clarify 5.5 160 vs 6.5 296 interchangeable parts

[jessez]

Ok so I did some searching but had not found exactly the answers. I have a 6.5 pre greyhound clone and a 5.5 Honda ( parts motor). I got the Honda cheap and want to do the head and piston. What else to use.
From what-if understand the heads are 22 cc vs 18 cc right?
And the piston will be a pop up piston +.10ish?

My big concern is takin genuine Honda to clone. Pretty sure everything matches (minus valve covers) up just not sure
Am I on the right track? I have read the smaller head flows better? I am late to the clone mods but not to wrenching.

 

[Oldschool]

Ok so I did some searching but had not found exactly the answers. I have a 6.5 pre greyhound clone and a 5.5 Honda ( parts motor). I got the Honda cheap and want to do the head and piston. What else to use.
From what-if understand the heads are 22 cc vs 18 cc right?
And the piston will be a pop up piston +.10ish?

My big concern is takin genuine Honda to clone. Pretty sure everything matches (minus valve covers) up just not sure
Am I on the right track? I have read the smaller head flows better? I am late to the clone mods but not to wrenching.

Clone:
Do some research.
Its easier for you to search this site than it is for me to retype.

 

[Kenny1]

Clone:
Do some research.
Its easier for you to search this site than it is for me to retype.

If your not willing to help the guy you should just pass over the post. He wasn't asking you directly.

 

[Strigoi]

there's nothing wrong with telling someone to do a search when the subject has been covered many times.

i also agree that it's easier for them to search instead of typing it all out.

 

[jessez]

I have done searches I know both of you guys are knowledgeable and that is why I asked for clarification from who ever would put it. Next time I will PM you 2 directly thanks

 

[Strigoi]

don't PM me, i'll just tell you to do a search. i've had too many people PM me every question they had and it ruined it for everyone else (getting 10+ PMs a day from one person gets really annoying).

i'm guessing that you have a 2009+ 6.5 if the valve cover doesn't match.

to answer some questions....

you can't swap cranks between a 5.5 and 6.5 without a lot of work and the side cover is different on the new style ones (meaning different gaskets). those are the big differences between the engines besides the 5 bolt valve cover.

you can swap heads but you will need to use the correct valve cover (4 bolt or 5 bolt).

the GX160 should just have a flat-top piston in it, not a pop-up (stock 6.5 is a dished piston). i'd get new rings if you plan on swapping pistons.

i'm not sure if the 18cc head flows better than the 22cc, but you gain a small bump in compression going with a smaller CC head.

NR RACING has compression chart that breaks it all down so you can see where you're at (under Documents & Tech at the bottom left). if you're just going with a stock 18cc head (not milled) and a flat top piston you'll be fine on 87 pump gas. you should also keep the 6.5 head gasket because it's thinner than the 5.5 one (.010 vs .045).

i wouldn't worry about reliability until you start getting into the big cam, big carb, big valve head stuff. i had a mildly modded 6.5 with a small cam, Mikuni, 18cc head (plus supporting mods) and it never missed a beat with me beating the shit out of it.

 

[jessez]

Yeah I seen the chart on NR's web site. I was being a smart ass about PMs.


I actually have 2 clones one being the the older square tank and one being the newer one. The one I would build is the older 1 which I have abused but have never taken off the governor and don't plan on it unless I buy a billet rod and flywheel. I wasn't planning on swaping cranks because I figured that is prob where the displacement is lost.

Where I was coming up with the doubt in my mind was more in the piston I guess and you answered that question thanks

I planned on new rings no mater what I do. And prob a valve job and maybe 18lbs springs if I remove the governor.

 

[Oldschool]

If your not willing to help the guy you should just pass over the post. He wasn't asking you directly.

There is so much info here.
You just need to search.

Yes I could type a pile of things.
And guess what.....

new fellow would be building a motor based on my motors

maybe he needs to do some research to better understand what kind of motor he can build and make an informed choice.

 

[jessez]

There is so much info here.
You just need to search.

Yes I could type a pile of things.
And guess what.....

new fellow would be building a motor based on my motors

maybe he needs to do some research to better understand what kind of motor he can build and make an informed choice.

And you still have added 0% to anything but your post count

 

[pickupman6]

the smaller head does not flow better but will bump up the compression. since its a honda head though it will be pretty close to your 22cc clone head. nothing a good port job wont take care of. and take it easy on oldschool. there is plenty of info on this sight if you search for it. i don't think I've ever asked a question because I've used the search and they've all been answered. and oldschool is one of the ones I've gotten a lot of info from.

 

[Strigoi]

And you still have added 0% to anything but your post count

what Oldschool said is 100% true.

maybe he needs to do some research to better understand what kind of motor he can build and make an informed choice.

 

[Oldschool]

And you still have added 0% to anything but your post count

Then let add another empty post to your query.

What do you want understand and why.

I know a few things and it took me a while to get where I am.

Best advice is make small changes and try to understand the effects and causes. For every gain you make in one area there is a trade off.
In every design there are trade offs in particular with regaurd to cost.

The single biggest thing you need to do is remove the strucutral weaknesses in these engines.
Flywheel.
Rod.
Valve train.
Wrist pin.

Then you need to adress the compromises.
Dish pistons and large open chamber heads for lower HC.
Cams configuered for reduced emissions.
Retarded timing for NOX reduction.
Lean jetting for lower HC.
restricted flow from stock porting, carb, and exhaust

Once you figuere out how to deal with these( and these are just the most glaring starting points ) you need to decide what the performace parrameters you require are.

Do you want more peak power in a high narrow band ( this is fairly easy ).
Do you want more toque in the lower RPM band ( this is fairly easy too ).

Do you want more a modest improvement in everything across the RPM range ( this is easy with just minor chages by removing any of the before mentioned compromises ).

HARD:
Is getting big power with lost of low end torque in a reliable engine that burns pump gas.

So I say think small.
make small changes.
Keep a log.
Be prepared to spend money.

If you don't like these answeres buy a kit motor from NR or Afordable gokarts.
The single biggest mistake people make when buying a kit though is they don;t understand the changes this will make in he engine and have trouble with tuning and drivability because they made some bad choices.

 

[jessez]

I know a few things and it took me a while to get where I am.


The single biggest thing you need to do is remove the strucutral weaknesses in these engines.
Flywheel.
Rod.
Valve train.
Wrist pin.

Then you need to adress the compromises.
Dish pistons and large open chamber heads for lower HC.
Cams configuered for reduced emissions.
Retarded timing for NOX reduction.
Lean jetting for lower HC.
restricted flow from stock porting, carb, and exhaust

This is where I am going with the engine I am going to address those weak links as I do a mild build don't plan on having a motor that is putting out gobs of power just a little bit more I appreciate the info. I was more or less trying to get a confirmation on the track I am on. Which after a little while I have gotten thanks guys.

 

[Oldschool]

Get a 14cc head and clean it up a little.
Get a header, nothing too large.
Bump up your timing 4 deg.
Rejet carb and get an after after market filter.
Add a helper spring to the governer.

This is a simple, great first build I have posted many times.
It requires no internal work and won't exceed 5000 rpm where most of ths stock components start to become a serious concern.
It will start and idle nice with improved torque down bellow and a little more top end power.

And its non of my doing.....
if you did a search here you would have found many references to this combination.
Many people since long before i got here have posted this combination in part or whole.

Now once you have done this, and you have a decent running engine between the rails go out and buy another motor.
Do the internal work.....
Build on what you learn from the first and second engines.
Always keep a log of what you did and how.
Always keep one engine in reserve that runs incase you screw up and need something to put between the rails.