shoot, detonation sucks

[ski4]

well i was doing some more tweaking and guess something was not right!

took a nice chunk out of the rear piston, not sure why, i am betting to lean inthe carb since that is what i tweaked with last nite, but damn she was running good

i think the bore can be used not even a scratch on it, i hope the same can be said to the crank

[Matt_E]

What jetting was this?

I might have an intact Pro-x 82.5. Not sure. I'll look.

[ski4]

i was running 75 pilot, 132.5 main, 1.5 ns and 65 gm spring

was having a lean spot in the low end so i decreased my pop off and put in a smaller pilot ( was 80 and 95 gm spring)

tuned in the carb and she ran like a raped ape for about an hour, then the dark cloud ( dj) rode it and blew it up in 5 minutes. ( just playing korn you did (i hope prevent further dammage by not starting it again)
i was thinking i was lean on top but i have a feeling it was more on the bottom

it was not starting as easy as it did with the 80 pilot i need to give it some throttle to get her to go

that would be cool if you do have another slug laying around but i am thinking you may not these were yours to begin with

i have a new set of 83 mm sudco's but would like to try and keep the bore

i think also gonna go up to a 77.5 pilot and 135 mains nexst time out

[Matt_E]

Oooooh....you're running the ones I was thinking of then. Sorry bud...

[ski4]

shoot, any one else???:frown: :banghead:

[MADMAT]

Bump. Any one gots an old 82.5?

[ski4]

well the crank is out , spent about and hour and a half with air oil and gas cleaning it out, there where a couple little tiny pieces of aluminum in it. seem a ok now though. stupid me, i forgot to take off the coupler when i pulled the motor apart. any ideas on how to do that with the crank out

[ski4]

good call i will do that tonignt, thanks

[djkorn1]

bump...

[ski4]

well got the pistons yest, woo hoo.
the crank and bottom end is back together and ready to accept the top end, will deglaze tonight and slap in the pistons and pop on the head and pressure test

any thoughts on were i should go with the jettng?
when dj was riding he was not going wot. and it still deto'd

something happend when i lowered the popoff and decreased the pilot jet ( i am sure it had an effect on the wot fuel delivery and want to bump the main jet) but not sure if i should bump up the pilot too? man the bottom/ mid was crisp for the first time in a year and a half:cheer: :banghead:

it was a bit tough to start needed to goose the throttle to fire it up in the water with a load

[waxhead]

It looks to me that it broke of the side electrode on the plug
this is from deto

what size domes what squich clearance do you have
need to know more about the engine to make a diganostic about why it did what it detonatited

[ski4]

the electrode took a hit yes, we determined it got smashed by by debris from when the piston crumbled

the domes are for stock mm set up, i can't remember off the top of my head what they were in diameter
pistons are 82.5

not sure about the squish, paul actually machined these domes for me to get me up to about 180 compression ( and i sat at 178) cuz the cylinder had been decked too much i am 99% sure the squish should be ok though he had me get readings from the ports and what not to find out how to cut the domes. once i get the top end re assembled i will measure the clearance though

[ski4]

hey wax i just looked at the pictures i posted and the plug was not in the pic so i am thinking you thought the plug broke apart? the electrode just bent upwards and stayed intact, the chucks are pieces of ring and piston

[Jr.]

I have built & tuned many of these, the jetting is always
Pilot 75 L adj 1 1/4 T
main 135 H adj 1 1/2 T
stock spring & N/S

check to see your stator didn't move & is on the stock marks.
another problem I have been seeing is when the new ethnol based fuel is used. not only is there a water problem, but the octaine levels don't remain consistent. If you are running that fuel, raise your main jet one size.

On another note, did you happen to do a pressure check before tear down?
You might have had a small air leak & didn't know it.

ski ya, Paul

[ski4]

hey paul, i actually started with jetting by your rec at 137.5 and 75 and it was too rich on top and too lean on the bottom it seemed. ran terrible and was very hard to start in the water. at times i had to prime the motor to get it to catch

it was too lean on the bottom it seemed and upped the pilot to 80 . it made starting way easier and idled good but still had a strange low end hesitation.

the top end at 137.5 seemed off . it was gurgling and poping and would not rev out. so i went richer seqeuntly, took the jetting up to 145 ( which would not let me even get off idle, any gas there bogged it right out) so i worked back down and she seemed to like the 132.5 the best which bothered me a ton since stock with a b pipe should be 135


i monkeyed with jetting for weeks and finally got to where i was sitting the day it deto ( and it was the first time she seemed to realy ru n strong.) that day decreasing the pop and the pilot to 75 again


the stator was still in place and on the 0 mark, i didn't do a pressure test prior to tear down shoot

[Matt_E]

I think the 132.5 main is suspect - considering deto occurs (usually) in the high speed range.

[ski4]

I think the 132.5 main is suspect - considering deto occurs (usually) in the high speed range.
my fear as well. i think having the big pilot disuaded the motor from blowing up till i cut back to 75

on that note, there are a few dings in the dome as well that have been smoothed out by dj's brother, he says it should be ok to run .do you all concur?

[ski4]

the more i think about it i fear when i open the carbs i'll find i put in a 70 or a 65 pilot in the rear carb. i can see it now, all tired and wrenching and sticking in the wrong jet. man i will shoot myself.:lightning: :banghead: :woot:

[djkorn1]

Your top end was still not running right... As soon as that main jet would kick in, it sounded like it is starving to death for fuel. (Almost sounded like it was miss firing).

We will get it tuned in after a good dunking in MicMacs test tank. :arms:

[djkorn1]

The bottom wouldn't have hit like that if you did... (the deto has to be from the main jet, right?) or at least 99% of the time.

[ski4]

yeah but i need to jet it better before i even fire that new motor up, no use keeping it jetted the same if it is off

[djkorn1]

Absolutely, I would go up one on the main.

[ski4]

The bottom wouldn't have hit like that if you did... (the deto has to be from the main jet, right?) or at least 99% of the time.
i am thinking the pop off is the culprit of the hesitation i had on the botom cuz man tht is gone for sure withthe lower popoff

this is my proposal
keep the popoff where i am ( it is 1.5 n/s and 65gm spring) was at 1.5 and 95 gm with a early throttle hesitation

take the pilot to 77.5 ( to help with continuued rough starting tht i had after bringing the jet down from 80 and starting with a touch of the buttom) and the main to 135
does that sound reasonable to anyone / everyone given i just exploded and like a dummy did not do the pressure test again before tear down to verify an airleak. :banghead:

[djkorn1]

Leave the pilot where it is at... we can still richen it up a little to get more gas in there by turning the screw. The low end was ripping (why change it?). Only change one jet at a time.

I know you'll be putting that other one right back in ... it'll be too rich on the bottom and you'll be bogging.

[ski4]

yeah maybe? just odd that it was easy to start with 80 and not so at 75
i figured cut the difference and go middle of the road, maybe i'll leave it at 75 then though

[djkorn1]

Shooot, would you rather have to give it a little gas to start it... and have it run like ********?

Or a little harder to start and rip.

[felix5oh]

Like he said, change one jet at a time.

And, of course it was running great , it was lean. They always run realy strong and responsive when your leaning from an air leak.

leave the 75 (start rich and work your way in)
change to 135 ( it takes alot of time)

[ski4]

there has to be a happy medium

[ski4]

Like he said, change one jet at a time.

And, of course it was running great , it was lean. They always run realy strong and responsive when your leaning from an air leak.

leave the 75 (start rich and work your way in)
change to 135 ( it takes alot of time)
i was at 80 on the pilot prior to the bringing her dwon to 75 and blowing up though


i am gonna leave teh 75 for now, jump up to 135 and keep the pop off low since that is where the best throttle response was

i hope it was not an air leak, the fresh motor only had about 10 hrs on it and held pressure for like 15 or 20 mibnutes when i did a pressure test before installing it

now i got to go get a helicoil kit though, the heat from deto weakened some cyl. threads damn:banghead:

[djkorn1]

It was still running like poopoo on the top. I think that is where it was too lean. I doubt it had an air leak.

[ski4]

me either, unless that rear crank seal was leaking but it seemed super solid when i pulled the crank out

[djkorn1]

Jeffro says around 11 or noon at his shop for the test tank...He says when we leave, we will both be carb masters. He plans on giving us a tutorial while he dials your ski in. I'll call you in the morning. My engine is now put back together. All I gotta do is put on the manifold and carbs and drop it back in...:woot:Any luck with the heliocoils

He said it will go very quickly in that tank. :biggrin:

[ski4]

cool
just have to pressure test and put the flywheel on then stick her all back together
oh and swap out the jets

helicoils worked like a charm

[ski4]

damn. leak down test is showing i have a leak. stupid thing is i can't find it.

sprayed the whole thing with soapy water . the crank seals are holding , nothing seems to be letting air out but it's not holding pressure. maybe it's my rig. shoot
i did have one leak where i capped off the intake manifold but that was an easy find and easy fix. nothing else is bubbling though.

[superramjet]

check your squish. I would suspect that more than your jetting.

[djkorn1]

Maybe the gasket goop on the base gasket? Aren't those supposed to be dry???

[ski4]

nope, base gasket is not leaking i can't find it but it's not there, i ran out of dish soap so have to try again another time????????????????????????????????/

all i can think of is somewhre onthe bottom of the cases or intake, that is the only place i have not really looked at yet

i put the last base gasket in dry but 3 people told me i should put a thin coat of 1211 on it

[djkorn1]

You don't need 1211. They allready have a coating on them that makes them stick... Adding 1211 is making it like you have 3 gaskets.. more places to leak.

Did you try just pumping air into a capped off hose to see if your system is leaking?

[ski4]

on a oem gasket it has a small bead of funk the one i have is paper only, so it's is not really a whole lot of anything extra,

i pumped the air into a bottle and it held pressure, so it's not the rig, it's the motor:bigeyes: :banghead: :banghead: :banghead: :banghead: :banghead:

[Matt_E]

Make sure you have the flywheel and stator off for the leakdown test, so you can inspect there.

[ski4]

thanks matt but it's off and that seal and area of it seems also to not be leaking? i am at a loss

the only think i can think of is the o rings in the head are not sealing right and the air is leaking out of the cooling tracts, i will have to plug those up tonight if i get time and try again?????????????????????????????? cuz the bottom of the motor had no areas with leaks either

[Matt_E]

There aren't that many places, right?
I would check the entire case circumference, every mating surface. Both crankseals
Intake gasket area
Exhaust gasket area
Base gasket area
Head


Even if you plug the cooling passages, you would still have a leak (if that's where it is), because they will be at ambient pressure, and your cylinder will be higher than that.
If you really suspect that's where it's at, take the head off and inspect the O-rings. When you put them back on, put some vaseline on them, too.

I am sure one of the site pros will chime in - surely they have experience with gremlins like this one.

[djkorn1]

Get that sucker together, Mr Nurse!!!!

[ski4]

i have sprayed that entire motor down with soapy water top sides seals head , spark plugs manifold mating surfaces everythin. it is the only thing i can think of.

that will suck if that's the case that my orings are bad cuz they are fairly new and i don't think i will get any before the ride this w/e, maybe i will buy some today and hope for the best

[Matt_E]

Hoping for the best is probably a bad idea.

[ski4]

oh nooo not like that, hoping for the best that if i order some orings they will be here before the w/e and i can get them installed

no i wouldn't run this this way with the new top end again i'm too poor to play that game

[Matt_E]

Gotcha :biggthumpup:

[ski4]

well she lives!!!!!!!!!!!:cheer: :woot: :cheer: :woot: :cheer: :woot:
fired right up and is idling great.

will take her out and break her in tonight.

my fingers are crossed for the jetting i have this round::frown:
man i hope i dont' blow up again.

it's what paul called for this time again with the lower pop off though
we'll see:bigeyes: :bigeyes:

[djkorn1]

She'll Rip... like a piece of paper.

[ski4]

well she seems strong. woo hoo

[djkorn1]

F'n Rip it!!! Barrel rolls tomorrow... looks like we got waves!!!!
:Banane01::hail:

[ski4]

:biggthumpup: now if i can get out of work at a decent time:frown:

[ski4]

the difficult starting is still bugging the hell out of me, that did not go away .
damn

i will have to open the lo speed adjusters some more maybe

[ski4]

just for ********s and giggles i checked my squish, and the best of my abilities i am getting .065 does that mean anything to anyone? in some of the readings i am finidning it should not be less than .040-.045. so is more ok? what does it mean if it's more as in this situation