top end noise

[redharley1200]

Just did a 883 to 1200 upgrade.... problem is I get it up to 3000 rpm and get a lot of noise in the FRONT cylinder, it sounds like the top end. If I back it down it sounds fine...idles great... I've checked to make sure the push rods are correct ( longer one is exhaust )... any suggestions ???

[wfolarry]

Did you change cams with the upgrade?

[claydbal]

was this a boxed HD kit, or did someone convert for you?

[TheNowhereman]

Check your lifter/valves for being set up too loose.
You could have a lifters that are not getting oil.

[redharley1200]

Originally Posted by wfolarry

Did you change cams with the upgrade?

I used the Stock cam

[redharley1200]

Originally Posted by claydbal

was this a boxed HD kit, or did someone convert for you?

It was a boxed kit

[redharley1200]

Originally Posted by TheNowhereman

Check your lifter/valves for being set up too loose.
You could have a lifters that are not getting oil.

You think I should use adjustable push rods ??

[claydbal]

my first check would be pinging. and i would eliminate that immediately.

[redharley1200]

Pinging ?? what do you mean ??

[RattFXR]

Clay is basically asking if the carb was jetted for the conversion. If you are running the already lean jets for and 883 in a 1200, then your air/fuel mix is way lean. THATS BAD. You will burn a hole in a piston quick. If all that was changed was the bore, then technically speaken, you shouldn't have any problems. If you have "top end" noise on a stock converted motor, then you should check out your oil. If your running a low level, it can cause the problem. If it's normal then try a higher viscosity such as a straight 50. This will stay thicker and help keep things snug. There are mean things that can cause this problem, but the air/fuel and oil are the first check. If you set the motor up, and the pistons are tight, then you might have an overheating problem which is causing the oil to break down and not absorb the heat, which will eventually melt a piston.....see the trend? Fuel (air/fuel ratio) cools the combustion chamber, and the oil cools and cushions motor. A converted 883 is basically the same thing as a 1200. If it ran right before the conversion, then it will run right again.

[claydbal]

two things came to mind.
1. going to 1200 and retaining the 883 heads puts the compression through the roof, installing 1200 kit (with 1200 heads) on top of stock cams may do the same, and with no overlap it would run hotter. both situations cause ping.

2. as mentioned, lack of tuning. timing AND fuel need to be addressed, not doing so-------ping.

[redharley1200]

I guess I should have been a little more specific about the the build....sorry, like I said I'm a newbie....here's what I got .....883 with 1200 conversion kit (cylinders, pistons, rings) S&S (e) Carb 0with thunderjet set-up, H-4 crane ignition. I started with Mobil One 20w-50w took that out and went straight 50w with some Lucas additive.The sound I hear is more of a knock, than a ping....almost like a rod knocking but coming from the top end. Like I said it doesn't do it until I take it over 3000 rpm.

[wfolarry]

I haven't done an 883-1200 conversion in a long time so I'm out on a limb here but I'll throw out a few things I remember.
They used to give you a template for opening up the combustion chambers to reduce the compression. Do they still do this? Or do the pistons have a dish top? Just trying to get a little more specific on what you did & maybe find the problem.

[Hillside]

Larry,
Wiesco(if that was used) offers a dished unit.
Scott

[redharley1200]

Don't remember off hand......I'm gonna pull it apart and find out. If something don't jump out at me I'm gonna turn it back into an 833 for the summer and re-do it over the winter.