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Can Never Be Another GDC
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Discussion Starter · #1 · (Edited)
Ok, now what are the chances that the 2 750 motors I purchased would have 18G (1000) cams in them. I just took one apart 2 months ago and it had 18G cams, and the one I just put in my bike also had 18G cams.

WTF!!!
 

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Can Never Be Another GDC
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Discussion Starter · #3 · (Edited)
Yes, I did not run the first motor I simply tore it apart and suprisingly it had 18G cams in it. The second 750 motor I have that I just put into my bike is running like shit. I took off the valve cover and it has 18G cams..... It is timed correctly, but is not running right at all probably because of the 1000 cams. Its half choking itself out, and when I stop the motor atomized fuel/air vapor comes out of the exhaust and rises out of the intake bodies, so it is DEFINATLY a timing issue.

My wonder is why would someone put them in there if its making it run like crap? I also now have to find 2 sets of 750 cams because I have 2 sets of 1000 cams lol, I thought this was going to be simple =p
 

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Can Never Be Another GDC
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Discussion Starter · #4 ·
01-03 and 04-05 750 cams are the same correct? I know 2000 and under are different, but I need another source confirming that 01-03 has the same profile as the 04-05. I have a pair of 01-03 I may use for now.
 

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Engine Tuning God
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GSXR6BOY said:
01-03 and 04-05 750 cams are the same correct? I know 2000 and under are different, but I need another source confirming that 01-03 has the same profile as the 04-05. I have a pair of 01-03 I may use for now.
00-03 750 cams are the same profile
04-05 750 cams are different. longer inlet duration, shorter exhaust duration and a touch more inlet lift than 00-03.
Have you tried mapping the fuelling with the 1000 cams in. Should work fine.
 

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Engine Tuning God
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When you say its timed correctly, is that with degree wheels fitted or stock sprockets lined up on the markers as per manual?
If stock sprockets, then that might be the problem. Although many of the cams will swap over, the distance between cam centres is not the same on all the motors and hence the timing could be miles out.
 

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Can Never Be Another GDC
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Discussion Starter · #8 · (Edited)
First off, thanks you Tim for coming in here. I am sure you could at least shine some light on this since you build motors.

Stock sprockets. When I turn the crank to the timing mark and look at the cam sprockets, they are timed correctly. Now won't 1000 cams will be slightly off in a 750 to begin with because of the different deck height, or does the next pin on the chain perfectly make up for the difference??? (I hope that makes sense) I did pull the spark plug from the closest cylinder, and I watched the timing relation between the piston top and the valve open/close points. It did seem to be off a little, but without proper tools I don't know how to verify that.

I guess the questions I should ask is, will putting bone stock 1000 cams in a 750 work as far as timing is concerned. Second, will it cause the engine at low rpms to sort of choke out, and almost start to breathe backwards, but aid in top end power? I am just concerned because I had an experience with my 600 that with improper cam timing it ran exactly like this.

The exhaust pulses start to get worse sounding if I rev it up a few throusand rpms. It also sounds like the engine starts to knock (not piston slap). Maybe I should put the other 1000 cams in there, maybe these sprockets are degreed wrong?
 

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Engine Tuning God
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Its impossible to guess at what might be where. Obviously i check things with degree wheel and dial gauge but not everyone has this equipment. Making assumptions on timing might cause you a headache and sore wallet.

Just looking through the manuals i have here on my laptop (near midnight here, so i've been home about 2 hours!!) and they show the following for cam alignment
03 750 14 pins apart
06 750 12 pins apart
05 1000 14 pins apart

Now the 01-04 1000 heads are the same as the 00-03 750. I've not tuned an 04 750 so can't confirm they are same but i'm sure the intake valve is slightly bigger so maybe the ports and head are different.

I did drop some 03 1000 cams into my 03 750 and the timing was poor showing decreased power until peak power, maybe suggesting cam timing was out quite a bit. I did try running the inlet cam back a tooth just to see what happened and got piston to valve contact and terrible low rpm running to the point where it wouldn't tick over. Sounds a bit like your issues so maybe this might help you a bit. Just hope the knocking you here is not ptv contact. Does your bike tickover ok? If so as what rpm?
 

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Can Never Be Another GDC
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Discussion Starter · #10 · (Edited)
I don't think its ptv noise, mechanically it sounds good, but the exhaust pulses are not constant. If this makes sense, instead of a vvvvvvvvvvvvvv sounds it is more like vvvvbvvvvvbvvvvbvvvvvbvvvvv. I believe the 04-05 750 heads are the same as the 01-04 1000 heads, minus the titanium valves, but the deck height is different between the 750/1000 so the chain is a factor right? It may be a few degrees off because your starting the timing higher on the chain, so where the pin at which the 1 marking slips into on the 1000 sprocket might end up being a gap on the 750 setup right? (Hope that makes sense lol)

I am going to put my 03 750 cams in there just to see if it clears up and runs decent. If it doesn't then I am thinking about just tearing the engine apart. I would really rather not do this though.

Maybe that is why this guy sold his motor, because he thought it was brokedid but it just needs some timing love.:biggrin I am going to make a sound clip of it, as well as study the valve/piston relationships again. I remember something looking like it was way off.
 

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Can Never Be Another GDC
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Discussion Starter · #11 ·
Took out the cams, and referenced them to other 18G cams that I had and they were not timed differently. Referenced them to 35F "03 750" cams I have and they were almost identical. By now I was skeptical that it is the timing, and am worried it is something in the bottom end. I put the 18G cams back in and made sure timing was correct. I then put her back together and started it up. The same thing is still happening.

One thing I noticed while working on the head was the oil looked slightly discolored, granted I have brand new oil in there.... it almost looks like there is a hint of a green hue. Mother F#%[email protected]! I say to myself, and I also verified this through the oil window. I will also post a pic of that. So, I believe it to be a possible bad head gasket :(

When I get home, I will post sound/movies/pics whatever.
 

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Can Never Be Another GDC
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Discussion Starter · #12 ·
Here is the coil "coolant-oil", mind you this oil has about 10 minutes tops of run time on it......also notice the wet spot on the header, thats because something is running down my header and dripping on the ground when the bike is running. Yay gaskets!
 

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Engine Tuning God
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1,773 Posts
The stuff that is running down. Is it oil or water based? I'm assuming oil or it would not show after running on hot exhaust.
Did you torque the head correctly?
Have you checked that any of the rubber gaskets on top of the head have been pinched?
 
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