Venture 06 - Not starting + Backfires

[Scalare2k3]

Hi.
I have a Yamaha Venture TF -06 that i bought dead thinking it could be a "fun" project. However now i am starting to run out of ideas.
It turns over and seems to good compression on all 3 cylinders. But it backfires. Sometimes so hard that it actually chewed gears of the starter. And not starting.

Tried to understand if maybe timing was of or if the chain jumped. It looks allright on the top end with everything lining up. But the bottom end does not seem to show | in the window when cyl nr 3 ( closest to the flywheel? ) is TDC.

Took some pictures today when i finally got the cover off. MAN that was terrible to get it of!!

https://imgur.com/q254BUP

https://imgur.com/8j29CNv

https://imgur.com/yMkwmWs

Any suggestions? If its actually so that the engine is aligned. Could it be the trigger maybe? Had good spark togh

 

[74Nitro]

Can you post some pictures of the bottom side of the spark plugs?

 

[Scalare2k3]

Can you post some pictures of the bottom side of the spark plugs?

Hi.
They look new ( probably not even started up after beeing replaced. ) Guess i am not the first person who has been trying to get this to work.

Any thoughts on the bottom part markings not matching the topend?

 

[MrSled]

How well did you go thru the carbs?

 

[Scalare2k3]

How well did you go thru the carbs?

Not at all yet. But they was rebuilt by previous owner ( however this is probably a good idea to go over again )
I was just so blinded by it trying to start with ignition totally off. Atleast it sounds like it with it backfires so hard it even wipes a few tooth of the starter sprocket.
But maybe the carbs can also be part of that puzzle?

 

[MrSled]

I have seen issues with bad pilots or pilot circuit that can cause all kind of backfires.

 

[maim]

milage on sled? could be valve adjustment.

 

[74Nitro]

Did the seller give you any details on what led up to this?

 

[Scalare2k3]

Thanks for your input. Thinking that maybe i should start putting it togehtor with a new gear for the starter.
But still a bit worried that i dont get the markings corecct on the flywheel. But with the timing looking good on top it also seems strange that something should be wrong.

I have no adea about milage since it has not been started for a long time.

Did the seller give you any details on what led up to this?

The seller said the starter went bad and had it sit for a while. After it was changed it never started again. However there might be more to the story that that. Maybe it started to backfire and thats what killed their first starter? You cant always trust the seller.

 

[Srxspec]

It's possible when it backfired that it sheared the flywheel key and the flywheel has turned on the crankshaft. This would lead to the timing marks not lining up in the window of the flywheel cover and also would lead to the timing (ignition) being out of time because the timing pickup is off the flywheel, just thinking out loud...

 

[Scalare2k3]

It's possible when it backfired that it sheared the flywheel key and the flywheel has turned on the crankshaft. This would lead to the timing marks not lining up in the window of the flywheel cover and also would lead to the timing (ignition) being out of time because the timing pickup is off the flywheel, just thinking out loud...

Yes, i think you are correct. Or atleast on the right path. I pulled the flywheel a few days back and the key was broken clean off!
Not sure why, but could be a few reasons. Ordered everything new now and will do an update asap when its back together if this fixed it

Thanks for your input on this.

 

[Srxspec]

When the starter was going bad, the engine "kicked back" while the starter was engaged. Starter spinning one way and engine trying to go the other way = sheared flywheel key.