• 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.

Main jet size on 1135 engine

J

John Kat

Forum Sage
My 1100 Katana runs with an 1135 engine inside.
The BS 36's carburation is spot on except at WOT.
I have to "nurse" the throttle around WOT to get more power.
I'm running with the complete OEM air filter setup, new carb boots and 120 main jets as per the OEM spec.
The exhaust is the OEM Katana exhaust.
I noticed that in some places the spec for the main jet is 120, 122.5?
I suppose this means that two carbs get a 120 jet and the others the 122.5?
Which ones get which?
Could this be the issue?
Katana1100SZ007_zps3abfc7c3.jpg
 
John Kat said:
My 1100 Katana runs with an 1135 engine inside.
The BS 36's carburation is spot on except at WOT.
I have to "nurse" the throttle around WOT to get more power.
I'm running with the complete OEM air filter setup, new carb boots and 120 main jets as per the OEM spec.
The exhaust is the OEM Katana exhaust.
I noticed that in some places the spec for the main jet is 120, 122.5?
I suppose this means that two carbs get a 120 jet and the others the 122.5?
Which ones get which?
Could this be the issue?
Katana1100SZ007_zps3abfc7c3.jpg
Click to expand...

It sounds like you should be setup pretty close to a stock 1150 (or the 84-85 GSX1100 in Europe.) The 122.5's would be on the two inner cylinders as they run hotter. Other than a little less lift on the cams and a 1mm smaller intake valve you are pretty much at where the stock 1150 is.


Are you sure you do not have an ignition problem? Also even with a stock bore on my 83 GS1100 (but pods,pipe and cams) I would run out of gas due to petcock flow limitations (sustained high speed in 4th or 5th gear). I went to a pingle and problems solved.

The difference between 120 vs. 122 would be hard for you to tell at WOT unless you had an O2 sensor or were an expert reading a plug
 
John Kat said:
I noticed that in some places the spec for the main jet is 120, 122.5?
I suppose this means that two carbs get a 120 jet and the others the 122.5?
Which ones get which?
Click to expand...
Yes, the outer carbs get the 120s, the inner ones get the 122.5s.

.
 
posplayr said:
It sounds like you should be setup pretty close to a stock 1150 (or the 84-85 GSX1100 in Europe.) The 122.5's would be on the two inner cylinders as they run hotter. Other than a little less lift on the cams and a 1mm smaller intake valve you are pretty much at where the stock 1150 is.

Are you sure you do not have an ignition problem? Also even with a stock bore on my 83 GS1100 (but pods,pipe and cams) I would run out of gas due to petcock flow limitations (sustained high speed in 4th or 5th gear). I went to a pingle and problems solved.

The difference between 120 vs. 122 would be hard for you to tell at WOT unless you had an O2 sensor or were an expert reading a plug
Click to expand...

You are right, it feels like fuel starvation!
The ignition seems OK and the spark plugs are new.
I did the tests in 4th and 5th gear at well over 100 mph:rolleyes:
I'm not sure I understood the differences you are mentionning about the smaller intake valve between the different bikes?
Did the 1150 come in different versions?
Many thanks for the input:)
 
John Kat said:
You are right, it feels like fuel starvation!
The ignition seems OK and the spark plugs are new.
I did the tests in 4th and 5th gear at well over 100 mph:rolleyes:
I'm not sure I understood the differences you are mentionning about the smaller intake valve between the different bikes?
Did the 1150 come in different versions?
Many thanks for the input:)
Click to expand...

I'm assuming your 1100 kat has a stock head which came with 27mm intakes, the 1150 came with 28mm intakes. The 1100 Kat also had close to the same valve lift as the 1150. A ported head can significantly improve the flow.
 
Last edited:
In fact my engine is a true 1135:)
According to the engine identification number it should originate from a GSX 1100 EFF from 1985?
I'm eager to test it again with the proper fuel flow!
 
John Kat said:
In fact my engine is a true 1135:)
According to the engine identification number it should originate from a GSX 1100 EFF from 1985?
I'm eager to test it again with the proper fuel flow!
Click to expand...
Humm.......... I assumed you had an over bore kit. The head appears to be from 1100 which would probably be 82-83 head with 27mm valves. This must be some type of European version as the 83 manual for the SD Kat is not 1135 cc but the same 1074 cc as all the other 1100e's
 
Last edited:
John Kat said:
In fact my engine is a true 1135:)
According to the engine identification number it should originate from a GSX 1100 EFF from 1985?
I'm eager to test it again with the proper fuel flow!
Click to expand...

If the motor is the one in the picture you posted above, that is not an EF 1135 motor (well, the head certainly isn't).

As for the jetting, stock mains for the EF are 120/122.5 as stated by the others.

Are you running a fuel filter or anything else that might impede fuel flow? This could be an issue if the problem is only at high RPM / WOT.
 
What does the front of the block say?
That is not an 1150 head as stated.
 
hillsy said:
If the motor is the one in the picture you posted above, that is not an EF 1135 motor (well, the head certainly isn't).

As for the jetting, stock mains for the EF are 120/122.5 as stated by the others.

Are you running a fuel filter or anything else that might impede fuel flow? This could be an issue if the problem is only at high RPM / WOT.
Click to expand...
You guys are making me doubt about my engine:o
As I bought the bike from a guy who used to do drag racing, I suppose every combination is possible...
I guess the engine has been prepped one way or the other?
When I rode the bike two days ago, I was amazed at how easily the bike revved when you blip the throttle to engage a lower gear?
Not at all like my other GS's...
With respect to fuel starvation, yes there is an inline fuel filter.
I'm concerned about running without one but at least I could easily replace it and try again:)
 
John Kat said:
The block is stamped 1135.
I suppose the head is from a GS 1100?
Does that give me more CR?
Click to expand...

If someone was smart enough to swap out the 1074 block for a 1135 block they probably did other things to the engine as well. You could have an 1150 crank in there with a set of stock 1135 pistons (20mm pins v.s. 18mm for 1100) that came with the block. Given all that it would not be a big surprise if there was some head work done including putting 28mm 1150 valve into that head if all that were the case then they probably threw the 1150 cams in as well.

Have you had the valve cover off to measure the lobes or see if there is a cam gear? The 1150's were electronic ignition so there was no cam gear. All of the ED/ESD bikes had gears on the cams.
 
posplayr said:
Have you had the valve cover off to measure the lobes or see if there is a cam gear? The 1150's were electronic ignition so there was no cam gear. All of the ED/ESD bikes had gears on the cams.
Click to expand...
No I haven't opened the valve cover yet.
I thought all GS's post 1980 had electronic ignition?
Where are the cam gears supposed to be?
Sorry for the ignorance on the 16v bikes...
 
You must log in or register to reply here.
Back
Top