• Required reading for all forum users!!!

    Welcome!
    Register to access the full functionality of the GSResources forum. Until you register and activate your account you will not have full forum access, nor will you be able to post or reply to messages.

    A note to new registrants...
    All new forum registrations must be activated via email before you have full access to the forum.

    A Special Note about Email accounts!
    DO NOT SIGN UP USING hotmail, outlook, gmx, sbcglobal, att, bellsouth or email.com. They delete our forum signup emails.

    A note to old forum members...
    I receive numerous requests from people who can no longer log in because their accounts were deleted. As mentioned in the forum FAQ, user accounts are deleted if you haven't logged in for the past 6 months. If you can't log in, then create a new forum account. If you don't get an error message, then check your email account for an activation message. If you get a message stating that the email address is already in use, then your account still exists so follow the instructions in the forum FAQ for resetting your password.

    Have you forgotten your password or have a new email address? Then read the forum FAQ for details on how to reset it.

    Any email requests for "can't log in anymore" problems or "lost my password" problems will be deleted. Read the forum FAQ and follow the instructions there - that's what we have one for...

  • Returning Visitors

    If you are a returning visitor who never received your confirmation email, then odds are your email provider is blockinig emails from our server. The only thing that can be done to get around this is you will have to try creating another forum account using an email address from another domain.

    If you are a returning visitor to the forum and can't log in using your old forum name and password but used to be able to then chances are your account is deleted. Purges of the databases are done regularly. You will have to create a new forum account and you should be all set.

Compression numbers and pinging

  • Thread starter Thread starter gearhead13
  • Start date Start date
G

gearhead13

Guest
So, I did my first compression test after my rebuild ~1000+ kms done so far. Got 150-160 psi from all, one of them required a few more cranks to get to 150. All dry.
On one of my last rides I noticed a new noise at 7k- redline, but I couldn't pinpoint it. I thought it may be pinging:confused:
From my auto days, pinging usually occcurred at lower rpms when you stepped on the throttle. Could I be getting pinging at these rpms (if my main jet is too small I am thinking) I havent done high rpm plug chops lately, since I installed my new carbs. I am a bit worried cause I dont want to break or burn something. I have a 137.5 mikuni main on the 34mm carbs. Plug look real good and tanned.
 
I just did the 1168 kit, and so got my feet wet with CV's and jetting. Chef was backing me up all the way with help from Rapid Ray at the Julian base camp :o.

You should be able to pull hard to red line otherwise the jets are not right. That is the first step. Your needles don't matter till it pulls strong to 9-10K (what's redline :eek:).

Another thing is I had to run Premium with the 1168 kit at 10.25:1 .

Make sure your ignition is in good shape. I did the Coil relay mod to power my Accel coils Dyna S as well.

I has bobbling at high RPM and MID RPM at different time. It seems to be much different that cars (at least in my experience).

For a while I was wondering if we would get it sorted. Now it purrs.

JIm
 
Take a pic of the threads of the inner two plugs. If you have color on the threads above three threads go up on the mains. Maybe even a 142.5. Start rich and work lean. As I said before I almost melted a head trying for peak performance instead of keeping an eye in combustion temp.
Are you running a stock ignition? I forget.
Also if you are running high compression pistons you need to run high octane fuel.
 
Thanks for the replies, guys. I ALWAYS run premium 94 octane. I have color maybe 6 or 7 ? threads up on the plugs:confused:
It pulls real nice n' hard right from 4k rpm up to and past redline. I have the dyna coils with coil relay mod and stock ignition. The next set of mains I have are 145's. I will drop them in and see how it runs, at least it will give me an idea. People tell me 137.5 is way rich now, oh well what do I care what they think, eh?
 
With six to seven threads you are asking for trouble.
I have some jets I can send you. PM me
 
Thanks for the offer, Chef. I put in a set of 145's today, and it runs pretty good, not overly rich or anything. Actually if my butt dyno is right it is making better power. Checked a plug when i got back and they look the same, would have done a plug chop but pretty hard to do at rush hour.
 
Im still learning my carbs, but i just dont see how you can be lean pushing an 816cc mill with 34mm carbs at 137.5 main jets. Thats bigger than what im running in my 1100... :confused:
 
gearhead13 said:
Thanks for the offer, Chef. I put in a set of 145's today, and it runs pretty good, not overly rich or anything. Actually if my butt dyno is right it is making better power. Checked a plug when i got back and they look the same, would have done a plug chop but pretty hard to do at rush hour.
Click to expand...
You'll need new plugs to check the heat range with the new main. Once the threads are heat colored it's there to stay.
 
Gearhead

Gearhead

So what was done to the head? How far oversize on the valves?

My 1168, ported head with 28/23 mm valves (95 cfm flow at 0.340) is running 145 and seems quiet happy with about 2 rings of heat.

Bill with nearly same motor but 28.5/23 valves (less radical port job) is now running 152.5 1-2 rings of heat now (Bill to confirm)?

So seems even with the same valves and engine(carbs, cams, pistons) , the port job is making a difference.

Bill and I still need a show down where hopefully I'll stay in gear. Bill be forewarned if we get to redline in 3rd I'll probably back off :oops:

Pos
 
The valves are stock size with a back cut. I worked on the head for a few weeks on and off removing unwanted aluminum from the ports:rolleyes: Not hogged out, just nicely smoothed out and radiused.
The idea of putting a larger carb on a smaller engine makes it so there is less of a signal to the carb fuel passages, making it need a larger main to let in enough fuel with the lessened signal to the main jet. (my assumption)
That said, it is really hard to tell, but it could go to a 140 or 142.5 and be happy. Doesnt seem to wind out as fast on the very top, but lots more in the midrange. I will go and buy some new plugs and drop them in. How long til the plug threads are colored again?
 
Doesn't seem to wind out as fast on the very top, but lots more in the midrange. I will go and buy some new plugs and drop them in. How long til the plug threads are colored again?
Click to expand...

Maybe someone will chime in (Bill how are the Lakers doing) but you need to 1.) get a strong pull to red line then leave the main ALONE and 2.) then and only then move on to the needle. In other words don't worry about mid range till you have it pulling strong to red line.

The Factory pro directions for CV;s said this pretty much exactly. So unless you go back and fix that you will be futzing :( Posted here just last week.

Jim
 
It pulled strong to redline with the 137.5's, but apparently a little lean.
But what I did learn is that I needed to be richer in the middle. And at least now I dont have to worry about frying my engine.
If you can spare them, Chef that'd be great.
Richard
 
You must log in or register to reply here.
Back
Top