Thread: Stx-r domes size?
01-04-2010, 06:34 AM #1
Stx-r domes size?
I have bought a stx-r with a engine breakdown, because they have run it on pumpgas with to much compression (36cc domes).
I dont wanna do same misstake.
Srx-r 1200 setup:
Novi 48 with tauceti
M16 reed valve & intake manifold with spacer
no cylinder porting
miller head dome size?
factory triple pipes with cdi
R&D intake & ride plate
Skat trak pump 12 vanes
question 1, what dome size can i use with pumpgas 99okt?
question 2, is it possible to run a 50/50 mix on e85 and 99 okt to use a smaler domesize?
01-04-2010, 02:36 PM #2
It seems you have bought someones limited ski.
If it has miller heads it may also have flattop pistons. May want to check before you think of another head.
I dont think miller has domes any more for the MSE heads for the stxr. If he does probably only race gas heads and flat top ones.
You need about 140 psi or less for a 50/50 mix and about 120-130 psi for 92 octane.
You have to run higher octane because of the pipes and cdi. You may want to check to see if the cdi is on the race curve. Which is a little white plug that is on the right side about where your knee would be if you where sitting on the ski but inside.
If the white plug is in then it's in the race gas curve and needs to be taking off and just put in a bag for safe keeping.
Best thing to do is get stocks heads and put them on and go. Cheapest and easiest way. Check to see if you have flat top pistons before you do anything with the head
01-04-2010, 08:57 PM #3
Im with johnny on this one, sounds like you bought a race boat.
With the pipes you need stock heads to run pump gas. I think they are about 46cc. If it has flat tops in it then that will change what heads it needs. Also check under the cylinders for spacers, just in case it happens to be a raised port setup.
Post some pics of what you got that would help us steer you in the right direction.
01-08-2010, 03:12 PM #4
The damaged piston is a wsm, not a flat topp, maybe it was wrong pistons for the cylinderhead? However i will get new piston and bore it upp one size (it is not nicasil). Do you think it will add to much heat to the piston with the triple pipes when it not nicasil?
I thinki will get a ada cylinderhead and 44cc domes and mix 50/50 99okt/e85. I know i must rejet the carburators for about 15% more fuel, but how du you kalkylate what jetsize it will be?
Thanks for tips/ideas..
01-08-2010, 09:26 PM #5
If any jet change is required it will probably be small.. Like a 145 to a 142.5 or the other way. I would go leaner if it was me but thats me..
I would go stock heads way cheap.....and if ya want to run race fuel put the other heads on.
01-22-2010, 04:05 PM #6
01-22-2010, 04:09 PM #7
Little hard to tell try another pic of the dome at more of a angle. Looks like flatop but not a 100%...
01-22-2010, 04:44 PM #8
01-22-2010, 05:26 PM #9
race boat yes!!
It is an old race boat and it will be this season to. But the last owner had no knownedge obout how a engine works. He just filld it with pumpgas and go for a ride. Later that day he sink it to bottom of a river. Then i bought it. So i have a lot to do with this boat. Must check evrything, jetting, cdi, domes...etc..
It gonna be some threads in this forum...he he
01-22-2010, 09:56 PM #10
yes that is for flat top pistons. Which means thats more than likely all your gonna get.
When you figure out what your gonna do wih the ski like race it or rec ride it let us know and we can help get you lined out for pistons or compression and what ever else.
K till then
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