Topic: 550 Engine Guru's, I Need Your Help!

[bryanj]

Fork look OK. Primary is not cheap BUT when worn it eats into the oil galleries and wears a hole which lets all the oil out---Not A Good Idea---my honest opinion is you are that far in do it right and leave it allone afterwards

[B.O.X.N.I.F.E.]

Fork look OK. Primary is not cheap BUT when worn it eats into the oil galleries and wears a hole which lets all the oil out---Not A Good Idea---my honest opinion is you are that far in do it right and leave it allone afterwards

Crank is out, primary is off! Glad too, found a badly scratched con. rod bearing, which begs the question...

How the hell do I pick a con rod bearing when ordering? Looking at the fiche there are A, B, & C types, with two different part numbers listed for each letter (guessing one is top, the other bottom?)

[B.O.X.N.I.F.E.]

Holy Crap, replacing this rod bearing is going to be hard. Can someone give me the run down on how to choose the bearing? My micrometer only goes to one decimal place, am I going to have to find a micrometer that goes into the thousandths? These are crazy tight tolerances requiring way more precision than my tools (or brain) can handle. 

[paulages]

your best bet is to take it to a machine shop with good tools and have them measure against specs. it helps to know if your journals and rod big ends are round before you go picking bearings. if your journals don't need polishing, you might be able to just replace the scratched bearing with the same size new one. the chart tells you how to figure out what bearings you have in there, based on the number and letter printed on the rod and crank. you can measure yourself using plastigage. i tend to think it's a pretty crude way of measuring, but it's always given me the same results (more or less) that mics and bore gauges have as far as clearances go. the range of tolerances on these is fairly wide. just make sure the rods don't move while you're torquing them down, or it'll screw up the reading.

once you measure what kid of oil clearances you already have, you can cross reference with the chart in the manual. they move in .004" increments, so if you have browns for example with too much clearance between the rod bearing and journal, you can move to black bearings. this is off the top of my head... i don't have a manual in front of me. if you are still confused, i or someone else can help if you give us precise numbers.

[bryanj]

The con rod has a number code and the crankpin a letter code to work out the size of shell you need

[B.O.X.N.I.F.E.]

Ok, let me see if I got this. The letters & numbers printed on the crank throws are NOT indicators of the bearings, but production codes. Same for the letters stamped at the back of the cases. Ignore them.

Rod bearing sizes are determined by A) Number code stamped on big end of rod and B) one of two ranges of measurements on the crank journal...

A: 34.99 - 35mm
B: 34.98 - 34.99mm

Looking in the manual, based on my con rod big end number (1), I would need either D (yellow), or C (green) con rod bearing, depending on how the journal specs out.

I think I can handle that. But doing it the above way would be a best case scenerio, or for setting up brand new parts. What if, say, the journal specs at 34.97mm? And none of the above accounts for wear in the big end of the con rod.

The journal is not scratched. And the bearing actually looks great other than one long deep scratch. A chunk of something nasty came in through the crank oil hole, scratched the bearing, without doing any more damage. Bearing did not spin.

[bryanj]

There should be letters on the crankwebs relating to the journal size as in the table, its not easy to get Hondas accuracy in measurments without air gauges.

If in doubt use the tightes tollerance shell and "run it in" for 1,000 miles

[B.O.X.N.I.F.E.]

There should be letters on the crankwebs relating to the journal size as in the table, its not easy to get Hondas accuracy in measurments without air gauges.

If in doubt use the tightes tollerance shell and "run it in" for 1,000 miles

With my caliper I'm getting 34.98 with .02 +/- accuracy for this tool, so there's no way to definitevly choose based on the reading.

My crankweb for this journal has "A 2" stamped on it. Guessing A for the bearing, 2 for some other production code unrelated to bearing size?

So if this is an A journal (34.99 - 35mm), and if it possibly has .01 of wear on it, which bearing would be the safe bet, Yellow (d) or Green (c)?

thanks, coudn't do this without your help!

[bryanj]

Me, I'd fit Green and run in carefully.

Before now I have fitted black (tightest tolerance) on all end and mains then run in for 2,000 and had no problems

[B.O.X.N.I.F.E.]

Me, I'd fit Green and run in carefully.

Before now I have fitted black (tightest tolerance) on all end and mains then run in for 2,000 and had no problems

Sounds good to me, I'll go with green.

What is the run in procedure? I'll have about 2 weeks to do any break in before I leave for my road trip. I can probably get a few hundred miles done before I leave.

[paulages]

Me, I'd fit Green and run in carefully.

Before now I have fitted black (tightest tolerance) on all end and mains then run in for 2,000 and had no problems

Sounds good to me, I'll go with green.

What is the run in procedure? I'll have about 2 weeks to do any break in before I leave for my road trip. I can probably get a few hundred miles done before I leave.

that's a big can of worms there... there are plenty of differing theories. the middle of the road seems to be to break in in like you ride it, being careful not to go too crazy for a bit and vary the rev ranges. my method is to use the first heat cycle (20 minutes or so) to make sure all reciprocating parts are happy, then change the oil also looking for metal to make sure all's happy. then i run the #$%* out of it, making sure to go heavy on engine braking. compression is what makes the rings seal, not the spring force of the metal. those first few miles are when the rings seat, and compression is important. i change the oil again after a couple hundred miles to look for shiny bits again.

break in procedure is like oil though.... ask and you'll get lots of strong opinions. 

[B.O.X.N.I.F.E.]

Me, I'd fit Green and run in carefully.

Before now I have fitted black (tightest tolerance) on all end and mains then run in for 2,000 and had no problems

Sounds good to me, I'll go with green.

What is the run in procedure? I'll have about 2 weeks to do any break in before I leave for my road trip. I can probably get a few hundred miles done before I leave.

that's a big can of worms there... there are plenty of differing theories. the middle of the road seems to be to break in in like you ride it, being careful not to go too crazy for a bit and vary the rev ranges. my method is to use the first heat cycle (20 minutes or so) to make sure all reciprocating parts are happy, then change the oil also looking for metal to make sure all's happy. then i run the #$%* out of it, making sure to go heavy on engine braking. compression is what makes the rings seal, not the spring force of the metal. those first few miles are when the rings seat, and compression is important. i change the oil again after a couple hundred miles to look for shiny bits again.

break in procedure is like oil though.... ask and you'll get lots of strong opinions. 

The rings were installed 1,800 miles ago and I went through a similar procedure to what you describe. Got good compression accross all 4.

bryanj said to 'run it in' when I install the new rod bearing, but I don't know what the bearing run in procedure is.

[bryanj]

Lots of oil on assembly,

get oil light out before starting,

Run for a MINIMUM of 15 minutes when you first start it unless you have a major problem

change oil and filter at 500 and 1,000 miles

When riding DO NOT let the engine lug down its better to rev momentarily than labour in a higher gear

[B.O.X.N.I.F.E.]

Appreciate it. Just placed my order, 175$ for a primary chain, two bearings, a handful of oil seals and two clutch plates. Ugh!

Will report back when it's all done.

[bryanj]

Sounds about same as here in UK, some years ago I found Austie sold chains a lot cheaper and a freind out there bought me a few and posted them