is this a cause of detination 421 serval cold seize

[Nutwood 472]

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

 

 

yeah M&M couldnt belive i had 160 psi compression with 22cc domes at 420 ft above sea level,i should of have 150 or 155,not 160psi with 22cc cub domes,before break in i had 160 on both cylinders and after break in i had 165 on the right and 163 on the left and i had a good squish of 46 to 49 on both cylinders,so i'm not sure if it was comp or timing,thanks for the input man

[sleeper06]

yeah M&M couldnt belive i had 160 psi compression with 22cc domes at 420 ft above sea level,i should of have 150 or 155,not 160psi with 22cc cub domes,before break in i had 160 on both cylinders and after break in i had 165 on the right and 163 on the left and i had a good squish of 46 to 49 on both cylinders,so i'm not sure if it was comp or timing,thanks for the input man

dangerous mixture of both

[shanYE west]

I would cc the domes to make sure they were infact 22's.

[Snopczynski]

Anything we added above the timing that came on the dyna when we dyno tested the serval saw a decrease in HP. It made the most power with the factory programmed curves in it on our dyno session.

[RadarRacing]

I'd go all stock CDI.Stator etc before I'd put it back together with that dyna on it. Theres bikes with all stock ignition components making big power.

[Snopczynski]

I'd go all stock CDI.Stator etc before I'd put it back together with that dyna on it. Theres bikes with all stock ignition components making big power.

People lose site of what the Dyna is for. There is no dispute that Drag bikes make big power and run stock cdi's and stators. Heck I run a stock stator with a dc conversion. However Drag bikes operate in a tiny little rpm window at the upper rpm and its not hard to just set up the timing and have them be ok with a stock cdi. A serval is made for low-mid power. It was designed for using all different ranges of the power curve, so having an ignition like the dyna can emphasize these ranges through its alternate curve settings. rolling off the throtle and back on for whoops, trails, hills, etc.........is something the Dyna does better than a stock cdi, and you can feel the difference it makes in these lower rpm areas.

[RadarRacing]

Well then he will probably want to keep the dyna then since there is absolutely no way the dyna could be in any way related to these burned up motors, it is however a constant here with all three. It would be too easy to just stick on a $75 used CDI and use it.

[bigborebanshee]

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

 

 

It is not your Dyna ignition,Its the Stator causing your problems.Same thing happened to my Stock cylinder 421,except my o-rings were even more melted!

 

Mine was breaking up very little on the top end .i figured it was jetting until i pulled the head off upon teardown.I could not figure it out either.Until i tested the stator during reassembly.

 

The pistons had no deto marks and the domes were good,but the o-rings were fried.

 

Dump the ricky stator before you change ANYTHING.

 

 

At the time,the spark plug porcelin was coated in thick yellow glaze..I searched the web and found that this condition may cause misfiring at high engine RPM. Shiny deposits usually suggest that temperatures have suddenly increased during hard acceleration. As a result, normal metallic deposits do not have a chance to slough off the plug and they melt and form a conductive coating which causes the misfire. Yellow or tan deposits, as shown below, usually indicate the use of leaded fuel.

 

Which was probably caused by the bad stator.

Edited April 15, 2011 by bigborebanshee

[Nutwood 472]

It is not your Dyna ignition,Its the Stator causing your problems.Same thing happened to my Stock cylinder 421,except my o-rings were even more melted!

 

Mine was breaking up very little on the top end .i figured it was jetting until i pulled the head off upon teardown.I could not figure it out either.Until i tested the stator during reassembly.

 

The pistons had no deto marks and the domes were good,but the o-rings were fried.

 

Dump the ricky stator before you change ANYTHING.

 

 

At the time,the spark plug porcelin was coated in thick yellow glaze..I searched the web and found that this condition may cause misfiring at high engine RPM. Shiny deposits usually suggest that temperatures have suddenly increased during hard acceleration. As a result, normal metallic deposits do not have a chance to slough off the plug and they melt and form a conductive coating which causes the misfire. Yellow or tan deposits, as shown below, usually indicate the use of leaded fuel.

 

Which was probably caused by the bad stator.

 

 

Well Bigborebanshee I hate to hear you went thruogh the same problem I am going thruogh right now,it really sucks,but I am happy to hear that I am not just the only one who has the same symptoms,becuase this is been one big mystery to me and others.I will be changing the stator and the cdi,to be on the safe side,and i tested the rs stator before i installed it and the stator test good,18 on the ingition side,but Andy at M&M said he has tested them,and they tested good,and they would start freaking out and start jumping timing and shorting out,I would like to send the stator to sheerider1026 and have him rewire the stator and see how burned up the wire is underneath the outside wire,then i might feel safe to run the dyna,lol just dont know yet,The Dyna has been programed a couple times and we cant take a look to see if it took the programed curve for the serval or if the curve for super cub is still in there and which one the dyna is using,so thats why we are changing both stator and cdi,just to be on the safe side,these engine builds are costing my kids their college funds,lol"jk""but it is stressing me out to the max and costing me a fortune and making the the cub setup look like a big joke to my riding crew,and they are telling me to sell it and by a fucking 4-stroke,lmao thanks for the input and info man,much apperciated

[bigborebanshee]

Yea,i sent my stator back to RS and they sent me a new one.I ebayed the RS stator and bought a used stock stator for what i got from the RS.

 

 

The 200watt stators are absolutely the worst.

[Nutwood 472]

Yea,i sent my stator back to RS and they sent me a new one.I ebayed the RS stator and bought a used stock stator for what i got from the RS.

 

 

The 200watt stators are absolutely the worst.

 

 

If you have any problems with it,send it to sheerider1026,he rewires with a heavier gauge wire with a double high temp coating on it and does a real good job at it,from what i hear.

[2strokespirit]

Interesting.... I am building a 7mm Serval on pump gas.... I am also going to run a Dyna....

 

The UCCR in this case is around 12.68:1, I am not familiar with your fuels but for 92, its on the edge.... Just a little timing might run you into problems..... At sea level you should be at 157 cranking psi (roughly) I don't know, sounds to much on the edge....

 

Other thing is, how is the cylinder piston wall clearance? I know it "should" be fine, but I'm just curious.... Cold seize with forge pistons can happen very easy, especialy with a tight clearance....

 

I did not see the pistons, understand it was due to cold seize, so it should rule out detonation (99%) anyway... If there is any sign of deto, I say your UCCR is to high for 92.... I won't run over a 12.5 UCCR on this motor MAX with 92... Add some timing and it will blow very quick!

 

Let us know how she runs after rebuild...

 

PS I heard of more stock cdi go wrong then Dynas....

 

Hope she runs soon!

[No Limit Powersports]

We have had tons of dyna's fail so we typically try and stay with the stock cdi. Not because the dyna isnt a cdi just because of the unreliability. With the dyna software you can only upload the curves to the box there is no way to know 100% if they are actually in the cdi, and I have had other dyna cdi not take the curve and said it did. I am confident that the stator or the dyna is causing his problem as Jon has had hell with motors in the last few months. Im cutting him another set of domes as well to get the compression ratio down a bit.

 

Andy

[Snopczynski]

Here is what we found with shanes serval. At break in we ran it and checked compression warm at 156-158 psi with 22cc domes at about 500'-600' elevation. We ran it on pump gas, and it started detonatiing after break in down at the dunes. It closed up a set of plug gaps when he was racing Builder. We re-checked the compression and it came in at 170-173 psi range at sea level. We had to put 50/50 race gas in it to run it the other 2 days down there. He is gonna have new domes made for it to get back down to pump gas range.

[No Limit Powersports]

With a flat plate 22cc volume dome at sea level should put you about 13.1:1 if i done my math correctly so that would be a little bit much for pump fuel. At elevation that should be about right with little to no added timing. Taking Jon down to a flat plate volume of 24cc which should put him at 12.1:1.