Missing oiljets in inlet tract!

[lasse]

Hello guys!

I have a ported cylinder, where the oiljets in the inlet tract has been removed. I've been told that they might not be neccessary, is this true?

If not, I'd like replacements.

[tz375]

I usually punch them out when I port a barrel and don't re-fit them.

I would speculate that they are designed to release oil into the fastest moving part of the airstream (at full throttle) but at street throttle openings, the highest airflow is at the bottom of the bore under the slide, so it probably makes little difference.

[Vintageman]

I envision better oiling if they are in: 1) Air flow is near zero at the surface and 2) with them in the diameter of the oil hole is smaller. If you run the oil pump with a drill you will see with smaller hole the oil will shoot up a ways. I don't think it will with larger hole you will get that affect. I remove them for porting but put back in. maybe not always as high if they block flow that depends where they were placed to start (some are centered well in front of divider some not). Also on twins, not 100% sure if that changes oil metering between crank and cylinders... should check that.

my 2 cents

[oldjapanesebikes]

... I remove them for porting but put back in. maybe not always as high if they block flow that depends where they were placed to start (some are centered well in front of divider some not)....

So for clarity - you have been able to remove and re-install the brass injector oil probes on the Suzuki GT750 block ?

[Vintageman]

The ones I have removed for mild porting/smoothing and reinstalled on Suz

73- GT550
72 T350
74-GT250

GT185 ( Not 100% sure. I opened that one up quite a bit to match 22mm carb from 20mm and had to blend all the way down to liner. and would have moved if in the way).

T305 jugs: I added these from spare GT250 to be like T350 blocking the hole in liner below intake (T305 like T500).

74 GT380 (Did not remove for no need. it was centered well in front of divider and near piston. Nice! And GT380 has decent intake passage area)

I did not remove from my 75 GT750. I only opened up the first 3/4" to match rubber boot. Yes they are in the middle of one of the two passages but, near the end

I see no reason why they can't be removed? You need a longer punch to reach. I think GT550 was in ways too, but not as far. That allowed me to put back in not quite as high My punch set just reached gt550 and was just barley enough to push out. Punch would not reach the GT750 ones. I had access to precision pins if I wanted to push them out, but as stated did not try for passage looked pretty good for stock

After I punch out I run the proper drill size to remove any mushrooming. They tap back in a little easier of course, but still very snug.

Mike