Topic: Paul Smart by KDI -Homage (re) Build-

[materializer]

Whether you glass bead or vapor blast (preferred), you will definitely need to completely disassemble the engine -- AND thoroughly clean it after blasting and before re-assembly.  Blasting media gets into the oil galleys.  You will want to blow compressed air through all of the passages AND clean all tapped/threaded parts of the engine.  IF you don't, you'll end up with blasting media in the oil or blocking oil flow.

Running early  (1969-76) 750K carburetors is a good performance upgrade.

If you are going to disassemble the engine, definitely mill the mating surfaces of the head and cylinders flat to help prevent leaks.

Concerning the milling of the cylinderhead and cylinders. As i've come to understand: mostly it is the cylinder head that might warp for various reasons. Would just milling that one do or are there obvious reasons (which?) for the cylinders themselves to need milling aswel?

Monk

[materializer]

The head surface (mating surface against cylinders) is prone to warping. If you have the motor apart, it is only prudent to have the top of the cylinders "decked" to insure as flat a surface as possible. Honing the cylinder bores is a good idea simply to refresh them and provide best compression and oil sealing. If your pistons and rings are good, re-use them. Just check the end gap of the rings, and bores for measurement to spec. These parts should be fine given the mileage, but, with the neglect the bike has seen, its difficult to know for sure.

Cal,

Ah, kind of felt that would be the answer, just have the head decked..

I just found a wet blaster in my town, he'll do the whole engine for €60 ))

On a forum in NL for car tuning I found a link to a guy that does cylinder head milling for €40

Ánd, I may have tracked down the carbs for a 750 to accomodate the pod filters..

About honing the cylinders: am I correct to assume that a smooth surface needs no touching up? And scratches or rough surface-> hone?
Cost involved with cylinder honing is €38 per cylinder locally. Which is a relief, figured it to be an expensive chore.

With these kind of prices i'll be able to get a lot of stuff done over the next couple of months.

Monk

[materializer]

Cal,

I actually saw these DIYs when googling for a honing business.. I think I dare to do it myself 

Indeed cost about €30, so saves €100 FTW

Monk

[Lostboy Steve]

The head surface (mating surface against cylinders) is prone to warping. If you have the motor apart, it is only prudent to have the top of the cylinders "decked" to insure as flat a surface as possible. Honing the cylinder bores is a good idea simply to refresh them and provide best compression and oil sealing. If your pistons and rings are good, re-use them. Just check the end gap of the rings, and bores for measurement to spec. These parts should be fine given the mileage, but, with the neglect the bike has seen, its difficult to know for sure.

So are you saying "decking" the cylinders is a good idea? I have heard both opinions and can't decide what's right and wrong as far as these engines go. I had my head cut as minimal as possible but didn't do anything with my cylinders other than clean and hone them on my 550. It was a low mileage motor anyway but had been sitting for 25 years.


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[materializer]

I figure Cal ment to say deck the head as i think those are most prone to warping. (But i see the typo? )

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[SOHC4 Cafe Racer Fan]

Correct.  It's common sense.  If the surfaces between the head and cylinders are warped, decking one and not the other only fixes half of the problem.  Decking both will help insure a good seal.

[JoeCooley]

Sounds like a cool project. Do you have any pictures of the build so far? These builds are more interesting with pics. Also, you can easily modify the first post to convey a more "homage" build.

[Lostboy Steve]

I figure Cal ment to say deck the head as i think those are most prone to warping. (But i see the typo? )

I didn't specify having the head surfaced in that reply as it was a direct explanation to your prior reply.

For clarity, head warps most. Mill the head. In your situation given the neglect and mileage, I would also have the cylinders decked. Then both surfaces are flat and true. Decking/milling should always be done for the minimum amount, unless a specific HiPo goal is being designed.

Hope that clears it up.

That's what I thought you meant. My questioning was genuine. It's always good to know a little more and possible ways of doing things. Thanks Cal.


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[Lostboy Steve]

Cal,

I actually saw these DIYs when googling for a honing business.. I think I dare to do it myself 

Indeed cost about €30, so saves €100 FTW

Monk

Honing isn't rocket science. Just don't overdo it. I like the head planing diy videos. Anyone wanna try that? Get yourself a piece of granite and glue some sandpaper to it... waalaa home made head decking.


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[materializer]

So I tracked down two types of single side swing arms of the VFR RC36. And I'd like to ask you all some advise on which one to choose.
Both have slightly different fitting / width. I measured that the fitting between the two axle holes on my CB are 23,7mm.
Type one of the VFR rear end measures 22,8 mm


The other 24,2 mm


I'm temped to choose the one thats slightly under the required width and fill up the gap with spacers to match 23,7 mm.. : any reasons thinkable why I shouldn't?

Also I noticed that there's a bracket on the swing arm to attach the/a shock onto, which might make the build a little less complicated.



In the PS version I noticed the shock appears to go "through" this hole in the swing arm and this in turn needs a complicated customisation to keep it in place:



Any thoughts of you guys on why KDI might have gone down this road other than having a taller shock, or having it installed low in the frame as it is?
It's very difficult to make out in the pictures how exactly they they designed the geometry of the lower part.. Has any one ever seen a similar approach and would you be able to point me to images of that instance?

Monk

[SOHC4 Cafe Racer Fan]

Remember that just because a show bike was featured in blogs doesn't mean that it's even run or functions well.  When it comes to suspension linkage, if you don't understand the engineering involved please consult someone who does so that it functions well and is safe (especially since this is for the wife!). 

As for adapting the swingarm width, you are talking about either milling the larger cast arm or making spacers to fill in the width.  Remember that you want this portion of the swingarm to be as stable as possible.  Maybe creating gaps in this high stress area with spacers is not a good idea.

[Steve_K]

You will also need to check that the front and rear wheels line up.  I would not be surprised if some machining will be needed. You cannot be sure the other frame was centered the same way as your bike.  Research is your friend.
Good luck with the build.
Steve

[materializer]

You will also need to check that the front and rear wheels line up.  I would not be surprised if some machining will be needed. You cannot be sure the other frame was centered the same way as your bike.  Research is your friend.
Good luck with the build.
Steve

Now Thats a good pointer! This will surely be a decisive point in deciding how to advance this part.

Monk

[MRieck]

So I tracked down two types of single side swing arms of the VFR RC36. And I'd like to ask you all some advise on which one to choose.
Both have slightly different fitting / width. I measured that the fitting between the two axle holes on my CB are 23,7mm.
Type one of the VFR rear end measures 22,8 mm


The other 24,2 mm


I'm temped to choose the one thats slightly under the required width and fill up the gap with spacers to match 23,7 mm.. : any reasons thinkable why I shouldn't?

Also I noticed that there's a bracket on the swing arm to attach the/a shock onto, which might make the build a little less complicated.



In the PS version I noticed the shock appears to go "through" this hole in the swing arm and this in turn needs a complicated customisation to keep it in place:



Any thoughts of you guys on why KDI might have gone down this road other than having a taller shock, or having it installed low in the frame as it is?
It's very difficult to make out in the pictures how exactly they they designed the geometry of the lower part.. Has any one ever seen a similar approach and would you be able to point me to images of that instance?

Monk

I know the cylinder head works in that bike because I did it. The fella that built that bike is in Connecticut.   
.

[materializer]

So I tracked down two types of single side swing arms of the VFR RC36. And I'd like to ask you all some advise on which one to choose.
Both have slightly different fitting / width. I measured that the fitting between the two axle holes on my CB are 23,7mm.
Type one of the VFR rear end measures 22,8 mm


The other 24,2 mm


I'm temped to choose the one thats slightly under the required width and fill up the gap with spacers to match 23,7 mm.. : any reasons thinkable why I shouldn't?

Also I noticed that there's a bracket on the swing arm to attach the/a shock onto, which might make the build a little less complicated.



In the PS version I noticed the shock appears to go "through" this hole in the swing arm and this in turn needs a complicated customisation to keep it in place:



Any thoughts of you guys on why KDI might have gone down this road other than having a taller shock, or having it installed low in the frame as it is?
It's very difficult to make out in the pictures how exactly they they designed the geometry of the lower part.. Has any one ever seen a similar approach and would you be able to point me to images of that instance?

Monk

I know the cylinder head works in that bike because I did it. The fella that built that bike is in Connecticut.   
.

Hi Mike !,

So you actually worked on this bike!?! I noticed your name pop up in one of the blogs covering this build, fantastic to find out your part of this forum!
I m not attempting to do the kind of engine pimping done in the one KDI did but I am very eager to approach the styling of this build.
In particular the tank, swing arm, front end and bodywork. I've tracked down most of the parts and am confident that i can get this done.
The ONE thing that will or will not have me do this build is whether or not the installing of the swing arm is a go or not. (if...if...if...:S)

I would be very grateful, like really-REALLY grateful if in some way you could introduce me to Kevin Dinsmoor. I have not yet tried to contact him as there's no website and just a facebook page.. and contrary to others I refuse to take part in that.. Is there any way you could introduce me to him so that I may work out with him how exactly the handled the rear end engineering?
There's just too much research involved in working out how to do this safe as some have pointed out. And since this build will be a gift to my wife, be my sole investment for the coming year or two I would need to have a certain base of knowledge and reference to definitively go ahead and put all my eggs in the basket and do this.

Looking eagerly out for your reply,

Monk

[Darren Jakal]

I'm searching for something else, but came across this build. It may be useful (oops, this looks like this is the bike you are talking about and have probably seen this already).

cheers, Darren

http://www.dotheton.com/forum/index.php?topic=31281.0

[materializer]

I'm searching for something else, but came across this build. It may be useful (oops, this looks like this is the bike you are talking about and have probably seen this already).

cheers, Darren



http://www.dotheton.com/forum/index.php?topic=31281.0

Darren,

Thanx buddy, but indeed thats fate.. Just this morning i found this thread on dotheton aswel! So now i sort of have two lines to the builder of this dream machine. Mike is making an effort to contact Kevin Dinsmoor and hook me up to him as he knows him personally and that just feels a bit more appropriate. Really hope this'll get me the much needed pointers on the rear end of my build.

Thanx a bunch though for the pointer, well appreciated!

Monk