Thread: Pre-Beachbug rebuild
08-14-2007, 07:09 AM #1
I had a WOT shut down this past weekend, so I'm now in full ball-busting mode to get a rebuild done before the 23rd so I can get out and try to break the ski surf jumping at the BeachBug. The exhaust, carbs, and intake manifold came off last night, and beforehand I ran a compression test and came up with 155/159/145 PSI. Looks like the third cylinder is my lead suspect.
I found a few good and bad things while pulling parts. The good, after all the horror stories I've read, is that the stuffers in my V-Force III reeds were in good shape. These things were really trimmed down to the point where I cut partially through the side and the remaining material was translucent, and I couldn't break them by bouncing them off the floor. These stuffers came with a Fercho kit in spring 2006.
The bad: black "soot" spots on the carbs, cylinder, and even hull around the third cylinder. Looks like I've got a leak somewhere. The third cylinder was repaired by Millennium - they welded a crack and machined the base for me. I'm a bit worried that the third cylinder height might be off a bit. Hopefully that's not the case, and it's just a matter of me being cheap (believable) and reusing a gasket that I should have replaced. Tonight I'll pull the head and see if I need to replace a piston.
Also tonight I'm breaking down the carb rack to check pop-off and jetting and fuel filters. I'm looking for advice on jetting too. My ski is a GroupK 1390BB with Advent running YAM-84 curve, V-Force III reeds, accelerator pump and choke plates removed, primer installed, D-plate, free flow.
So far I'm just out a few gaskets, but I get the feeling that's about to change. Speaking of gaskets, what's the best place to buy a head gasket bored out for 87mm pistons?
Wish me luck on a speedy rebuild. I don't wanna miss out on all the fun at the beach!
08-14-2007, 09:21 AM #2
What are your current carb specs? and how was it running prior to the failure?
I just ordered a 1300 head gasket machined to fit the 1390 from Lowell $89 this on a 1200 to 1390 conversion. Some guys prefer the 1200 gasket machined and remove a layer.
08-14-2007, 07:36 PM #3
If I ever get out of work I hope to have the jetting specs tonight! I'm using the stock carbs with accel pump disabled, choke plates removed, primer installed, premix. Jetting was set at GroupK and I've left it where they set it, tuning to 1 3/8 - 1 3/8 - 1 1/2 out on the highs and 7/8 out on the lows. Prior to shutting down the ski was running great, holding steady at 7160 (7120 heat soak) RPMs turning a Danafly pitched to 15/26.
08-14-2007, 10:19 PM #4
What kind of F/A's are you running?
08-14-2007, 11:03 PM #5
Gah! I've been foiled by the metering block screws trying to get to the jets - stripped every one of 'em. Looks like tomorrow will be a trip to Sears for an impact screwdriver.
I did pull the head to check out the piston wash and cylinders. The piston wash is a bit small - slightly smaller then dime sized wash by the intake ports, so I'm guessing a rejet is in the cards.
The front two jugs looked good, third had some scuff marks, and strangely enough the "fixed position" powervalve had some play to it. Tomorrow I'll check the piston/cylinder clearance (looked a bit looser than I'd like) and pull the cylinder to see if I can get away with an acid wash and honing.
Thanks for the info on the head gasket. I was hoping there was a cheaper source, but looks like that's the going rate.
08-14-2007, 11:04 PM #6
Prok flame arrestors with Pro-Tec adaptors and outerwears.
08-14-2007, 11:09 PM #7
I have found a couple things with the metering block screws
1. if one does not seem to budge I try the other. it seems the one that was tightened last usually loosens easier.
2. When they do strip I drill the tops off and the screw comes right out. I use a drill bit just slightly larger than the diameter of the screw.
08-15-2007, 10:33 PM #8
Okay, story for tonight... the impact driver worked like a charm. Yet another tool that goes on the "why didn't I buy one of these before now" list - which is pretty long already! The jetting is: lows 110, highs 125, N/S 1.5. How does that sound given my mods listed above?
08-15-2007, 10:59 PM #9
And by the by, GroupK advertises the 1390 head gasket for $69 on their web site, but sells them for $99. I was very not happy about this.
08-16-2007, 12:23 AM #10
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