X80A motor?

[benutne]

I'm sorry to have to report that after 3 months and about 550 miles this X80A motor has failed. What a pity too, because it was a strong runner.

I was riding night last when a nasty noise started coming out of the motor. I was just doing easy cruising at the time. I think the crank bearing has failed, but won't know for sure till I get inside it. Nothing dramatic happened, it just started making a loud scraping sound. I rode it 2 miles home under power after it happened. It still had good power.

I'm thinking something may have been wrong all along, because this motor always made a lot of squaking noise at about 5,500 rpm but sounded ok below that. It's been a concern from the start.

So far all I've done is remove the primary cover, and spark plug. When I turn the motor over, I can see the pinion gear looks like it's wobbleing around. Looks like the crankshaft could be bent or something, but I'm not sure how that could have happened. Maybe from someone installing the pinion gear with a hammer lol. A sound is coming out of the spark plug hole that sounds like the piston might be contacting the head now too.

I'm going to try to rebuild.

Keep us in the loop man. Especially if you have trouble finding parts.

 

[mapbike]

Dang-it man..........!

I hate to hear that, I've had one engine fail because of the lower rod bearing, after getting the engine toe down I saw that it had a very inferior bearing to start with, it wasn't a caged bearing they installed on that engine, there were just loose roller/pin bearings installed between crank journal and con rod before the other side of the crank was pressed on, they didn't put enough pins in and it had lots of slop between the rod and crank journal, I accidentally ran that engine a bit lean and the bearing seized enough to break one of the pins and a piece of it made it into the tranfer port and then between piston and jug wall it wrecked that engine big time.

Now, what seems to be the most common failure is the top bearing/wrist pin bearing, I changed one in one of my engines a couple weeks ago, I started hearing a knocking/rattling noise sounded up top so I figured it was the wrist pin bearing, I replaced it with an upgraded bearing I ordered from Motion Industries and that solved my problem, actually the bearing I took out looked fine but the wrist pin itself had massive amount of wear, it was hammered out on one side, just junk soft material is what caused that.

It's also possible that you had a main crank support bearing fail.... I guess once you get it tore down you'll know for sure.

Best wishes to ya, I hope you can salvage that little engine.

Peace, map

I'm sorry to have to report that after 3 months and about 550 miles this X80A motor has failed. What a pity too, because it was a strong runner.

I was riding night last when a nasty noise started coming out of the motor. I was just doing easy cruising at the time. I think the crank bearing has failed, but won't know for sure till I get inside it. Nothing dramatic happened, it just started making a loud scraping sound. I rode it 2 miles home under power after it happened. It still had good power.

I'm thinking something may have been wrong all along, because this motor always made a lot of squaking noise at about 5,500 rpm but sounded ok below that. It's been a concern from the start.

So far all I've done is remove the primary cover, and spark plug. When I turn the motor over, I can see the pinion gear looks like it's wobbleing around. Looks like the crankshaft could be bent or something, but I'm not sure how that could have happened. Maybe from someone installing the pinion gear with a hammer lol. A sound is coming out of the spark plug hole that sounds like the piston might be contacting the head now too.

I'm going to try to rebuild.

 

[biknut]

Thanks guys, it's no biggy. I still have the Atomic BB to ride. I've already ordered a new motor from the same place, but it's a different motor I think. The most important thing is, I need the a big front mount motor to fit in the Cadillac.

What this teaches me is that these motors are like 70s harleys. After you buy one, it's best to take it apart right away and build it right.

 

[mapbike]

Thanks guys, it's no biggy. I still have the Atomic BB to ride. I've already ordered a new motor from the same place, but it's a different motor I think. The most important thing is, I need the a big front mount motor to fit in the Cadillac.

What this teaches me is that these motors are like 70s harleys. After you buy one, it's best to take it apart right away and build it right.

Yep you hit that nail right on the head........!

best wishes to ya.

map

 

[Acraze]

Well that's a downer. I have the same motor for about 3-4 months and I ride it hard. Hope nothing bad happens to mine because I don't know as much about these motors as you do.

 

[biknut]

Well that's a downer. I have the same motor for about 3-4 months and I ride it hard. Hope nothing bad happens to mine because I don't know as much about these motors as you do.

Except for the noise it's been making, I've been liking this motor a lot. It made more power than a SkyHawk 80 MB I made.

I blame poor quality parts, and assembly on this failure, but I don't blame the seller.

 

[biknut]

This is how far I've gotten.

 

[biknut]

I'm now ready to split the cases. I've removed all the fasteners, but it doesn't seem to want to come apart.

What I tried so far is, I grabbed the block with my manly bare hands, and used raw brute force on it. That didn't work. Then I tapped it with a rubber hammer, and tried again. Nothing.

Can someone that actually knows what they're doing please tell me how to split the cases?

[/QUOTE]

 

[inked1974]

Have you taken out the bolts that hold the case together? I see in the above picture that they are still in place. There is a shorter one on the under side as well. I am sure you have but.... just a thought

 

[biknut]

Have you taken out the bolts that hold the case together? I see in the above picture that they are still in place. There is a shorter one on the under side as well. I am sure you have but.... just a thought

All the bolts are out, I just didn't take a new picture.

 

[bluenosegoat]

I assume you have removed the clutch-if not there are a couple screws behind it that must be removed.

 

[biknut]

I assume you have removed the clutch-if not there are a couple screws behind it that must be removed.

Yes, for the third time. All the screws are removed. I assume the only thing holding it together now are the crankshaft bearings.

 

[Greg58]

B/K I have not worked on that engine but if you have a helper hold the block and put the nut back on the mag. end of the crank you can use a block of wood and hammer to break the bearings loose. This works a-lot on industrial drive units.

 

[biknut]

B/K I have not worked on that engine but if you have a helper hold the block and put the nut back on the mag. end of the crank you can use a block of wood and hammer to break the bearings loose. This works a-lot on industrial drive units.

Thanks for the suggestion. I threaded a spacer to fit the mag side, so I can start whacking on it. I was trying to make some kind of press, but so far nothing.

 

[biknut]

I figured out a easy way to make a special tool to press the crankshaft out of the block. This is a lot safer than hammering on the end of the crank. When I tried it the first time it worked so easily, and I had the crank out of the block in about 2 minutes.

 

[biknut]

Now that I got the whole thing apart, I guess you'd like to know what went wrong with it in the first place. I don't know? Nothing stands out as being clearly bad, or worn out.

My guess is the mag side bearing is poor quality, and the motor is out of balance. I can also detect a slight amount of slop in the rod bearing too. I don't know how much it too much though. It's possible a combination of bearing slop, and out of balance crank, might have caused the problem.

 

[Greg58]

Did you find any debris inside the cases like some have found?

 

[biknut]

Did you find any debris inside the cases like some have found?

No, nothin. The inside of the cases look good.

 

[biknut]

I bought a dial indicator today and measured the play on the big end of the rod. It's about 0.003"

Does anyone know if that's too much. It seems like a lot compared to the small end. It's hard to measure any slop at all on the small end.

 

[biknut]

This is the crappest crankshaft I've ever seen. I don't know if this was the cause of my problem, but I'm thinking this crank is junk.