im back haha piston video new !!!!!

[purpleblaster]

so i got my quad running good idles nice then i rode it today for a good hr or 2 got back and sometimes it would start first kick sometimes third sometimes it will only start if i give it gas almost every time i give it just a little gas it will start fine . it will idle for about 10 seconds then shut off ??? help! carb is clean to me at least... idle screws and mixture screws are set ok . piston has side to side wobble they say thats normal it HAS NO UP TO DOWN PLAY . does everything look ok in the video if not please post. do u think i need a top end rebuild kit and if i do buy one what size should i get ?

 

[Wifesblaster]

You have to do a compression test to see what kind of shape the top end is in? Does the cylinder have scratches? After you put it back to gether and do a compression check you need to do a leakdown test to make sure everything is sealed up.

 

[boomadge]

To get the info your looking for you will have to measure the inside diameter
of the cylinder wall with inside micrometers,and use a dial indicator gauge to
see what kinda of runout there is."AKA out of round"..

Then you will have to measure the diameter of the piston.
Also you will want to take the rings off the piston and place them into the cylinder and check the ring end gap.

And from what I see from the bottom end,the rod bearings and spacers are worn out and will need to be replaced.

Sorry to say but it looks as though you'll have to split the case and do some lower end work.

 

[wwholden]

Cant really tell from the video what condition your piston and cylinder walls are. If you have any gouges that you can snag a figer nail in then its too deep and needs to be bored out. The size will depend on how far it needs to be bored out and what size bore its currently on. If needs to be I would check or a service on ebay for a blaster top end boring service by summit off road. They did a great job for $150. Just ship them you cylinder and they will bore it and get a piston for that size.

 

[wwholden]

To get the info your looking for you will have to measure the inside diameter
of the cylinder wall with inside micrometers,and use a dial indicator gauge to
see what kinda of runout there is."AKA out of round"..

Then you will have to measure the diameter of the piston.
Also you will want to take the rings off the piston and place them into the cylinder and check the ring end gap.

And from what I see from the bottom end,the rod bearings and spacers are worn out and will need to be replaced.

Sorry to say but it looks as though you'll have to split the case and do some lower end work.

I dont know if id worry about the side to side slop. As long as there isnt no vertical gap then I would say your fine. You just dont want a knocking rod.

 

[boomadge]

Its not the side to side that bothers me, take a close look at the video. The lower rod appears to me as though its got some serious angle rocking going on. To each there own but I would not consider that even close to being with in specs.

 

[wwholden]

Its not the side to side that bothers me, take a close look at the video. The lower rod appears to me as though its got some serious angle rocking going on. To each there own but I would not consider that even close to being with in specs.

Ehhh if you got money to blow on it then yeah. But hows it going to hurt when the piston is being guided by the cylinder walls. Its not going to be relying on the rod. The rods only purpose is to hold the vertical forces acting on the piston. I think hes fine. Just need some better pics of the cylinder walls and piston.

 

[purpleblaster]

Ehhh if you got money to blow on it then yeah. But hows it going to hurt when the piston is being guided by the cylinder walls. Its not going to be relying on the rod. The rods only purpose is to hold the vertical forces acting on the piston. I think hes fine. Just need some better pics of the cylinder walls and piston.

i agree and i defff do not have money to blow on it FACT. i wasent even going to go this far into the engine the furthist im going is getting a piston rebuild kit aka piston rings seals just need to measure it for size will have to get it honed and bored probably .or do u think i will even need a rebuild kit ??

 

[nd jat]

If the rod tilts on the rod bearings more than a few mm it's out of spec, And will result in rod bearing failure. They have needle bearings in it so tilting play is a sign of wear. Now if it slide side to side that's not a critical.
You may get by with it for awhile but it will fail soon if ridden hard.

 

[wwholden]

i agree and i defff do not have money to blow on it FACT. i wasent even going to go this far into the engine the furthist im going is getting a piston rebuild kit aka piston rings seals just need to measure it for size will have to get it honed and bored probably .or do u think i will even need a rebuild kit ??

Really need some high resolution pics of the cylinder walls and piston to tell you what it needs. If there are marks thats are deep enough to snag a fingernail on then it needs bored out. If not a hone and new rings should be fine. New gaskets as well. Everyone on here seems to say dont go with any other brand beisdes cometic.

 

[Blaaster]

There does seem to be a lot of side play on that rod, specs say a deflection of 1mm max at the rod tip.

You can get away with about 2 mm, but your big end bearing seems too worn to be servicable.

 

[purpleblaster]

ill try and upload some new pics of the cylinder and all with my good cam what im thinking is just new rings and gaskets im 100% not splitting the engine thats also a fact lol . the most i was thinking about doing was sending the cylinder to a shop to get bored and honed with a new piston but not sure yet the piston looks in good shape so maybe ill just have it honed try to have new pics up tm afternoon been busy workin