Predator 79 Transmission Options?

[ColdCruiser]

Thanks Aleman!

Yes, I installed that small aluminum brace on the SBP jackshaft. I'm a tiny bit concerned the chain might barely touch the bolt holding the brace. I might have to grind something.

There is another brace at the bottom of the SPB kit. It bolts to a U-bolt. Mine was missing a nut so it's not attached yet either. I went and got the nut yesterday.

The last sprocket I needed along with a chain and some half-links showed up today. I'll be sure to get the chain as tight as possible. Got my dog trailer today also.

I'm somewhat concerned about the 40t I put on the pedal sprocket. It's hard to pedal and to get going. Now that the bike rides, I think I'll put the 30t back on and see if it's better.

I'm going to need a different fuel tank. The aluminum cylinder tank will not fit with that exhaust where it is. I'm thinking a Whizzer tank might be good.

The exhaust was pretty cheap but it was the one that had the best chance of fitting. It was sold for a Preddy 212. I had to drill-out the holes on the flange and grind down one of the cooling fins on the head to get it to fit correctly. Looks like it will work just fine now. I'm working on a chain guard and exhaust guard to keep my leg from getting burned and chewed up. It's made from 3" ABS pipe. I hope it doesn't melt. Waiting on some thermal header wrap.

Not too much left to do! I should be test riding in a week or so!

 

[The_Aleman]

40T -> 15T is definitely a rather tall pedal gear without the engine running. I have 44T -> 15T on my bike and I only use 1st and 2nd gear (5-speed) if I pedal while engine is off.

That's the drawback of trying to sync engine and pedal powerband. There's always a compromise somewhere! It should work great once your engine is running, tho.

The 30T will make it easier to pedal, but you'll lose some speed when engine is running as well as a lot of the engine-and-pedal synergy we worked on.

 

[KCvale]

I'm going to need a different fuel tank.
The aluminum cylinder tank will not fit with that exhaust where it is.
I'm thinking a Whizzer tank might be good.

Whizzer tanks are ~1.2 gallon, and they don't mount friendly on a rounded bike top bar, but they can work.
I used one on my 79cc pred build.

The rear was easy. A motor mount bracket on the bottom, a muffler clamp top piece, a set of spacers bolts and nuts.

The front required a really long spacer, same setup as the rear but with steel tubing for support.

I use strips of bicycle grips on both sides of the curved frames high point to support the frame above that high point. The rubber/plastic gives it nice little cushion to tighten against.

That should look sweet with that tank, if you can find one.
I got mine from **** Kremmer (Helmut), a local Whizzer guy, last I talked to him he only had yellow tanks left I think.

 

[ColdCruiser]

UPDATE

I put the 30t front sprocket back on and got everything lined-up again. It's still no picnic to ride, more like pushing a wheelbarrow. Without the engine, 5 mph isn't too bad and I could probably make it a few miles. With the 40 lb trailer and 80 lb dog, I might be good for a mile or two (without the motor).

It seems to me that slow speeds is where I'll most need to pedal. There are some areas where the motor is prohibited and I'd have to shut if off.

I weighed the bike... 80 lbs dry. Plus 6 lbs of fuel, 40 lbs of trailer, 80 lbs of dog, and 215 lb pilot, ~10 lbs misc, is 431 pounds!! yikes! ...which is why it has a motor!

 

[ColdCruiser]

KC,

Thanks for sharing that. I had no idea. I assumed it would fit easier than the China tanks.

I'm trying to imaging what it would like like with that size tank. Do you have a picture of your whole bike?

I also wonder about a small motorcycle tank. Perhaps a 250 Honda Rebel or such. Probably a 3 gal tank and is much too large.

Another thought is to go ahead and get the 4" x 10" aluminum barrel tank and mount it to the handlebars or something until I can get the exhaust out of the way.

I suppose I could also mount the mower tank to the rear rack for the time being.


Regards,

 

[ColdCruiser]

UPDATE

One of the last things holding me up is the throttle linkage. It was low on the list but now it's coming up. I want to leave the stock setup alone for now, at least until I've tested everything. That means leaving the governor and linkages untouched.

The throttle assembly did not hold any clues as to how to hook it up at all. It's just about 1.5" of brake cable sticking out the end of the cable shroud. If I can use the entire throw of the cable it will be about 1/3 twist on the twist throttle grip. However, some of that will be used to ATTACH the cable to the throttle linkage! Seems like there should have been a couple extra inches of cable on the end.

Another issue is the engine wants the throttle cable to come from the REAR as if it were on the push bar of a mower. With the throttle control on the handlebars in the FRONT the cable will try to pull the throttle lever THE WRONG WAY, unless I loop the cable around from the rear. EXCEPT, that's seems silly to me AND my "extra long" cable is no where near long enough to do that.

SO, it looks like what I need is a lever with a pivot attached to the throttle linkage so it will pull in the right direction and so it can be designed to use the full length of the cable to get as much twist as possible out of the twist grip. I'll also need to find a good and appropriate return spring.



It all started off pretty good but once I got it in there, I had to make adjustments. Now I think I have something that is pretty close to what I need. It looks like it will work. unfortunately, I'm going to have to make another one because the metal I used was just too flimsy. I don't think it will hold. I also don't like my adjustment splice. I traced out a new [linkage adapter arm] and made a cardboard pattern. I'll recheck my measurements and linkages then find a suitable piece of metal to cut it out of.

I'm surprised that I didn't find more info about throttle linkages. I'll try to post a good image of the gizmo if I get it to work correctly so anyone else using a Preddy motor can have the throttle cable facing the right way also.

 

[KCvale]

KC,

Thanks for sharing that. I had no idea. I assumed it would fit easier than the China tanks.

I'm trying to imaging what it would like like with that size tank.
Do you have a picture of your whole bike?

Yep.
I built mine on a 29" Micargi Fatal Love.

Full finished bike topic here.
http://kcsbikes.com/topic.asp?TOPIC_ID=648

One of the last things holding me up is the throttle linkage.
It was low on the list but now it's coming up.
I'm surprised that I didn't find more info about throttle linkages.

I documented my 79 build.
About 1/2 way down on my build topic here is throttle linkage.
http://kcsbikes.com/topic.asp?TOPIC_ID=639

Hope that helps.

 

[ColdCruiser]

KC,

Ah yes, I have read those threads amongst hundreds of others when I was doing my initial research. But you know it makes little sense until you start getting your hands dirty, lol. I have learned a lot from sites like yours and others. That Whizzer build was one of my inspirations. I also heeded your advice on jackshafts.



I considered a throttle linkage like yours but really didn't want to start messing with the governor just yet. Reading your post was a lot of deja-vu of my issues and thoughts.

AZ has a reputation as "Motorized Bike Capital of America" and I just happen to be here now, so I thought "what better time to do my build?" I knew I'd be here for at least a few months but I really pray that I can get gone before it gets hot again! Anyway, I was thinking that there may be an event I could attend or perhaps I can meet you to get a first-hand opinion and any suggestions? (I'm on the west side.)

 

[ColdCruiser]

EXHAUST IS IN THE WAY...

It might be fine. If it's not a big deal, I'd like it more horizontal. This would allow for more space on the rear rack and under the seat where I'd like the fuel cell to be.

The OMB exhaust is very sturdy. The flange is MUCH thicker than the stock one and the 1" pipe is larger too.

So my question is, Do I need to have a custom pipe welded together OR can mine be bent to the correct angle?

What type of shop would do this cheap? ...or should I just put it in a vice and whack it with a hammer or such?

 

[KCvale]

Ah yes, I have read those threads amongst hundreds of others when I was doing my initial research. But you know it makes little sense until you start getting your hands dirty, lol.
That Whizzer build was one of my inspirations.
I also heeded your advice on jackshafts.

Glad I could help.
Pictures help but like you mention, until you have your hands on it you can't really start.
Speaking of pics, neat compilation, 7 of those builds look familiar ;-}

I considered a throttle linkage like yours but really didn't want to start messing with the governor just yet. Reading your post was a lot of deja-vu of my issues and thoughts.

Ironically, why I tend to detail things in a build topic is so I can give myself Déjà vu if another similar build comes up. It's not enough to be an instruction manual, but enough for me to clearly remember.
None more than this 10 page long Topic http://kcsbikes.com/topic.asp?TOPIC_ID=144 about the adventures with the Giant Suede bike for my very first shifter build.

That's another even longer story than just that topic but relevant to your exhaust question below.

AZ has a reputation as "Motorized Bike Capital of America" and I just happen to be here now, so I thought "what better time to do my build?"
Anyway, I was thinking that there may be an event I could attend or perhaps I can meet you to get a first-hand opinion and any suggestions? (I'm on the west side.)

What a great time to be in Phoenix, at least until the end of the week.
I took a ride in shorts and a T-shirt yesterday!

I don't know of any MB specific events but plenty of bicycle, motorcycle, custom car events that would welcome an MB, heck, dozens of outdoor events every weekend for everything people that live in snow do in the summer this time of year here.

Sure you can come by, I am in Sunnyslope, just off 15th Ave and Peoria east of Metro Center up against North Mountain.
Where are you?

EXHAUST IS IN THE WAY...
So my question is, Do I need to have a custom pipe welded together OR can mine be bent to the correct angle?
What type of shop would do this cheap? ...or should I just put it in a vice and whack it with a hammer or such?

View attachment 59684

I have a conduit bender that will usually work, it depends on where and how it needs to bend.
Whacking it with a hammer in a vice usually doesn't provide rewarding results though hehehe ;-}

What I do when I can is just cut the pipe just after the the flange pipes initial bend, hold the new pipe where I want it, cut each pipe end to match, hold it in place and get a tack weld or two, pull it back off and weld seal it.

I just used my local muffler shop for my exhaust needs back in '11 -'12.
Catch the shop on a slow weekday when the workers are just sitting around and you can stand right there and work with them for what you want as they do the cutting and welding for you cheap.

The Giant Suede exhaust project was way more difficult and 2-stroke, but answers the exhaust help question you asked, and kind of a fun way to express how I can completely relate to having 'hands and eyes on it' to know what to do.

This was the Suede with a SBP X-chamber before, and after I had the muffler shop add a glass pack to the exhaust.

Way off topic now, but I figured you would like that.
The whole spirit of 'well.. lets try this...'

I am just starting another of those today as while I was typing this post the Fito with most of the parts I need for my new build just arrived ;-}