got my bike to fire up and run,, then uh oh!

1742 Views 11 Replies 5 Participants Last post by Tank801, Sep 17, 2013

bootneyleefonsworth

Discussion Starter · Jan 3, 2013

Man what I thought was gonna be great.eve . I mountEd the mc49 saw clone I put together and mig welded the mouth to fit.

1st problem. I mounted the motor backwards. Started and ran great, just backwards

So I switched it around and had to eliminate the use of the jackshaft. Now I had to slice a groove so the chain won't run on the bottom of the plate the motor would normally mount on. Seeing the bike has a suspension do I need a chain tensioner?

2 nd HUGE PROBLEM: when it was idleing as I was waking it to the road it started to rev, uncontrollably and sounded like it was seconds from explosions.

Kill switch didn't work so I pulled fuel line and it stopped 10 seconds later

Anybody know what's wrong blessed hel

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NosMan

· #2 · Jan 3, 2013 (Edited)

I would say yes to your first question.

For question #2. That's what a 2 stroke does when running out of fuel. Maybe the carb needs to be cleaned or you have a air leak around the manifold. Could be lot's of different things but I would start there first.

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bootneyleefonsworth

Discussion Starter · #3 · Jan 3, 2013

When I test fired it vegetal times on the bench, everything went great, now its like a grenade waiting to blow

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EPR

· #4 · Jan 3, 2013

Are you sure your piston pin clips are in right. When you start a new engine the rings are real tight and add alot of drag. Look at your sparkplug. Make sure the engine is getting enough gas, I run all my new engines rich & alot of oil.

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bootneyleefonsworth

Discussion Starter · #5 · Jan 3, 2013

ok, im gonna look into that, i know i ran a ton of oil, the mix was pretty dark just so id be sure it wasnt short on oil, i also well oiled the interior of the motor before putting it back together

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EPR

· #6 · Jan 3, 2013

Look into the intake or exhaust or both first before you try to pull the cylinder up. See if there are brokens rings or alot of scratches on the cyld walls.

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bootneyleefonsworth

Discussion Starter · #7 · Jan 4, 2013

EPR said:
Look into the intake or exhaust or both first before you try to pull the cylinder up. See if there are brokens rings or alot of scratches on the cyld walls.

I checked the rings, and they seem to be intact and serving their purpose (i believe)

I have been told their is a possiblity that their is a major air leak, and now i worry that when i fixed my motor mount, the motor was still on it because im super lazy and it takes forever to pull the motor from my mount that i made (next mount im building tonight or tomorrow will have that issue removed from the design)

so now im wondering if doing about an inch of welding heated the motor up and cause something to warp.

the motor im talking about is a 80cc mcculloch saw clone motor. It sounds awesome and cant wait to see this thing rip A$$ down the street, i have another i just finished, with a few mods so i may try to buildn a new better mount with my NEW WELDER

i feel like a baby macgeyver now that i have a welder. I love this stuff.

I heart making motor mounts

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EPR

· #8 · Jan 5, 2013

I have a 60cc Mac but don't know much about them. If you welded it, and it got to hot. it could warp maybe. Were the cranks seals in the engine when you where welding??

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bootneyleefonsworth

Discussion Starter · #9 · Jan 6, 2013 (Edited)

EPR said:
I have a 60cc Mac but don't know much about them. If you welded it, and it got to hot. it could warp maybe. Were the cranks seals in the engine when you where welding??

the motor was completely assembled

im gonna pull it and put it on the bench mount (that i made

) and check it out.

I have several macs, they are all 80cc's i havnt been lucky enouh yet to score a larger saw. but am constantly haunting CL waiting for one

I am currently working on some saw to kart/minibike motor converssions, not much of a difference.

just cant wait to get one mounted and running properly for a test ride

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CAM2

· #10 · Jan 6, 2013

bootneyleefonsworth said:
im gonna pull it and put it on the bench mount (that i made ) and check it out.

I have several macs, they are all 80cc's i havnt been lucky enouh yet to score a larger saw. but am constantly haunting CL waiting for one

I am currently working on some saw to kart/minibike motor converssions, not much of a difference.

just cant wait to get one mounted and running properly for a test ride

You did have a larger saw...That 95cc monster you traded or sold off..........

Theres a good possibility something warped..The extra oil you used could of weighted the reeds down too much and caused them to warp......warped reeds wont seal and the compression will feel weak......

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bootneyleefonsworth

Discussion Starter · #11 · Jan 12, 2013

thanks for the reminder lol

yeah im wishing i had kept that now. that would have made my mini street quad project pretty sweet i think. and i guess i could have painted it yellow, for some reason i dig the mac yellow/black combo

CAM2 said:
You did have a larger saw...That 95cc monster you traded or sold off..........

Theres a good possibility something warped..The extra oil you used could of weighted the reeds down too much and caused them to warp......warped reeds wont seal and the compression will feel weak......

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Tank801

· #12 · Sep 17, 2013

did you weld it with eletronics/mag still on the bike. the mag picks up RF signals and screws it up when welding.

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