The bolts & spark arrestor from your Big Gun would disagree with you on that point pardner. Also, have you replace your kickstand plate yet. Maybe you left it in the edge of that lake when buried your rear wheel during your "mud-out".

If anyone wants the back story to any of these jabs, just let me know and I will be happy to elaborate.

 

Touché..... ya got me, lol.... dont worry everyone theres no story at all behind that stuff

 

I did a little FYI comparison between Ron Ayres and MRCycles. Not much difference after you add the shipping.

Looks like the cylinder is the money saver.

 

Timing the cams involves a small amount of trial and error, at least for me. First thing is make sure the engine is still at top dead center. Note the timing mark and the "T". There is another mark just preceding this one labelled "F". It needs to be at the "T":



If it is not, be VERY careful when turning the crank if the timing chain is not tight around the cams and the tensioner not installed. (I think this is how I dropped my chain off the lower sprocket, more on that later.)


Next, position the cams as shown - see the timing marks? The intake cam is on the left and the exhaust cam is on the right. The sprockets on both are identical, they both have timing marks for intake and exhaust. However, for the intake cam on the left, the mark labelled "IN" sits just above the cylinder head to the left, and the exhaust cam on the right has the timing mark labelled "EX" sitting just over the clinder head on the right. The one on the right is a little hard to see because of the shadow. Then loop the timing chain over the cams - you may need to move the cams to get the timing chain on. Do this with the tensioner removed:



This is the tensioner:



And it goes here:



This is where the trial and error part comes in. Now re-install the tensioner. Note that you need to release the mechanism as shown in the above photo and install the barrel first with the two outside bolts. Then install the center spring and its backing center bolt.

Check the timing. Are the marks still aligned? They can sometimes move when the tensioner takes up the slack in the chain. If they have moved, remove the tensioner, and make the adjustment to bring the cams back into time. Usually just one tooth or so of either cam. Note that, from pin to pin, the cam chain should show 32 pins from the top of the cylinder head on the left to the top of the cylinder head to the right. So you need to make sure the marks are lined up AND the right number of pins show between the cams. Count the pins in the 2nd photo - should be 32.

Reinstall the tensioner like before and recheck the timing. Repeat as necessary to get it right. Note that the timing step may require patience. Sometimes you get it on the first try and you think, wow, that was easy. Other times you can't seem to get it after several tries and you think this sure does suck. But be patient - this step MUST be done correctly otherwise you could have serious engine damage if it is out of time because the piston might hit the valves. If that happens, you have a very expensive repair. But like I said, it is not hard, just don't rush through it and as long as the correct number of pins show on the chain and the marks are aligned and the tensioner is installed correctly, you are golden.

Regarding how I think I dropped my timing chain on the 2nd install. Tracing my steps backwards, here's what I think I did. I think I did not put the piston at Top Dead Center, TDC when I did that step. Remember I said there was another timing mark on the flywheel just preceding the "T" mark that is labeled "F". It is only seperated by a degree or so, so they are very close together. I think the "F" mark is when the spark fires. Anyway, I think I positioned the crank to the "F" mark instead of the "T" mark. When I had it all apart, cams removed and head removed, I noticed my piston was not quite level with the top of the cylinder. I peaked into the site window, and sure enough, I had it on the "F" instead of the "T". I thought, no problem, I'll just advance it a hair. I did pull up tension on the timing chain when I did that, but it apparently was not enough and when I advanced the crank it was just enough to probably "bunch" the chain on the bottom sprocket, i.e., the chain advanced down one side but slipped coming back up. Or something like that.

Anyway, that's my theory, I think that's what I did. It was just enough to drop the chain and then it wouldn't never quite go back onto the sprocket. At that point, I was tired and called up the shop and they said they could work on it right away and besides I didn't have any right side cover gaskets otherwise I probably would have fixed it myself. As it was, I took it to the shop and they put the chain back on and finished off the top end. I had already had the cylinder and all that back together - it was basically just retiming the cams and reinstalling the cylinder cover and they didn't charge me to much and they had the needed gaskets there.

It really is not hard. There are just a few things to be careful of. First the timing chain - careful to not drop it off the bottom sprocket by moving the crank if the chain is not tensioned. Also, of course, be careful of getting any old gasket material in your engine hole. Even though it is soft and probably would hurt the gears or anything, it could clog an oil tube and keep oil from flowing up to the top end and that would surely suck. Be sure the piston rings are position properly - there's a specific recommended pattern to position where the "slit" of each ring goes, presumably to minimize any blow-by through the small gaps. Clean off the new gasket seating surfaces well. They should be clean and dry. Prep the new cylinder with contact cleaner to get all the manufacturing gunk off, especially in the bore area and then prep it with a _very_ light coat of your favorite oil. Stuff clean rags into your engine opening to keep anything from falling in there - that would not be fun. It would be easy to do, too - the piston pin clips have a habit of flying away in random directions when installing and removing them. They could easily fall into your engine if it is not covered.

Oh, be sure the piston is installed in the correct direction. Remember, "Arrow forward":



Arrow points to the front tire. The 300cc piston has an arrow. The 331cc piston does not, so you need to match up the valve pattern - the intake valves are the large ones and they go toward the rear:



And this simple setup works pretty well as a ring compressor:



And don't forget lots of coffee:





Also, whether I plan on posting or not, I like taking photos of the steps along the way, especially when I'm about to take something apart that I might not remember how it goes back together. And like Deej, I have a tiny bit of that OCC (just not cleaning - more like that guy with the light switch ) so after I did my 331cc and it was all back together, I couldn't help but wonder, "did I install the piston in the r

 

 

To advance to TDC, you remove the two caps on the left side cover - one in the center to expose the crankshaft nut and the one above it is the site window. You just fit a socket on the crank nut and rotate counter clockwise. Since it's a 4-stroke, you need to do one full turn where the valve lifters move down and then back up, and then about 1/2 turn more, turning slowly and you'll see the timing marks go by in the sight window. And yes, you do that before the engine is apart - need the cylinder cap removed, though so you can see the valve lifters. My mistake was positioning to the "F" mark as opposed to the "T" mark on the 2nd install.

Yes, if the engine is at TDC, and your timing marks are positioned as in my photo, and you have 32 pins showing on the timing chain, and the tensioner is installed and applying tension to the chain, then you are timed perfectly.

The manual is a requirement - it explains all the little details. My photo thread just shows what to expect. The manual covers the ring placement and orientation, the tensioner, procedure for finding TDC, all that. Not to mention all the torque values needed.

 

Hey man, I am glad you found a way to go to school and keep your bike. Awesome.

 

Thats one thing the manual is good for. Explains checking the valve clearances and such, and how to get it to TDC, timing the bike looks pretty straight forward. Highly reccommend getting the service manuals if your gonna do the 300cc upgrade