stunter01 Posted October 9, 2017 Report Share Posted October 9, 2017 Hi guys I know there is a lot of threads about this topic My question is this. When your sleeve is fitted on the engine and you turn the crank must the top outer side of your piston Line up with the sleeve ? , not talking about the dome I only get like 87 psi on standard banshee with new wiseco pistons,fresh bore etc Other thing is I'm at 5000 ft above sea level would that be ok ? Quote Link to comment Share on other sites More sharing options...
stunter01 Posted October 10, 2017 Author Report Share Posted October 10, 2017 Hi I fitted a coolhead last night with 18cc domes and now i got 145 psi It seems ok after searching the forum and found this info Thanks anyway Quote Link to comment Share on other sites More sharing options...
blowit Posted October 12, 2017 Report Share Posted October 12, 2017 Your cranking compression value will vary, especially if you have porting. I would highly suspect either the wrong piston, or a comp gauge that is not right. If there is no schrader valve in the threaded tip that goes in the head, the value will NOT be correct and will read low. I would no go throwing smaller domes at the engine to try to get a magic value from a compression gauge. Lets figure out why it is low first! If it is assembled, use solder to test the squish band clearance first. Report back. Brandon Mull Engineering Quote Link to comment Share on other sites More sharing options...
stunter01 Posted October 13, 2017 Author Report Share Posted October 13, 2017 first of all thanks for replying I have 2 banshees this one I newly rebuilded the top end with 66mm pistons , rebored I saw that some porting was done on the sleeves not sure how much etc. I got a lighter flywheel on and timing plate at +4 , I also fitted VForce 4 reeds . the standard carbs was bored out to 28 mm in the front. main jets are 300 and the pilots I drilled out to round 27.5. im at 4800 feet so that is why I suspect the low compression with standard head. my other banshee is stock with only pipes done and gave me 85 psi on both cylinders. forgot to mention both banshees have pro flow air filters on and tors removed.i bought the coolhead secondhand and just fitted it to see the difference in compression it came with 18 cc domes , with the standard head I checked the squish with a 1.5mm solder wire but it touches nowhere I couldn't test the bike because the orings were leaking antifreeze only got a new o ring kit this morning and going to assemble the head later today and test the bike i'm using 95 octane o yes and I adjusted the needle clips to 2nd groove from top read something about it on here that it needs to be done when fitting VForce 4 s would the more compression give me better bottom,mid or top end power I suspect I got a mild porting but don't really know the difference I'm from south Africa and the resources are few for mods on these bikes thanks again for the reply Quote Link to comment Share on other sites More sharing options...
stunter01 Posted October 13, 2017 Author Report Share Posted October 13, 2017 oh and yes my pressure gauge have the valve in the bottom and the thread equals that of the spark plug I read your post on your site Quote Link to comment Share on other sites More sharing options...
blowit Posted October 13, 2017 Report Share Posted October 13, 2017 I would not go further until you can determine the squish. You already know it exceeds .060", which is a concern. The timing edge of the piston should come up flush with the top deck of the cylinder. If not, there is an issue there. Quote Link to comment Share on other sites More sharing options...
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