Author Topic: son of a b!#$% (Read 17884 times)

C-Leigh Racing · « **Reply #45 on:** March 05, 2015, 11:15:27 AM »

Where are all the powders made at, here in the USA or overseas ?.
Neil

udontknowme · « **Reply #46 on:** March 05, 2015, 11:28:35 AM »

Quote from: dem3500;51010

annealing of aluminum is is in the 350deg-400deg range depending on the type of aluminum.

where did you get that info ? It doesnt match the info I have

dem3500 · « **Reply #47 on:** March 05, 2015, 11:40:53 AM »

Quote from: udontknowme;51024

where did you get that info ? It doesnt match the info I have

Some google searches and a little of what I remember from my metallurgy classes. I'm not claiming I'm 100% right either lol

TRXjeeper · « **Reply #48 on:** March 05, 2015, 01:41:38 PM »

I powder coated a few set of cases and haven't had any problems yet, Maybe they put you case in a burn off oven. I measure a set of cases with our CMM before and after a typical heat cycle.

Jerry Hall · « **Reply #49 on:** March 05, 2015, 03:02:52 PM »

Quote from: udontknowme;51007

anyone know what series of aluminum the cases might be and if its tempered at all ? for aluminum to anneal i think it would need to be more like 600f-1000f depending what kind it is but thats not to say it wouldnt start warping or change shape at a lower temp. then factor in that it was in a oven for several hours

Cylinders and heads that are sand cast are usually made from A356 or an alloy that has similar chemical mixture .

OEM cases, clutch covers etc are usually made using a process called die casting which uses metal moulds. The alloys used for die casting typically has a high silicon content but varies depending upon the complexity of the mould, strength needed, time it takes to fill the mould and pressure of the molten aluminum.

udontknowme · « **Reply #50 on:** March 05, 2015, 08:16:10 PM »

Quote from: dem3500;51025

Some google searches and a little of what I remember from my metallurgy classes. I'm not claiming I'm 100% right either lol

i guess it could be 350f but then again it could be much higher. without knowing the material its almost impossible to say for sure. there seems to be a very large annealing temp range. even if it doesnt reach the anneal temp maybe it could still distort the item ? ive got some old cases (not honda) and im thinking they might be forged. ill have to take a closer look one of these days.

C-Leigh Racing · « **Reply #51 on:** March 06, 2015, 09:48:24 AM »

If I remember right, OEM Honda TRX250R cases are injection die cast & it could just be a run went through, with a different type of aluminum than normally used ( some of our jets shot down in war time & scraped ) & this is the results showing it.
All those area where bearings are to be installed, need to be carefully measured to see how much they have expanded. I might could be, they could be PCed on the inside & then the bearing areas cleaned up & bearings pressed in. How thick does the PC coat build up ?.
Theres got to be some way to repair them that wont break the bank.
Neil

dem3500 · « **Reply #52 on:** March 06, 2015, 09:54:33 AM »

I'd have to spray something and then cross section it to measure but I'd guess .010 give or take .005. Just my off the wall guess. I'm spraying this weekend so I'll spray a scrap piece and measure

Jerry Hall · « **Reply #53 on:** March 06, 2015, 01:25:57 PM »

The interference fit should be .0015" to .0020" on the main bearings. Fitting the bearings any tighter than .0020 will usually cause the outer race to shrink enough to cause the bearing to bind and cause it to overheat and fail. Out of round bearing pockets will also cause the bearings to overheat. I have not found any hand calipers that will accurately measure bearing pockets. It is best to use a bore gage that has .0001" resolution when measuring bearing pockets.

I have tried a lot of products over the years to try to fix loose bearing pockets. Some work a little longer than others but not of them have been a permanent fix other than resleeving the bearing pocket

JesseA420 · « **Reply #54 on:** March 06, 2015, 02:42:20 PM »

general rule of thumb is .001" PF per each inch of bearing diameter.

Jerry Hall · « **Reply #55 on:** March 06, 2015, 04:45:20 PM »

Quote from: JesseA420;51072

general rule of thumb is .001" PF per each inch of bearing diameter.

Is that for C3 or C4 bearings?

JesseA420 · « **Reply #56 on:** March 06, 2015, 05:28:34 PM »

c3.
c4 would be .0015". general apps like PF on inner or outer only, not both. of course depends on the application thats why i said generally.

croat1 · « **Reply #57 on:** March 07, 2015, 05:38:46 AM »

Quote from: d-rock;50964

I had the engine assembled last 2 weeks ago. But the paint looked shity , so I pulled it apart again and sent the cases out. All of the new bearings were tight in the cases, now they are loose. There is no power on the inside at all. It was taped off. The power coating is called sparkle silver. Then cleared. I don't know if it was actually powder coated twice, maybe that was the problem. Too much heat maybe.
The cases are from a 85 atc engine that has never ran but was assembled.

how was the paint removed....were the cases chemically dipped to remove the paint prior to powdercoat?

d-rock · « **Reply #58 on:** March 07, 2015, 12:41:19 PM »

cases were bead blasted, but not on the inside, still has factory overspray inside.