I picked up some take off cylinders and heads a while back and finally decided to do something with them. I had them bored to 103 and picked up some 10:1 flat tops. The heads were also cleaned up, had a valve job, and new guides. I know there are a lot of cams to choose from and for better or worse I picked up a set of andrews 57. I have read that they will do okay with the 10:1 but I'm not sure about the head gasket. Would a 0.030 gasket be okay ???

Thanks Jimmie

 

What is the combustion chamber volume?
What is the displaced cc's of the pistons, ie, valve reliefs?
Are the pistons above/below deck?
Scott

 

Thanks for the reply. I was afraid it might not be a straight forward question.

The take offs were from a 09 stock 96. When I had the work done I was tight on cash and probably too conservative. I just asked that the cylinder be bored for the 103 SE 10:1 flat tops. I also had the heads and asked if he could "clean them up". The machinist did a valve job, replaced the valve guides, and did what he referred to as a "pocket port". Unfortunately experience comes with a learning curve. I did not have the heads chambers measured and until I dig into it, I do not know where the pistons sit.

I might add I have a 2009 with a 96 and an Andrews 48. Before that I had a SE 204 (couldn't leave well enough alone). It runs good and I have about 40,000 miles on it. However, the past couple years I have been chasing noise in the front head/valve train. Changes lifters, rocker supports, rocker lockers, etc. When I saw the take offs available I figured - why not. I don't want a lot - just a solid running bike that I can get another "trouble free" 40,000 out of.

I almost forgot - even though I was being conservative. I later called them up and added manual compression releases.

I ain't scared but I am a little nervous about digging in - so any advice or encouragement is welcome.

Thanks Jimmie

 

I was just reading the thread about the 57's and CNC heads. I see that 10:1 with 0.030 head gasket was advised without issue. But what I really took away from that was DJL's comment - "don't over think it".

I won't be starting the project for at least a couple of weeks. Unless someone chimes in with a red flag, I think I will go 0.030 - like I said experience has a learning curve.

Jimmie

 

Only thing I would add is PNs. People often refer to pistons as 10:1, 10.5:1, etc. without part numbers and when referring to HD parts, that can lead to problems. There are two sets of HD pistons that make 10:1 static CR with OEM or CNC ported heads (85-86cc) chambers. 21966-07 is the cast piston and 22942-00A is the forged piston.

Using those pistons with worked OEM heads and a .030" head gasket works; I would even say, take a .010" cut on the heads to true up the surface and pick a bit more CCP..........

 

DJL - thanks for the reply.

I went searching for a top end gasket kit. On the cometic site it looks like C9844 is the one I want (0.030 head gasket) but went I went to other sites to get prices (i.e.- amazon, ebay, dennis kirk, etc) some said it wouldn't fit ??? Can anyone confirm?

Also, DJL I have seen you recommend CYCO gaskets but when I went to there site I couldn't seem to find the right kit. Maybe I am just missing something. Do you have a number for a top end kit that would include a 0.030 head gasket for a 103 ???

Thanks

 

The 103" cylinder bore is 3.875; same as a 95" bore. All you need is a top end kit for either. The CYCO kit you need is TE1550MLS030; the Cometic kit is C9844 and I have no idea why someone told you it would not fit. CYCO doesn't sell retail or to the general public. Challenge whoever is telling you the C9844 kit won't work and just tell them to order it. If you don't believe me, call Cometic and confirm..........

 

good stuff here
thanks guys

 

No "person" specifically told me that the cometic gasket kit would not fit. Some of the sites I went to like Amazon have a fitment guide - you put in the make and model, etc. I imagine what might have happened ...... a stock 2009 St. Bob came with a 96. The app. is not smart enough to know I am boring to 103 - so the fitment guide says it won't fit.

I went ahead and ordered the Cometic C9844 - once it arrives I just need to find the time. Hopefully within a few weeks - I will report back.

Jimmie

 

If 85cc chambers are what is suspected, then a .030"gasket will have a flat top 103" at/very near 10.0 cr.
That is a good place to be for an Andrews 57.
Scott