Very tiny air leak?

I just got my Morini MO2 engine running for the first time, and I decided to check for air leaks. The idle is not very high, and it did change when I adjust the idle screw on the carb (Sha 14:12). However, when I sprayed some of the carb cleaner on the head gasket and the base gasket, the engine dies. This means I have an air leak right? But maybe just very minimal since the idle isnt high?

I used new paper gaskets when reassembling, but I did use the old head gasket. I will try the new aluminum one I got with the kit.

Re: Very tiny air leak?

It's the little things that make the big things run or die an early death .

Re: Very tiny air leak?

Idle is not going to change your compression/vacuum ratio. A leak is a leak regardless of RMPs. Your head gasket is usually a "special" gasket and usually fairly indestructible. It often needs to be a specific material to transfer the heat from the cylinder to the head properly. Put if back in if its not destroyed. The base gasket needs to be replaced EVERY time you pull the cylinder. Also, the mating surfaces need to be thoroughly cleaned. The base gasket often leaves pieces behind. They need to be cleaned off without scratching the mating surfaces. Also, make sure to torque the cylinder and head back down to the manufacturer's recommended ft/lbs.

Re: Very tiny air leak?

An update on this, after torquing the head bolts again when the engine was warmed up, it looks like the leaks are gone. Must have just been that it needed to be tightened.

Re: Very tiny air leak?

Keep an eye on those head bolts. They can loosen up over time. Heat cycling will cause them to be loose after a fresh rebuild so you may have them get loose on you again. Head bolts, intake, and exhaust bolts are all things that should be double checked before a ride. I may not check them on every run around the block, but I will always spend 10-15min before a big ride making sure everything is tight as it should be. I just had a shock nut vibrate off the bike recently, thankfully while stationary and going over things anyway. Mopeds are fun like that.

Re: Very tiny air leak?

Haha, that is good to know thanks or the tip. I have been using blue locktite on most of the stuff I took apart on the bike, but maybe I should add some to the rest too.

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