Topic: CB750 finned starter cover

[wolf550]

when I looked at it from the side not so much

[bert96]

WOW!!!!

I want one!


 Bert

[wolf550]

I did not think that it would have that much gap between it
when I took it off I remembered i did not grind down the nubs from the vents that were on the inside of the cover!
I decided to try on one of the others

[wolf550]

WOW!!!!

I want one!


 Bert

you got one coming to you Bert!!!

[wolf550]

I still have some fine tuning to do on these though
when I put the other cover on it fits so much better leaving a smaller gap between but still a gap

[bert96]

WOW!!!!

I want one!


 Bert

you got one coming to you Bert!!!

😀😀😀😀😁😁😁😁

 Bert

[wolf550]

I was stressing over the tolerance if it was going to slide between the starter and the chain adjust but it does with no resistance or touching

[wolf550]

there is still a gap but there is not a gasket on this just aluminum against aluminum.
Ill see how a couple layers of gasket will look

[wolf550]

the gap is more noticable from the other side on the corner
I can build that side up or remove some of the material from the right inside bolt hole to bring it down more

[bert96]

 Do you have a milling?

 Bert

[wolf550]

at the most I have a bench drill press and some bits that I use mostly for leveling bolt holes
on the 550 cover I just built up the bottom of the original and then just spent a day sanding and checking sanding and checking
if I can get this thing done right and I mean:
cast with no cavities
have it fitted with no gaps without a gasket
holes drilled to allow the spacing from shrinkage
I will be satisfied

[wolf550]

after getting that engine out and up into the garage I had to check on how much this thing weighs.
it was a struggle to lift this thing but it is akward in grip
after googling it ranges from 172 to 200 lbs
this is not a weight to skoff at
before covid I was taking the 550 engines in and out of the frames numerous times to check things and it was no problem
so after a few years I decided to head back into the gym
at my peak deadlifting 405lbs was right along with almost getting to the 1000lb club (total of bench, deadlift, and squat)

i came across that video of lifting safety these motors just picks it up off the bench bends over and carries it away like a pot o gold!
Ill get back to lifting like that in a year or two.

[wolf550]

so today I am going to work on the cover and get the rest of those scratches and crevices smoothed down where the aluminum does not cover all the way leaving cavities and not a good looking casting pour.
also I have a few more techniques to try with catch traps, pressure reliefs, port hole alignments etc. to get this cast proper
Ill build up the bottom on that side some more to see about getting it even on the next pour.
this may take awhile but I am on the right track

[wolf550]

took awhile but scratches are finally gone
it would be nice to have a longer carbide burr that would fit the entire length of the fin

[wolf550]

the edges on the side were removed
have to give it a try
going to keep working on the other pieces that were cast to see if the bottom lip can be leveled and smooth the fins the same way

[RAFster122s]

Looks nice

[wolf550]

thanks rafster
it should mould nice to the sand and I think casting will deliver positive results
with comparing to the 550 cover everything is similar except for the 550 cover is flat
on the 750 cover the top has the three angles
im going to try a cast using the same past method
if this does not yield any results then I will try two other methods to test.

[wolf550]

had some time after work to keep building up the side that was falling short
after looking at a few of the previous castings they were off center a ways
I went to work sanding down inside while building up the other outside

[wolf550]

I didn't smooth out the fins to a finer finish and went ahead and started a sand mould
came out good

[wolf550]

after reading up on some size charts, i talked to a guy on the forum and explained what I was trying to do
I was told make the entry way smaller that what I was using so instead of two I went back down to one
with a smaller entry way the aluminum will feed more slow instead of gushing through
sanding down between the fins was a good call with those scratches the area would fill those in with sand. this would take away sand from those areas leaving small holes and cavities not really seen but when the aluminum would fill they would break away more sand causing those areas to have bigger cavities
adding a trap and a false gate will help to keep the aluminum from getting crazy in the chamber and reducing air and gas
I also had to remake a new sprue extension that would fit the smaller opening
if the weather is good I will start on this one and make another but leave the options on hold until this one is cast to see what I get

[RAFster122s]

Looks good, hope you get good results from the new input and mold.

[wolf550]

pretty day today
had to take the wife out for breakfast and do alot of chores around the house before she would let me play outside
checked over the mould to make sure I couldnt see anything that could go wrong
sealed it up and started cookin
while the aluminum was heating up I worked on the second mould and to go the 550 cover process with a straight gate and sprue
both looked to come out pretty good

[wolf550]

the fins were thin from having filed the middle valleys smooth that the fins were having trouble in some parts

[wolf550]

went with the first cast getting it cut sanded and grinded down
still had the same problem with the side

[wolf550]

after building up just the right side about a millimeter it still looked like it was showing the same amount of space
the bottom of the cover is flat but the inside was hitting where the bolts screw in and another part toward the back
after back and forth with grinding inside near these spots, fitting, and sanding the bottom again to no avail the only choice was the gasket