BA
Pro
Posts: 1592
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posted December 29, 2003 07:11 AM
Pro's & Con's for 1270/1272 vs 1290
Looks like I will be purchasing a piston kit for my bike.
The top end is apart already and I do not want the added expense of splitting the cases.
I am going to be able to get a very good deal on the parts and labor via a friend in the business, but I probably shouldn't push it to involve messing with the crank.
(My engine has 11,000 miles on it, so I don't feel too concerned about longevity)
I was mildly concerned about thin cylinder walls on the 1290 and how it might affect either HEAT in around town driving, OR the addition of nitrous in the future.
I was wondering if the 1270/1272 were maybe more reliable with nitrous since they have the slightly thicker cylinder walls.
Any advice or thoughts would be greatly appreciated guys!
Thanks!
  
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addisonzx12
Expert Class
Posts: 213
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posted December 29, 2003 09:35 AM
Had a 1290 on my bike for 10k miles, no problem. Have a 1380 now, 1290 + 4mm stroke. Got about 250 sae hp on a dry shot no problems, bike was dynoed with the 250hp after 6k miles since the stroke job.
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psycho1122
Pro
Posts: 1608
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posted December 29, 2003 11:29 AM
The BIG and Only difference between the 1270 (Muzzy) kit and the 1290 kit is the rings. The Muzzy kit uses the High-Zoot "Slipper" (thin) rings from Japan and the 1290 kits use the JE rings. Bigger rings=More Friction.
Stick w/ a Muzzy Kit 
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zxlnt
Needs a job
Kawpuke Extraordinare
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posted December 29, 2003 07:46 PM
 Edited By: zxlnt on 29 Dec 2003 21:07
Remember just because an engine is bigger doesn't mean that it automatically makes more heat. The only time it makes more heat is when its making more power.. With that being said my 1270 runs just fine in town, no overheating problems...
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psycho1122
Pro
Posts: 1608
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posted December 29, 2003 08:53 PM
Edited By: psycho1122 on 29 Dec 2003 20:53
You can also combat heat problems by making sure your map is not too lean. These engines like LOTS of gas!
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addisonzx12
Expert Class
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posted December 29, 2003 09:15 PM
Physics is physics. More power equals more heat, no way around that!
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zxlnt
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Kawpuke Extraordinare
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posted December 29, 2003 09:42 PM
Right but the only time the engine is gonna be making a more substantial amount of heat is when your running the hell out of it. Normal day to day driving shouldn't be much different. Are we on the same page? 
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zxlnt
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Kawpuke Extraordinare
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posted December 29, 2003 09:44 PM
Ba re-reading your first post, you didn't want to split the cases. Did you know the 2nd gen Muzzy 1317 kits are now a true bolt on. No case splitting needed????? Its a lot more $$$$ than the 1270 though...
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BA
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Posts: 1592
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posted December 30, 2003 05:31 AM
Edited By: BA on 30 Dec 2003 11:34
I agree with ya zxlnt that a bigger engine doesn't mean more heat.
I do have a concern about the thin cylinder walls though. Seems like it would be less ability to dissipate the heat, and possibly a more likelyhood of problems if you were using nitrous a lot.
Kinda makes me wonder if anyone is making 1290 "nitrous" pistons, where the ring-land is moved down a little bit.
I'll go check the price on that 1317 real quick, but I am on a serious budget here.
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Marcos Peguero
Zone Head
Posts: 568
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posted December 30, 2003 07:57 AM
What is normal Rwhp for a 1270 muzzy kit. on normal gas.
What is the increase from a normal piped, PC3r bike.?
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VincentHill
Needs a life
Posts: 6520
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posted December 30, 2003 08:22 AM
I have seen "1" THAT MADE 3 hp Less than my bike at 180 HP I ahve seen "1" that made 195 Hp which is the most I saw. The person that mentioned the size and location of the rings was really on the mark! Specially for NOS! I want to run stock piston size with good rings and location so I can spray a lot!
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Marcos Peguero
Zone Head
Posts: 568
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posted December 30, 2003 09:39 AM
I thogth that the 1270cc kit made like 20 more Hp.
Anyway the stock bike is 2 much for me at the moment.
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zxlnt
Needs a job
Kawpuke Extraordinare
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posted December 30, 2003 04:15 PM
MY 1270 made 181.6 horsepower on a stingy, yes I said stingy dj150. My bike just piped and filtered made 174 on dj250 and 166.7 on the same stingy dj 150. So I am guessing only its actually closer to around 190 horsepower or so.
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kcadby
Pro
Posts: 1733
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posted December 30, 2003 06:44 PM
BA...Tony at MTC makes a 1290 ProLight Piston Kit that is pricey but very nice looking and it WILL handle NO2...just depends how much you want to spray before you NEED "NO2 pistons" hell...Brian has been spraying a 80-shot to STOCK PISTONS for...a LONG TIME!!!
THAT is what I am going to put in John's bike (MTC 1290 ProLight) (it is TOTALY appart right now)
I haven't given any updates for a while so here it goes...
He BROKE a gear in the tranny at the PStar race (first day no less)...he missed a shift (bottle was low...DUH) on the previous run and pulled a Homer and pushed the button again with the revs still HIGH...I beleive THAT fractured the gear because it came appart on the next run 
BAD news is...a peice of the gear tried to exit the rear of the cases
The ONLY thing that stopped it from fully venting the cases was...the case bolt that goes through the cases where the gear tried to exit...
The cases can be repaired but since he's going to race it WITH SPRAY...I told him to get a new set...OUCH...
Gonna be a good motor though...
The FIRST 1270 I built made 182+HP at 500 miles on HPC's dyno over a year ago...it came here for a tire and complete mapping...it made 195HP on our dyno after I mapped it...I bout fell off the bike when the #s came up 
I believe our dyno reads maybe 3-4 higher than HPC's so I guess the motor broke-in VERY nicely
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psycho1122
Pro
Posts: 1608
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posted December 31, 2003 06:46 AM
My 1270 made 202 h.p on a MJP dyno. On the same dyno the stock engine made 173 h.p.
The base run BEFORE maping the 1270 was 185 h.p. Needless to say, I was VERY happy! My tuner indicated to me that it was too lean almost everywhere and we ended adding up to 25% more fuel in almost all mid and high rpm sectors! As we added fuel, the engine would smooth out, backfireing would dimminish and overall engine temp's cooled. Even the exhaust header would not glow orange as much as it did at the start.
We hit a wall at 195.5 h.p., at this point we added a little timing and BOOM! 200 h.p.!!
For our final run we hooked up the crankcase vent to the air injection valve for the exhaust,..........202.5
If you don't belive the numbers because dyno's "Vary", look at the gains from base and from the stock engine w/ pipe.
mrsantafe also came out to Phoenix and expierienced the same results w/ his "1290 Carpenter" kitted 12.
See his post in the Dragbike Zone...."Thanks NVH/Psycho1122"
If you tune your modified 12 on a DJ 250, in most cases that I've seen.....it will be too lean and you will not get the gains your expecting.
My 1270 is nothing special.....I used the Muzzy fuel pump (A MUST!!) and paid attention to the details during assembly. We also "Cleaned-up" the ports and made sure the pistons were at Zero deck before bolting on the head. It's wonderfull to run this much compression on "PUMP" gas and have all the smoooooth power and torque.
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BA
Pro
Posts: 1592
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posted December 31, 2003 09:22 AM
how much compression psycho1122? Static compression or cranking pressure?
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dougmeyer
Needs a job
moderated
Posts: 2713
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posted December 31, 2003 10:03 AM
BA,
Cylinder walls don't "dissapate" heat, they conduct or transfer it to the coolant which transports it to the radiator which transfers it to the air.
There could be a case made that a thinner cylinder wall eases this transportation, allowing the cylinder to remain cooler moving more heat into the coolant quicker.
In any event, most of the heat of combustion is moved out through the cylinder head, not the cylinder wall.
Doug
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Marcos Peguero
Zone Head
Posts: 568
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posted December 31, 2003 10:13 AM
Why is the fuel pump in this kit a must.?
Doug.
Then the heat is not a problem of cilinder walls is a problem of the heat transfer of the radiator.
I wonder wy the indutry havent tested any other liquid for cooling.?
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BA
Pro
Posts: 1592
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posted December 31, 2003 12:51 PM
Sweet Doug. Thanks for the education.
yer basically saying "donworry'boutit" which makes me happy.
I was effectively trying to apply known issues that happen in real world examples of things I'm more familiar with, say, "a 350cid chevy bored .060 over", or maybe a built up 400cid.
The experience in those two area's is just that they have more tendency to overheat under power. (ie. extended rpm racing.)
I was just concerned if a similar situation might apply with a 1290 but, heck, I won't be under power for long so what the heck am I worried about?
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Y2KZX12R
Needs a job
CompetitionCNC.com
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posted December 31, 2003 01:58 PM
I guess the real question is what is the thinnest un-sleeved cylinder that is still reliable.
Doug? did you do any testing on this, or do you guys just have a min you like to stay with.
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Y2KZX12R
CompetitionCNC.com
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psycho1122
Pro
Posts: 1608
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posted December 31, 2003 03:39 PM
BA....13.8-1
Cylinder pressure is at 230 psi COLD at 1,200 ft. altitude.
Muzzy pump has more than TWICE the flow rate of the stock pump (00'), this helps insure that no "lean-out" can occur during long duration high speed runs.
With my map needing up to 25% more fuel than my stock engine w/ a pipe, I don't have a thing to worry about.
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entropy
Moderator
Posts: 8671
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posted January 01, 2004 05:39 AM
pyscho,
how do you know its 13.8:1; did you actually measure it?
Tomorrow JohnnyCheese & I will put my new buret to work and measure/compute my bike's CR and I would be interested in any tips you have on the process.
thanks!
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EastBayDave
Needs a job
Posts: 2245
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posted January 01, 2004 07:09 AM
quote:
For our final run we hooked up the crankcase vent to the air injection valve for the exhaust,..........202.5
I'd like to see a pic of that? Anyone?
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02' ZRX1200
00' ZX12R sold
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silver01bullit
Expert Class
on here too much
Posts: 333
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posted January 01, 2004 08:23 AM
I don't think I'd adjust those exhaust valves too tightly on a big engine...
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entropy
Moderator
Posts: 8671
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posted January 01, 2004 10:01 AM
Edited By: entropy on 1 Jan 2004 10:08
double post
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