POS blaster

[soupnutz]

I'm at the end of my patience with this thing. A few years ago I upgraded from stock to a pwk33 carb. I haven't been able to get it running right since. I originally had it running decently until I lost compression, the rings were burnt up. I cheaped out and replaced just the rings then jetted it rich as hell just in case. Seemed to run good after that, then on the way to the trail it started revving high as crap. Shut it off and towed it home to find the intake manifold cracked. Replaced that and got one good day of running out of it. Went out for about three hours. The next day, I make it around the block and it dies. No compression. Pull the top end to find the rings melted to the piston and the cylinder badly scored. Fast forward a year and I just got it back from being bored and honed, (73mm), got it installed with a wiseco piston.

I only get it to start with the choke on. Push the choke in and it wants to die. I have to stay on the throttle to keep the rpms up, responds very sluggishly, ad if the rpms get too low it dies, regardless of throttle.

So I get it through three heat cycles like that. Compression is at 155psi.

Then I set about to actually get it running decently. Seemed like it was running rich so I went from 170/55 jets down to 155/50. Still does the same thing. Will only start with the choke on and rpms are really high, turn the choke off and it dies. Giving it suppose throttle it slowly bogs and dies. Completely removing the air screw and the airbox/filter slightly improved it, but only a little. Pulling the carb it looks like there's a lot of fuel residue in the intake boot, and the plug comes out black and wet.

The carb has been cleaned, the float height is right at 16mm. I have a 40 and 45 pilot jet on the way, but from what I've read I should be able to get it to at least start and run with those jets. I'm close to putting the stock carb back on and giving up on this thing.

Mods are an fmf fatty and silencer, no lid, k&n filter, vforce 4 reeds, pwk33 carb, vitos bbk at 73mm bore.

 

[jbuckster07]

Couple things I have to ask.....

1. Why did you put on a new larger carb? Was the stock bad? Is the motor built to require a larger carb? If so, please list MOTOR mods.

2. To my knowledge, Wiesco doesnt make a 73mm piston. those would be L.A, Wossner and Vitos. I would double check that 100%

Suggestion: Ditch that carb, go back to a stock carb. These really isnt a reason to have a larger carb unless you have a heavily ported, stroked, BBK motor. Stock carb is a great carb, easy to tune and TONS of information about it here. There are not many people that will be able to help you tune your current carb.

 

[soupnutz]

Got a bigger carb due to the big bore kit. Had read that getting a bigger carb would work better with it.

As far as the piston, it is from Vitos, but I thought they were manufactured by wiseco. There was a slip in the box that said something about wiseco.

Right now just the 240 kit, from what I read, the pwk line seemed pretty popular to upgrade to. The 35 and 28 to a greater extent, the 33 to a lesser one.

 

[dirtysquared]

Running that Pwk, there is a few things that I know to look for. Make sure you have a CEL needle. If your in a higher elevation there is a different needle.....I can't remember the code off the top of my head. You need a #5 slide in that carb too.

Is the intake boot stock size or is it for the larger carb?

I understand your frustration. I switched over to a 34PJ last year, and never could get it dialed in well. I went back to the stock carb, and never looked back.

Alot of people run the Keihin carbs with great results and swear by them. Nothing wrong with that. Everyone has a preference, and mine is the stock carb just for the simplicity and it's very forgiving ability to tune it.

Good luck boss.

 

[jbuckster07]

If its just a BBK, honestly a stock carb works just fine, better than fine actually. Its a great carb!

 

[soupnutz]

Finally got around to putting together a leak down tester. I can't get any pressure whatsoever to build in this thing. The tester is good, can plug it with my hand and get 20psi. Clamped onto the engine gets me zero. Sprayed around the base, reed, and head and didn't get any bubbles. Haven't pulled the covers off yet but have a seal kit on order. I'm using a piece of inner tube to plug the exhaust, so I'm going to pick up one of few expandable plugs and double check. If I have to split the case a stroker kit is going in.

 

[Blaaster]

With the FMF Fatty, the best carb you can use is the stock one.

 

[soupnutz]

Found my problem. Have a pinky finger sized hole in the bottom of the crank case, just left of center. Going to clean it up and attempt to epoxy it. I realize that's not a permanent fix, but I've spent all the money I'm going to spend on this blaster for now at least until I get my mustang back together.

 

[Blaaster]

Be wary, epoxy has a 5/5 warranty for repairs, 5 seconds to 5 years.

 

[OConnor Racing]

I'm glad you found your problem. Trust me on this. I've been doing this stuff for most of my life and your fix isn't going to work. You're already frustrated and this fix is going to put you over the edge. Bite the bullet Boss. Split the cases (I have vids) and get used ones or have them welded. I've found them as inexpensive as $100 for the set. When you're done, you'll have a great running machine that you don't have to worry about. Nothing sucks worse than pushing a Blaster.

 

[soupnutz]

So I patched it up. Filled hole with some jb weld, put in a piece of sheetmetal, then three more layers of jb weld. I do plan on replacing the case at some point but just wanted to get it running. After curing for two days I did a leakdown test, holds pressure after replacing a crank seal and getting rid of that sh*tty paper gasket and using some copper rtv on the intake flange. Cranked up first kick. It's idling rich. I had ordered some smaller pilot jets to install, but my dumb ass misplaced and lost the little envelope they came in, (with them still in it). I can't find them anywhere.

Ran it around for about 30 minutes and she was running pretty good. only issue was my left front brake caliper was dragging. Pulled the tire to find bracket that holds it was slightly bent, bent it back and re-shimmed it and all is well. Just need to fine tune the jetting.

it does suck pushing the blaster, anytime I go far enough to worry about though, my daughter will be with me on her ttr125 and I'll have a rope in cae I need to tow it, (like last time).