SZR660 Project

[basser23]

yes you could make some $ if you supplied the single carb manifold..there are a lot of folks that would like the simplicity.....

[sanddune51]

The single carb manifold, though not difficult, is more complex and time consuming than the twin carb adaptor. I'll stick to my day job

Mark.

[sanddune51]

Having successfully managed to drill out the sheared exhaust studs. I fitted "Helicoil" thread inserts and had the head skimmed.

I cut the valve seats for the oversize valves and hand cut the blends into the port throats.

I got to wondering about the carb adaptors and which ones I should run. I thought maybe a second cylinder head might be possible, but incorporating a different valve scheme. Before I could talk myself out of it, I bought an inexpensive dismantled engine with a good cylinder head.

[sanddune51]

The idea this time was to spend a little less on valves but at the same time to try and produce as much power and torque as possible by using differentially sized valves. I wanted to try and improve combustion by introducing swirl to the incoming mixture, as opposed to just tumble. I hoped that improving the flow at one side of the cylinder head would cause the mixture to swirl anti (counter) clockwise down into the cylinder mixing and purging the exhaust at the same time. The cost of new valves bigger valves would be roughly 60% of my first modified head.

[edfmaniac]

From the little I've read about porting, and just going on my impressions from the photos, you took out entirely too much material unless you are trying to build a drag racing engine. The flow should never slow down after leaving the carb and should maintain it's velocity until entering the combustion chamber. From the looks of your photos, the mouth of the ports have been opened up way larger than what will be coming out of the carb and the chambers look to have very high ceilings. If this is the case, both will slow down the flow of gases and rob you of power. What are the diameters of the ports where they meet the intake manifold and what are the diameters of the carb bores? They should match or slowly taper down to the valve. Sharper radius short sides and low ceiling heights will keep the flow rate up as well.

How much would people be willing to pay for a nice single carb manifold? I might be interested in making some if the price is right. They would be fabricated to match the factory ports, or at least what the carb spacer manufacturers use as specs for their Raptor 660 carb spacers.

[sanddune51]

Edfmaniac, I'm not convinced that you are at all qualified to tell me I have taken out entirely too much material.

For your own project, you stated you were sending your cylinder head "off for port polish and valve job to a guy who comes highly recommended on the Raptor forums" also "and who will do the whole job for $350 plus any valves or other parts that need to be replaced"
Clearly you didn't feel confident enough to port your own head but evidently feel qualified to make criticisms of the work I have carried out on mine.

When encouraged by another member on this forum to have a go at your porting your own head you replied "I'm not going to spend the amount of money that's going into this project and guess about the porting"
Again this implies a lack of knowledge and/ or experience and any porting work you may perform would be guessing.

Further, you write above, "From the little I've read about porting, ......................................... you took out entirely to much material unless you are trying to build a drag race engine"
This implies to me that you've never even ported one cylinder head, just read a little about porting.

A few words about forums in general. There are many hundreds of people who carry out all their own work showing others what they have done and why. There are many more indeed who see fit to criticize that work, whilst not actually doing their own. The former spend a lot of time, thought and effort, mostly for their own satisfaction to do that work and then post it up for others. The latter spend next to no time, and with apparently little thought, to belittle the work in the post. I certainly know which type of post that I'd rather read.

I have been porting 4 stroke cylinder heads for 32 years both for myself and friends. I have never taken a fee.

A member above asked me to make a manifold for him after seeing the one I made for myself, another suggested I could make some $ if I supplied the single carb manifold. I politely declined.

You then asked "How much would people be willing to pay for a nice single carb manifold? I might be interested in making some if the price is right."
If your motivation is profit for yourself, then please go right ahead. Perhaps you could start a new thread. If you need to belittle my work to achieve this, I'd prefer you didn't.

Many of the assertions you have made above are just plain incorrect.

I stand by the work I have done and have enjoyed doing. The final arbiter of my work is the dynamometer. This will be the same one, to compare the rear wheel output of my bike before, and then after the modifications I will carry out.

Mark.

[edfmaniac]

Oh you can read. Then you probably deduced that I wanted the absolute best results for my bike and that I found a very qualified, highly skilled technician to do the final work, Kenz Cycle Tech. I also spent at least two hours on the phone with him because he hadn't talked much about the MZ 660 since teaming up with the guys who brought us many of the most well respected upgrades for this bike over the years. Sorry you feel insulted but this is criticism, not a personal attack. If none of us criticized each others work, we'd all end up with what we thought was cool and hip instead of functional and proper. Learn to take some criticism. Anyone can increase the performance of a bike, it's squeezing the most out of what you have that is the challenge and the goal for anyone looking for the best instead of a pat on the back. I'll give you a pat on the back but I'm not going to blow wind up your skirt and tell you that you did a hell of a job. Do some more READING and you might discover a thing or two about modern porting design. Talk with a professional who builds engines at every conceivable level and you'll learn even more.

And what's wrong with providing the community with parts that they want if it's worth it to the person who's going to have them made? You need to lighten up a bit and learn how to take criticism. I didn't even make fun of you, just a comment.

[edfmaniac]

And for the record. I'm not afraid to go grinding on my parts, I just like to know what I'm doing first. I did the port matching on the boots, spacer and intakes before sending it off for the port shaping and polishing/surfacing.

[sanddune51]

I am reminded of a quote attributed to George Carlin (1937 - 2008)

"Never argue with an idiot. They will only bring you
down to their level and beat you with experience"



Mark.

[samandkimberly]

Guys - this doesn't have to be personal. There is more than one right approach to porting and at the end of the day we're all dabbling in a science that it about as simple as predicting weather. Perhaps aiming questions at technique rather than qualifications might help not ruffle feathers on both ends.

At the end of the day, I think the overwhelming majority of "tuners" out there tend to call their successes science when its really more of an iterative hit/miss technique. Good port design needs to consider not just overall flow, but flow transition at different velocities, density changes, fuel absorbtion and more - this is hard for anyone but a large OEM lab to figure out on a quantative basis. So, IMO we, and most of the professionals we consult are just hacks, some more successful than others. The better ones openly admit this.

That said, I really appreciate all data points, including both of your perspectives. Sso don't go offending each other, OK?

[edfmaniac]

I agree. That's why the statement that offended someone is chock full of caveats and humility. I was trying to be as nice as possible without making anyone feel like they were being attacked but evidently the reader couldn't see that I was handling the issue with kid gloves. Sorry to offend, just trying to share the knowledge imparted to me by someone who's been working on these particular heads for decades and turning them into anything from a 55hp fire road torque monster, to a 100+hp flame belching sand dragster. My bad for trying to share some info.

This guy needs to go over to caferacer.net if he wants to see what it looks like when people really speak their minds. LOL They have no personal attack policies and everyone treats you like poo poo until they find out whether or not your skin is as thin as wet tissue paper.