My Bike Project

[DeDONRAGE]

So this is what Im working on. The bike is a 1967 Gilera. Its a rare Italian cycle. Common build for these are cafe racers. But Im making a Predator 212 powered motorcycle for the backyard.

 

[mckutzy]

That's kinda cool.
How are you going to mate the rear sprocket with your clutch?
Is that a custom sprocket or you having a jack shaft?
What was wrong with the original motor?

 

[DeDONRAGE]

I am not interested in restoring it. Original motor isnt froze but would need a rebuild. Im going to run a jackshaft. The chain that fits the sprocket is a #40. That matches the clutch sprockett and the jackshaft Im doing. Hoping to get all this mounted this week.

 

[landuse]

Nice bike!

 

[DeDONRAGE]

Had time to do more work on the bike. Its coming along. I do need some chain tensioners on both chains. I have tried to tighten them the best I can. Still have to get a lot of misc parts. But it is coming along.

https://www.youtube.com/watch?v=Ju7Q4LZs38M

 

[mckutzy]

Umm what's your gear ratio???....
If I'm correct in seeing... You have a 10-14-14-56 tooth count sprockets....
That would make it a 5.6:1 ratio... With that tire (a guess 24" od, at least?) size your going to have a bit of trouble moving it off the line... Without a burnt clutch.
I'm thinking at least go with 6:1 as a starting point. I did and it was an alright ride.

 

[DeDONRAGE]

10-14-10-53 with 17 inch tire. Im not having any problems going. I need to put a tensioner on the chains. The swing arm causes too much slack. So what sprockets do you think I should change?

 

[itsid]

10-14-10-53 with 17 inch tire.

uhm NO.. with tyre on 17" RIM;
that's a difference.. with the stock 2.5x17 a difference of 5" (22" wheel diameter).

even worse IIRC 2.5 is the front;
the rear was wider (and higher) 2.75 x 17?
IDK...but it's the same thing.. two times the first number plus the last gives you an approximation of the wheel diameter.

for the biggest possible 3.5x17 that's 24" (I think that's the biggest tyre to fit the stock rim)

Anyways, that ratio is 7.4something :1 and sounds as least possible to me for a bike like your's,
since it's small and lightweight.

Still sad to see a Gilera 106ss with a predator

'sid

 

[DeDONRAGE]

I really appreciate the input and suggestions. Its just a fun project Id like to finish. You think I should change gears? If so which ones? I got this bike next to nothing. Figured it would be excellent for this type of application.

 

[itsid]

don't worry about me...
Just because it makes MY heart bleed, it doesn't mean that you shouldn't.

Anyways.. ratio.. I guess the 7.4 is a good start for a bike like yours;
I don't know your weight, so I can't tell if it'd work or not;
but if you can see your feet under the shower, I think you should -at least for now- stick with what you have and see how it goes.
you can dial in the JS sprockets later.
I mean you already have them, so a test won't harm much (that is if you give up in case it doesn't take off before the clutch is toasted)

'sid

 

[DeDONRAGE]

Flat tires in the yard it pulls just fine. Sadly second lap the chain slipped. Because the swing arm one needs tensioner. Ill get that sorted. Still having fun with this.

 

[mckutzy]

That will be a difficult one to solve as your chain drive line is higher than the swingarm pivot point.
This presents all sorts of problems as that could potentially cause the chain to snap if there is too much rebound, as opposed to bound with a chain slipping off.....

 

[DeDONRAGE]

Tempted to remove the suspension. Just add metal bars there. Would eliminate the swing arm issue all together. No faster than the bike will really be going shouldn't be an issue.

 

[itsid]

please don't

Move the jackshaft down... closest to the swingarm bolt you can; that way the effect will be minimalized.

(the actual swingarm bolt would be the ideal place for a jackshaft, unfortunately that's out of question on that bike.. or swingarm to be precise )

But you can have the Jackshaft in a way, that the JS-out sprocket sits where the original engine's sprocket would have been;

You might need to fab a new brake pedal in order for it to not interfere with the JS-in... but that
shouldn't be a big deal

Also you could reinstall the original toolbox or the fender at least
since you don't have that JS sitting up there anymore

[EDIT]
quickly made a crappy mockup...



'sid

 

[DeDONRAGE]

It sounds good except the jackshift that low rubs the tire.

 

[DeDONRAGE]

On that note I do have a question. I have never worked on a motorcycle. If I wanted to use smaller wheels/tires say 14 or 16 instead of the stock 17. How hard is it to find compatible wheels?

 

[mckutzy]

For that machine, probably hard. It's hard to find and European.

 

[DeDONRAGE]

Ok thats what I was thinking. I am going to drop the jackshaft and see how close it gets. Not much clearance.

 

[ML-TOYS]

These bike builds i see happening makes me wonder how the 16hp duramax would do on my kawasaki for riding around town.

 

[DeDONRAGE]

This is really a backyard bike. For sure nothing more.