flatslides

[ROBIN]

almost no gain for 38rs flatslides
flatslides on top
rs38 mik
holeshot header zzr cams quicks 4adv
bottom same with jetted stock carbs

[ROBIN]

any thoughts?
is head next restriction
least exp way yo up power?

[ZrexRich]

Not what you'll want to hear but IMO your $'s should have been spent on more compression(1224 kit or stock bore high compression pistons). The zzr cams like more compression. Once you have that, then you'll notice a small gain with the flatslides.

[SteddyTeddy]

The head is the main restriction. The stock 36mm carbs are right for a stock head. Once you start building the motor and increase its ability to flow, then larger carbs are needed and real gains can be seen. I've made as much as 154hp on my stock bore, high compression motor, running ZZR cams with stock carbs. Now my big motor is a different story. Stock carbs would of choked it up.

[ROBIN]

thanks for info
got carbs cheap on thanksgiving trip
big bore kit to much money,(untill motor blows)
any one know reasonable valve job and head porting shop
will pull base gasket at same time
maybe leave tool in so motor will go
then sleeps with boss will let me by big bore kit

[SteddyTeddy]

There is no cheap route from here. If it runs good and your happy, leave it. IF you really must have more then dig deep into your wallet. Your looking at another $2k for real gains.

[schmoo]

thanks for info
got carbs cheap on thanksgiving trip
big bore kit to much money,(untill motor blows)
any one know reasonable valve job and head porting shop
will pull base gasket at same time
maybe leave tool in so motor will go
then sleeps with boss will let me by big bore kit

krexken does a good job porting and is pretty reasonable , I believe he is fairly close to you.

[MPFab]

Were the runs done on the same day? If not what were the correction factors for the given runs?

[ROBIN]

SAME DAY DYNO OPERATOR CORRECTED WITH COMP

[sillyhillbilly]

thanks for info
got carbs cheap on thanksgiving trip
big bore kit to much money,(untill motor blows)
any one know reasonable valve job and head porting shop
will pull base gasket at same time
maybe leave tool in so motor will go
then sleeps with boss will let me by big bore kit

I dont recommend leaveing off the base gasket, there is solittle room for squish area that you risk metal to metal contact somewhere on the top end. as teddy put it, untill you open up the ports and or add compression your at your bang for your $$$$$$ threshold.

add compression will be a big boost from 4500 rpm up to redline, porting the head does wonders, that could be added with a dremel tool and sume time on the work bench.

[beantown]

ZZR pistons, ZZR cams with NO base gasket, .009" deck height. Add the head gasket and ya have plenty of squish room. Runs AWESOME! No porting done to the head yet, 40CVK downdraft will be on soon. Seriously the pistons really made the cams come alive. Right around 11.2:1 compression ratio with the ZZR pistons and base gasket removed. From 2500 to red line it pulls like a freight train.

Me on the right, KillerKaw middle and CJs Pipe, Pods and jetted 1200 on the left. Tom and I were doing a roll-on after the pistons were installed. Toms Turbo 1224 ROCKS!

[ROBIN]

ive done banged my $$$$ pretty good after 2 years
i thought leaving out base gasket was common
no different than milling head
several hd guys said as much as .018
with no problem
ill pull the head and probably use extrude hone since i know them from the indy cars back in the 90s
the base gasket trick is tempting ,since if latter u go with pistons u can still use your head
guess ill mike the base gasket when it comes apart
brring elves i mean when i pull it apart
thanks for all the info uall

[beantown]

ive done banged my $$$$ pretty good after 2 years
i thought leaving out base gasket was common
no different than milling head
several hd guys said as much as .018
with no problem
ill pull the head and probably use extrude hone since i know them from the indy cars back in the 90s
the base gasket trick is tempting ,since if latter u go with pistons u can still use your head
guess ill mike the base gasket when it comes apart
brring elves i mean when i pull it apart
thanks for all the info uall

Robin,
Go back to the stock advancer and un-plug your KTRK harness and run the Dyno again. It will be real close to a ZZR1200 timing curve. When I was running just the ZZR cams, it ran better without the 4 degree advancer. Bill "mudnducs" is running the ZZR pistons, cams and no base gasket like I am. PLUS Arlie took .008 off Bill's cylinder block, he's running literally zero squish! And has not had any issues with his Rex.

Shane

[btl68]

Robin,
Go back to the stock advancer and un-plug your KTRK harness and run the Dyno again. It will be real close to a ZZR1200 timing curve. When I was running just the ZZR cams, it ran better without the 4 degree advancer. Bill "mudnducs" is running the ZZR pistons, cams and no base gasket like I am. PLUS Arlie took .008 off Bill's cylinder block, he's running literally zero squish! And has not had any issues with his Rex.

Shane

If you are talking about the green bike Bill has, it's tore down. At least when I was out there in September. If not, then disregard this post. He only had the green ZRX and his Honda RC51 four months ago.

[SteddyTeddy]

Running near 0 squish is a VERY BAD THING! If you want your engine to live a long time I would stay in the .012" to .015" range. I like taking .010" off the head myself. Gives you close to a .5 bump in CR and doesn't affect piston to head clearance.

[ROBIN]

just deleting the base gasket should be okay?
others have done this and milled head and installed hc pistons?
no ktrick with mikuni fltslides
can try run wth stk adv
but probably wait till i do head

[sillyhillbilly]

no where near the zzr curve
zrx curve stops at 32.5 degrees around 4600 rpm

the zzr curve goes to 44 degrees at around 6800 rpm
the horizontal flow head doesnt like the extra timing that the zzr cdi give
nor does it like the rev limiter being a fuel cutoff and not an coils cut off rev limiter
since the rex doesnt have fuel pumps nor float bowl solenoids the fuel cutoff on a rex means you got no rev limiter if you use the zzr cdi box

[Mojo Risin']

A guy could rip apart a motor with a zzr cdi

[sillyhillbilly]

A guy could rip apart a motor with a zzr cdi

like this you ask?

http://www.zrxoa.org/forums/showthread.php?236730-Ouch

[KWICK]

The real question is "Who's advancer?"

My +4º is a real +4º, you could also try a +2º, and/or stock to see.
Ted's is a +0.5º and really won't make a measurable difference, except the motor won't be as smooth as stock, or with mine.

[doug]

From my drag racing engine builds, No base gasket BAD. (it's do-able but NO) Go with the skinny/thin little base gasket. Shaving your head to raise compression is cheap and you can check your valve clearances easy enuff... Some of the head work can be gone on the bench, and I would find someone to degree my cams..

Idunno? just my .02c?

[ZrexRich]

If you are talking about the green bike Bill has, it's tore down. At least when I was out there in September. If not, then disregard this post. He only had the green ZRX and his Honda RC51 four months ago.

Brian, Beantown is reffering to Bill's old 02' red zrx that he sold to his nephew before your visit out here. The green bike was Arlie's(itchy butt-R.I.P.) old 1224 rex that Bill bought after Arlie past away.

[ZrexRich]

I've been thinking for awhile now on how to hop up Barndoor's 1200 on the cheap and figured the easiest way would be to have the block decked the diffrence in height between stock 1200 pistons and zzr1200 pistons. The cam sprockets would need to be slotted so the cams could be degreed and a APE manual cam chain tensioner installed. The only hangup I can foresee is the cam chain would probably be too long. The solution would be to take one link out of the chain, but I haven't looked into the avaliability of a new pin to reassemble the chain.

[SteddyTeddy]

I've been thinking for awhile now on how to hop up Barndoor's 1200 on the cheap and figured the easiest way would be to have the block decked the diffrence in height between stock 1200 pistons and zzr1200 pistons. The cam sprockets would need to be slotted so the cams could be degreed and a APE manual cam chain tensioner installed. The only hangup I can foresee is the cam chain would probably be too long. The solution would be to take one link out of the chain, but I haven't looked into the avaliability of a new pin to reassemble the chain.

Why would you need to take a link out of the chain? If you have to mill that much off the block you are going to have other problems!

[doug]

Why would you need to take a link out of the chain? If you have to mill that much off the block you are going to have other problems!

I agree!!