stunter01

Sure , thanks

Hi I got a fresh built 421 serval cub, 68mm x 4mmr crank. 4 deg advance,billet intakes,vforce4 reeds ,pods with 35mmpwk Cool head with 21cc domes (145 psi) on elevation 5000 ft Got 48 pilots with 165 mains Just ride it in and done first plug chop Please give me some input on the plug chop ,

I couldnt find only got 20cc will fit them over the weekend and check compression

Rode it yesterday after i adjusted the floats again . Elevation 5000 ft Im on 145 mains at the moment going to fit 21cc domes over the weekend and check my pilot size because after the float adjustment the bike struggles to idle. Also need to fit a pingle i think. After that ill do a plug chop. It feels little dead on higher rpm

I think you are right it says 95 oct but could be a lot lower Please tell me about your set ups , would love to get an idea Which way i must go. At the moment im on 145 mains not sure about the size of the pilots but will check this weekend think they are to big . Bike was idling fine but when i test it the one side was running out of fuel so i adjusted both float levels and now the idling is worse than before. Would it be a good idea to fit a pringle double outlet valve? Thanks again for all the information

Thanks screamer im just riding it in at the moment just going low rpms. I was looking for a compression indication for pressure ratings on these oversize cylinders with different dome sizes but couldnt find. I forgot to mention i am on +4 deg also Thanks gusto i found 21 cc domes locally was the last set . But maybe in the future i ll press your button 👍

Thanks for the reply i also thought to rather fit 21cc. Will buy them from you anytime but im in south africa lol

Anybody ?

Im on 5000 ft have a fresh built 421 serval built with vf4 and keihin 36 carbs. They send me 17 cc domes with the kit. I get 175psi when i kick it over. Is this too much pressure im running on pump gas 95 oct. My squise is about 0.9mm. Want to use this bike for the dunes so if i go to sea level must i change the domes ? Sorry maybe this had been discussed before. Please help i dont want to break my engine these parts are very expensive Thanks

I would love to do that, the problem is in south africa you can't buy it off the shelf There is not really shops that import the stuff they only keep the basic parts

Hi guys I'm building a new engine with 4mill stroker crank longrods I got pistons with the sleeves wsm 68 mill think they are specially made for stroker crank My question is , do you get domes for this set up. Oh i forgot to say i got a pro design coolhead . The piston edge are about 2mm out of the sleeve at tdc

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

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

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