New build...HF 79cc in a Trek

[scotto-]

OK, finally got the new chain on today.....sorry to keep you in suspenders Silverbear, things have been hectic around here as of late. I can tell you right now, you're gonna love your new build.

Wow! This thing flies! I can say this build is a success....and a lotta fun too ride. Took it around the neigborhood for many laps, testing it against an HS w/4G and a 50T rear sprocket on a Schwinn Point Beach......the HF pretty much smokes it. The HS had marginally better take off, but that was very short lived as the HF just motors by and says bu-bye. The top speed so far is approx 40mph, the HS Schwinn w/50T won't even come close. The HF has good smooth pull and gets you to 30mph pretty quickly. Another nice thing about this build is when you roll off the throttle, the compression of the motor slows you down without the clutch kicking out immediately like the 4G. It really has the feel in that aspect of a 4-stroke and it is as smooth as glass on the top-end....virtually vibration free!

We tested it with and without the little B&S muffler attached and it is definetly faster and pulls harder without it....doh. But it is a fair bit louder as well...what can I say?

So all and all it was a challenging, yet fun build and the results are better than what I was expecting. Cheers!

Oh, the throttle set-up works flawlessly and the front and rear V-brakes are more than adequate stoppers for this beast.











There are only 3 minor things left to do to this build...
1. hook the kill button up (to the throttle assy)
2. install the hand grips (on the handlebars)
3. Paint that blue engine shroud black and affix Bintang sticker to the pullstart cover. That's it.....finally!

 

[silverbear]

Well,
I'm greatly relieved to remove these danged suspenders and to hear of your success. With my 65T driven sprocket it sounds like I'll be able to realize the goal of hill climbing capability along with 30 or so for cruising. A couple of questions.
I'm running my exhaust as you have, up and back under a rear rack and know nothing of this heat wrap. Where do you get it? Is that something NAPA would carry or do I need to order it? How hot is that exhaust pipe a foot and a half back? Mine will be running under the behind the seat gas tank, which makes me a bit nervous, so I want to be sure I not only don't destroy the family jewels or start a fire on me backside. I'm using the Whizzer flex pipe kit from EZM which has no muffler, but does have a fishtail reducer at the end. I have the same thing on the HS Motorbike and like it a lot. So that's one question about the heat wrap stuff. What is it, where do I get it, how is it installed? I guess that's actually three questions about one thing.
Where I am, kind of stymied at the moment, is I'm at a point where I now have the motor secured to the home made mounting plate after drilling, opening up the drill holes, grinding a bit here and there to get the motor in the right position to line up with the driven sprocket. Lots of fussing with that, but I believe its good to go. The current issue is bolting the Qmatic transmission to the Greyhound. The transmission comes pre- drilled to mount with four bolts to the HS engine (or the Honda it was cloned from). On my Motorbike build this took a few minutes to accomplish, then mount the #41 chain and vroommmm... "hi ho Silver and away"! The Greyhound motor has a completely different bolt pattern which is going to require drilling new holes in the transmission mounting plate. Trial and error was fine on the motor mount and if I had botched it up badly enough I could always cut another one. But I want to measure twice and drill once, so to speak, with this transmission mounting plate. How did you determine where to drill your mounting holes? I mean, what did you do? Make a template of the Greyhound hole pattern and lay it out on the transmission mounting plate? With what as reference points? I have a lot of hesitation at this juncture, being unclear with myself about how to proceed. Once the holes are drilled it won't be long before the engine and transmission are married and off on their honeymoon, but at this point it feels like a shotgun wedding with a lot of resistance from the bride and groom. Any suggestions on how to proceed with this critical union? Many thanks. I'm so glad to hear things are going well with your build. It sure looks good.
SB

 

[Dan]

Awesome Scotto. Looks great too.

 

[skyl4rk]

Nice build Scotto, what is Bintang?

 

[azbill]

looking good Scotto
nice write-up on the build too

 

[jbcruisin]

Looks really good Scotto. I always wondered if you could cut the exhaust flange at the weld & weld it facing more towards the back so the pipe wasn't coming out straight up? Is there clearance for that?
Jay

 

[Quenton Guenther]

Hi Scotto,

LOOKING good!


I have a suggestion you all might consider on the path of the exhaust system. As many know EZM did some minor testing on the best all around performance exhaust for the HF motor [thanks to several EZM dealers]. And one of the most important features of the EZM flex pipe for the HF motor is its "flexability".

Consider running the exhaust forward and then down [like most MB & MC exhaust systems]. If you alter the exhaust manifold and turn it forward, the HOT pipe will not be close to the following........important parts of the human body, seat, rear mounted gas tank, painted fenders, rear carrier racks, saddlebags, etc. The flex pipe can be installed forward and can easily be formed [bent] to match the contour of the bike frame.

Have fun,

 

[Fossil]

Hi SB
The exhaust wrap I used I got on Ebay. It works well too. I can grab my exhaust while running without burning my hand. Exhaust header wrap it what I searched for on Ebay.

Jim

 

[silverbear]

Quenton,
I hear what you're saying about routing it forward and down, but i do like the look of Scotto's and may try it that way. Nothing is set in stone and can't be changed. If it seems to hot and feels like it poses a significant danger then I can change it. But I'd like to see. One consideration is that I want to make an in frame copper tank for it this winter and running the exhaust to the front takes it very close to the copper tank then. I like the exhaust coming out lower on the HS engine than out the top as on the Greyhound... for a bike build it is an inconvenient location.

Jim,
I did a little looking on ebay and on Monday will check with my local NAPA store to see what they can do for me. I see that there is a silicone to treat the fiberglass wrap with. Did you have to do that, too? If so then I might go with the treated wrap which is supposed to be better anyway and the coating would eliminate the need to use the silicone spray. Can you use two layers of that wrap to further insulate the pipe? Is the heat from the pipe noticeable on your leg... not burning it, but is it uncomfortable?
Also, Jim, how did you figure out where to locate the new holes in your transmission plate for matching up with the Q'matic transmission? I'm hoping tomorrow to get it drilled and bolted up.
SB

 

[Fossil]

Hi sb
No silicone on the wrap here. Just one layer of the wrap held in place with mechanics wire. I guess you can use two layers. I don't see any reason why you can't. I have no heat issues at all. I don't even notice any heat from the exhaust.


Jim

 

[scotto-]

OK, I finally got home from work and can respond to some posts.....thanks everyone for the kind words, the build really did turn out well, suprisingly well in fact. To answer skyl4rk's question first, Bintang is a beer made in Indonesia....the rest is history. Now on to Silverbear's concerns.....you've come to the "fun" part of the build, everyone that has done this type build (HF and any gearbox, but in this case the EZM) knows what I'm talking about. First off, what I say here is what was done and I can't recommend it because you shouldn't alter things in this manner per the manufacturer's original intentions of they're usage....in other words don't try this as it voids all warranty's (if any) and you should leave well enough alone. But in this case as you know by now, you have to adapt and make necessary adjustments to things if you want things to work correctly on an obscure build, so to speak.

With that bs outta the way, let me see if I can help. The first thing I can recommend is get your engine placed in the correct position in the frame. This is nearly impossible to do without having the tranny to know what the correct position is.....right? So let me tell you on this frame, the correct position is with the oil drain plug and the sparkplug dead center on the frames center. In other words the oil drain plug centered on the downtube and the sparkplug centered on the seat tube. Once you have that, at the correct elevation (so that the length of the engine clears everything) which is up pretty high in the frame and keeping the engine level fore and aft, you can hold the tranny up to the engine (with the tranny cover off of course) and try to center the PTO (driveshaft) to the backing plate (mounting plate) of the tranny.

OK, does the tranny fit up snug to the mounting surface of the engine? Of course not, and not in any position. Do the mounting holes of the tranny line up with the mounting holes on the engine? Of course not, the holes are not spaced the same as the Honda or HS mounting holes, but we already knew that.

So yes, you must make a template of the HF engines mounting holes that will work putting the EZM tranny in the correct position so that everything clears and the plate mounts up flush to the engine. You still with me here? Well things still aren't lining up right because the tension idler pivot bolt is right in the middle of the road, so to speak. If you want to know how this situation is remedied, shoot me a PM so I don't bore you and the world to death with how to overcome some more obstacles....is that fair?

 

[scotto-]

Silverbear, here are a few more answers to your exhaust wrap question(s).....you can get 15' of black-ish 2" wrap from Kragen/O'Reilly Auto Parts store for $20 and also prolly at NAPA. Or you can get it here as well: fd44x

Yes this pipe gets HOT, and a double wrap of the stuff wouldn't be a bad idea. You start the wrap by clamping one end of the wrap, then start wrapping overlapping each wrap by half roughly. If you have enuf, clamp that end and start wrapping back the other way, then clamp the very end. You'll have no probs with this stuff as you're a natural at this kinda thing. When you put the EZM cover on after the build is complete, the cover will conform (melt) around the exhaust manifold, no need to cut or file the cover there. Just so ya know.

 

[scotto-]

The next build is almost underway.....looks just like the HF, only bigger with a smaller valve cover and weighs about twice as much....the bike it's going on is much different.....

 

[silverbear]

Scotto,
Thank you for your detailed comments as they are much appreciated. And I know that others will read them who are contemplating a build similar to yours or mine and will benefit from my experience as I have benefited from yours. There are already some aspects of mine which are directly influenced by your build. One is the exiting of the exhaust under the seat and the rear rack. I suspect we may see this again in other builds, but yours was the first I saw. Another is in the plate you used for the rear V brake. I had a donor bike from the dump sitting there with a similar plate welded to a front fork and realized I could cut it off and mount it to my front suspension fork. I had been on a path of setting up an old caliper brake and know the V brake is much better.
I will indeed PM you about what I suspect is a repositioning of the idler bolt or a slight modification to the engine casting if it makes contact with the bolt where mine does. I appreciate your advice. The process of making a template is something anyone will need to do using an engine other than the H.S. One cool thing about the Qmatic transmission is that with different mounting holes it could be used on different engines. It would be good if we created a little file of templates a person could copy and save themselves the headache of figuring out where to drill the holes correctly. I've been staring at mine for a couple of days now. Time to get this thing mounted. Heat wrap on Monday. Vroom!
SB

 

[silverbear]

Hi sb
No silicone on the wrap here. Just one layer of the wrap held in place with mechanics wire. I guess you can use two layers. I don't see any reason why you can't. I have no heat issues at all. I don't even notice any heat from the exhaust.


Jim

That's good to hear. Thanks, Jim. I'll try to get some on Monday.
SB

 

[Dan]

Keep meaning to post but is real important to break in the HFs according to manual. Not like a plug an' play Honda. I keep forgetting to mention it. Have one test HF that I used the wrong oil (10W 30) and "rode like I stole it" from the git-go to find their limits. Still runs but not well and becomes spare parts today.

Oh, also after hard riding, exhuast is 500F at the manifold. Have exact temps but they are for leading the pipe forward. Cools down rather fast and in a short distance.

 

[Quenton Guenther]

Hi everyone,

If you will make a template using the original 4 mounting holes [where drive bolts to motor] as a reference, EZM will print and include in the Q-Matic drive kit. Be sure to include as much information on the motor description as possible. This way all your hard work can be passed down to others to make it easier for them.

If we need to relocate certain bolts, nuts, etc, to fit alternate motors we can consider on next production run.

Have fun,

 

[scotto-]

Thanks Quenton, I'll take some measurments and such and let you know what I've got. And for a note of interest SB, take a look at the angle closely in my pics of the tranny in relation to the mounting plate and such....it cannot angle up any higher than what you see, otherwise the exhaust manifold would require major modification....no fun.

Putting the final touches on this build today, then it's time for more fun in the saddle.....wooohooo!

 

[KilroyCD]

One is the exiting of the exhaust under the seat and the rear rack. I suspect we may see this again in other builds, but yours was the first I saw. SB

SB, Jim's might have been the first with that configuration (Sept. of '09). When building it, we thought it would look cool to route it out the back under the rack. Until we got that exhaust tape on there it was a real crotch-burner. Two things helped - the aforementioned exhaust tape, and a larger seat. The Worksman saddle is not only more comfy, but it shielded more of one's anatomy from the exhaust.

 

[scotto-]

This build is a done deal, finished everything up today and took her out for some realtime testing......she came out the winner! Faster and smoother than the HS builds and a motorized bike to be reckoned with. Some final pics.....

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a couple more to come, pics that is.....in a minute or two