding is not an issue as long as I have a good service manual and parts diagram. I do have the UFOCRE CF800-3 service manual and I have looked at the parts diagrams on line. The rebuild seems pretty straight forward, but I do have some concerns on replacement parts as there are a few items that have multiple parts with different "Mark" numbers and it doesn't really say why or specific use. A phone call to my CFMOTO dealer did not help much. So I am reaching out to see if any members can provide advice/assistance.

OK so here it is

Crankshaft: Parts diagram says there is a Crankshaft A or B. It does not say why or if it makes difference what crankcase you have. So I am assuming Crankshaft A or B will fit in the crankcase I have.  I did see and read that the bearings for the crankcase need to be either Blue (B Crankcase) or Red (A Crankcase). My replacement Crankcase, both half cases are stamped B so I need replacement 2 x Blue bearings for each half of case for  the Crankshaft.

Connecting Rods: Parts Diagram shows 2 different connecting rods,  Mark I and a mark II as well as several differ color plain bearings (Red, Blue, Black) for the big end of the connecting rod that connects to the crankshaft pin.  I also see the article in the manual on which plain rod bearing goes with each rod (Mark I or II) and the relations ship to the Crankshaft A or B so that is not an issue. What the manual does not say why there are Mark I and II rods and where to use them.

Pistons: Parts diagram show 2 different pistons, and photos on line show them marked as "I"  (on line dimensions says 90.94-90.95 MM) or marked as "II B"(on line dimensions 90.95-90-96 MM) but again the manual does not say why there a 2 different pistons listed (and in this case Mark II B is  a bit bigger than Mark I) or what cylinders they are for (are the interchangeable between front (Cyninder #2) and rear (cylinder #1)).

Cylinder Sleeve: The parts diagram shows a Mark (stamp) on the side and I see this stamp  as I have 2 cylinders; It has a number 1 on one and a number 2 stamped on the other. I see on line the measurement of 90.96 mm listed for the Cylinder. Other than the number stamp, there is no difference with the cylinders and the manual does not state which cylinder goes in which cylinder location in the crank case.  Does this stamped number refer to the Front Cylinder which is cylinder #2 and the rear Cylinder which is cylinder #1 as per the manual?

So after further reading on line, AI (evreyones friend......) AI says for proper engine function you must use the complete corresponding set; a Mark I piston requires a Mark I Connecting Rod and a stamped 1 cylinder (which is rear cylinder if placed as per my comment above).  So if that is the case, then for the Cylinder stamped 2 (The Front Cylinder and piston) it would need a Connecting Rod Mark II and piston II B.
 
If you go this way, you now have 2 different size pistons in the cylinders sleeves, be it only by .01 MM, (as per the Piston measures I stated above)

Any comments on this configuration, is this out to lucnch, make sense etc,

As for replacement parts, I see online several sites that offer the Crankshaft with the connecting rods attached for a very good price. Anyone purchase one of these and if so any comments. The store site does not list if it is a Crankshaft  A or B assembly or what connecting rods it includes (Mark I or II),  While this is not an issue as it will have the bearings already installed;  it is an issue if the connecting rod Mark  (I or II) Needs to be  the same as the piston mark I or II.

Has anyone in Canada bought one of these and if so did you have to pay import tariffs (the checkout cost on the website does not say if it is subject to tariffs)

Sorry for the long post, but hoping someone who may have done a rebuild or repair can provide some insight or inform before I start ordering to make sure I get the correct parts

Thank you in advance.

I'm not sure about the Uforce, but my Zforce manual didn't have a lot of options. I assume the 800 engines should be the same.
You had a lot of technical questions in that post. I can tell you what I did and found out along the way of my rebuild.
The crank kit I bought already had the connecting rods and bearings installed on the crankshaft. All I did with that, is check the torque specs on the rods which was good.
The bearings, on mine anyway, are for the left and right case halves and are colored red and blue for the corresponding case half that have to be in the correct half. They also have to line up with the oil ports correctly when you press them in. I too obsessed over this because my manual isn't super clear on this. One would assume that the different color bearings are different in size or thickness, but they are not. The colors indicate which case half they go in. I measured both color bearings and they are the same, so if there is any difference it may be slightly beveled that I can't see on my calipers.
When you press the case halves together with the crank installed, make sure the correct rod is through the correct hole, the cylinders are slightly offset and must be in the correct position before attaching the case halves together.
The pistons were marked/stamped with a l and ll to note which cylinder they go in. They also have an arrow on the top of the piston that has to be pointed the correct way , see the manual.
The cylinders and heads are marked l and ll also, so it's hard to mix anything up.
It was a fairly straightforward process.
Mines a 2014 800ex so I would assume our motor long blocks at least are the same.