Dusting off the neglected square nose

[BIG JOHNSON]

I imagine a 9th grader rebuilt this carb in a dirty shed with no light. The weather and water must've been nice to put these screws back in after boogering them up on removal. Two bucks gets you 12 new screws at Lowe's.

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[BIG JOHNSON]

Had problems in the past on my old js750 with the factory pipe head pipe bolts backing out and pipe trying to fall off while riding. No amount of red loctite would keep them on so I drilled all the bolt heads and ran safety wire. Opted to do it now and not have to worry later. I'd like to ride it this weekend but I'm not in a hurry to half ass it.

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[BIG JOHNSON]

Putting a jm ada girdle head on while I'm at it. Head and gasket sat there loose after I took the bolts out, I've done 3 or 4 top ends over the years on my old quadzilla and always had to fight the head off and scrape gasket material. Figure if the base and intake gaskets are anything like the head gasket may as well replace now.

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[BIG JOHNSON]

Does the smart guy throw a new set of rings in and take the jug in for a quick hone since I'm replacing the base and intake gaskets?

Still has cross hatch, top and bottom end were rebuilt shortly before I bought the long block a few years ago.

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[DAG]

If the compression was low or uneven, yes great time for hone and rings

 

[BIG JOHNSON]

If the compression was low or uneven, yes great time for hone and rings

Compression dead even, just thinking since I'm this far might as well. Probably will not achieve different results so I'll probably just place new gaskets and stuff it

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[DAG]

If you have good and even compression I don't see honeing it more going to improve anything, only potentially make it worse as the bore grows or cause some other unknown issue at the machine shop. Just my non professional opinion that's worth less than it cost haha

 

[Mike W]

If it were me I would just run it and put the money towards something else. The chamfer on the exhaust port looks a little funky. I would address that though.

 

[Ducky]

Hey man, where did you get the new B Pipe from? I think I am going to order one as well.

 

[BIG JOHNSON]

Hey man, where did you get the new B Pipe from? I think I am going to order one as well.

Ordered from blowsion worn the steering parts for the new ac pole, took about a month.

The ada head and everything else I got from jetmaniac. Wish I'd have just ordered it all from him, hell, I have him payment and he ordered it easter Sunday and I had it that following Tuesday.

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[BIG JOHNSON]

So was going to do a leak down test on it yesterday before I tear it down any further and found the head bolts bottom out before it tightens the head, might explain why the head slid right off and left a loose gasket on the deck. My neighbor, whom works for Husqvarna, stumbled over to my garage last night and said it looks like I have a detonation issue judging by the pattern of the carbon. Now I'm getting hesitant, wondering if it's been making too much compression and had a leaking head gasket all the while. Darn thing runs so good I never had an issue. I trust my compression tester as far as I can throw it. Fwiw, the bolts tighten down leaving a washer's thickness and yes I filled threads with brake clean and picked out what I could with an awl but they're clean. Maybe they will ram down tight enough to make you think they're torqued but I haven't tried since I don't want to bottom a bolt and destroy threads.

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[jo5hi3]

Looks a little rich to me, judging by the piston wash. I don't see any detonation issues from the pictures.

 

[BIG JOHNSON]

Looks a little rich to me, judging by the piston wash. I don't see any detonation issues from the pictures.

Kinda what I thought, do you suppose someone could've machined the deck enough to make the head bolts too long?

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[jo5hi3]

I guess that is possible. I would check squish once you get the new head installed to be sure you won't run into issues.

 

[DAG]

. My neighbor, whom works for Husqvarna, stumbled over to my garage last night and said it looks like I have a detonation issue judging by the pattern of the carbon.

Your neighbor was drunk. just check squish as Josh says it only takes a couple minutes for the piece of mind. I'd also cut the stud or double up on washers if you suspect them bottoming out.

 

[BIG JOHNSON]

I'll research on how to check squish. I will hit up jetmaniac to add a head stud kit to the cart and maybe some alternative thickness base gaskets.

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[BIG JOHNSON]

Ok squish test reveals .0445"

Threads were packed with junk and some of its own aluminum threads. I lost the hole I thought I was going to lose pictured. Maybe I'll let it slide being between two girdle studs. Can't believe I've never owned a micrometer, this thing is awesome. Btw the stock head bolts come 6mm shy of bottoming out.

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[BIG JOHNSON]

https://www.amazon.com/dp/B003RMBFYI/ref=aag_m_pw_dp?ie=UTF8&m=A2J41G0RQ2IUXB

Assuming this is the kit to get. I'm going to do head studs if that makes a difference with the repair. I don't care even if I drill and tap up to the next sae size and stud it. I'm not dealing with these bolts to swap out domes later or when I have it apart again, I think bolts that get torqued into aluminum is always a bad idea, just like the factory head pipe to manifold.

I have a friend who owns a machine shop that is local, I may run the jug to him to check it for flat and just have him fix it

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[Mike W]

The headbolt threads are 1.25.

 

[BIG JOHNSON]

The headbolt threads are 1.25.

That's what I meant, I bought two 8x1.00 bolts at Lowe's first to make a couple slices in it for a thread chaser to clean the old threads vs using a tap, it was wrong so I ended up sacrificing one of the original head bolts to slice and chase the holes out

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