Please help! Powermax Clone 13HP

[Cdrew11]

Hey guys, last year I bought myself a 13hp honda clone in hopes of using it on my go kart. After putting in the welds and the jackshaft setup to accommodate it I tried to start it. After pulling on the recoil starter a good while I thought that the engine would never get going until I pulled one last time and Heard the thing rev up higher and higher until it suddenly stopped. After that, the engine locked up. I cracked it open to investigate and later got the engine to turn by rotating the crank backwards. The only problem now is that even though the engine turns, at some point in the rotation, the cam looks like it's separating from the crankshaft. After a stiff pull though, it eventually turns again and the cycle repeats. It might be worth noting that I accidently ran the motor for the first time dry- long story.

If you need photos, video, any content you need to diagnose the problem please, don't hesitate to ask.

 

[845mx5]

Im not sure what would bec auseing your problem. And im not sure what it means that the cam is seperating from the crank. The only thing that connects the two is a gear, and those gears just make contact with each other. they are not actually "connected". Id say fill it with oil and try to start it again. Maybe you seixed it up. If it wont start try tuning the carb. i hope someone with some knowledge can help out.

 

[vette66_00]

You bent either the Cam shaft or the crank. Thats all I can tell you.:doah:

 

[Cdrew11]

Awww damn, I hope it's the cam. I'll double check tomorrow.

If it is the case, anyone know where I can get spare parts? or will I have to call the company that sells the engines for them?

 

[845mx5]

A bent crank or cam would make sense as your saying the cam pulls away from the crank. That makes more sense in my head now about what you said. HOWEVER, how would your crank or cam bend if it hasnt been used? Only started

 

[Cdrew11]

Well it was started without oil, and the thing started, revved up and up and up then Clunk! sized up. Again long story about how I let that happen, but what's done is done. So...Bent crank or cam is the diagnosis. Are you sure it can't be related to a busted rocker or a stuck valve? I mean, the engine still turns but at some point in the engine rotation It gets real stiff to the point where you have to heave the recoil starter to get through it.

 

[Strigoi]

pull the engine apart and see what's messed up.

 

[edwin]

a friend of mine did the same thing to the same size motor, it siezed to a halt. we got it rotating again, and then added oil. it was noisy at first then after a few minutes it quieted down. he raced it for a couple of laps then started to slow down again, so he shut it off. most likely like his, you galled up the rod and crank. depending on how bad it was galled. you might just be able to get a new bilet rod from AGK that comes with bearings for $145. and clean up the crank. with super fine sand paper and then polish it. good luck. AGK (affordablegoKarts.com)

 

[845mx5]

Edwin mirto, do you work for AGK? Just curious. I figured AGK workers/staff/owners would be supporting members. Like i said, just curious.

 

[edwin]

Edwin mirto, do you work for AGK? Just curious. I figured AGK workers/staff/owners would be supporting members. Like i said, just curious.

no i dont work for them just have done alot of business with them.

to cdrew11, i just read your first post a littl more carefully, when you said you cracked the engine, you mean you took off the side cover, correct ? and then you said you at some point during the rotation, the cam wants to separate from the crank. well that will happen if the cam is not supported by the cover unless you take spring pressure off the cams. does that make sense ?

 

[Cdrew11]

Ahh that I understand, but I've been able to get smaller engines to turn without the needing the side cover on. Then again, they're smaller engines so I guess that's understandable. Still it doesn't really explain the stiff engine rotation. I'll post when I do some further investigation. In the mean time, thanks for all your help.

 

[Strigoi]

the side cover provides support for the crank and cam. i didn't realize that you were trying to turn it with it off either.

 

[tracktrends]

With the sidecover on and properly aligning the crank and cam, with the spark plug removed, the crank should turn over freely. If the engine ran with no oil it probably ate up the rod. The aluminum rod will got hot real quick and start to melt onto the crank journal. The rod will need to be replaced and the crank journal will need to be polished if possible. Polishing the crank is not as simple as people like to make it sound. You can do it but you need to really take your time and be very careful or you will end up with an undersized, egg-shaped, hour glassed journal. Use fine cloth and work at removing the aluminum only. It would be best if you have a micrometer and know how to use it so you can monitor your work. If you have any questions on this subject just ask. I have specialised in crankshaft repair for 30 years.

 

[Cdrew11]

Okay, so I managed to get off of school early so I could work on the engine before I ran out of light. I took off the air filter, the exhaust, and the fuel tank. After I took the bolts from the crank case and pulled out the cam to check for any deformities- none were spotted. I then popped it back in and tried to turn the engine and found that the parts shown in the picture (I don't know them by name, but I do know they manipulate the valves) were stopping the engine rotation. I took those out of the engine and it turned like the day I bought it.

Now I'm unsure what to do so again I'm open to any further suggestions

 

[Strigoi]

if it's fine without the lifters and push rods, take the valve cover off and see how everything looks in there. you'll need to do that anyways to reinstall those parts and set the valve lash.

 

[Cdrew11]

Thanks Strigoi, it's good to see a familiar name 'round here, but then again you're all over this forum right? I'll take a look at that tomorrow when there's light out. At the moment the garage is cluttered with stuff and the cold weather means I can only work on the days I can stand the temperature.

 

[Cdrew11]

just took off the valve cover. Nothing seems to be wrong with the rockers or the valve springs. Everything seems sound. I'm thinking I should expose the piston to see if anything isn't going on there.

Anyone have any ideas of what may have gone wrong?

 

[Cdrew11]

Update: Nothing is wrong with the piston either

Probably going to put this back together and see what I get