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shaving the head?

Posted: Sat Oct 11, 2008 12:09 pm
by PimpinSpree
I'm gonna try and make more power out of my motor, but i don't want to compromise the reliability of it. Will shaving the head make me need to worry about blowing a hole in the piston? Also, im wanting more midrange power, will shaving the head give me that, how about porting the intake. or port and polish the exhaust? any other suggestions?



thanks -Jimmy

Re: shaving the head?

Posted: Sat Oct 11, 2008 2:44 pm
by Kenny_McCormic
PimpinSpree wrote:I'm gonna try and make more power out of my motor, but i don't want to compromise the reliability of it. Will shaving the head make me need to worry about blowing a hole in the piston? No, just wasier starts and more top end power Also, im wanting more midrange power, will shaving the head give me that, Nohow about porting the intake.gives ya low and mid or port and polish the exhaust?Higher RPM and more everything any other suggestions?



thanks -Jimmy
Watch your CHT(buy a gauge!), watch your jets, use plenty of oil (25:1).

Posted: Sat Oct 11, 2008 3:20 pm
by Arnadanoob
Shaving the head will increase your compression, may give you more power but not sure if it'll be noticeable. If the compression's too high, your electric start may not have enough power to deal with that. Naturally you'd want to run higher octane fuel and like Kenny said a CHT gauge is definitely something I'd install.

Personally I wouldn't shave the head but that's up to you. It's more likely that you'd stand to notice and gain more midrange power with a ministroke setup but the problem with ministroke cranks is that all of them are made cheaply, we break a lot of them here.

Porting a Contessa is good stuff but you need to know how to port it. Some guys have polished the exhaust port and wondered why so much carbon sticks to it. I don't know if your block is ported but that's another area you could work on. The bore's intake and boost ports needs the rough casting removed and then the exhaust port can be worked on. Keep in mind that you'll likely have to re-tune after this with jets and weights again. There's some guys I know who run stock cranks that will beat ministrokes simply because they know how to port.

Posted: Sat Oct 11, 2008 4:50 pm
by PimpinSpree
will a stroker crank fit on an se50? If that were the case, i wouldn't mind putting a dio crank in there for a little bit more stroke, but then the piston would probably hit the head

Posted: Sat Oct 11, 2008 5:55 pm
by Arnadanoob
Silly me, I didn't notice that you were using the SE50. I'm not sure if they do make stroker cranks for that but oh well. I'm used to seeing custom Dio motors in Sprees so I overstepped my comments.

Posted: Sat Oct 11, 2008 7:38 pm
by veedubh20
PimpinSpree wrote:will a stroker crank fit on an se50? If that were the case, i wouldn't mind putting a dio crank in there for a little bit more stroke, but then the piston would probably hit the head



stroker crank was made for dio motor only.

Posted: Sat Oct 11, 2008 11:39 pm
by Kenny_McCormic
Watch your squish, being kitted it might already be close enough.

Posted: Sun Oct 12, 2008 2:07 am
by Bear45-70
From my experience with CHTs, it will defenitely tell you when you fried it. But give you and indication soon enough to prevent it, no.

Posted: Wed Oct 22, 2008 12:04 am
by PimpinSpree
so i shaved the head. Instead of wasting 5 gallons of premix. I just added some octane booster too it, with bad results. After it got hot it started pinging, so i went to shut if off, and it had so much compression i couldn't shut it off, i pulled the spark plug boot and it did nothing. I had to stick my glove over the exhaust.


Would running premium fix my problems? I think im just gonna go back to a normal head.

Posted: Wed Oct 22, 2008 6:24 am
by Arnadanoob
First of all octane boosters in bottles/cans don't work. When the bottle says "raises the octane 3-5 points" it means:

If you're using 87 octane gasoline, raising it by 3-5 points will yield octane of 87.3 to 87.5

Posted: Wed Oct 22, 2008 10:41 am
by noiseguy
Did you raise the compression on your 65cc kit? Those piston/bores are already running at higher compression than stock. Check your compression and report back; I'm interested in what your static compression is with that shaved head. With Spree, you're raising it from around 110 to 130-140 PSI.

You can probably keep using the shaved head if you run 2 head gaskets.

Posted: Wed Oct 29, 2008 1:12 pm
by scooter trash
i got a stupid :?: whats a CHT :?:

Posted: Wed Oct 29, 2008 1:48 pm
by ALOW1
scooter trash wrote:i got a stupid :?: whats a CHT :?:
Cylinder Head Temp Gauge