Another Honda engine

[Mattysmith]

So... I ended up finding this little engine and transmission from a 1983 Honda ATC185. I thought the price was right at $0. lol
I'm sure it's not a good idea, but I'm considering wedging this into the bike.

It is a 5 speed semi auto clutch, so I will have to shift through the gears, but no need for a clutch lever (which will still keep my handlebars clean)

At 9hp I think it's a little much for the frame to handle, but it's not like I'm going to be wringing this things neck at all...ever.

I'm a little hesitant to do it because I will have to cut out the tank support, and cut a notch in the back of the tank for the carburetor to clear the back of the tank under the seat.

Has anyone ever tried this? Or better yet, does anyone have any reasons to or not to do this? I'm not thrilled about cutting the frame. (the tank I'm not so worried about because it's fairly dented up on the one side)

So far the reasons I have for wanting to put this in the bike are as follows:

-manual transmission with centrifugal clutch  <--- this is a big one for me, I prefer shifting gears but don't want a clutch mucking up the look of the bars

-4 stroke with CDI ignition, no messing with oil tanks fuel mixtures or points

-COST (obviously)

I'm VERY interested in everyone's opinions on this. I feel it's a pretty big decision to cut into the frame or not.

I will admit though that I am leaning more to the shove it in there side of things.

Thanks in advance for your thoughts or opinions on this guys

Cheers
Matt

[ndian22]

Interesting for sure. I can't give advice on should you do it, but if you want to see a similar Honda up and running with a vertical 5 speed check my thread "Simplex 5 speed" in non-original motor section. It contains more info than anyone is probably interested in. One key item is that this family of motors all center & balance with the four lower motor mounts. Center these on the bikes centerline. Properly aligned the clutch side motor case extends outside the frame considerably further than the left drive side case housing. Looks awkward in a bare frame but builds out nicely. You will also note I stretched the frame as well increasing the height of the frame to gain some additional mounting space. I also beefed up the frame while I was at it, but my frame was truly worthless. A good solid stock frame should cope with the extra weight and power of the Honda under restraint of common sense riding. Good luck! Rick C.

[Mattysmith]

Wow... That's quite the bike, looks like lots and lots of love an attention went into that thing! Great work!

I'm going to try to keep the frame as stock looking as possible, I think I will end up cutting out the tank mount, and clearancing the rear of the tank to make room for the carburetor. I think it will look fairly stock as most of what I'm hacking up will be hidden behind the tank itself and under the seat support.
I'll weigh out my options and think long and hard about this.

Thanks Rick

[pd]

Maybe you could make an intake 'manifold' that would leave the carb lower .

Pete .

[Eitek1]

I understand your problem, or rather I think I do.  For me the biggest problem would be cutting the tank. Reason being is that it's old and it's lasted this long and so on.

You still need a smaller tank so you will have to cut it, maybe. What if you found a smaller tank? Somewhere on this site is a picture of a tank with a non-familiar decal. Folks that know more than me say it's off something different than a servicycle and it's smaller. It looks like a servi-cycle tank meaning that the radius on the front looks right. It may be possible to procure one of those tanks and have the clearance you need without cutting the one you have.

Just a thought.

[ndian22]

Thanks for the complements. I'm more than pleased with the way it turned out & it's fun to ride as well. Good suggestions by the guys. Several after market companies make the rubber Honda style manifolds that angle the carb to one side or the other, but custom fabricating one will get what you need instead of accepting what they have for sale. Nothing looks better than the original tank, but more room has to be found by some means if you use the Honda, been there done that & made several false starts with tank concepts before mounting the cross frame cylinder tank. Take a look at Kart Jockey's beautiful stainless tank it has the Simplex feel & could be redesigned to allow fitment of your motor, still not stock though.

I understand your reluctance to modify your Servi-cycle & appreciate your respect for a good survivor frame.  The original Simplex design is a handsome one and required no additional embellishments to make it stand out decades ago or today!             Rick C.

[Ricks]

Are you going with the honda engine only because it was free, and you think this will be cheaper than buying a motor?  Are you looking for a rider that can go faster than a stock bike?  I feel you need to answer these questions for yourself before you can move on. 

If you think using this motor will save money, I think you will be mistaken, as every other part you use will have to be custom.


Are you planning on retaining the belt drive or converting to chain drive?  That in itself will present issues.  If you use the potential of the motor, you will need to upgrade your braking, and add a front brake, just for the sake of safety.  Simplex brakes are barely adequate for a stock simplex speeds.  Are you thinking of going to moped brakes?  Or a disc setup?

Rick C did an amazing job putting a similar motor into a simplex frame, but every part was built by him with safety in mind, from the frame on up.

Imho, if you are not prepared to go as far as Rick C did, you are much better off sticking with a Honda GX200/HF Predator/clone motor following a proven path.

I hope I am not raining on your parade, but just pointing out some things you may not be thinking about.

[Mattysmith]

Not raining on the parade at all!

This I why I like this discussion board, I really appreciate the advice you guys have given already. I'm still unsure about putting the motor in this bike. I'm leaning towards yes, but you raise some valid points concerning safety. Especially the braking aspect.
 I do think it will be a cheaper option than getting the "tried and trusted" engine options. There is no limit to what you can make with a little trial and error. (plus I like a challenge)

If I do use this engine, I will find a way to relocate the carb. The more I thought about it, the less keen I am to modify the tank.

At the end of the day; I do want to ride this bike fairly often in the summers, So I do need to compromise "the look" for some safety (keeping in mind these things don't sound like they were to safe from the factory.)

I've also picked up my next challenge that will move into the garage once the simplex is done. Can't wait to throw the simplex in the back of it and go to a drive night.

Thanks for the advice guys, I'm going to do some more thinking and see if I can come up with a plan here.

 

[pd]

The box is too short . A simplex won't fit . If I had a garage , I'd say you should just give it to me .

Neat project , for sure .

Pete .

[ndian22]

Yeah buddy, you gonna' fit right in...& the Simplex will look natural in the hauler!

                                                          Rick C.