Titan R3 vs. GXH50 and a couple others...

[conradcliff]

So, I've pretty much figured out what I want to do and I'm just about completely sold on the Honda GXH50 but before I committed to it I wanted to get your opinions about what engine you suggest.

My first choice currently is the Honda GXH50. I think it will work very well for my purposes but if I can get the same or more power with the same or better reliability for a cheaper price I may change my mind.

From the pictures on thatsdax it doesn't look like I can simply attach a sprocket to a solid shaft on that engine (which is what my current build design calls for). Is there a way to do this? Also, if there isn't can I simply get a 10 tooth clutch bell for the attached clutch(I'm thinking no)? I do like that the Titan is slightly cheaper and has a gas tank already.

Browsing around I came across these 49cc engines from bikeparts.com, I couldn't find any useful info on their site about them though. Does anyone have any experience with these? What kind of power and reliability can one expect from them?
The first one looks pretty kick @$$ don't you think?

Anyway, I am so close that I can almost taste the bugs in my teeth! I just can't wait to get this project off the drawing board!

Thanks again to everyone that has helped me out so far! And thanks for any more info you guys can provide!

 

[Dan]

From researching, the Honda GX50 turns very fast so has to be reduced to work for a MB b4 a clutch will work. can be done but adds cost. basically one would have to buy a gearbox or build one. And the GX has a very short drive shaft. A grubee gear box will work and the only box I have found on paper that will work. I am in no way an expert, but thats what I have found out so far.

Also a 4stroke will need wider then normal peddles.

 

[Dan]

I have to ask for permission to post, but have some information from a manufacturer on how to work with a GX50. I had the same questions.

 

[conradcliff]

Thanks for the reply, however I already know exactly how I will gear up the GXH50. What I'm curious about is what people think about these different engines as far as reliability and performance are concerned. Plus I had a few specific questions about the Titan in the main post. I intend to utilize a 10 tooth sprocket on the drive shaft which will then lead to a 24 tooth sprocket on a jackshaft. On the other side of the jackshaft I will have my centrifugal clutch.
With these numbers I have a ratio of 2.4 to 1 giving me a rotational speed of 1,125 RPMs on the output side of my jackshaft. So far the only clutch I have found that engages near this speed is the hilliard extreme duty with the 1200 RPM engagement springs. It's a bit more than I wanted to spend but it's probably going to be my only option unless I do some design changes.
These numbers may change a bit depending on what the available engagement RPMs for the clutches in my price range are. And if I find contrary information concerning the idling speeds of the GXH50 which I currently know to be 2,700 RPMs. Or if I decide to go with one of these other motors I will need to change my ratios to match its idling speed and the engagement of my clutch.

Thanks again for your post..hopefully I'll be able to come to a decision soon.

 

[conradcliff]

After some more thought, I think I might want a clutch that engages closer to 2K RPMs as this would allow an engine RPM range right at 4400 which is right inside the beginning of the operational/power band of the GXH50.

Wow, I'm glad you made me think about that a little more

Edit: I'll probably be going with an 1800 RPM engagement clutch and a 10 tooth to 24 tooth which will give me a ratio of 2.4 and an engine RPM of 4320..right at the start of the sweet spot

 

[Bikeguy Joe]

Are you sure you want that kind of rpm before the clutch engages?
I don't know the redline on that engine, but I would think you need it to engage just a little over idle wouldn't you?

 

[Large Filipino]

I'm sure the Honda is a great engine but the Titan is a "complete package" if you will because it already has the 5 to 1 reduction gearbox so chaining it up is a snap. And as a testament to it's reliability my Titan engine has passed 4,000 miles and still runs like a champ shared between my bike and my trike.

 

[conradcliff]

Are you sure you want that kind of rpm before the clutch engages?
I don't know the redline on that engine, but I would think you need it to engage just a little over idle wouldn't you?

I could be wrong, at first I thought about having a clutch engagement engine RPM just above idle which is 2700 RPMs but at this speed the engine has very little power and is still not within its recommended operating range according to this chart:

I figured that if my clutch was engaging just above idle that I would be bogging down my engine at take off (though at my lowest gear I will have a considerable amount of torque so it probably wouldn't matter too much). As you can see from the chart the limits on the recommended operating range for this engine are right around 7700 RPMs.

Feel free to pipe in and tell me I'm wrong; I want to make sure I get this right the first time around.

I'm sure the Honda is a great engine but the Titan is a "complete package" if you will because it already has the 5 to 1 reduction gearbox so chaining it up is a snap. And as a testament to it's reliability my Titan engine has passed 4,000 miles and still runs like a champ shared between my bike and my trike.

I was under the impression that the Titan motor did not come with the reduction box unless you bought the kit. If I could get the Titan for the advertised price of $179 w/$20 shipping and it came with the reduction box then I would definitely consider it. However, I believe you are talking about purchasing the entire kit which would not be copacetic with my current build plans. If I do decide to ditch all my plans I may very well choose the Titan kit as my primary option, but I don't think that will be happening.

If you want a better idea about what I'm planning for my build you can check out this thread.

Thanks again for the help guys...so far the GXH50 is keeping its lead...

 

[HoughMade]

The GXH50 idles at 2500 +-200 rpm, so you don't want it engaging below that and probably want to let it get a little more speed because it will bog if the clutch engages too soon, so you are right. I would want it engaging over 3000 and not all in until at least 4000, maybe more.

 

[conradcliff]

Excellent, I wasn't even think about partial engagement. I guess a clutch that is rated to engage at 1800 RPMs is just starting to engage at that point.
At 2.2 to 1 1800 give me an engine RPM of right around 4000 RPMs. I think that's probably where I want to shoot for.

Thanks again for your help!

 

[ocscully]

When buying the Titan engine seperately from Dax (no kit) the gear box is an additional $35.00 I believe. Two cavets though first the 5:1 reduction gearbox reverses the direction of rotation of the output shaft/driver. and Two the motor and gearbox measures 11 & 3/4 in. wide

ocscully

 

[conradcliff]

If the gear box reverses the direction then I would definitely only be able to go with a straight clutch from the Titan otherwise I would have to add an additional jackshaft to "re-reverse" the direction back to counter clockwise. I'm thinking the Honda is going to be the engine of choice, though I wish someone had some info on that really cool engine I linked to in the first post.

 

[Dan]

Mr. Donovan at Max-Torque was kind enough to give me permission to post his reply to my question about using a clutch with a GX 50. Just wanted to share his thoughts and pics. I know the RPMs have been covered but the out board clutch is a great thought.
I am not affiliated with them but soon to be a customer;

"Dan-- you have quite a challenge with that engine. The crankshaft
length is only 1.250" long which is too short to support a clutch, the
engine idle speed is around 2,700 to 2,800 and top rpm is 7,200rpm which
means you are going to be going like a bat out of ****. Several people
have done it and they used the Whizzer pulley belt which is almost the
rim size of a 26" bike. We made a crankshaft extension for them but it
isn't the easiest way but what the heck all you have is time to get it
to work.

I have another suggestion. Do a jackshaft arrangement so you are
slowing the crankshaft turn speed down so you have a controllable speed.
See attached pictures. We are going to shorten the tube by 4.5". The
gear on the engine is 12 teeth and the lower sprocket is 24 teeth. What
does this do? When the engine is turning 3,000 rpm then the jackshaft
is only turning 1,500 which prevents you from bogging down the engine
when you initially get going and then at full rpm of 7,200 you are only
going 3,600 which is standard for most 4 cycle engines and the clutches.
This way ANY clutch you want to buy will work on the jackshaft."



James F. Donovan
Max-Torque, LTD.
2180 Corporate Lane
Naperville, IL 60563
Phone: (630) 369-9600
Fax: (630) 369-9686
Website: MaxTorque
Email: [email protected]

 

[conradcliff]

Thanks for the post, I've also been in contact with Donovan and we have had the same conversation. It was this conversation that convinced me to go with the jackshaft idea.

 

[thatsdax]

HI.. In the past I have sold a lot of Honda engines. Lots of other engines as well. Various uses, Tansfer pumps, Trash pumps, Generators, Motor cycles, ect. Hondas are good engines. I have found they are rated very precise. When Honda says output power is 4hp. You can take that to the bank. When Honda says 4hp rated, they mean it. The do not mean you can put a 5hp load on it. That means... It can power a 4hp load. Hp being converted to KW in a non reactive load. This is not true with American engines however. When Onan rates its engines at 4hp, they mean 4hp constant load. I have had Onan Engines that would run 4 to 5 times its rating. Call it surge rating or reactive rating. Truly amazing for sure. I have run Onan engines at more than 5 times the engine rating for up to 30 secs or so. Long enough to know I have reached the max power of that engine and loading it up any more would lock it up and stop it dead in its tracks. Maybe shear the crank . Yikes !!! I have put so much load on them it gets scary. Onan under rates their engines and PTO's and for a reason. It is done to handle reactive loads. This is real world stuff. Honda has no reactive ability. It has very little anyway. But.. Keep this in mind also.. Onan can cost 4 times more than Honda.

My point is this... For what we need and what we are doing, we need reliability and efficiency. Titan is all of this. Titan R3 VS Honda GX is on. I have ordered a GXH50 and will be here soon. I hope... I will be comparing and testing to see what the differences are . Also I will be testing Titan Carrier components to see what all will fit the Honda. Most of the GXH50 engines I have seen have governor controls. This is not desirable for MAB "motor assisted bikes". I will see what is involved in removing governor controls and then install a Titan carb on to the GX and test. I know there are a lot of GX motors out there and those that wish to use them with the Titan setup. Since they already have the motor for what ever reason and they would love to put it one a bicycle.... So.....I broke down and paid the expensive price for the Honda GX series motor. The Motor which the Titan is a model of. Some anyway. As you all may know, Honda has spent billions on engine research, and if you ever want to build a good engine of your own, Using Honda as a model is a great approach. Then you can add your own High Performance mods as needed. This is what Honda did with American and European engines several decades ago and is now going full circle. So.. Here we are with Titan and Super Titan. I was told I have 4 Super Titans. I have not been able to find them in the boxes.. Yet.. When I do.. I will test these as well. They are supposed to be Factory Souped up Versions of Titan. I am not sure I will inventory these and sell these as they are engineered to be really fast.. I mean.. Really fast.. How fast? I will find out.. That is..when I find them. I was told by my Factory they marked the boxes that they are in. I do not see the marks.. And since the engines are identical looking motors to the Standard Titans..And ..If I can not find them... and Well.. If someone that has Bought a Titan R3 and every time you throttle up you pull wheelies and hit 60 mph in nothing flat, let me know.. You got a Super Titan.. 1 of 4... And I can swap it out and I will pay you the shipping to send it back and I will pay the shipping for the normal Titan to send to you. Thanks..Enjoy the ride... and stay tuned............

 

[Dan]

Dax Sir, Just a side note. I always enjoy reading your thoughts, observations and experience. I bought my first chinagurl from you folks yrs back and a couple of months ago found out it is still running. (I rode it to a hardware store and a local bar owner bought it from me as he was on his way to a biker rally and thought it would be funny. He is still ridding it. dunno actual miles)

I will be starting a thread about this but some folks and I here are talking about a Not for profit to help folks. One way I am thinking to raise funds is a MB or MAB Bible (book on building, buying and owning) and I would like to ask you to contribute some of your writings. Just a thought and still on the drawing table as of yet.

 

[conradcliff]

Can't wait to hear the verdict about the comparison!

Also, great idea Dan!

 

[thatsdax]

well..I did it.. A customer just emailed me to let me know he finished his Titan install and got on to ride his bike for the first time , throttled up and then laid down a black line, high sided, flipped into a ditch. Yep... He got a Super Titan.. Yikes !!! Just kidding.. About the black line and flipping part. He did get a super Titan . Now I know the difference, the Super Titan has 8mm engine mounts verses the normal 6mm mounts. He could not mount his Titan into the plate and asked me if I had Sent him an R2 by mistake. Yikes !!! I asked that he send me that Super Titan back and I would pay for all the Trouble and send him a normal Titan. Wow !! Now I know what to look for. Problem is, I have shipped several Titans, some to Europe. Yikes !!! I do a lot of inspection prior to shipping and the Supers are Identical. Except for the larger Mounting holes. They are so large the bolts needed are too large for the plate slots. So..That is how I know. Now I know.. Also I am mad at the factory for not marking the boxes. I was told there are 5 of these super Titans. They must be powerful in order to require 8mm bolts to mount? Yikes !!! and..O yes !!! Now that I know what to look for, I will be Testing a super soon. Pray for me !!! Yes !!! O yes.. Forgot.. Temps went from 60 degress to a record smashing -19 below Zero in 24 hours.. Where is Al Gore when you need him? I guess he is down near the equator somewhere inventing the internet again. O well.... Enjoy the ride..