Author Topic: Determining rod length while bottom end is still together? (Read 3890 times)

daydustin78 · « **on:** May 09, 2015, 04:55:39 PM »

You can see in my info I guess (just joined a minute ago) as to what I am working with. 85 atc bottom end but am unsure of what was taken off the top end and while it should be a short rod maybe a custom build with a long rod? Trying to track down what I need on the cheap and the sooner I know what I have to work with the better. Hoping to reuse the crank/rod assembly (no discernible play up and down on rod) so if there was a measurement I could get while it is assembled that would be great! I will be doing a complete breakdown and reassembly with new bearings and seals throughout. Already got a jug and head I will have to caliper it at work but while I cannot remember the advertised current bore I seem to remember that I would probably have to take it to a 68 1/2mm. Already have an esr pipe (mid too low end) but have no idea how to proceed with a matching affordable carb (with appropriate jetting) and reed block intake setup. Also I need all the plastics/mounting brackets but they are definitely more then I want to spend. Wife says I need a hobby and I don't know anything about quads or two strokes but I like wrenching and learning so here I go :shame:.

Jerry Hall · « **Reply #1 on:** May 09, 2015, 07:17:34 PM »

If the piston is a 85-85 piston and it does not need a spacer plate under the cylinder to keep the piston from hitting the head, you have a short rod.

Remove the reed valve so that you can see the intake skirt of the piston.

The 85-86 piston has a half moon shaped cut out in the intake skirt of the piston. The 87-89 piston has a full skirt with a window about half way up the skirt.

daydustin78 · « **Reply #2 on:** May 10, 2015, 10:21:33 AM »

Sorry, I probably should have clarified that this is only the bottom end with no piston on the connecting rod. So these checks don't work for me. Was hoping someone just happened to have their top end off and could pull a quick measurement from those drum thingies to the top of a known short or long rod that I could compare to.

Usmoneylover · « **Reply #3 on:** May 10, 2015, 11:01:22 AM »

What are the numbers on the rod, that should tell you what you have.

Skeans1 · « **Reply #4 on:** May 10, 2015, 01:30:02 PM »

http://www.eddie-sanders-racing.com/category_s/113.htm
That'll tell if it's a long or short rod

daydustin78 · « **Reply #5 on:** May 10, 2015, 03:38:17 PM »

Thank you very much!

daydustin78 · « **Reply #6 on:** May 13, 2015, 10:45:03 PM »

It has the Honda KA4 but I can't find any the reference or info on the last number which is a 5. Or does it have any significance at all?

Jerry Hall · « **Reply #7 on:** May 14, 2015, 04:24:41 PM »

Quote from: daydustin78;54322

It has the Honda KA4 but I can't find any the reference or info on the last number which is a 5. Or does it have any significance at all?

The KA4 is the short rod from the 85-86 engines