Yosh build part deux

[first timer]

the engine with the #'s is Craig Smiths 1200cc 8v motor, he is from new zealand they do things diffrent down there

I am basing some of my hole locations on his motor.

 

[first timer]

so here is a fun little exercise in math, (Jim this one is for you!)

here's a little table showing how much loss or gain in surface area can be achieved by drilling the fins.

To be noted a 1/2mm in any direction (height or dia) can really throw the numbers into a differant direction.

So basically if i went with 3/8 holes i would be comitting to a 19% loss in cooling from the material removed. Which is not to be confused with total effieceny loss in cooling of the entire motor. To calculate that I would need to know the surface area of the engine........ But basically it would be a lot less then 19% when you comapare the surface area being removed from the availabe surface area of the fins, ( i think anyways math is not my strong point and it's late here )

Ok back to actully doing work instead of playing on the computer.

 

[posplayr]

so here is a fun little exercise in math, (Jim this one is for you!)

here's a little table showing how much loss or gain in surface area can be achieved by drilling the fins.

To be noted a 1/2mm in any direction (height or dia) can really throw the numbers into a differant direction.

So basically if i went with 3/8 holes i would be comitting to a 19% loss in cooling from the material removed. Which is not to be confused with total effieceny loss in cooling of the entire motor. To calculate that I would need to know the surface area of the engine........ But basically it would be a lot less then 19% when you comapare the surface area being removed from the availabe surface area of the fins, ( i think anyways math is not my strong point and it's late here )

Ok back to actully doing work instead of playing on the computer.

Ryan,
I got close to the same answer, you must have truncated PI to only 3 significant digits .

So at 4mm if you drill 5/16" holes there is no loss in surface area
if the thickness is 3mm then it drops to less than 1/4". Bu then there is a loss in cooling efficency due to teh holes being too small.

I think you should do what ever Yoshi did and be happy with the replica, that is the point right?

Jim

 

[first timer]

yeah i think i will mix it up with 3/8 holes and 1/2 holes, probably use mostly 3/8 holes, at least see what it looks like, you can always go bigger right just not the smaller

 

[gs road racer]

quote

"I am going to replace my guides with bronze ones, found some from Kibble White, what do you guys think? Anyone else you like? "

Unless they're worn (not likely) stay with stock. This kind of setup wears very well as opposed to the 4 valve motor with tappets that impart some sides forces. Or you want to go to smaller stem sizes as Pops did back then.I had spoken with APE about that and they'd have to be custom valves gets a bit expensive.. although in 80 you could get a bike for $10k in todays dollars $50k+....all relative.

What I have found in my yosh motor was top end oiling problems the cam journals scored badly as did the head. I think the 750 gears which spin the pump 30% faster would be a good choice and they'll be in my next build.

 

[first timer]

Now you are making me feel guilty, motor is still in pieces and and it's almost been a year since my last post.

Was planing to do the bronze since i picked up some ss os valves and some TI retainers and under buckets. Was going to use bronze since it helps dissipate the heat and is a little more slippery then iron guides. I also don't think the OEM stuff I have is in full spec.

Have a set of 750 gears and was planing to use NOS cylinder studs not the oversized stuff.

A builder friend of mine also recommended getting cam assembly lube from the cam supplier and using that on virgin cams. He sezs the first 5 miles makes or breaks how the cams are going to wear and the right lube will impregnate the cam and help it wear well.

quote

"I am going to replace my guides with bronze ones, found some from Kibble White, what do you guys think? Anyone else you like? "

Unless they're worn (not likely) stay with stock. This kind of setup wears very well as opposed to the 4 valve motor with tappets that impart some sides forces. Or you want to go to smaller stem sizes as Pops did back then.I had spoken with APE about that and they'd have to be custom valves gets a bit expensive.. although in 80 you could get a bike for $10k in todays dollars $50k+....all relative.

What I have found in my yosh motor was top end oiling problems the cam journals scored badly as did the head. I think the 750 gears which spin the pump 30% faster would be a good choice and they'll be in my next build.

 

[BadBillyB]

A builder friend of mine also recommended getting cam assembly lube from the cam supplier and using that on virgin cams. He sezs the first 5 miles makes or breaks how the cams are going to wear and the right lube will impregnate the cam and help it wear well.

It,s been my experience that the first minute or two of engine running is the most critical. I always use MOS or moly lube on the tappets and lobes, and pour straight 30wt motor oil over both before putting the valve cover on. The trick is to NOT let the motor idle for the first few minutes....After installing the new guides the valve seats will need to be redone. Find someone with a "Serdi" valve seat machine to perform this job. APE probably has one.....Billy

 

[gs road racer]

Ditto with the moly lube.... a year???? what have you been doing in that year?YOu should feel quilty...what would happen if you didn't talk to the wife for a year???Shame...

 

[first timer]

09.... not much, buyin a house with a 4 car garage (apparently not to work in it...), riding my sv...

You see the problem i have is, after moving to tucson from chicago, there is way more stuff to do all year round which really cuts into the garage time. But don't worry the GF is ****ed at me and says she is tired of showing up at vintage events and GS events on a new bike and has threatened me that i better start working in that garage or ELSE!

So keep turning the screws and applying that pressure to see this project done guys.

-R

 

[gs road racer]

Now I am dealing with trans bearings, figured i might as well replace them with everything is apart. Trippivot recomends using some bearings from a bearing house because they are newer and have better alloy then the OEM stuff that could be sitting for years. The only catch is the bearing house stuff doesn't have the little hole drilled for the pin (to keep them from spinning) like the oem, But I don't think that will be a problem the bearing house stuff has the clip still and the sealer and clip should keep the bearings from spinning in the cases without the pin.

Not so the pin is what stops it....Better alloy?? Questionable..Newer? depends on how they are stored, there are better grades of bearing (read fit , maybe different metal) but not for this application. They are instead of being $25.00 bearing they are over $200.00. The application is shop machinery where tolerances on runnning shafts with high loads/speeds are critical. Lubrication requirements for these also may differ . Some bearings especially the crank main bearing ones if you can find OEM use them ( most of the time not available).I'm not saying the tranny replacements will spin just making a comment on what you posted.There was a post on here about fretting on the steel case inserts , happens with the all the bearings use red loctite in small quantities...it'll help. We've all used standard sizes instead of OEM but I'd prefer OEM over the regular anyday. Ok I'm off the soapbox....