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Mike Kojima posted on February 22, 2010 19:00 
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| To show how tiny the parts we are dealing with are, here is a quarter compared to our modded valves. DPR had to work with small tools and great precision to do the work from the porting to the valve job. |
We also did all of the other tricks done in our last engine, including our radius valve job, recontouring the valves and valve stems. Unlike our last motor, we did not quench weld our combustion chamber. This is a hard to do and expensive step that most people could not duplicate. Instead to raise our compression we milled our head by 0.015 inches. This gained us almost as much quench surface as welding and will also retard our cam timing by about 3 degrees which will gain us some top end power while probably costing us some bottom end. The milling leaves us with a compression ratio of 13.8:1 which is almost a half point higher than our old engine. Hopefully detonation on pump gas won't be a problem as we feel that our engine's small bore will resist detonation. We also went to a slightly more aggressive Web camshaft for this build.
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| We used Embee thermo barrier coating on the combustion chamber, exhaust port, valve faces and the backside of the exhaust valve to protect these parts from heat. Now the heat of combustion can be used to drive the piston instead of heating the water jackets of the cylinder head. |
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| We reduced the rocker arm reciprocating weight by 40% and lightened the valve spring retainers by 30%. This will give us some valve float headspace. The lightened rockers and retainers were polished to reduce stress risers and WPC treated to eliminate any areas where stress could start a fracture. The lustrous sheen is the result of WPC treatment. WPC was used on the entire valvetrain to reduce friction and improve life. The rocker arm bores, rocker shafts, retainers, valve springs and camshaft all are WPC treated. |
We made more extensive use of WPC Treatment in this build. WPC is the Japanese mirco blast surface treatment that greatly reduces wear and friction while increasing strength. We WPC treated our engine's entire valvetrain. Since we are going to be revving our engine to 10,500 rpm, 1600 more rpm than stock, we decided to lighten our valvetrain components to reduce chances of valve float. We had significantly lightened our rocker arms and valve retainers and WPC treated these parts to help strengthen them and eliminate any stress risers we may have created in them during the lightening process. We WPC treated our valve springs to improve their fatigue properties and applied the WPC process to our rocker shafts and valve guides to improve wear and reduce friction. We also WPC treated our valves, valve stems and valve seats as this will help them maintain a good seal for longer. We also gave the WPC treatment to our camshaft.
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| Our completed head with coating, ported intake manifold and Chanito thin head gasket. |
Tuesday, February 23, 2010 7:40 AM
Love it can't wait till the summer I am going scooter shopping! I dont have a far to travel to get to work and this would be a much cheaper/fun way to arrive on most days!
Tuesday, February 23, 2010 12:58 PM
I have been following this series religiously! I am doing a similar project on a 1970 Honda CT90 and besides being air cooled, the engines look very similar. Keep them coming!
Wednesday, February 24, 2010 2:55 PM
Wow, after reading all of these, I kinda want a ruckus. It would be the perfect campus cruiser, and it wouldn't need a parking pass. And I could drive it home when I wanted to. Now where did I put my spare change?
Monday, March 01, 2010 12:13 AM
I have been going over your project for days trying to decide what will cross over to my ct90 project. THe CT90 is older and has a fairly large domed piston already, but only 8.2:1 compression. If i decide to have my cylinder welded up like for first project, what will be my deciding factors for how high of a compression ratio that I can acheive? Does this engine being air cooled change that in any way? I am a big fan of ceramic coatings from my dd and my rally car, will they have as much benefit to the air-cooled engine? THanks, can't wit for the next installment.
Monday, March 01, 2010 9:46 PM
Being air cooled I would be really careful about the compression ratio. Having closer to a flat top piston with a compact combustion chamber with quench for turbulence is always more effective but not always easy to do without valve shrouding, messing up the cam timing or crating too much heat with an air cooled engine. Perhaps I would monitor cylinder head temp. Stuff around 350 degrees is dangerous. I think 10-11:1 would be conservatively ok.
Wednesday, March 03, 2010 3:31 AM
It's good to see North Americans tune scooters. All of Asia is racing scooters, so I've grown accustomed to seeing built-up engines on mei-mei motos...
Saturday, September 24, 2011 1:22 AM
I have read this article front to back, awsome job. Im sorry to say we in hawaii have been building mopeds for well over 20yrs now, we have made yamaha razz do a easy 50mph all with porting alone. We have built mopeds to reach 100mph, and thats still not enough. So what is ruckus? I say its the future, i have great appreciation for these thumper peds, but nothing can compare to the smell, the instantaious torque of a well tuned two stroke af16 honda motor. Heres the deal any thing honda is kick butt tune able, and thumpers ARE the wave of the future. I cant wait to see how far this advances, im just waiting till i get wheeled off the line on a ruckus. P.S. I did build, own, and race a 117cc stroker honda SPREE. Try build that and whisky throttle.
Saturday, September 24, 2011 2:04 AM
The mopeds in Hawaii are SICK!
Sunday, April 29, 2012 5:21 PM
I was wondering when are you going to post the final results of the reworked engine in part 7 of "Project Honda Ruckus"?
 
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