is this a cause of detination 421 serval cold seize

[Nutwood 472]

hello,built serval,my mods are 22cc cub domes,noss cool head, shearer sb in frames 160 comp,420 elevation,35pwk air strykers 52 pilot,165 mains,cgl needle middle clip,6 inch pods,br8es ngks,DYNA programable cdi,cdi programed for 3 degrees on stock curve ,DYNA high out put coil,rs stator on zero degree on timing plate,in line 3 inch cooler,pro design over sized radiator,pro design high flow water pump,billet intakes with built in cross over, running 92 pump gas with klots super techplat 20%castor 32:1 ratio,did compression test when we got back to the shop,right side was 160 and left side was 30 psi,took exhaust off and carbs and did leak down test and held for over 20 mins,then drained coolant and took head off and cylinders,orings in the domes looked funny,never seen orings look this way,ive had this shit happen to three other new builds,so M&M said to lose the junk dyna cdi and go back to a stock one,they think the cdi is advancing the timing curve on the top end rev and detination is the results,all pics are in the gallery of the domes and pistons,if i dont get to list them all in the post,like to show everybody and get some views,thanks for all the opinions guys much appericated

[Snopczynski]

Shane runs a Dyna CDI on his 421 Serval on pump gas with no problems. It has a good 4 hours on the motor and puts down 80hp.

 

Dyna ignitions work well, I would look elsewhere for your issue. If you think the cdi is bad, send it back to dyna to have it checked. We run 3 dyna cdi's and never have issues with them. I even run a dyna coil.

[crazycanuck]

Wow sorry bout your luck dude. what did you end up doing with your super cub??

Edited April 12, 2011 by crazycanuck

[BUILDER]

I have never ran the dyna ignition but I know lots of guys that do and they have had good luck with them. From the pictures that thing looks like it was just lean to me but hard to tell from the pictures. That sucks on a new motor man!

[RadarRacing]

Any pics of the piston crown, underside of the piston or is there any pitting at all on the piston or dome? Any damage or funny coloring on the plug? I would have thought your jetting was in a fairly safe range. I'm with Andy and the stock ignition.

[Nutwood 472]

Any pics of the piston crown, underside of the piston or is there any pitting at all on the piston or dome? Any damage or funny coloring on the plug? I would have thought your jetting was in a fairly safe range. I'm with Andy and the stock ignition.

 

 

there are pics in gallery of pistons,no pitting in domes,but domes have a light green tint and so do the pugs on the metal tab,both plugs and the porcian was white,no pics of under side,just sent everything to Andy today,going to put stock cdi back on and now im looking for a good used stator for a 1995,thats the year of my bike.The orings were flaten and melted looking around both domes,I have been thruogh this problem breaking pistons on a 472 t-rex,sold it,bought super cub,broke pistons again,twice on each build,traded the super cub on a serval,and guess what,it happened again,and the only thing that wasnt changed on each build,The dyna CDI and the ricky stator,tested stator and tested good on all circutes,but Andy said that doesnt mean nothing,rs stators are known to jump timing at high rpms,so I'll give it a try,everything else is new,from carbs to exhuast,lol when it climbs into the high rpms,it seems to take off like a turbo and screams and dont stops,even with 190 mains and 52 pilots and there is no air leak to be found,i run a daul pingual and 5/16 or 3/8 fuel line and the tank cap is drilled out,so just dont know,im just tried of chaseing this problem,ive bought enough pistons to build another engine,lmao all i can do is keep my head up and hope this will fix the problem,and Andy cant belive i have 160 comp with 22cc domes,so he's cutting some different domes for me,He's a hell of guy and a excellent sponsor to,I would refer M&M to anyone who wants to go fast,lol

[05stroker]

That is definitely not good on a brand new motor. Did you know that the "stock" curve in the dyna is not the same as the oem cdi's curve? If I read that right you added 3 degrees to the "stock" curve in the dyna. That would be 3 degrees at 3,600 rpm's, almost 4 degrees at 6,000 rpm's, 5 degrees at 7,000 rpm's, a little over 6 degrees at 9,000 rpm's and 7 degrees advanced at 10,000 rpms. I don't know that that would have anything to do with a cold sieze, but you may want to change the timing around in the dyna if you plan on keeping it and running pump gas. I can post up a pic of the stock curve drawn on the dyna sheet if you want.

[Nutwood 472]

Wow sorry bout your luck dude. what did you end up doing with your super cub??

 

i had the same problem on the super cub and the t-rex,so i traded the super cub in on the serval,because 300 or 350 for a set of pistons cost to much,lolcompared to a 68mm,lol but the only thing that has been on all three builds is the dyna cdi and the ricky stator,which tested good,but Andy said that doesnt mean a thing,becuase they are known to jump timing at high rpms ,and said when they down load a curve into the cdi,theres no way of seeing on the curve on the program without running the cdi on the bike and a dyno and then check it with lap top i guess ive bought enough pistons to build another engine,lol so ill put my stock cdi on and im looking for a good used stock stator for a 95 yrs bike,not easy to find,lol i can put 190 mains in it and it will scream and look lean on plug check and there is no air leaks,before and after cold sieze,im just stump,lol but i love my banshee,lmao

[Nutwood 472]

That is definitely not good on a brand new motor. Did you know that the "stock" curve in the dyna is not the same as the oem cdi's curve? If I read that right you added 3 degrees to the "stock" curve in the dyna. That would be 3 degrees at 3,600 rpm's, almost 4 degrees at 6,000 rpm's, 5 degrees at 7,000 rpm's, a little over 6 degrees at 9,000 rpm's and 7 degrees advanced at 10,000 rpms. I don't know that that would have anything to do with a cold sieze, but you may want to change the timing around in the dyna if you plan on keeping it and running pump gas. I can post up a pic of the stock curve drawn on the dyna sheet if you want.

 

 

Andy at M&M programed the Dyna for the set up,so I have no ideal how that works,but i still have my Dyna sheet too,so i know what it looks like,thanks anyway,and thanks for the input and I'll have to ask Andy about the stock curve.

[Snopczynski]

Shanes motor is running only 4 degrees of total advance over stock I believe, so if your running pump gas, servals don't like timing added to the curves in the dyna they already come with. We only manipulated and changed the curve progression, but did not add timing to them. The stock curve in a dyna comes advanced over what stock really is at high rpm, so you just need to take the dyna and bolt it on and run what they come with if your not changing the low-mid rpm curve progression.

[sleeper06]

i was thinking 160 psi a lil timing an shit gas lately,IMO 92 isnt enouph,if there anything like cubs they dont like timing on pump gas

[crazycanuck]

I agree with sleeper, I wouldnt move off +4 with pump fuel.

 

I know im prolly missing something, but maybe the UCCR is too high for pump fuel. sometimes cranking psi is just piece of the puzzle.

[camatv]

if its a "cold sieze" then you know what happend ( wayy to much rpm before it warmed up) most cast alluminum cylinders are not as prone to cold siezure due to the pistons and cly warming up at the same time

 

almost looks like lack of oil or lube or a lean out. you can usually hear deto when its doing it.

 

those domes look a lil more than a 22cc might want to check that out also. the marks on the o-rings are from installation they squished out on the top of the cyl and the head they most of the time wont do that if you grease them well so they kinda slip around when you are installing them. but more often than not they kinda do that anyways.

[Nutwood 472]

if its a "cold sieze" then you know what happend ( wayy to much rpm before it warmed up) most cast alluminum cylinders are not as prone to cold siezure due to the pistons and cly warming up at the same time

 

almost looks like lack of oil or lube or a lean out. you can usually hear deto when its doing it.

 

those domes look a lil more than a 22cc might want to check that out also. the marks on the o-rings are from installation they squished out on the top of the cyl and the head they most of the time wont do that if you grease them well so they kinda slip around when you are installing them. but more often than not they kinda do that anyways.

 

Yes cam,a true cold sieze is from not letting the cylinders heat up with the piston and so on,but the engine was warmed up to operating range and had been riding half the day,and the domes M&M cut for the serval and the o-rings for the domes had some engine rebuild lube on them to keep them in the domes for installation and if they were leaking,i would of notice when i checked for that,before i installed the exhuast,i'm really a nit picking bastard when putting these engines together,I've had this same problem on a 472 t-rex,a 472 supercub,twice on both builds and now this one and the only thing on all the builds that has not been changed is the dyna cdi & ricky stator,M&M programed it twice,once for the super cub and once on the serval,on every build,i was breaking pistons,and i can put 190 mains in and it would scream on the top like a freaking turbo and with no air leaks,so they are thinking the CDI is advancing the timing to much at the top of timing curve,but i dont program cdi's,so i dont know,and i never seen the o-rings on the domes ever push out and melted around the edges,pics suck,because they are from my cell phone,they were like that on both domes,just not one,so hope fully we get this figured out,lol but thanks for the input cam

[Nutwood 472]

I agree with sleeper, I wouldnt move off +4 with pump fuel.

 

I know im prolly missing something, but maybe the UCCR is too high for pump fuel. sometimes cranking psi is just piece of the puzzle.

 

 

the serval is a +3 timing,if you go to +4 you will have a drop in horse power,and the cdi was programed for a +3 timing curve,thanks for the input though,