Any ideas why his would carbon up and look like that so fast?

This may be it - The last 5 tanks of gas were taking from a larger conatiner and measured out. Leaving the large container covered but with space to cause hygroscopic. This is the only thing that was recently changed. The last time you rebuilt this motor (( Internal Combustion Engine ? )) it was running on the same oil, but was fed from a small container where the entire container was used then discarded.

I was searching for an actual picture of, or description of causes or damages of hygroscopic, but have not come up with anything yet.

How much of this oil do you have left, any chances in you switching oils I would hate to see this happen again.

yes - i will switch oils.

please specify the type of oil and the mixture being used. I will take the advise and go with what is working.

The only thing I'm giving up is, as King KX says, "the smell"

"H" you might want to check his Engine oil leval and his seal I have seen pistons that looked like that, they had lost crank seal and strated pulling in Engine oil. By chance did he have to start topping off his oil leval or fill with out using check bolt and is it venting propperly. The carbon build up on exhaust manifold is from the wave pressure were it meeet the cylinder pressure in time and where the manifold meets pipe thus causing it to start to build up at the ridge. I would be willing to bet that there was some pre enighting be caused by the carbon build up on the bottom side of the piston retaing heat and raising the piston crown temp.May sound crazy but wipe the bottom of piston and taste or take q-tip wipe the inside of plug and taste. I tends to collect the oil residue in the tapper at its narrowest point. Ya I have been know to lick a plug or two. What fuel did he say he was using with the oil.

Good idea that totally slipped my mind, cafercr35 go check the oil level in your balancer case, usually when your sucking oil in from a trans or in this case a balancer case you see more smoke than normal in the exhaust and the plug will be darker than normal...

I opened the check plug. Showed no oil seeping out. Added 2 ozs. It began seeping. I haven't checked the oil level since changing it 15 hours ago.

Yes the plug was black and looked like the exhaust manifold did. But there wasn't any more smoke than usual.

You see the inside of your silencer where the pipe connects?

Its a huge restriction.

Search words pipe fix, pipe porting

I was going to cut a taper on my lathe to flare it out but the belt busted so in my search around the shop I found my home made clutch alinement tool that has a taper and used it and a hammer to flare out your pipe.

The pics suck and don't really show the problem and the fix well when you get the pipe back you will see what I mean.

Here it is sticking in the male part of the pipe its almost big enough I wish it was a little bigger.

Inside the silencer where it needs flared out.

Flared out, now it will flow as intended, this is why some run a little better than others I wish the pipe builder would do better .

I cleaned the spark arrester screen and did a little flow work to the silencer outlet, added a little bevel and radius to the outlet and increased its ID at the mouth a little for more flow.

Their was one screw missing from the spark arrester I didnt have one the right size, I think its a #12 screw 24 threads per inch, I put high temp silicone on the threads so they wont fall out.

Looks like fiberglass packing material on the screen to me.

I shipped all your parts back, you need to clean all the parts before installing, I put a light coat of oil on the cylinder wall.

I remove all the cylinder studs and lapped the top of the cylinder, reinstalled the studs, I repaired the damage to the head by machining.

I installed a new exhaust manifold gasket and tighten up the bolts you will not need to change the gasket, I bolted the reed cage back on and snug the bolts I was not sure what your going to do, replace the cage or just the reed petals, I would upgrade to another reed cage rather than install new reed petals on the old cage..

The head is installed without a gasket and the nuts just snug for shipping.

The cylinder was bored and honed to fit the piston you sent.


What carb you running again?

Any questions or problems just ask.

I'm running a stock carb but was wanting to upgrade......would this be a good time to upgrade or should I break in the motor (( Internal Combustion Engine ? )) first? What carb it the best to go with? and what jets should I get?

Also...thanks for all you extra time you put in for me....your the man...

No problem, you can add the carb anytime you feel.

The only 2 oils I have any long term use with is Golden Spectro and Amsoil both mixed at 32:1.

I found 4 cylinder nuts on my bench last night check and see if you sent yours with your parts, if these are yours I will send ASAP

I'll check once I rec the parts -

So what carb do you recommend?

The only reason why I quit using Golden Spectro and started using the Amsoil was they about doubled the price of the Golden Spectro oil. Ask your local buds what they are running and how they like it and availability.

Can you take some detial pics of your bottom end in its current condition?

yes - I was planning on doin the rag thing today and draining out the case oil to inspect it.
I will take the pics when doin that.

I drained the oil - looks good - no particals - also sweeped through a cloth and found nothing.

Here are pics of how it is currently.,

You have the cylinder nuts?

actually - I do not - I did leave them in the bag with the rest of the parts. Drop them in ups tomorrow. I want to order the reeds and cage before assembling.

Will service honda have the cr250 one?

I was going to send the nuts USPS if that's ok? Send to the same address?

Any Honda shop should be able to get the reed cage I doubt anybody will stock it