Pocketbike Forum banner

1 - 20 of 46 Posts

·
Registered
Joined
·
23 Posts
Discussion Starter · #1 ·
Well a couple weeks back a few buddies bought Giovanni bikes on ebay and showed me the pics of their fun during a nice evening campfire- promptly I cruised into the house and hit buy now times two... GF gets one too haha.

I found another on Kijiji and brought it home in the meantime. It's not a bad little bike, but had to do the standard fixes. Brakes adjust, chain tension, clutch and drum clean/resurface, carb cleanout etc etc.

Handy tip- being an ex-mechanic of ten years I have tooling and leftover goodies- of which I found that the brake caliper pin lube works fantastic in the throttle grip where the cable just wraps around the plastic radius.

So last night my two Giovanni bikes arrive and I found that I had to go over just about everything I wouldn't want to be a kid riding one of these straight out of the box- geesh.

Started with my black one and fixed the major brake adjustment issues, loctite'd everything, aligned the chain, lubed the throttle cable, castrol chain lube on the chain etc etc. Ran it through 6 thermal cycles using my IR camera to monitor (I'll post up the pics later) FYI the emissivity of the cylinder and reflected apparent temp mess with measurements using a spot type IR thermometer. Not that this is overly critical anyhow.

This bike seems to get stronger and snappier with every cycle- The difference is quite pronounced and I haven't even rode it yet. I'll do a few more then ride a couple tanks and swap the plug for a good NGK.

Did the GF's red one next. Same drill but didn't have time to get it running. Took a bit more work with chain alignment and lube to get this one freed up and smooth. Should be a good toy soon...

Thanks to all who post in the forum, I got alot of useful tips for sure. And more to come I'd bet. Here's a couple pics.








Cheers
Eric
 

·
Banned
Joined
·
21,742 Posts
Looks good and glad someone did the right thing before resisting the urge attempting to ride right from the box.............Lots of fun and good rides on them.................:thumbsup:
 

·
Registered
Joined
·
23 Posts
Discussion Starter · #3 ·
Thaks Cam. I am still going through your posts and have got a huge amount of information from all your posts/pictures. The thermal cycling was entirely learned from you. Back in the day we broke in RC engines similarly, but usually at higher rpm- your method seems extremely logical, very easy, and is totally non destructive- I love it.

I would take compression readings too- but my guage is broken. Have a nice Snap-On leakdown tester though, just itching to be tried on the 2 strokers.

Cheers
 

·
Banned
Joined
·
21,742 Posts
Thanks man....The heat cycling is similar to the way you break-in r/c engines......

Like I say about the process youll actually notice the engine loosening up and I see you mentioned how you noticed it...

If you just rode it straight out of the box the piston would be massively scored up and trying to ride a tight engine high in friction and high heat will do more destructive harm to the engine than good...

The heat cycling eliminates a ton of harm on so many levels and im sure you saw how fast the engine got up to and surpassed normal operating temps the first 3-4 heat cycles....That high temp condition could lead to ring scorching and premature blow-by that will stick the rings from early on.......

After I get them heatcycled ,,broken-in and the topspeed numbers and topend revs recorded I tear the engine off the bike to soup-up the stock head with some extra uumph using my trusty dremel........

Really good work your doing so far and thanks for the good words..Keep up the good work...:thumbsup:
 

·
Registered
Joined
·
23 Posts
Discussion Starter · #5 ·
Haha perfect! I was thinking the same- I couldn't decide wether to mess with porting etc right away, or break it in first then do some cutting. I chose the same way you mention. Made sense to me as well. Plus I'd then have a baseline to judge from.

I have a cheap tach on its way- along with a big bore complete engine for the yellow one. It needed a few things anyhow and thought what the heck- might as well give it a try.

Here some of the pics of the heat cycling- I didn't get a chance to optimize them for span etc- so they aren't the best.

Thanks for you help and kind words! Cheers







 

·
Banned
Joined
·
21,742 Posts
Cool pictures and it definately shows alot of good useful info that most may know but dont actually realize.................
 

·
Registered
Joined
·
162 Posts
**** those new gios look cool! I had one of the older model gios and that think was balls, engine was a crapshoot. But you seem to know what your doing to break those in, Good job.
 

·
Registered
Joined
·
23 Posts
Discussion Starter · #8 ·
Thanks. Heat cycled the red one tonight, but I fear it will not last long. This thing is nowhere like the black one. Motor has a very pronounced clanginess which sounds like skirt smashing the cyl. Took the externals off to investigate but its definitely internal as you can note it over TDC. Oh well- not much I can do but run it for now. Less pronounced when it warms up so I'm not too worried.

Learned a few things

-don't run them dry as something will lodge between the needle and seat causing a mess. Doh.

- When on a tilt the float does bind up on the bowl (I assume) running them dry, leaning out and quitting... should have smoothed out the bowls before running at all. Noted...

- Pegs fixed up with JB weld for now as I know the would have lasted about 5 seconds. Thanks to other friends who wrecked a good ride due to this, saving me the grief.

Anyhow- on track for some riding now.







 

·
Registered
Joined
·
162 Posts
tip on those pegs, grab a short piece of angle iron (3-4 inches for each side) and weld (or jb weld) then to the mounts itll give you a better foot mount that dosnt break off 24/7
 

·
Registered
Joined
·
23 Posts
Discussion Starter · #10 ·
Sounds good for sure. I thought I'd give them a chance before throwing them in the trash. Here's the ridiculous ones I put on the used CAG. They need to be trimmed yet, but solid enough LOL. Such a poor fix I'm embarrassed, but very functional for now. They are crazy solid considering the contact area...



Cheers
Eric
 

·
Registered
Joined
·
162 Posts
oh by the way watch that ignition system. I just bought a bike that had one that was wired wrong, caused the bike to instantly kill itself -,-

those foot pegs look decent however ****nn thats long! haha, bet ya can get it sparking if you turn.
 

·
Registered
Joined
·
23 Posts
Discussion Starter · #12 ·
Hahaha Ya, as I mentioned- they need to be trimmed. I'll shorten them up and make some endcaps with my 3D printer- if it ever gets here.

I wouldn't wanted to corner on asphalt with these- guaranteed to eat $&!* LOL

Cheers
Eric
 

·
Banned
Joined
·
24,145 Posts
Anything is better than the stock pegs, they last about 5 minutes,lol.
 

·
Banned
Joined
·
21,742 Posts
I weld on BMX stuntpegs..First I drill and tap them,,nut them and weld them for extra security....If they become a problem theyre easily trimmable.......



Some pics of a low budget big bang for your buck syock modified 49cc thats gonna spin atleast 13,000rpm's with a stock crank.........

When you pop those Gio bike cylinders theyll look like this one but without the boost port I grinded in....





 

·
Registered
Joined
·
23 Posts
Discussion Starter · #15 ·
Nice Bud! :)

I finally made it through your whole thread and in hindsight I really should have copy and pasted the tips into a txt file or something. I see you do a few like above- sleeper stocker versions.

Any tips on Boost port height/width? I see some exhaust work, but anything done to the piston? I saw a bit about this but the details of which I missed.

Thanks for sharing the great ideas! I'd love to bump up the stockers and see how much I can squeeze out of them once they have a few miles on em.

Cheers
Eric
 

·
Banned
Joined
·
21,742 Posts
Nice Bud! :)

I finally made it through your whole thread and in hindsight I really should have copy and pasted the tips into a txt file or something. I see you do a few like above- sleeper stocker versions.

Any tips on Boost port height/width? I see some exhaust work, but anything done to the piston? I saw a bit about this but the details of which I missed.

Thanks for sharing the great ideas! I'd love to bump up the stockers and see how much I can squeeze out of them once they have a few miles on em.

Cheers
Eric
I do enhance engines no-one will do and I do like making sleeper engines...Everyone mostly makes judgement on things based on how it looks...I love it when someone shows up on a flashier looking bike and everyone thinks its faster,,,until it gets beat then my comment is atleast their bike still looks pretty............LOL...

A 43cc engine will have some good comparable power to a 49cc power with serious revs...For some reason the thicker 40mm cylinder holds its shape better and deforms less when thermally expanded....This is an old mildly modded 43cc piston



The piston is indeed modded...Its lightened 2.7 grams,,It has 4 ports facing the stock windows thats 7/64" and a 5th port facing the 3rd boost port I cut into the cylinder..then I raised the sideskirt profile a lil bit,,deburred the piston edges,,thinned the Wiseco rings a tad,,polished the ringtops and the piston sides,,polished the top too but left the piston top pebble finished this time for the differing results on this engine............





 

·
Banned
Joined
·
21,742 Posts
For your exhaust port youre gonna notice the inner part of the cylinder port side its gonna be rectangular shaped..You want it to look more rounded on the top with widened and rounded exhaust port sides while keeping the bottom untouched and flat.....

Out towards the exhaust flange youll notice the flange opening looks like the letter D,,,,,I give it more of a rounded square shape thats matched to my exhaust flange opening size...............





 

·
Registered
Joined
·
23 Posts
Discussion Starter · #18 ·
Very cool. I'm sure I'll figure it out when the time comes. A few grey areas;)

Help me out- which way do you put the carb float- ridged side up or down? I've now found them both ways. I would expect the ridge goes up against the forks. The cleaning threads seem to miss this.

Had to take the carb off the black one and clean it- something was causing the needle to be stuck open and make a mess. Definitely was a bit of debris in the bottom of the bowl.

Shouldn't be piddling all over the floor when I'm done...

Cheers
 

·
Banned
Joined
·
21,742 Posts
Very cool. I'm sure I'll figure it out when the time comes. A few grey areas;)

Help me out- which way do you put the carb float- ridged side up or down? I've now found them both ways. I would expect the ridge goes up against the forks. The cleaning threads seem to miss this.

Had to take the carb off the black one and clean it- something was causing the needle to be stuck open and make a mess. Definitely was a bit of debris in the bottom of the bowl.

Shouldn't be piddling all over the floor when I'm done...

Cheers
The ridge goes down..The ridge should mate with the bottom of the bowl at full drop.Some carbs have rounded float bowls and some have squared off float bowls....Ive sanded and polished the mainjet carb casting tube to get a smoother up n down float action and I still got puddles on the floor from time to time..wanna stop the mess in the floatbowl get ethanol stabilizer or two stroke oil that has it mixed with-in like Stihl HP Ultra Synthetic 2 stroker oil,,,

Ever since switching over to hp pumper carbs did I have ever so much fun on my cags.....If my cags still had floater carbs theyd be in the shed rusting away............. the X1s,,twin engined mini harley and stand-up scooters would be the most frequently used bikes again......
 

·
Registered
Joined
·
23 Posts
Discussion Starter · #20 · (Edited)
Thanks muchly. I'll check again, but didn't notice a recess at the bottom of the bowl. This one was very smooth so I didn't bother to smooth it further.

I expect I had a piece of dirt- but there is another possibility. I found the needle quite snug in the seat bore- far more than I would normally expect. If I had a spare I would have tried a few looking for a bit smaller "fin" diameter. I was going to try taking off some material, but my luck with no spare- I would have marred the needle, of had it too loose to get cocked in the bore.

I rebuilt quite a few carbs over the years and this one was defenitely a bit more snug that I'd like. Meh no biggie.

*EDIT* Just noticed your other post on the exhaust port etc... Thanks! That helps out for sure.

Also- Yep I'm already running the Stihl Oil. Had a case for my MS261 so thought I'd give the cags a real oil to run on.
 
1 - 20 of 46 Posts
Top