RagunCajun Posted June 9, 2007 Report Posted June 9, 2007 ClimbAnyHill, i might be getting rid of my 21cc domes. I was over 130psi with them. I might not need them if my 20cc domes work with my new mods(flotek port job, 20cc domes, 93 pump gas etc). I can let you know if you want them. Quote
ClimbAnyHill Posted June 9, 2007 Author Report Posted June 9, 2007 Thanks for your help guys.. I going with topend rebuild sometime this summer! I didn't warm up the engine before the compression test, after a good warm-up it now reads 115. I have two sets of domes 19cc & 21cc so I think I'll go ahead and try the 21cc's. Does anyone have a diagram showing where all the Orings go? Are you guys using silicone on these Orings or cylinder surface where the head sits? I'm also having a hard time finding the copper washers. The ones I found are double the thickness. Will these work for me? How import is it to use the recommended thin flexable washers? Final question, and I know it's been covered many times. What's my max compression to keep her running on pump 92 Octane gas? Quote
XxMeltIcexX Posted June 9, 2007 Report Posted June 9, 2007 Thanks for your help guys.. I going with topend rebuild sometime this summer!I didn't warm up the engine before the compression test, after a good warm-up it now reads 115. I have two sets of domes 19cc & 21cc so I think I'll go ahead and try the 21cc's. Does anyone have a diagram showing where all the Orings go? Are you guys using silicone on these Orings or cylinder surface where the head sits? I'm also having a hard time finding the copper washers. The ones I found are double the thickness. Will these work for me? How import is it to use the recommended thin flexable washers? Final question, and I know it's been covered many times. What's my max compression to keep her running on pump 92 Octane gas? -The o-rings should have a groove they fit in, put grease on them and make sure they stay in place while installing. (Dont have a diagram-its fairly easy) -No silicone -Are the nuts cap nuts? or regular 'ol nuts? If you get a full amount of threads, depending on what coolhead you have, it should work fine (just dont strip the nuts out) - also put silicone inside the cap nuts if they fit properly. torque them down to 20 ft/lbs (increments of 5) - I dont like going over 150 psi with pump gas. (doesnt sound like youl have that problem whatsoever) Eric Quote
ClimbAnyHill Posted June 9, 2007 Author Report Posted June 9, 2007 Cool.. I have acorn nuts to go with them. I'm just waiting on my Orings to get here so I can get busy! The comp tester used was Actron from Sears. It's all they had. I was actually looking for the Craftsman. I'm returning it once I'm done with this fix, hopefully trade it for the Craftsman! Thanks again!! Quote
XxMeltIcexX Posted June 9, 2007 Report Posted June 9, 2007 Cool..I have acorn nuts to go with them. I'm just waiting on my Orings to get here so I can get busy! The comp tester used was Actron from Sears. It's all they had. I was actually looking for the Craftsman. I'm returning it once I'm done with this fix, hopefully trade it for the Craftsman! Thanks again!! Ya ive tried many comp gauges and really the best ive found is one at checkers :biggrin: craftsman gave me the same reading... Keep us updated, by the way it sounds you might be able to run those 19s with pumpgas... They arnt hard to change if you try them both out Eric Quote
Snopczynski Posted June 9, 2007 Report Posted June 9, 2007 Here is a chart. Expect to see lower numbers than it says for a 21cc dome since your starting at 115 psi essentially with a 22cc (stock)dome. Did you hold the throttle wide open and have both plugs out when you did the compression test? Approximate Cranking Compression These pressures are estimates based on fresh stock bore, piston, porting, and deck height. It is recommended to check your compression after installation. Sea Level 1000' 2000' 3000' 4000' 5000' 18cc 197 178 171 170 165 145 19cc 183 167 160 158 152 137 20cc 169 156 149 146 140 129 21cc 156 145 138 134 128 121 stock 130 125 118 112 106 100 Quote
dajogejr Posted June 10, 2007 Report Posted June 10, 2007 I use thin RTV coat on all the orings, and the studs as well. Cool heads are ok...they like to leak...the downside. Fighting it myself right now... If your crank is already welded, use the smaller domes and race/pump fuel mix. If your crank isn't welded...use the larger domes.. Either way, you know you're ready for a rebuild real quick... Quote
RagunCajun Posted June 10, 2007 Report Posted June 10, 2007 Aw....they like to leak. That sucks to find out. Anyways, i figured out where the o-rings go in no time yesterday. The 10 tiny o-rings go between the two head parts(there's grooves for it). Dont be afraid to use some grease because the orings are a bitch to make them stay, same with the doomes. I rebuilt it with the engine IN the bike so that means the orings where facing DOWN when i put it on. Some fell off like 5 times before my dad mentioned use grease. You might need someone else to help you. I found it much easyer to put the head on with an extra set of hands. That's about all the help i can give you. I'm pretty new to this stuff. Quote
ClimbAnyHill Posted June 10, 2007 Author Report Posted June 10, 2007 Thanks guys, Orings arrived yesterday & I'm getting it done today. One thing I can't understand is what holds the domes in the head? The head is two pieces put together, the domes fall out the bottom.. Is there another gasket that goes under the head or something to hold domes in place? Quote
. Posted June 12, 2007 Report Posted June 12, 2007 put the sparkplugs in them and use them to drop it all down. They should fit snugly but they can slip in and out. it's a lot easier to hold all together if you have an extra hand to help you, but the sparkplugs usually help pretty good Quote
ClimbAnyHill Posted June 13, 2007 Author Report Posted June 13, 2007 put the sparkplugs in them and use them to drop it all down. They should fit snugly but they can slip in and out. it's a lot easier to hold all together if you have an extra hand to help you, but the sparkplugs usually help pretty good I atuall set the domes over the cylinders.. If you line up the notch on the domes directly with the stud infront of it [the one above the exhaust port] the base plate will drop in perfectly. Then I dropped in the top piece. Now I'm having a leak problem thru one of the studs. Anyone have tips on this? I used new Orings & copper washers. I greased the Orings & used high temp RTV under the washers. I torqued in 5 lbs increments up to 20lbs & in the appropriate pattern but dammit it leaks :: Can anyone help? I can have this, I need to ride for Fathers Day. Quote
Snopczynski Posted June 13, 2007 Report Posted June 13, 2007 Pull it back apart and check the area where it is leaking. Quote
ClimbAnyHill Posted June 13, 2007 Author Report Posted June 13, 2007 Pull it back apart and check the area where it is leaking. I checked everything & all was in place.. I'm going to try silicone on that stud oring. Quote
Snopczynski Posted June 13, 2007 Report Posted June 13, 2007 Personally I wouldn't silicone an o-ring head. If it isn't sealing then you got a cut o-ring, the wrong o-ring or something misaligned. Quote
dajogejr Posted June 13, 2007 Report Posted June 13, 2007 Personally I wouldn't silicone an o-ring head. If it isn't sealing then you got a cut o-ring, the wrong o-ring or something misaligned. Sorry...but I've done a lot of motors with cool heads and pro design heads. They leak from time to time, that's all there is to it. That's why I put a dab of RTV on each stud when I'm threading it into the jug, a real thin coat on all the orings, and I even put a dab on the bottom of each head nut, too.... If it's worth doing, it's worth doing right. Quote
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