mrviper700 said:
Thanks for the instructions MrViper. I'll have to wait to do that as Pat Hauck had me send him the parts so he could look them over. I sent him both heads in case he needed to match them after smoothing the ring rash. I think Pat is going to work with me on this so that makes it a little better.
The only compression check I have is after the break (previous post).
Detonation or too lean??? Pat thinks it was lean. I ran this engine for 2000 miles before the cyl/piston/head mods with absolutely no issues and it was the best running thing I had. The jetting was 135 mains baselined at 3000' with a Holtzman ATTAC and no shelf in the air boxes. After the mods I changed the baseline to 5000' with 130 mains. Now, these are leaner than Yamaha charts but are one size richer from PSI's recommendations.
With Hauck's mods, I was thinking the engine would breath much easier - which is why I was checking the plug burn constantly, thinking I might have to richen up. The piston wash was not black as it was before mods but more of a medium brown. I suppose it could have been too lean or water in the fuel - I just saw no evidence on the plugs or piston tops before it broke. I was probably right on that fine line.
We'll see what Pat says after he looks over the parts. Not being familiar with the PSI quads and ATTAC unit, he's thinking maybe jetting richer or putting the air shelves in.
I'd say the pitting in the head is not from detonation, rather from a chunk of ring riding up and down about about a 100 times on the piston in the second before it stopped.
I think Holtzman recomends going 2 steps richer with pipes than recomended, or something to that effect I know that he mentions piped sleds needing special care.
Plug also looks like there were a few specks of aluminum on the electrode.
Latest picture looks almost exactly like my piston after burn down.
They run great right before they blow.
It'd been interesting to see EGT's on this particular run compared to previous runs it survived.
Good luck
Erik
My new personal goal is to take up a little more space by backing away from the edge a bit, hopefully making my junk live a bit longer.
I think Holtzman recomends going 2 steps richer with pipes than recomended, or something to that effect I know that he mentions piped sleds needing special care.
Plug also looks like there were a few specks of aluminum on the electrode.
Latest picture looks almost exactly like my piston after burn down.
They run great right before they blow.
It'd been interesting to see EGT's on this particular run compared to previous runs it survived.
Good luck
Erik
My new personal goal is to take up a little more space by backing away from the edge a bit, hopefully making my junk live a bit longer.
KING OF THE LAKE
New member
Wildmax, Did Pat Open Up The Windows On The Intake Side Or Did You Do It? Also Where Do You Have Your Carb Vent Lines Run To? - In Stock Location Or Rerouted Somewhere Else. I Am Fixing A Sled With Real Similar Problem. It Looks To Me That The Damage Done To The Top Of The Piston Was From Broken Ring Piece Or Parts Of The Piston Itself. Detonation-? Most Likely - Now Finding Out Why It Detonated Is Your Next Step. Good Luck
Hey King,
Pat did all the machine work. On the cylinders, the windows are not opened but he added 2 holes, one each side of the carb intake, that go directly to the lower case.
Carb venting is not stock because I'm running a Holtzman ATTAC unit. All vents are connected and run to a compensator inside of the airbox.
Yes the damage to the piston top was obviously a piece of ring at 140 beats per second but that was after the fact. I am guessing the ring caught the exhaust port on the down stroke and popped the piston edge off along with a piece of the top ring.
Maybe running too lean could have caused the piston to seize but not melt and push the ring into the port.
Pat did all the machine work. On the cylinders, the windows are not opened but he added 2 holes, one each side of the carb intake, that go directly to the lower case.
Carb venting is not stock because I'm running a Holtzman ATTAC unit. All vents are connected and run to a compensator inside of the airbox.
Yes the damage to the piston top was obviously a piece of ring at 140 beats per second but that was after the fact. I am guessing the ring caught the exhaust port on the down stroke and popped the piston edge off along with a piece of the top ring.
Maybe running too lean could have caused the piston to seize but not melt and push the ring into the port.
KING OF THE LAKE
New member
Wildmax., What Size Diameter Is The Window Hole Then On The Intake Side Of The Piston?looking At Your Pictures It Appears They Are Rather Large Unless I Am Looking At Them Wrong. Please Measure If You Can And Let Me Know
Hi King,
I saw your question on the vmax4 site and got you covered on all the mod specs there. I've seen some monster holes in those pistons on some sleds. One guy had squares. They really dwarf the stock set up.
Yea, we'll get this figured out.
I saw your question on the vmax4 site and got you covered on all the mod specs there. I've seen some monster holes in those pistons on some sleds. One guy had squares. They really dwarf the stock set up.
Yea, we'll get this figured out.
Looking at the other pistons and not seeing any wash marks, thats too lean for trail riding, along with that holtzman unit, ya need to jet it up some more. Usually same thing happens with a tempa flow, they dont show ignorantly lean, they just create enough heat to start detonation and or melt the exh edge off, rings exposed, poof it goes squeek. The bad piston is too messed up to get any real information off of, but the good ones show lean to me, theres black from one edge to the other with no cushion there for temp change. I would jet it up a couple sizes for sure!!
BTW- did ya do anything with the needle clips? ya need to set the sled up richer then needed if your running a holtzman device, if its jetted on the money to begin with, then your going to get into trouble with a fuel flow device, cause when it changes the mixture again, you have no room to spare.
BTW- did ya do anything with the needle clips? ya need to set the sled up richer then needed if your running a holtzman device, if its jetted on the money to begin with, then your going to get into trouble with a fuel flow device, cause when it changes the mixture again, you have no room to spare.
mrviper700 said:
You are probably right on the money, mrviper. As for the jetting: Last season I ran 135 mains baselined for 3000' and the air box shelves are removed. Clips are at #2 position. (This will seem lean as per the charts but is one step richer than PSI recommendations). Since the engine ran great with this jetting for 2000 miles, I used it as a starting point.
After the Hauck mods I went leaner to 130 mains but for a higher baseline of 5000' - still one step under PSI charts - so kept the same jet/altitude ratio. However, I was keeping a close eye on the plugs and piston wash since this was a new set up and supposedly adding 8 or 9% more power.
I think what I'm going to try is go back to 3000' baseline elevation with 140 mains. Leave the air box shelf out and clip at #2. If its still lean, I can put the shelves in or drop to #3 clip.
I knew it was borderline lean and was going to change it after the ride - Oh, well - makes for a good post. Here's the sled - one of my custom jobs.
Attachments
YAMMIEGOD3:16
Active member
DUDE, SORRY ABOUT THIS. I HAVE NOT BEEN ON VMAX4.COM BECAUSE OF INTERNET PROBLEMS, BUT DEAN CALLED ME ABOUT YOUR BAD LUCK. HERE WE GO AGAIN, YA NEED TO UP YOUR OCTANE DUDE, IT WAS JUST YOUR HARD LUCK THAT A PIECE OF RING BROKE OFF AND CAUSED THAT HAVOC. THE BAD NEWS IS THAT HEAD MIGHT BE DESTROYED. ITS GONNA REALLY HAVE TO BE CUT DOWN TO REMOVE ALL THAT DAMAGE. HOPE YOU WERE ATLEAST RUNNING MY CLUTCH SET-UP. 3:16 (tony)
Hey, Tony! How ya been?
Don't waste any sympathy on me - I was probably asking for it trying to get the ultimate burn so I could beat that SRX. If you're gonna ride like we do, this stuff happens now and then - just part of the game. Heck, you know that. What would we have to talk about if we didn't bust something up now and then???
That was 94 octane!!! Pat says I should be fine with 91. Probably border line lean + maybe some bad fuel. Was running pretty good then I fueled up at a place that I never used before.
Know of a head if I need it? Pat will have both of mine again. He's gonna look them over.
Clutching is similiar to yours but with different weights. Before the Hauck work I was right on - Hauck orange, no shim, 8bu with 13.9 in and 13.3 out, 3-6 with a Dalton 49/43, turning 8850 with 4000 engage, 110mph.
After Hauck mods, I lost maybe 400 or 500 rpm so I took 1/2 gram off the inners. Might need to take some more off 'cause I think it's still short 200. Maybe just run without inners and 13.9s out. The piston broke before I could really mess with it some more. I like the 90 degree secondary versus the backshift from the 100 (tried that) but might loose a little quickness on the shift. When you have as much power and torque that these mills churn out, you kinda like to display it.
I didn't get around to checking the shift out yet but the sled did not have the top end that it had before - maybe 10-15 mph less. Might be clutching but IF it was short on fuel that might have something to do with it. I'll rejet before I do any more on the clutch.
I do believe I picked up some low and mid range hp with the Hauck work. Wish it would have stayed alive for the rest of the day. I switched to a SRX and found a guy with a new Apex to look over. It's power and torque was very similar to that Vx800.
Don't waste any sympathy on me - I was probably asking for it trying to get the ultimate burn so I could beat that SRX. If you're gonna ride like we do, this stuff happens now and then - just part of the game. Heck, you know that. What would we have to talk about if we didn't bust something up now and then???
That was 94 octane!!! Pat says I should be fine with 91. Probably border line lean + maybe some bad fuel. Was running pretty good then I fueled up at a place that I never used before.
Know of a head if I need it? Pat will have both of mine again. He's gonna look them over.
Clutching is similiar to yours but with different weights. Before the Hauck work I was right on - Hauck orange, no shim, 8bu with 13.9 in and 13.3 out, 3-6 with a Dalton 49/43, turning 8850 with 4000 engage, 110mph.
After Hauck mods, I lost maybe 400 or 500 rpm so I took 1/2 gram off the inners. Might need to take some more off 'cause I think it's still short 200. Maybe just run without inners and 13.9s out. The piston broke before I could really mess with it some more. I like the 90 degree secondary versus the backshift from the 100 (tried that) but might loose a little quickness on the shift. When you have as much power and torque that these mills churn out, you kinda like to display it.
I didn't get around to checking the shift out yet but the sled did not have the top end that it had before - maybe 10-15 mph less. Might be clutching but IF it was short on fuel that might have something to do with it. I'll rejet before I do any more on the clutch.
I do believe I picked up some low and mid range hp with the Hauck work. Wish it would have stayed alive for the rest of the day. I switched to a SRX and found a guy with a new Apex to look over. It's power and torque was very similar to that Vx800.
YAMMIEGOD3:16
Active member
DUDE, DON,T BELIEVE I HAVE A SPARE HEAD, BUT I,LL CHECK FOR YA. LOT OF 800 STUFF IN MY GARAGE. ANYWAYS DUDE, I AIN,T PAT HAUCK, BUT DO YOURSELF ALITTLE FAVOR AND KEEP IN MIND THE STATE OF QUILITY OF FUEL WE HAVE TODAY, YA RIGHT PUMP SAYS 91 OCTANE, BUT WHATS MOTOR OCTANE 88 ? DUDE MIX UP YOUR OWN GAS. GET RACE GAS AND PREMIX 50/50-60/40 WITH YOUR SO CALLED 91 OCTANE. ITS A MUST ON A QUAD PIPE 800 ESPECIALLY WITH ENGINE WORK AND THAT HOLTZMAN. IT COULD SAVE YA. !! 3:16 (tony)