never seen this before.....

[quam]

i put in new rings and honed the cylinder last month. also installed an f7 pipe and the outerwears box cover and rejetted.
broke the her in and took the bike out for a day ride and about 5 hours into the day she stopped workin!
let her cool down, then tried starting her again.....she'd run at high revs, but would bog down at low revs. didn't matter what part of the throttle band she was in.
so i figured either it was a rich jetting and the plug was real carbon fouled, or maybe a reed cracked. but the reeds are pretty new, i installed the vforce3 cage just about 3 months ago.
i got home and pulled the plug and there were little balls of metal jammed into the spark plug between the housing and the insulator.....weird.
so now i'm thinkin maybe i didn't clean the cylinder well enough after honing, or maybe i knicked one of the ports during honing and now it's starting to shear away.....
what you guys think?

 

[Blasterb0y794]

did you do a "break in" after the rebuild?

 

[regal81455]

i can tell you from experience exactly what happened, your wrist pin bearing broke, you've got little pieces of roller bearing welding to the spark plug, same sh*t happened to my brothers bike, your gonna need a new wrist pin bearing and all new gaskets becuz likely your gonna have to split the cases to clean out the crankcase, at least i had to cuz several little bits got down there and work there way to the outside edges where a flush just wouldnt get them out, sorry to hear it...

 

[89custom]

regal you seem to be the bad news guy lol.

and splitting the case is a biotch. just lettin you know, i just did it. if you can get some tools, all you need is a crank puller/installer tool. nothing else. other than gaskets and you problably want to do a main bearing replacement.

 

[pittboss45]

What was the tolerance between the piston and the cylinder before you started. By honing and installing the rings without doing a check on the wear of the cylinder then you might have found the problem.

You also said you broke it in. How did you do this and what was the jetting. I think that with the balls of aluminum that have collected to the plug that you've melted things.

 

[quam]

well guys, i figured out the effect, but still have no idea of the cause.
last night, i pulled the top end apart to have a look and i as i pulled her apart i saw a little square chunk of metal and some shavings in the intake right under where the reeds sit.....that confused me a little bit, until i got the cylinder off.
what do you guys think could have made this happen?
yes, i did do a "properish" break in, and took it easy for the first half of the first ride on top of the break in i did at home.
and come to think of it, it seems that the kick starter would kinda catch on something sometimes when i'd kick her, but a little push would free it up.
only thing i can think of is maybe i knicked the exhaust port (that's the side that's chewed up) when i honed.....

 

[quam]

oh, and the wrist pin and bearing look to be ok.
i had her jetted to 350 w/ the f7, uni and outerwears box cover. i'm about 400ft above. when i got home, i checked and saw that the jetting was a little on the rich side, so i dropped down to a 320.
but there's obviously gotta be tons of metal bits in the crankcase.
so i guess i gotta get a crank puller. isn't there a case splitting tool that i'll need as well?
the tranny's separate from the crank case, right? don't need to worry bout any bits in there?
anybody try swishing a magnet around in there to get the larger bits out then flush w/ oil?

 

[jdub86]

youre transmission is right in the crank case... when you pop it open all the gears and the starter are at the back of the case and the front you have the crank...

here watch this

Its a guy rebuilding a Blaster it will give you some insight as to how the motor is assembled.

Good luck!

 

[tjsdaname]

320 seems to be alittle rich..... i have that same setup and i run a 290 just fine......

 

[quam]

are you at around 400ft above sea level? altitude plays a HUGE role in jetting. as does atmospheric pressure, barometric pressure, ambient temp.....
the lower in alt you are the leaner the air is. so if you live in colorado, then you'd prob run like a 250 main jet. down here near sea level, we need much bigger jets.
i still have some fine tuning to do on the jetting, but i think i remember tryin a 290 and finding the plug read lean.

 

[pittboss45]

What I'm seeing here is a sure sign that there was too much clearance between the piston and cylinder. That will snap the skirt off the piston every time.

I argue with people on a daily basis on the issue of just honing a cylinder and installing new rings when in fact that it actually needs bored.

Sorry for your loss and I'd be splitting those cases and looking for damage where the case halves match up.

 

[yamahaulling]

We live at 2200 feet and when we ran the stock carb we jetted at 270 when it was cold outside and a 260 when it was hot. and that was on vp and a highly modded 66 mil bore blaster. The main thing is ya just want the plug coco brown!!!!

 

[quam]

260/270 at 2200 feet sounds about right. down here nearer sea level, i think the 320 will be near to perfect for me.
pittboss, your logic is sound man. the piston flapped around a little too much and maybe kept kickin off the exhaust port and chipping itself away.....would also explain the jerky kickstarter.
so, what's the next size up on the bore? seems like everyone around here likes the 240cc.....what size piston/bore would that be? also, anybody got any tips or tricks to help me pull the motor and split the cases?

thanks a bunch for everyone's input.

 

[hickskateboarder]

ouch.... pay attention to where everything came from when you take it apart. and get a repair manual and go step by step. may as well stroke it while its apart if you haven't already...