Help, please.

[Iliketogofast]

I blew up the stupid 310 kit I got already. It only lasted 15 minutes. There has to be something the matter with the bottom.

The plug is clean and tan. It ran great and absolutely screamed, then I broke the chain and didn't end up starting it again until today. I had to pull start it both times , because I couldn't kick hard enough to get a decent spark. So today when I rode it, it was a little tough to pull start. It started up for a second but died right away and just kind of bogged for a few seconds before firing up again and running awesome just like the day before. I rode it around the yard once quick and everything was fine, then I took it down the road and it started bogging like the sprocket was slipping or something, and it finally died. I pulled in the clutch when it did and while it was still rolling I bump started it again and it started up, but died 10 seconds after and wouldn't start again. When I kicked it it had no compression. This is exactly what happened with the last 3 top ends - my original one died then I rebuilt it and put it back in - it went within 10 minutes, then I got the 310 and it did this.

Any clues?

By the way, on the first rebuild there was a hole in the piston right by the exhaust port. I'm sure it's the same this time too.

[Iliketogofast]

Please!!!!

[450rJam]

how did you break it in ?

sounds like your rings never seated and lost comp.
egg cylinder ? who put it togeather ?

fuel ratio ? what oil you using ?

[Iliketogofast]

I put it together. Brand new cylinder from ESR.

Fuel ratio 40:1 with Klotz oil.

I'm thinking that my halfassed break in might have done it. It had to be pull started because the coil is weak, and I only let it idle with blips for a few seconds then I really gave it hell, and shut it off within a couple of minutes. When I started it back up I gave it hell again for a few minutes, then it broke the chain and locked up, so I towed it home and replaced the chain but by then it was too late to take it back up. Started it today and gave it hell one more time down the road and it blew up.

Hopefully it will just be the rings. :cool:

[deathman53]

maybe the ignition, I know a guy that had his blow up 3 times, he got a cr ignition and no more top ends.

[Iliketogofast]

The ignition is definately a problem because it won't ever kick over, but it will pull start right away. The spark is very weak.

I don't see a weak spark ruining a top end, though.

[LathersR]

Your not putting the piston in the wrong way are you? Check that out for sure before it's to late.. and Check for a gasket leak and go through your wiring with a honda OEM 250r book. Take a wire brush and brush off the frame and any spots where a wire gets grounded to the frame. Also make sure no wires are touching each other that shouldnt.. then If it's not that then tweak your carburetor

[Iliketogofast]

The hole is supposed to go towards the intake, right?

[LathersR]

The piston side that has the small pinholes usually 2-3 holes go to the exhaust side. The Larger single oval hole goes to the intake side.

[Iliketogofast]

Yeah. That's how I put it in. I had second thoughts about it in the first place because it's been at least a year since I've even touched an engine, though.

[LathersR]

Ya I had a friend of mine do the ol' switch'er roo and it ran ok for a second and I just heard a big pop after a minute .. I'm surprised it even ran lol.. But check your wiring, ground.. go through it all.. then check out your stator and key way

[Iliketogofast]

Well, my wiring is bad and my stator is nasty, I already know that. I rewired the whole thing several times to the point that the wiring is kind of a mess. The flywheel is very rusty, but I've never taken it off and looked at the stator.

Why does the electrical cause the problems though?

[LathersR]

Well if it doesn't have enough power going to the wires then it is weak and performs weak spark.. the 250r already doesn't have as good of spark it should have. I'd run through your wiring and make sure it is all right and wire brush your ground's. Try that out... it can't hurt anything and can only help

[Iliketogofast]

The spark is very, very weak. It puts out a weaker spark than my buddy's 50cc pitbike.

I planned on replacing the coil so I could actually maybe kickstart it instead of bump starting it all of the time.

Like I said though, my wiring is screwed and I'll definitely be redoing it. I'll go to the store and get new sleeves today. I'm also going to replace the stator because when I hooked up the trailtech computer, the bike would run like **** because it was acting as a resistor to the coil power, then I hooked it up to my lights and it made them blink badly. So it definately has very weak electrical.

[Iliketogofast]

I wonder if that 310 is a nikasil plated cylinder? I really hope I don't have to get it bored out. Hopefully I can just change out the piston and rings. :blah:

[my88r]

let the engine breakin before you (gave it hell again for a few minutes) lol

[Iliketogofast]

Well, my previous assumption was that an extended "break-in period" was a bunch of ****, but I'm starting to think I was wrong. :)

Any word on the material that cylinder is made from...? :confused:

[LathersR]

Might my last 310 was a nikasil and so was my 265 pv.. but my 330 isn't

[louis]

what is your jetting? you said there was a hole on the exhaust side. sounds to lean. you sould have broke it in. If you gave her he** first thing. the jetting might be off.

[Iliketogofast]

185 main. Plug is tan.

There isn't a hole in the exhaust side, that was last time. This time there is just some wet, gray residue on the dome and on top of the piston. I didn't take the entire jug off - too lazy right now. I doubt there is a hole further down. Everything else as far as I can tell is fine, besides the fact that there is no compression. O-rings are fine.

I'll get a pic of the first piston it burnt (I chucked the other...

[Iliketogofast]

Burnt side. On the next piston, the exhaust gets a hole but I don't think there is any burning. This piston had been in for a year, but I assume that the same thing that caused the recent two to run for only 20 minutes is the same thing that brought an end to this one.

[Iliketogofast]

Bump.

Could it be the water pump?

[86 Quad R]

with the wrist pin removed, take a pic of the underside of the piston.

[sandspanker]

when was the last time you changed your crank seals? that would cause it to run lean. you prob. cold seized it. you should just put a 4 stroke in your frame. i am a 2 stroke guy through and through but their are some people that don't need to OWN them.

[Iliketogofast]

I haven't replaced the crank seals since I got it, which has been a couple of years. There were a couple of small shavings in the water pump, and the pump cover had rusty water on it but I don't think this is the problem because the impeller, shaft and splines are fine. So is the springy rubber seal, but I haven't taken off the metal seal behind that one yet.

And I definately don't want to ruin my quad with a clunky-***-tree-hugging four stroke engine. ;)

Attatched is the underside shot, I should get some shots of the 310 piston tonight. on a side note, does anyone know what size/type piston and rings I get for that 310? It won't need bored, only honed, so standard size please.

[Iliketogofast]

Okay, so the 310 piston looks exactly the same as the one pictured. There isn't a hole burnt.

[86 Quad R]

it would appear that the engine got hot. thats alot of black buildup for such little run time.

[Iliketogofast]

There's a thin layer of slippery gray crap on the dome and the top of the piston, too. The friggen cylinder won't clean up, so I'll have to bore it, but I have 2 setups anyways (I also have a stock, ported/decked cylinder and the PJ carb).

But first I need to find out what made it so damned hot. There isn't any rod play or anything and the water pump looked ok, but I tore up the freezeplug type piece taking it out.

But that piston had run for about 6 months. I threw the other one away and I haven't had time to take the other one off the rod.