Would an exhaust leak at the flange cause cutting in and out at high speed

[El_cheapo]

I'm running out of ideas here hoping i didn't spend too much on this problem child, I paid 760 bike runs pretty good but the higher the gear your in the more it cuts out if your trying to run it wide open. Kind of surges in and out while wide open can't really get it going fast. It'll stand up a wheelie in low gears through the mid rpm range.

700 ft elevation, fmf fatty exhaust, jetted 270 main, no airbox lid.

I'm putting too much money in this bike to keep throwing parts at it without a second opinion.

Carb is clean, just put reed valves in it, new air filter (had none), have jets on the way. I'm just not sure if it can be sucking air here and leaning out or if this isn't really an issue. If i put my finger on the left side while it's idling it's blowing on my finger pretty good. I can actually stick my palm over the exhaust pipe and totally cut it off, it keeps running like it doesn't notice.

I'm reading you can get some seals to go inside the exhaust pipe here and probably use some silicone as well, possibly something called a crush gasket. Can anyone point me in the right direction (no dealers around I'll be ordering stuff online).

If i grab the pipe i can tilt it around easily and kind of even it out but it's clear there's no much sealing at all going on.

 

[Larry's Shee]

Have you ever done a plug chop? That exhaust leak will cause it to run lean.

Repair is relatively cheap and easy. Remove pipe and clean BOTH inside of pipe and outside of flange pipe with brake cleaner/degreaser. Use high temp RTV silicon to install. Allow 24hrs to cure before use. Might consider new springs. Should be two.

 

[El_cheapo]

Have not done a plug chop, don't really have a run around me I'd have to go to my parents and do it which I'm fine with. Did a compression test yesterday and I'm getting about 88 pounds so maybe that's my real issue. It's weird it starts first kick but I think that gauge is accurate. Put it on a good running 4 stroke and it read 120+

Guess I'm learning to rebuild

 

[Larry morris]

Be honest sounds like a top end rebuild and fix the exhoust issue yes a flang leak is bad can burn yer rings up

 

[Larry's Shee]

Compression test: throttle wide open, kick until gauge stops rising.
Because of the small displacement compared to auto, a cheep guage will read low.

If you need to rebuild, PLEASE do not get cheap egay/Amazon kits

https://www.blasterforum.com/threads/more-info-on-the-chinese-blaster-cylinder.66076/

https://www.blasterforum.com/threads/oh-no-dont-use-cheap-chineese-parts.72185/

 

[El_cheapo]

Compression test: throttle wide open, kick until gauge stops rising.
Because of the small displacement compared to auto, a cheep guage will read low.

If you need to rebuild, PLEASE do not get cheap egay/Amazon kits

https://www.blasterforum.com/threads/more-info-on-the-chinese-blaster-cylinder.66076/

https://www.blasterforum.com/threads/oh-no-dont-use-cheap-chineese-parts.72185/

Well I think it was just the spark plug, now that it's running good it's clear the clutch is slipping. I'm sure my neighbors love me because I've spent the last few weeks trying to get it right then trying hard pulls to see if I did. It's had an incorrect spark plug.

Now I'm trying to make clutch adjustments then making hard pulls out in the road because it's unclear in my yard is I'm spinning tires or clutch.