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when idling she runs ok but when you open throttle she vibrates quit a bit.my mechanic said this has caused the float to wear on the pin and cause some overflow out of choke mechanism when reved hard,main bearings seem fine,rings were bit rusty and stuck in piston so he said ,any ideas?.will remove head any way and hav a look.

patgas wrote:...main bearings seem fine

How can you tell?

If you have vibes so bad, its rattling the carb apart.. you have issues.

Whats your history with the bike?

patgas wrote:...rings were bit rusty and stuck in piston

WTF?

if the rings are rusty, then so are the main and rod bearings, split those cases and get a rod kit, main bearings and do a topend. she'll be like new

also, if the bearings froze up from being rusty, then the crank journals probably wore out. if the crank fits loosly into the bearings, you will need a crank too. The good news is that the crank comes with a new rod and a rod bearing.

got her back today and mechanic was right,she vibrates when you rev her and fuel comes out of overflow due to worn nedlle and float i think,she doesnt vibrate at all on tick over and no fuel overflow.he reckons the worn carb parts could be due to the vibration,theres no wines rattles or anything like that ,but defenetaly vibration through bars and seat when sitting on her ,seems fine when going and runs ok any ideas?

Run it until it blows up.

not sure thats good advice ,just want to make sure im doing right thing and not wasting my money

patgas wrote:not sure thats good advice ,just want to make sure im doing right thing and not wasting my money

Wasting money would be putting a band aid fix to address a bigger problem. Fix it right and you fix it once, but half ass it and don't be surprised with half assed results.

Exnav wrote:

patgas wrote:not sure thats good advice ,just want to make sure im doing right thing and not wasting my money

Wasting money would be putting a band aid fix to address a bigger problem. Fix it right and you fix it once, but half ass it and don't be surprised with half assed results.

X2
I would split those cases and replace those bearings before they come apart and you have to buy 2 case halves, a jug, a head, a piston and a crank! main bearings are like $50 from the stealership and a rod kit is like $100 then gaskets and you have peice of mind. Or all the crap I listed would be closer to $1000 AFTER it grenades.
500s all vibe some, mine vibes pretty bad and I know what I have to do, but you have no idea what the inside of that motor looks like!

thats exactly what i will do guys no good restoring her and putting a shit engine back in,will try and post some pics of my progress thanks again

no problem, dude, hit us up if you have any questions. All of us have had out cases split a few times!

patgas wrote:not sure thats good advice ,just want to make sure im doing right thing and not wasting my money

We told you that excessive vibes are a precursor to bigger issues, and that rust on the inside of the motor is warning sign #2....

You didnt seem overly concerned about looking into either one.

Sorry to be so blunt, but the collective knowledge of this board far outweighs any you will find ANYWHERE on the net....


..... listen to it.

yep i was hoping there would be another fix for this problem ,and didnt really want to spend a lot on engine .not to worry come to conclusion need to split engine and spend extra cash to get her right plannin full nut and bolt resto should look suberb when done will keep you posted.thanks for the advice mutch appreciated.

hi guys engines out ,frames gone to powder coaters and gathering parts.took barell off and isnt so bad think she needs rebore and piston. some burn marks on exhaust port sides,and slight marks not scoring,burn marks on piston ,cross hatching(think thats what you call it) seems non existant.allso some fuel in crank case wich seems a little thick not oily though,probally couple of egg cups fulls .isnt any movement up and down on big end but is left to right, quit a bit and same on little end bearing. i can move con rod diagonally on big end.i am going to get crank cases split and crank rebuilt next. was just after some input and causes of the above.there isnt any signs of rusting on rings, conrod,crank ect like i thought pretty clean really.

A little side to side ok but a lot isnt. a little confused by how you say diagonally? while you got it out, and there is some time before ridin' season starts . if you can afford it i'd go ahead and , hone or bore it, and have a close look at all the hard to replace stuff like bearings, seals, tranny gears ect. better now than on the trail.

by diagonally, do you mean that you can grab the small end and move it to an angle? if so its rod bearing time!

Bad rod bearing =

yep by holding small end i can move at a angle ,would you replace conrod as well? and any explanation for scortching on barell and piston ?could this be related to vibration ? any info would be appreciated.

Dude you need to get the manual. In there its shows how much side clearance is allowed and how much diag.... that is allowable.

No use rebuilding the crank until you really know what the hell you got.

im not rebuilding tne crank my mechanic is ,was just afer some input on wether the what i hav found could be some thing to do with the vibration and poor starting and the causes of what i ahv mentioned.just trying to gain a little knowledge really,i hav a manuall and will look later.

right guys checked clearance on big end, 1.0 mm manuall says .07 so if this is correct thats way out.could this be ny vibration problem?

Thats the side clearance... not a big deal to be so close to the service limit.

What you want to check is the radial clearance, which is pretty damm close to zero.

If there is ANY perceived clearance, its junk.

if you have noticeably play moving the small end in any direction, its rebuild time. before you buy a rod kit, split the cases and make sure the crank fits tight in the main bearings (like it should be hard to sepparate them). if its lose, than the journals are worn and you should just buy a whole crank assembly.

ok will do,thereis a couple of degrees of wagle from left to right on big end,could this be my vibration problem .there doesnt seem to be any movement up or down on big or little end.allso there is some scortching on underside of piston what is the cause of this? allso noticed two small recesses on exhaust ports both in identicall places about 6 mm long and 4 mm wide and 0.5mm deep are these suposed to be there? info would be appreciated.

patgas wrote:...two small recesses on exhaust ports both in identicall places about 6 mm long and 4 mm wide and 0.5mm deep are these suposed to be there? info would be appreciated.

There in the manual.

I'm not sure how old you are or what year the bike is, but how 'bout go to the pub get a pint, sit by yourself and look at the bloody thing.