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 Xpit77 |
GT750 Squish Head |
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Registered User
Posts: 23 10/03/08 16:48:38 |
Where can I find the dimensions of a stock Suzuki GT 750 head re. the height ? Also, does anyone have the dimensions to make one into a squish ? How much do
you shave off of the height and how much do you remove from the domes ? Will it work without changing the angle of the # 1 and 3 spark plug holes ?
Thanks, Steve |
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Brownslane.diasio |
To Squish or not to Squish | #1 | ||
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Registered User
Posts: 65 10/06/08 11:21:00 |
I would NOT recommend removing head material for additional squish. That will not add power, but will significantly narrow power band....not something you want
to do on a road racer (solo car). Raising compression and "ramping" squish was a drag-racer trick...that, frankly, did not work very well. My daytona
engine was (and still is) the fastest GT engine we ever ran up here, and it uses a stock head and stock gasket...You'd be better off looking at your
chambers....and working with lengths to "tune" for results. Remeber, if you are working with an effective compression ratio of more than 6.5 to 1,
you will begin to have MAJOR problems with flame propogation and combustion control. A stock engine is 6.4 to 1....
If you are looking to create a squish band, I do not recommend that you make the band area more than 50% of bore. Remember, as well, that there will always be a portion of the combustion charge that will not burn; this is the area of "wetted" exposure to the exposed area of the cylinder head. This layaer of combustible gas will simply not burn due to its (relative) coolness as it it cooled by its' proximity to the cyl head...when you create a "squish", you increase this area, and partly shroud the cylinder area from direct exhaust port access...further reducing flame propogation and exhaust travel. You would be best served, if working with a squish, is to work with exisitng flame travel ...and modify that propogation channel to better direct it into the exhaust port...by changing the shape of the combustion dome....To do this you need to be able to read the flame track across the piston top and the cyl head...and then adjust as required. Remember that the ignited charge travels UP into the dome, then crosses the intake charge in a "Swirl" that both mixes the incoming charge and moves both it INTO the exhaust chamber, then is drawn back into the chamber where the closing post "traps" the mixed charge and ignites it...and so on. If you don't have it, I strongly recommend Gordon Jennings book, "Two-stroke Tuners handbook. This guy forgot more than most two stroke builders ever learn! Book was published by H.P. Books. Regards, Tom in Toronto |
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Xpit77 |
Thanks | #2 | ||
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Registered User
Posts: 24 10/06/08 16:59:02 |
Thanks Tom,
You always give me good advice. I guess I should have emailed you directly.I will Google that book and get a copy. Thanks, Steve in Kingston |
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Jack Marr |
#3 | |||
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Registered User
Posts: 20 10/07/08 09:23:43 |
I've got an extra copy of Jenning's book. PM me if you want it.
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Brownslane.diasio |
The best book | #4 | ||
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Registered User
Posts: 66 10/07/08 10:22:12 |
The Jennings book I have is dog-eared and a little dirty on a few pages. IF I were to only have one book that I could refer to regarding 2 strokes...this would
be the one. Not only chock full of info and practical application, it is written in a way that makes it easy to understand.
Jack, thanks for posting...I kinda thought I was the only die-hard two stroker out there. Thanks for making me feel a little more like I'm part of a "crowd" hehe Regards, Tom |
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Xpit77 |
squish head | #5 | ||
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Registered User
Posts: 25 10/11/08 15:52:14 |
Thanks for the offer Jack. I found a website where I could download the book in return for a small donation. I have been reading it and trying to digest some
of the info.
Tom, you will always be a member in good standing in the 2 stroke WB club. Cheers, Steve in Kingston. To all of the Canadian Apexspeed people, Have a great Thanksgiving holiday this weekend. |
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speedsports |
2 stroke tuners handbook | #6 | ||
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Registered User
Posts: 34 11/10/08 23:52:24 |
I found a free copy of 2 stroke tuners handbook at edj.net/2stroke/jennings/ I Googled Gordon Jennings and found the sight.
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Xpit77 |
2 strokers | #7 | ||
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Registered User
Posts: 26 11/17/08 16:42:41 |
Tom and Lee .
What engine and tranny oil do you use ? Steve |
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Brownslane.diasio |
Memory fading..... | #8 | ||
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Registered User
Posts: 82 11/18/08 16:44:51 |
Steve, I'll see if I can find my setup book to find out what lubricants I used. I remember BelRay for the pre-mix (I removed the SRIS system), Not sure
what else I can remember
Regards, Tom |
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Xpit77 |
Lubricants | #9 | ||
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Registered User
Posts: 27 11/18/08 18:14:19 |
Tom,
I use BelRay too. I just thought I would toss out that question to see what others used..Repsol, Castrol etc. I marshalled some bike races at Shannonville and the two stroke 125`s and 250`s used some oil that smelled like a combination of dead fish and cough syrup.Still trying to track that product down. I`m sure it`s a good product if their using it. The reason being is that, sometimes when I`m in an AutoX newbies and ricers ask me why my car is smoking abit ? I tell them it`s a 2 stroke and then I see this confused look on their face . So, when I`m waiting in line to launch I like to crack the throttle a couple of times to let the cars behind me know what a 2 stroke is. Now, if I can only find that smelly oil. I am easily amused. Steve |
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Brownslane.diasio |
Abnoxious | #10 | ||
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Registered User
Posts: 116 12/15/08 11:19:09 |
Ahhh memories....the difference between you and I is that you probably need a loud and smelly car to be abnoxious.....I found out that, even racing a four
stroke, people still think of me as noisy and smelly!! hehehe
Tom |
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Jack Marr |
#11 | |||
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Registered User
Posts: 22 12/15/08 11:29:34 |
A few years back I found a part can of Castrol "R" in the garage. A spoonful in the mower gas tank made trimming the yard a lot more fun!!!
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Xpit77 |
smelly 2 stroke oil | #12 | ||
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Registered User
Posts: 30 12/17/08 16:38:03 |
Hmmm.
Interesting concept Jack. So, if I was to put some smelly 2 stroke oil in the fuel of my lawnmower and, cut the grass in my backyard while my neighbors were having a pool party / family bbq it may disrupt it somewhat ? I guess the downside would be that I would have to pull the spark plug out and clean it or maybe buy a new one.....No Pain...no gain. Wind direction would be the critical element in this plan. To everyone on this board have a safe and happy holiday season. See Ya, Xpit77 |
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Jack Marr |
#13 | |||
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Registered User
Posts: 23 12/23/08 18:20:11 |
If these folks do not appreciate the nasal nectar of "bean oil" they obviously have no soul and are not worthy of living near you. |
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Brownslane.diasio |
That smell, that smells smelly! | #14 | ||
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Registered User
Posts: 121 12/24/08 14:24:28 |
For years, as I ran premix, I would dump the "mixed" fuel in my lawnmower, rather than risk some type of oil separation and then finding the melting
point of aluminum. "That smell" would (no lie) raise my heart rate just a little....and the old LawnBoy would run just as fine as it could...
That smell (like the cockpit of my Dad's aircraft or the interior of an old Jaguar) still takes me back in time.... Ya, my wife kinda thinks I am wierd.... Tom in Toronto |
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George Dean |
#15 | |||
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Registered User
Posts: 211 12/25/08 14:22:59 |
Oh yes, My first Daytona race in 1979, nothing better than the smell and sound of a TZ750 in the morning.
George |
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KMA4444 |
#16 | |||
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Registered User
Posts: 396 12/25/08 14:38:58 |
Love the smell of a bit of racing gas in the ol' mower. With some premix it takes me to my MX days.
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Xpit77 |
olfactory | #17 | ||
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Registered User
Posts: 33 12/30/08 17:19:56 |
Why is it that. When we go to a track, we can smell 5 or 6 different car related things and can describe each one in detail but can`t remember the smell or the
name of the perfume you bought for your wife or girlfriend ????
Steve, |
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Brownslane.diasio |
I know why!! | #18 | ||
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Registered User
Posts: 130 01/05/09 17:33:59 |
Because the human male cannot describe the scent of FEAR!!! hehehe
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Xpit77 |
#19 | |||
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Registered User
Posts: 36 02/08/09 10:36:51 |
Fear is how I felt when one of my EX GIRLFRIEND`s wore her favorite perfume........ Chanel # 666.
Still looking over my shoulder, Steve. |
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johnmccann |
A747 | #20 | ||
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Registered User
Posts: 230 06/06/09 12:12:24 |
No, not the plane, but I am convinced A747 is the best 2-stroke oil - period! Developed in the hay-day of 2-stroke GP racing it is specifically for racing,
water cooled, 2-stroke engines. It is 2/3 synthetic, 1/5 castor oil + addatives. Synthetics do things the castor oil will not and vice versa - thus combining
the two is a winner. ...AND YES, IT IS EXPENSIVE around $20/liter, which means you pay $8-10/gal for race gas + $2.35/gal for 747 (@32/1 mix). Oh well,
who's counting?
Well one racers opinion. John McCann '75 McCann ME-4B DSR PS Blew up my Ocelot 760cc trick motor (38-40 Lectron's, squish head, close ratio, etc.) on the dyno, now getting ready my Ron Grant 738cc motor w/Mukini's. I am blessed with Paul Decker's winning pipes :-)
Last Edited By: johnmccann 06/08/09 14:33:47.
Edited 1 time.
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