Had a little backfire...

SUPERJET-113

SUPERJET-113

GASKETS FOR CHAMP BRAP!
Site Supporter
Location
Lake Havasu City, AZ USA
Went for a good ride and was just cruising back to my trailer and the SJ back fired and locked up.

It was a good engine for 2.5 long Havasu seasons(Late Feb.-Close to Christmas) :), and it had a runaway episode last year too that didnt help things.

I was just getting ready to rebuild too, but had other projects I wanted to finish up before this one, and BLAMMO, she went...:shooter3:

Broke the connecting rod in half and blew out the side of the cases and a huge hole in the bottom of the cases. All epoxied and massively ported. Trashed one sleeve and a piston. Cylinder, 1 sleeve and one piston still good.
 

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djkorn1

djkorn1

kidkornfilms
Site Supporter
Location
Cleveland Ohio
I've been rebuilding mine every two seasons no matter what. I took out a couple engines back in the day after 2 1/2 seasons.
 
Idok

Idok

F1pro
Location
Nations oldest muthaF+++kin city
wait, so it backfired while cruising under steady RPMs?




or you got it on the trailer, went to fire it up and again and backfired?










Kenny:

There is nothing wrong with SBT stuff.......Its not the best stuff to use on a high HP build....but on a ltd stockish motor you cannot beat them!



but we have (and are still currently) running SBT cranks in a coupole of different surfboats that run every weekend almost year round and have had PLENTY of salt ingestion

that being said... OEM>everything!
 
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SUPERJET-113

SUPERJET-113

GASKETS FOR CHAMP BRAP!
Site Supporter
Location
Lake Havasu City, AZ USA
Yes it was a SBT crank with 2.5 long Havsu seasons. I cannot complain and would run a SBt crank again.

Engine: 61X fully freestyle ported cylinder, 84mm Pro-X pistons, 62T cases epoxied and massively ported, Bpipe with LPW head pipe mod/LTD chamber, dual Brackjack 44's, Vforce II reeds, MSD TL, ADA head 205 lbs. compression per cylinder. Fuel: half 91pump, half 110 Sunoco, Maxima Castor 927@40:1

Last year the throttle cable binded and it took off from me and went up the beach and ran WFO for about 3 minutes. I credit the 927 for saving it from blowing up. My friend grabbed the plug wire and was all wet and the 50,000 volts from the TL running WFO threw him back 10 feet on his ass and he said he couldnt rememeber his name for like 10 seconds.. LOL
So that didnt help the life of this engine, plus it gets beat on pretty hard.

I got a like new OEM crank now, but like I said would run a SBT crank again. I just got a great deal from a friend on the OEM.

Oh and to anwer your question, yes I was just cruising back to my trailer, maybe 20 mph and it just backfired once and died. I hit the starter for a second and it didnt move, so I just swam it in as I was only like 200 ft. from the shore. I havent split the cases yet, but was feeling down inside where the Vforce reeds are and can feel that the one reed block is loose. I'm wonder if a screw or something came loose in there and started the whole ordeal. I wont know really till I split the cases. Will update then.

I'm just happy it locked up so quick that the ADA domes are safe and the cylinder will be good once i put a new sleeve in one side. Other sleeve is good and the piston is still good.

To Kennay: What Idok says!! SBT for the win! :buttkick:

I bought that crank new from unclhhulka for $200 shipped. He won it at the 06'Lanier freeride..lol
I cant really complain. I think SBT cranks are just as good as Hot Rods cranks that are made in Taiwan.

:pancake:
 
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Big Kahuna

Big Kahuna

Administrator
Location
Tuscaloosa, AL
check your waterbox, make sure the baffles are intact. I had a bad FPP waterbox on a 550 that was bad (it was new), the ski was running bad all day when I hit chop or waves. Put the ski up on the pier, cranked it up. BAMMMM The hood lifted a few inches (with the 550 strap still clamped. Opened it up, the exhaust hose from the box to the pipe was blown off, the FPP half Pipe was blown off, there was a crack in my hull and the hood!!!!!!!!

Figured out the baffles were loose and blocked the outlet for just a second.
 
Shifty

Shifty

- SuperJet Thursday -
Location
Austin Texas - Lake LBJ
I recently had my MSD TL backfire on me, it wouldn't start and idle... Just crank, attempt to start, then throw out a big backfire. Turned out to be fresh water in the the Deutsch connector that connects the pickups to the brain. I figure they were shorting out and sending the the signal to the wrong coil on occasion, I would hate for that to happen at WOT.
 
S

sflsurfrider

big kahuna said:
check your waterbox, make sure the baffles are intact. I had a bad fpp waterbox on a 550 that was bad (it was new), the ski was running bad all day when i hit chop or waves. Put the ski up on the pier, cranked it up. Bammmm the hood lifted a few inches (with the 550 strap still clamped. Opened it up, the exhaust hose from the box to the pipe was blown off, the fpp half pipe was blown off, there was a crack in my hull and the hood!!!!!!!!

figured out the baffles were loose and blocked the outlet for just a second.
Click to expand...

what?!?!?!?!
 
ryan

ryan

Location
baldwin ny
i was going to say somthing . lol 550s are known to blow up like that. the piston port motors love to fill the box with gas and then boommmmmmmmmm! nothing to due with the baffles.
 
SUPERJET-113

SUPERJET-113

GASKETS FOR CHAMP BRAP!
Site Supporter
Location
Lake Havasu City, AZ USA
ryan said:
that broke for a hydro lock at one point. somtimes they run pretty long with a tweaked rod. then blammmm . nice job.
Click to expand...

Hey ya, that makes sense... Didnt even think of that, good call. There have been plenty of close ones(hydrolocks) on that motor. Maybe it just tweaked it enough to still run good, then BLAMMO!:party::ugh2:
Like you say! lol

I just scored some cases and an getting ready tear this bitch apart and rebuild. Missing the brap and tired of riding my kids stock Fx-1 and WBII.
 
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