luvsno
Member
Has anyone heard a 1998 700 and 2000 700 engine side by side. Reason is I know there were some changes to the 2000 but this one has a sound different then my 98. Both stock but the 2000 has a gear type noise in it at any engine speed. Best way to describe noise is if you have one running and you pull a plug wire off partially and you can hear the spark jumping a larger gap is what this engine sounds like all the time. Runs perfectly smooth but this noise has me puzzled. I don't know how it would be possible but there does seem to be a little more vibration at the mag side as its harder to hold the stethoscope to the cylinder jug. Sound is coming from cylinders all the same, not so much in the crankcase. Very strange. Just don't want to pull the engine and it be normal. Son just bought the sled not running and of course no one heard the noise with the bender can on it before. Thanks again for any help.
maybe a crank bearing?
luvsno
Member
That's my guess too except with stethoscope you hear it on the heads or jugs. Crankcase pretty quiet.
roudyroy1
Active member
broken power valve bouncing around?
Check for a broken motor mount also before you get too crazy.
I always remember them sounding the same.
luvsno
Member
It’s coming apart. I’ll let you know what we find. Top end is off and everything looks very clean in the crankcase so far.
If you listened to a running SRX with a stethoscope, you are certifiably deaf now.✌
luvsno
Member
Well we found a bad bearing in the middle where the aluminum spacer is (not the oil pump drive). I forget what it's actually called, so off for repair it goes.
luvsno
Member
Already have selective hearing with 2 kids and a wife.
luvsno
Member
Well engine is back together with rebuilt crank. Filled with coolant and mag cylinder fills up enough to come out exhaust. Pulled the jugs the base gasket doesn't look like it sealed at all. Its a Vertex kit but the gasket is just steel where the one that came off was paper with aluminum plate sandwiched in between. Torqued proper to 33nm new o-rings on the heads look fine not squished out. Has anyone else had this issue and what style is the Yamaha original. Can't remember when id got my 98 welded what the gaskets were like.
Jack99
Member
Hi luvsno. Glad to read you got its crank rebuilt and its inner bearing noise fixed. And, it sounds like it didn't cost you very much - by doing the repairs yourself. I haven't heard of this issue with the 600/700 triples. And, I haven't seen a weak design pattern on this forum either. Hopefully, this is a "one of" surprise fix for your sled.
luvsno
Member
Well the crank was $989 plus tax from CV Tech. Ordered Yamaha gasket and then get back at it this week to see where coolant came from.