MotoIQ's project honda ruckus 

 Project Honda Ruckus: Part 5 - Engine Bottom End

by Jeff Naeyaert

In the previous installment of Project Honda Ruckus, we worked with Dan Paramore of DPR racing to go where no one else had gone before by carefully porting the head of the Honda GET engine to maximize flow, improve combustion and raise the compression ratio.

stock honda ruckus head vs DPR qench head
The radical combustion chamber with the large quench pads is the most obvious difference when you compare the stock (left) vs the DPR head (right).

Now it was time to get into the engine's bottom end and do some magic. In order to raise our displacement and to get a tougher piston that could hold up to high RPM abuse and possible detonation from our high compression, we turned to Chanito Motors for one of their big bore high compression pistons. The Chanito Motors piston kit comes with a Wiseco piston that is 3mm larger in bore diameter than stock which increases the displacement from 49cc to 58cc. The compression ratio is also bumped up from the stock 11.9:1 to 12.5:1.

Chanito Motors Honda Ruckus big bore piston vs stock
9cc more displacement and 0.6 of a ratio more compression with toughness and strength are the advantages of the Chanito piston on the left compared to stock on the right.

The Chanito piston kit comes with a big bore, coated steel, thin head gasket and all of the other genuine Honda gaskets and seals needed to rebuild the engine. The head gasket is very thin, 0.009" thick which is good for reducing the quench volume which works well with our DPR quench head with the Singh grooves. The reduced volume helps the quench area produce detonation reducing turbulence for more complete combustion.

Chanito big bore head gasket for honda ruckus
The Chanito single layer big bore head gasket is great for performance but unforgiving for deck warp.

Using a thin single layer metal head gasket requires a lot of attention paid to making sure that the block deck and cylinder head sealing surfaces are absolutely smooth. This is especially important since the GET engine is prone to warp its deck surfaces with age. We hand lapped the cylinder and head on a surface plate with honing oil and 400 grit wet/dry sandpaper to get our surfaces absolutely smooth and flat. If you don’t have the ability to get the decks perfectly flat, then Chanito also has a 3 layer thicker gasket which is more forgiving, although you probably lose about half a point of compression and a lot of the advantages of quench with this gasket.

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Monday, November 23, 2009 1:47 AM
What did you do specifically to allow it to manage the much increased compression ratio?
Monday, November 23, 2009 4:11 AM
I understand why it's not, but I can't help but wish this was EFI'd. This would make a great project engine to explore like you guys have, but I simply do not do carbs, ever.
Monday, November 23, 2009 4:18 AM
Every time I read an update, it makes me totally want this bad-ass bike even more, Can you post a video of how this thing sounds/runs?
Mike Kojima
Mike Kojimalink
Monday, November 23, 2009 6:36 AM
If you read the articles, you will find that we quench welded the combustion chamber and installed a larger piston. These two things bring the compression ratio

The euro version of the GET engine is EFI. Its called a Zoomer in Europe. It has a 4 valve head but the valetrain is very heavy and the performance potential is perhaps less than the 2 valve engine.
Tuesday, November 24, 2009 4:26 AM
I read the article and know what was done to raise the compression. What I was getting at was if anything was done specifically to prevent it from detonating at that much increased compression ratio, such as using higher octane fuel or reducing the timing etc.
Tuesday, November 24, 2009 11:58 AM
Read quench area.
Mike Kojima
Mike Kojimalink
Wednesday, November 25, 2009 6:32 AM
And Singh grooves. Read part 4 for lots of details.
Wednesday, November 25, 2009 10:40 AM
One question I do have is are there power gains t be had by lightning the rear sprocket/ chajn and assembly? Maybe even the wheel itsef?
Mike Kojima
Mike Kojimalink
Thursday, November 26, 2009 7:19 PM
It doesnt have a rear sproket/chain, the thing has a belt drive with a CVT.
Friday, November 27, 2009 11:46 AM
Oh snap that, I was unaware of that.
Tuesday, December 01, 2009 2:23 PM
I see where the project ruckus is headed and I'm liking it more and more. I still would like to see a forced induction scooter build tho :p. No worries, I'm planning to do exactly that over winter break/spring semester. I'll try to keep the camera handy, and possibly do a write-up as well.

Anyways, keep up the good work and I look forward to seeing part VI sometime soon!
Mike Kojima
Mike Kojimalink
Tuesday, December 01, 2009 2:44 PM
If you can get us good photography, we can feature it.
Saturday, October 08, 2011 8:17 AM
I want a ruckus, yet id perfer to keep the Honda GET engine instead of the GY6swap, but it kind of dosn't or dose make sense that honda kept the cylinder in the crankcase as one mold, easier to swap cranks, BUT not the cylinder its self. Lets say if there was a bore kit available it would cost more to mold an machine so what would the largest size you could open it up to, plus add a stroker crank, concidering you cant raise the deck height. Is it possible to achieve the 72cc mark as for this is a common upgrade to mopeds in hawaii. Please correct me if im wrong. But the tecniques used on this block is exactly what you do to a car engine.
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