Capone Posted September 2, 2004 Report Share Posted September 2, 2004 Ok, my first rebuild, right before I rebuilt it, it lost alot of compression, would barely run and would overhead and spit out coolant out of the overflow. I called trinity racing, they said my headgasket was blown, when I took off the head, I noticed the top of the piston was really rough, and I pulled the jugs to take a look. When I pulled the left jug off the whole piston skirt was missing. both pistons wrings had seized and seemed like they were bouncing off the walls, I presume after the wrings seized. During/After the rebuild I used Vito's Power Pistons (Bore .040), put a cool head with 18cc domes, and didn't rejet from 290's, and ran 50:1 mixture. It leaned out really bad and my rings seized I supposed its because of a mixture of all the above. No cylinder damage was apparent except a small scratch that my machine Dr. honed out. I didn't see the Mic after the hone. This time I used Super Stock pistons, alot more beefy, rings are huge, they're really nice, I rejetted to vito's jet kit, the needle was put on the fourth clip down, and I dropped 340's in the carbs. Ran decent, bogged low end. Well, I went to Flat River and I ran through water/sand mixture all weekend, and there were traces of that in the carbs which I'm sure went through the engine. During the ride the jug stud nut came loose on the right side and it sounded like my pipes fell off. After replacing the nut, it got me back to camp, all the nuts were pretty loose, so I retightened all, and changed the plugs to new ones, and went back out on the dunes. We went trail riding, and one of the plugs got fucked, wouldn't fire no more, I think it got wet earlier from being under my seat. Well, I rode about 5 min back to camp on 1 cyl. with the other one backfiring most the way. Keep in mind this is my rightside cyl. I got back home, and Monday I started my shee up and took it down the street. It seemed like it would lose power right at the end of the power band. Vito's told me to take the air screw all the way in and back it out 1 turn. It pretty much fixed the problem, but about 20 seconds after that it blew up lost all compression. Died. Upon closer inspection the ring must have turned, prolly due to the ring to wall clearance from the hone, but the ring came off the pin, spun and caught on the exhaust port. The pistons had slap marks all over the sides where they had been sliding up the side of the wall, the left one especially, the one that had the scratch that needed honed. The left piston looks pretty good, small amount of sliding against the cyl wall, a small chunk taken off side of the very top. Is there anyway the crankseals are comming into play with the badluck streak I'm having? Any info/opinions are GREATLY appreciated. I dont want to sell my banshee but I'm not going to be able to afford many more rebuilds. To get the current scratch out Its going to be on its last bore, and I would really like to have a dependable bike for a while. P.S. I'm going to switch from the airbox to Dual K&N filters with outerwears that will get rid of 3 possible airleak spots, free up alot of space. Sorry for the long post. Quote Link to comment Share on other sites More sharing options...
ssbanshee Posted September 2, 2004 Report Share Posted September 2, 2004 your crank might be toast Quote Link to comment Share on other sites More sharing options...
Capone Posted September 2, 2004 Author Report Share Posted September 2, 2004 My crank is ok, the only thing I'm worried about is the airleak through the seals. The movement sidetoside in the crank is minimal, and it spins freely. I'm going to get it rebuilt before the next top end rebuild. Quote Link to comment Share on other sites More sharing options...
bigboybanshee Posted September 2, 2004 Report Share Posted September 2, 2004 That 50:1 mix on 18cc domes....please tell me you were running race gas. If not, that's a large part of your problem Quote Link to comment Share on other sites More sharing options...
rebelbanshee2 Posted September 2, 2004 Report Share Posted September 2, 2004 1)have you done a leakdown test??? you should have done one the first time your engine went and you may have solved the problem then. 2)Have you done a plug check when you rejetted? 3)And you best be running race gas with those 18cc domes!!! 4)Did you clean out the case after that psiton came apart??? If not there could be chunks it there casuing problems Quote Link to comment Share on other sites More sharing options...
PUSH THE THROTTLE Posted September 2, 2004 Report Share Posted September 2, 2004 18 domes have you done a compression test on that? I would guess you better be running race gas if your not already. Have you done any break in? I hope your not running 50:1 on a brand new rebuild. Quote Link to comment Share on other sites More sharing options...
Capone Posted September 3, 2004 Author Report Share Posted September 3, 2004 After the first rebuild, and break in, I ran 50:1 with race gas. I run 104. With the superstock pistons I ran 32:1 with race gas & yamalube, which I will continue to run. I never did a compression test or a crank pressure test.. which I should have done I know, but I didn't have the money nor the tools. Now I do, and I'm getting the crank rebuilt, topend bored & rebuilt, and hopefully everything will be gravy. I flushed the bottom end with Gas mix but never split them and washed them completely. Where abouts in the case would the pieces be? As far as the plug check, the first rebuild it was light colors tan & grey, which should have told me it was lean but the manual said light tan was perfect. I took the engine apart mostly from anger that it blew up again. Then when I cooled off, I read the manual and realized the tests I should have done to pinpoint it. Quote Link to comment Share on other sites More sharing options...
Bansheeman1121 Posted September 3, 2004 Report Share Posted September 3, 2004 Sound like me expet ive only rebuilt once but the coolent has been givin me trouble, im no expert but ill tell you what i have learned im in the proces of breakin in my motor and im running 3 and 1/2 ounces of amsoil to a gallon on 93 octane gas, after my piton melted into all little metal shavings i cleaned the case out real good make sure theres not dirt or anything in the case, make sure the rings are on the righ way the numbers have to face up or theyll last an hour worth of run time then grenade and fall into the bottom end becuase there coated a certain way to catch the oil, also check for air leaks in the intake , and jet it a bit on the rich side, let it idle for a good while then re torque the heads to 18-20 pounds then do it again make sure your gaskets are on the right way, and make sure the opening in the circlips are not lined up with the grooves in the piston make sure u slide the opening in the circlip away from the groove or the wristpin will push it out and score the cylinder other than that good luck 3 times a charm Quote Link to comment Share on other sites More sharing options...
lincster Posted September 3, 2004 Report Share Posted September 3, 2004 If you are going to clamp on air filters, you better jet up big. If you have 340s in with an airbox, I would go to 400s with clamp ons. You may want to go 110 low lead race fuel and stick with the 32:1 ratio. With that much bore and 18cc domes, I'll bet you are around 190 compression. Quote Link to comment Share on other sites More sharing options...
boonman Posted September 7, 2004 Report Share Posted September 7, 2004 SOunds like you better tear that entire motor down. You will have debris in the crank. Did you by chance blow a hole in the top of the piston? Also, are you on stock porting? It sounds alot like detonation, and an improper torquing down of things...... What kind of torque wrench do you have? How reliable do you think it is? What is your compression? On a fresh motor, you MUST leakdown test it. You should also do a baseline compression reading. After breakin, (3 heat cycles, please, please tell me you heat cycled it) take another reading. If the engine takes a shit, do a leakdown test on it BEFORE you crack a bolt. This will tell you if an air leak caused the problem, or if you should look elsewhere..... It sounds to me like a neglect situation, and improper installation/assembly is what caused this...... Quote Link to comment Share on other sites More sharing options...
Capone Posted September 7, 2004 Author Report Share Posted September 7, 2004 (edited) Actually what happened was inproper wall/ring clearance. The ring spun and the gap caught on the exhaust port, thanks though. There were no holes in the pistons, the only thing I seen that confused me was the slide marks on the sides of the pistons from sliding up and down the wall. My bottom end is getting rebuilt, and end seals replaced. After it was tore down there was no sign of any debris in the bottom end. The top will be .80 over now, replaced with Vito's SuperStock Pistons. Btw, It wasn't neglect, I didn't know or have the tools to do leakdown/compression test. Now I do, and they will be done. As far as the heat cycles, I did it last time, ran it, checked torque, ran it harder...etc, but I must not have let it heat up enough, 'cause in flatriver the jug nuts came loose. Tightened and it felt fine. Thanks for the suggestions. Edited September 7, 2004 by VitoBanshee Quote Link to comment Share on other sites More sharing options...
boonman Posted September 9, 2004 Report Share Posted September 9, 2004 On your heat cycles, be sure you just idle the engine. Do not ride it. Heat it up, shut it down untill comletely cool to the touch. THen do it again. Maybe blip it a couple times..... I just set the idle a touch higher than normal..... Quote Link to comment Share on other sites More sharing options...
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