Engine rebuild...

[postoak_imp]

I see the problem! They forgot to install the piston return springs on your Honda.

[QUINTtastic_imp]

I see the problem! They forgot to install the piston return springs on your Honda.

Oh darn! I’ll make sure to let them know

[glenncal1_imp]

I would certainly try to get your gas tested, but of course it may have nothing to do with whats in you current tank. IMHO (not worth much I admit) there had to be some contamination at some point. I don't see how that would be a mechanical issue, but who knows.

[flynrider]

I'm inclined to agree that some form of contamination led to the excessive carbon build up on top of the pistons. Who knows when it happened. For all you know, this could be something that started with the previous owner.

The only time I've seen anything like this was an old Kaw 750 twin engine I tore down for a friend. He'd had it stored in the garage for years and would start it up occasionally to "keep the top end oiled". This is generally not a good practice, but to make matters worse, the gasoline in the tank was well over 2 years old and had degraded to the point where it smelled like turpentine. On pulling the head, I found a thick layer of carbon deposits on all of the piston tops and scored cylinder walls.

[beardyweirdy@me.com_imp]

Hey QUINTtastic, That's a bummer! I unfortunately have a set of pics just like those, not from my CB tho. I had a bike that had it's petrol tank sealed by a previous owner. The newer fuel, with high ethanol and the like, had broken down the sealant and washed it into the engine. Is there any chancy someone could have sealed the tank previously? They are all long shots but could be....

[QUINTtastic_imp]

I'm inclined to agree that some form of contamination led to the excessive carbon build up on top of the pistons. Who knows when it happened. For all you know, this could be something that started with the previous owner.

The only time I've seen anything like this was an old Kaw 750 twin engine I tore down for a friend. He'd had it stored in the garage for years and would start it up occasionally to "keep the top end oiled". This is generally not a good practice, but to make matters worse, the gasoline in the tank was well over 2 years old and had degraded to the point where it smelled like turpentine. On pulling the head, I found a thick layer of carbon deposits on all of the piston tops and scored cylinder walls.

Yeah I have no clue. The first owner put 7k miles on it over the first 4 or so years of the bikes life. I put 4K miles on it in 4 months, so I’ve never had the same gas sitting in it for long aside from winter with stabil in it.

It’s just something I have to deal with, financially haha. Oy vey

Hey QUINTtastic, That's a bummer! I unfortunately have a set of pics just like those, not from my CB tho. I had a bike that had it's petrol tank sealed by a previous owner. The newer fuel, with high ethanol and the like, had broken down the sealant and washed it into the engine. Is there any chancy someone could have sealed the tank previously? They are all long shots but could be....

Oh no this bike was too new and too babied to have that happen. Crazy how so many different scenarios have done this to peoples bikes. Sad sad times. I can’t wait to crawl up in fetal position after I hand the dealer my credit card

[PowerDubs_imp]

You hit the nail on the head- babied engines build carbon.

There is a head and pistons on Ebay from a 4k mile motor that is just as black as yours. Go look.

I think a lot of guys would be surprised if they opened their engine.

The bike has a lot of owners that only do 2-3k revs lightly. That will cause carbon buildup.

I'm a firm believer in giving an engine the beans fairly often- italian tune up, to literally blow out / burn off the gunk.

All that being said- I do not think the carbon had anything to do with your valve issue.

And on the bright side- you will be the first guy with the factory honda oversize pistons.

If I remember correctly that is like a whole 8cc.

[QUINTtastic_imp]

You hit the nail on the head- babied engines build carbon.

There is a head and pistons on Ebay from a 4k mile motor that is just as black as yours. Go look.

I think a lot of guys would be surprised if they opened their engine.

The bike has a lot of owners that only do 2-3k revs lightly. That will cause carbon buildup.

I'm a firm believer in giving an engine the beans fairly often- italian tune up, to literally blow out / burn off the gunk.

All that being said- I do not think the carbon had anything to do with your valve issue.

And on the bright side- you will be the first guy with the factory honda oversize pistons.

If I remember correctly that is like a whole 8cc.

Yeah the bikes manual has stupid low shift points. When I read it I thought “yeah okay honda.. that’s realistic..” (then again this might be the recommendation for all their bikes.

I generally shift between 4-5k but sometimes higher as my favorite thing about this bike is how fun it is to bang through the gears from a stop. It may not be a sport bike by today’s standards or anything too fancy, but I sure love the torque it has. I’m not sure if you’ve looked up the cb1100s torque graph but it’s basically a straight increasing line with no dips or plateauing.

I haven’t asked about what piston size they’re putting in. I’ll have to do that tomorrow. I may get it back then. Too bad they didn’t wanna hone it out more and make it a cb1200

[DBM_imp]

Put a couple shots of Chevron Techron in yer tank every month. Problem solved.

[Retsel_imp]

I add Sea Foam regularly. I've never had a problem with an engine that I used it on but, can't say I would have without it. Just covering basis. I'm not a real religious man however, I still pray as well.

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