Originally Posted by Conrice

that's both. you see the scoring on the walls? that's the same width of the actual skirt on the piston. i've pulled one apart like that before, and the skirts on the piston are going to be just as bad. picture the piston moving up and down. it's not moving straight up and straight down, its pivoting when it goes in one direction and another. - that's what causes this type of wear. if the correct amount of oil had been in there, it would build up around the skirt and rings and "cushion" that pivoting - and there wouldn't be that much wear.

yup. that's what i'm doing.



yes. and to be honest, i think there's too much wear to only go 1mm. see, its not like i've put the extra space in there evenly. that cylinder is now egg-shaped. it needs to be perfect. but thats as far as you can go with a bore. the reason is as you thin out the amount of space in between the cylinders - you get serious cooling problems - as in it won't cool.



i'm going to sleeve the motor. sleeving is different than boring. i'm going to retain the 75mm bore. but what a machine shop is going to do, is bore the HELL out of it - way more than just 1mm. we're talking a good amount. then they are going to make a iron sleeve with an ID 75mm and they're going to press it into the cylinder block. it'll be WAY stronger than the nikasil lined aluminum could ever dream of being. iron also cools and dissipates the heat better than the aluminum too. i have a set of forged CP high compression pistons that are lighter, stronger, and have a wider skirt waiting to go in the block.

i'll put it this way. some of the guys on the net think the nikasil lining is amazing and strong. - but i'm not impressed. i've got 3 full motors - 2 of them have had this problem. and i'm sure its because of people not taking care of the motor and if you don't - the materials aren't strong enough to take abuse. this motor has 13k miles on it. my personal motor has 22k and is in way better condition.

as far as what my options are - i think this is the best way to do it. it will be bullet proof. i have a build thread going on in the fighter section. i'll put together a very detailed pic build of the motor itself.

the sleeving processes going to cost somewhere around $250 a cylinder

Originally Posted by Conrice

a little while ago, i bought an engine that had a valve tick. it was a few hour drive away from me, at a real good price, and the guy had a few videos of him riding the bike with that engine installed.... - and it did sound like a valve tick

the PO had since replaced it with a new motor because a dealership quoted $1000 to have a look - and a friend had a spare good motor.


so i bought it.... figuring it wouldn't be so hard to re-shim the valves - and if worse came to worst - i had a spare head that would work.

well... i checked the valves.... really good looking, all well within spec as far as shims anyways. so pulled all the caps off - all the retainers were still good.

now i'm thinking ****. well i decided to fill-'er up with oil and listen to it myself. it's definitely a lower end KNOCK. now i'm really pissed because it means i have to split the case - new bearings all around, put it back together and hope it works.


so i do that. as i brake the motor down, there aren't any spun bearings. plus the stator is TRASHED. so i put a spare crank i had in, new bearings, new flywheel, etc. decided to not take the pistons/rods out because i didn't think anything would be wrong with it (hint - foreshadowing for those of you still reading).

i put it all back together - same knock - i stethoscoped it - its definitely piston knock

****!

so i finally pulled the head off today to measure the piston/cyl. gap. spec is .0008-.0022. that's .8 thousandths - 2.2 thousandths. --not exactly a lot.

guess what mine is....


.012..... 12 thousandths...... that's right. a whopping 6 x what the service limit is! so needless to say, i'm pissed.

i can't figure it out. did the guy not believe in motor oil? did he have something against warming the motor up before red-lining it? i can literally pivot the piston back and forth in the cylinder with ease. it's pretty damn rediculous - that's for sure.


i figured i was getting a great deal with this motor... now i've completely burned a few hundred bucks. sorry for the rant. i just can't stand it!


lessons:
don't buy a motor (or part) because of what someone thinks - listen - see it first!
DON'T RUN THE MOTOR LOW ON OIL
OVER-REV IT
RUN IT HARD WHILE THE MOTOR IS COLD!


this is the 2nd motor i've gotten second hand that's had this kind of piston slap knock. i'm telling you, it's the kryptonite of the 954/929. so you guys watch out! take care of your motors. run the right amount of oil. don't run the bike hard while it's cold!


sorry for the long rant