78 Liquifire 440 Engine Rebuild - Advice Wanted

[deerefanatic]

Hi guys. Several years ago the pistons scuffed in my 78 Liq...... I shelved the sled for temporary and started riding my 77 only.... Then, in the winter of 07-08 I lost a rear idler wheel in the 77 and proceded to trash out the track... So I took the motor out of the 77 and put it in my 78... This is the sled I rode last year and was going to ride this year... I see Dennis Kirk is clearancing out their JD tracks at a good price, and I'm going to get one while the getting is good. I plan to rebuild my 78 motor and put the motors back in their proper sleds.... My 77 Motor is tired and needs rebuilt too, but that will have to wait till next year as it still runs good, but likes to get a bit warm if pushed very hard.......

I'm going to get oversized pistons from DK and new gaskets and oil seals throughout the engine. New needle bearings for the wrist pins as well. I want this engine to be like new.....

So, my questions are:

1: Reed valves.... After 3600 miles I'm sure they aren't in the greatest of shape.... The don't hang open much, although I can see a little light through them..... I thought I heard somewhere that Boisien has some reeds for another application that fit these motors.. Is this true and will they help performance any vs the stockers?

2: Should I have anything done to the head while it's apart? The headgasket is not blown, so it's probably ok flat-wise, though I will check it over for flatness.......

3: Anything else I should have done? I can't really afford to have the crank rebuilt, although it wouldn't probably be a bad idea....

Thanks guys......

-Matt

[harleysportster]

Hi guys. Several years ago the pistons scuffed in my 78 Liq...... I shelved the sled for temporary and started riding my 77 only.... Then, in the winter of 07-08 I lost a rear idler wheel in the 77 and proceded to trash out the track... So I took the motor out of the 77 and put it in my 78... This is the sled I rode last year and was going to ride this year... I see Dennis Kirk is clearancing out their JD tracks at a good price, and I'm going to get one while the getting is good. I plan to rebuild my 78 motor and put the motors back in their proper sleds.... My 77 Motor is tired and needs rebuilt too, but that will have to wait till next year as it still runs good, but likes to get a bit warm if pushed very hard.......

I'm going to get oversized pistons from DK and new gaskets and oil seals throughout the engine. New needle bearings for the wrist pins as well. I want this engine to be like new.....

So, my questions are:

1: Reed valves.... After 3600 miles I'm sure they aren't in the greatest of shape.... The don't hang open much, although I can see a little light through them..... I thought I heard somewhere that Boisien has some reeds for another application that fit these motors.. Is this true and will they help performance any vs the stockers? Not sure of the aftermarket reeds but I believe you could reverse the reeds on the cage blocks.

2: Should I have anything done to the head while it's apart? The headgasket is not blown, so it's probably ok flat-wise, though I will check it over for flatness....... Yes, check it for flatness and have it milled as neccessary

3: Anything else I should have done? I can't really afford to have the crank rebuilt, although it wouldn't probably be a bad idea.... New crank seals and carb mounts. Inspect the crank carefully and replace the bearings as needed
Buy a carb flow-meter to sycn them properly.
Thanks guys......

-Matt

[deerefanatic]

Ok. Thanks for the input.

I reversed the reed valves on the cages a few years ago when I had the sled apart..... The fit tightly. Just wasn't sure if there was an aftermarket reed that would fit that would help performance any......

I'll check the head out for flatness.... The PTO (IIRC) side dome is shot-peened..... Been that way since I got it.... Must have bombed a piston at one time in it's past.......

New seals and carb boots it is then.

I'll check the bearings and stuff in the crank over really good... Does that center seal ever cause problems?

Well, the jugs head off to the machine shop tomorrow...... This is gonna be fun!

-Matt