engine rebuild

[breahn riley]

So I just recently pulled the motor. Last season I was leakin oil. I would see about 4 or 5 quarter sized drops as I let my bike sit over night. Also I noticed my clutch slipping at 7/8 to full throttle. So I have ordered a gasket kit, the high performance clutch plates and new clutch springs from mikesxs. The motor has 12k on it. While I have it apart are there any other no brainer parts to replace? Parts to check for wear and tear? Anything with the cam? Also when I pull the jugs do I have to be TDC? Any info would be greatly appreciated?

 

[inxs]

- why do you need to remove the cylinders?...where is it leaking?...what do you really want to do with your motor?...clutch could simply be adjustment and can be done without pulling the motor...seals can be replaced without stripping the motor
- remove oil filters...look for filter damage and black plastic bits in the sump, if they are there you have a disintegrating cam chain guide-normal damage
- with 12K and time there shouldnt be too much other damage

 

[xsjohn]

Double post.......sorry

12K........Did you check compression..........is there a need to lift the cylinders......?.......just causes wear with new break in if not needed..........where is the oil leaking from.......

Front cam chain guide should be changed if you are there.....can be done just with the head off only.........

xsjohn

 

[breahn riley]

yeah sorry. i meant the head. its def leaking from the bottom of the case. the bottom is covered in oil. did not locate where exactly the leak is coming from. ive already ordered the clutch and gasket set. i have not checked compression. im pretty much just tryin to bullet proof the motor as intend to ride alot this summer. What mileage do clutches fail? what about head gaskets? are you sayin that i shouldnt need to replace gaskets at this point?

 

[xsjohn]

I got 60K from my 80 but never did like the 6 plate newer clutches........went to a 79 which is an older clutch with 7 plates...........you can use 3 of mikes stiffer springs and 3 originals spaced.......the clutch is noticable harder to pull with 3 so I didn't use all 6...........I rubbed the steels on concrete to help the clutch a bit but the 6 plate newer clutch never tickled me..........and using a high zink oil will make them slip........catch 22 there cause the engine likes the high zink.......ah what can you do.......

xsjohn

 

[inxs]

its def leaking from the bottom of the case. the bottom is covered in oil. did not locate where exactly the leak is coming from

- could just be flattened bung washer or old filter plate gasket

i have not checked compression

- good diagnostic tool...if the head is still on its not too late to do this...main thing is theyre relatively even...over 140 great ... 120 good ... under 100 not so

What mileage do clutches fail? what about head gaskets? are you sayin that i shouldnt need to replace gaskets at this point?

- biggest problem with clutches is proper adjustment-at 12K it should be fine
- head gaskets will leak if the head isnt torqued down properly and occassionally checked...if removing its not a bad idea to replace the rubber coated washers with thick copper ones
- IIAFDFI

 

[breahn riley]

so ive pulled the cylinder head cover. the top part that contains the rockers. im now looking at the cam and valves. can i just loosed the cam tensioner and get enough slack to get the cam out from under the chain. i dont want to spilt the chain. i want to pull the head next to replace the head gasket. any suggestions?

 

[inxs]

- relax the cam chain tensioner, ease the bearings off the end of the cam...will release the cam chain without breaking it...after removing the cam dont drop the chain into the sump

 

[yamaman]

Yep, take a photo of the cam & bearings, slide the bearings off & pull the cam out.
Then drop the chain down the tunnel & spend the next 20 mins fishing it back out!

Too slow.............

 

[breahn riley]

do i need to be tdc? on the cam chain there is the two pins that have the gouges in them that line up with a deep groove in the cam gear. is that tdc? i cant tell on the rotor where tdc is. the rotor is beat to shit and hard to tell if there were any markings on it.

 

[Gordon]

With both pistons at the top, look around at the rotor & check real good for the slash. It should be close to the timing tab on the stator housing. When you find it, make the mark better, so you will know where it is next time, like when you go to re-assemble the engine.INXS & Yamaman are right there with you, could not have asked for better guides. I remove the camchain adjuster completely for more room.

 

[inxs]

- pins up is TDC...makes it easier to reset it when putting together so long as you dont rotate the crank...use your head and line everything up as you go and it will work

 

[breahn riley]

So the head is off and I did not drop the chain. I am seeing a large carbon deposit on the top of the pistons and inside the chamber where the valves are. It scrapes off easily with a flat head screwdriver and some steel wool. I've only done this to the valve side bc I didn't want carbon chunks fallin down into the cylinder. Can I clean the valves using a wire wheel? If not what should I use. I had my carbs jetted too much and runnin to rich so I'm sure that's what I'm seeing now. Ill post some pics asap, let me know what you guys think.

 

[Gordon]

Yea breahn, you can use a wire brush, even with a low speed drill. You are removing the valves, right? Just make sure they go back into the pockets where they came from. When they are out, use a wire wheel on a bench grinder if you got one, makes the job go allot faster. The valves are hardened, so don't worry about hurting them with the wire wheel.On the carbon on the pistons, you can also use a wire wheel on them, but remember that they are made of aluminium, and can be damaged from the wheel. As far as getting pieces of carbon into the cylinders, clean-up is easy enough. After cleaning off the tops of the pistons, spray some PB Blaster on the tops, then move the pistons down into the cylinders, and you will find a ring of carbon at the top of the cylinders. Just wipe out the gunk with a lint-free cloth. Repeat several times if needed. Leaving a little is not going to hurt anything, in fact, when it runs for the first time, whatever is left will blow out the exhaust valve. After lapping in the freshly cleaned valves, it is very important to remove ALL of the lapping paste.It is very abrasive, and excess(XS) will cause unnecessary damage. PS, rich mix will cause excess(XS) carbon.

 

[breahn riley]

 

[breahn riley]

here are some pics i took....

 

[Gordon]

Breahn, that's really BAD!!!OMG!!! Just kidding, actually those are not bad at all.Not much carbon in there at all. Yes, that line on the rotor is the mark for TDC. However, it does look like you got a burnt exhaust valve in the left cylinder. No doubt that the valves will have to come out, to be sure. They should all be perfectly round & square. Round where they meet the valve seat, & the stem 90 degrees square to the valve face itself, (the round part). Your engine looks very clean inside, well maintained. Or kept out of the weather during storage. I have seen some really bad engines turned into dependable engines. Clean up the valves & do a very close inspection of them,esp. where they seal on the valve seat. Intakes should have no pitting, well they all sould have no pitting, but exhausts usually have a little. The only thing for a burnt valve is to replace it. Mikes has them, and , unless your pockets are real deep, stock should be fine. I am using the stock ones from them. On another look, the exhaust could be just excess carbon. Get them all cleaned up.,,,, Gordo

 

[breahn riley]

just pull them and bench grind them with a wire wheel is what ill do. ill keep the pics coming. i wanna pull the jugs to the bottom gasket but im worried to see what i find. i thought the guides for the cam chain looked good, the groove is still pretty shallow. when im puttin new gaskets down should i be puttin down some type of gasket sealer?

 

[Gordon]

Breahn, if you pull the pistons out of the bores, your gonna have to at the very least, hone the cylinder's. A way around that is to pull up the cylinders enough to reveal the piston pin holes, then remove the pins, leaving the pistons in the cylinders. That way, your not breaking the 'seal' & 'fit' of the rings to the cylinders. not all that hard to do, just takes some patience & a little juggling to get both pins out without disturbing them. Every winter I take the head off mine just because, & I haven't had to pull out the pistons yet. And no oil leaks at the cylinder base gasket area. I got 11,000 on mine. As INXS asked , why would you want to do that? Only thing to inspect there is basically cylinder wear, & a close inspection when the pistons are at the bottom will reveal any problems. Or potential problems. I feel that a 'valve job', or just a refresher on the valves(lapping& seals) should be sufficient for now. Some one told me a long time ago, "Don't fix it if it aint broke", but I do believe in being carefull, & confident.

 

[breahn riley]

maybe ill hold off then. thanks for the heads up!!