Mechsmoto's 9.4 Morini build

[itchybird]

My pipe took much more work to fit, but my motor sits low and is tight to the front tube. I had to cut the main chamber in half at the old weld and rotate a few degrees. I had to cut the stinger off and reposition a few degrees as well. But the bulk of the work was at the pipe inlet, I actually had to shorten the tube about three inches, and then cut and rotate in two locations. Finally, I had to build a new flange from raw tubing, and to get the right diameter it was off to online metals for the tube and to McMasterCarr for washers with the correct OD. The ID I had to open up about an 1/8" or so. I did all the pipe fitting, and Pat tig welded it back together. Nothing like a three dimensional puzzle to challenge the brain!

It was quite a bit of work for a proper fit, but in the end, I now have what should be a killer pipe. And the bummer is, I haven't even tried it yet! I fitted the pipe and added some final touches to my frame then tore it all down and off to the powder coater it went. It'll be a solid week before I even get to sample the fruits of my labor.

My previous pipe was a sick bike parts chamber with a small diameter inlet pipe. I am hoping to get some of what Camlifter says I should expect with a real pipe. The bike was respectable before, but I was not getting the full 9.4 HP from it. I expect the new pipe should wake up the motor in a big way.

 

[camlifter]

heres a pic of my modded kx 65 pipe

 

[mechsmoto]

Beautiful bike camlifter!!! How loud is that exhaust?? I found some online today for not a whole lot of money... cant decide what i should about this pipe.. its driving me craaazzy!!! Dean told me working on 2 months ago it would be sent. Everytime since then that Ive spoken to him its been "its ready to be shipped.. sending it tomorrow" .. He seams like a really swell guy and all that but my bike cant be enjoyed until it has an exhaust. I have a malossi MHR pipe($400) that was designed for the old vertical minarelli engines @ 70cc(looks alot like the motionbee pipes "J" shape.. but the silencer curves and come back would need to straighten it out... all it needs is a new silencer ($100) and a few minor adjustments to be mounted... I also have a metrakit handmade pipe.. but thats too much work to make fit... and now your kx65 idea. I feel like whatever i do will be wrong. Ive already done my mounts that i have to pay dean for, I feel like IF i do the exhaust.. his will finally be sent... and IF i dont do my own exhaust >> Ill be stuck here waiting forever!!! uuuuuggggg!!!!!!!!! Any suggestions guys???

 

[camlifter]

i got the kx pipe for $50 with the silencer used at a local shop, didn't take much to make it fit. being an up pipe it takes the room where a gas tank would go so you'll need a rear or front mounted gas tank.

 

[mechsmoto]

Hope your still logged in camlifter as Id love to order this pipe today... How loud is it?? Does it fit the flange the way you buy the exhaust or does the flange need to be modified to fit the engine exhaust port?? Thanks Camlifter!!

 

[camlifter]

the outlet of the morini and the kx are the same size, so the kx pipe won't fit inside the morini out let. you need to make a sleave about 1.5 inch long and weld it to the kx pipe so it fits over the morini out let, as a plus that moves the pipe out far enough that it fits around the outside of the bike frame (my bike is a worksman) i had to make one cut and rotate the head pipe about 12 deg and weld it back up. prety simple, you'll see right off what has to be done when you get your hands on a kx pipe.

as for noise it's a little loud for a motorbike, sounds the same as a mini mx bike.

 

[Goat Herder]

I think mebbe my pipe is larger than cam's and hydro formed? It is as light in weight as they come as I perceive it. I remember being impressed with how light it was. In my video displaying my bike working with the N.V. hub. In the beginning you can see the size of my pipe it is quite large. I had a slight prob making up my mind about a muffler as I had no support for mounting one being a full sus bike the back moves. http://www.youtube.com/watch?v=q4INNy4zEkk

A heavy China two smoke muffler [some what gutted out] is what I started out with. My welds always cracked on the muffler side with their cheap metal over time never on the tuned pipe side. If it was not for that I could have easily trick mounted a perfect muffler well supported along the rear frame. Mounting these exhaust is as important as mounting the engine in my opinion as anything rattling a bike destroys things.

From an engineering point of view it was Tesla that it was said to have rattled a whole building apart with a frequency generator. http://en.wikipedia.org/wiki/List_of_Tesla_patents

All through the video you can hear it pop itty pop pop pop right off idle the pipe was always coming on very nice for me. The air inlet side of the carb on a 5.8 Morini is actually very small like smaller than a dime seriously . These motors in the 9.4 area have a way better breathing carb and reeds. I suspect the crank induced [Primary compression] on these motors are very wicked strong.

 

[camlifter]

instead of buying a new kx pipe i would look on the mini mx forums or craigslist, should be able to pick one up for around 50 bucks, maybe even less for a dented one, your going to cut it open anyway so you could fix the dents ez.

 

[mechsmoto]

Awesome!! Thanks so much for all of your help camlifter, goathearder, and itchybird!!! What rear sprockets did you end up running guys?? and how about clutch settings(washer stacks)? estimated top speeds?? Im off to order the kx65 pipe!!!!!!!!!!!! May opt for a spark arrestor type silencer(national park certified) just to try to keep sound down as much as possible.. i want to drive it on the street for a while... then>>> in time>>> the metrakit and malossi parts will be added... but, i figure I outta get my $660's worth out of the stock cyclinder and crank first!!! lol!!! Once it goes to the drag strip driveability and reliability go straight out the window!!! Plus, i better test out my engine mounts everybodys hating on around here!!>>lol!!!!! I did add the fourth mount out of respect for other more experienced builders opinions!!! Its definitely NOT as pretty as the other mounts because the engine is 4" above the bottom post.... but, keeping with the stock crank and pedals means it must be in that location... Just the more i thought about it, i knew you guys had to be worried for a reason... then it hit me!!! 18lbs hanging from the cylinder head was a ticking time bomb... the head would have vibrated lose sooner or later for sure... with the 4th mount, the motor rests on it.. and is only stabilized by the top and rear mounts. Thanks again guys for all your help!!! PLEASE KEEP SENDING IN IDEAS!!!!! Theres plenty more to come... tires should be here friday...
exhaust hopefully ready somtime next week>> then VIDEOS... updates.... and finally the performance build!!! im talking full circle racing crank, 20000rpm bearings, metrakit 65cc big bore, malossi reed valve, delortto 25mm carb, big valve intake, porting, gasket matching, and top secret crankcase mods!!!! Watttttcchhhh ooooouuuuuuuttttttt!!!!!!!!!!

 

[mechsmoto]

goathearder... the reeds and intake are better on paper.. but i opened the intake to adjust the angle and reposition my carb and when i did i wasnt happy at all with what i found... i wish i would have took a picture.. it wasnt dime sized... more like a quarter or half dollar at the most(more like a quarter though).. but DEFINITELY MAJOR restriction on the intake side of the 9.4... Im guessing THIS was the Major difference between the ktm jr and sr??? maybe the sr had the restriction removed and the carb rejetted?? i would imagine you could add a ton more fuel IF the intake was open and true???

 

[camlifter]

i'm using a jack shaft so my gearing will be different, you;ll probably want to start out with the 44 tooth rear sprocket. should do 45+ mph, stick with the stock clutch spring stack untill you get some miles on it. it will probably break in to were the clutch feels good after some time on it.

the 9.4 is allready to much for a bicycle, after you ride it you may not think you need to hop it up.

 

[mechsmoto]

lol!! Thanks again camlifter!! The mods would definitely be just for a drag bicycle>>> Ive had alot of fun down here in miami with my lil scooters tearing up 600cc crotch rockets.. the scooters still weigh 150lb to 200lbs.. so i can only imagine what a 40-50 lb bicycle is capable of!!! lol!! its rediculous i know... but, if im honest... in the end the curiosity will make me mod it out... now, 44T really?? I have a 40T at the moment.. and was thinking of going all the way to 56T as Ive seen stories of guys doing 55mph on a 5.8 morini... I guess ill just try out the 40T and let the engine break in as you suggest... then, if i want a lil more pic up... ill move up in sprockets...

 

[Goat Herder]

That 45 tooth sprocket with those tires will be way faster than 45 miles an hour . Look out with the 40. I would put you at 50 plus very easily. As a drag bike you may very well like the stock clutch arrangement dunno. I have not chose that rought myself. I don't like to go that fast on a bike . lol. For me about 50 teeth will put in in the throws of the streets down here with the elevation against the mountains. I wanna cruise around 30 miles an hour and have a playful ride.

As for a muffler I would suggest getting something with nice baffles and no restriction.


From here. http://www.motomx.com/clutch_information.html


how the bike is presently geared. You have to treat gearing and clutch set up independently. Example: If you were to make a rear sprocket change to increase top end speed, (Less teeth on rear sprocket) then you loose some bottom end power. Now with the clutch set up you can change your power curve to compensate.

With my N.V. arrangement I had to get the clutch to come on right off idle. So not to destroy the drive train. I had chains all over the place and a experimental hub. I wanted a all around cruiser and I accomplished that. With my gearing I was able to compensate for the clutch. What I learned in the long run I prefer a single speed with the clutch set up to compensate now. Less moving parts less drag power straight to the rear wheel on a way more powerful motor.

 

[Goat Herder]

Something else I ran into in my China two smoke days. The exhaust pipe [stock] on the china would help loosen the head cylinder bolts over time for me if not supported correctly. I just looked at a stock china arrangement once and revved it up hard a couple of times in the drive way with the clutch pulled in. The amount of oscillated shaking at the hanging stock exhaust was a lot to me. Later on some of my friends and I put better exhaust on theirs [tuned] with the kind of support that absolutely could not shake think frequency resonance and weight against mounts and rattling. With these builds the more solid mounted the better in my opinion.

The China cylinder heads stayed torqued better for me after better exhaust support. The Morini is so well built I never ever had a problem with the head but I mounted everything I as solid as all possible on my last build.

 

[RebelHellbilly]

ya bike looks good hows the weight balance feel with the motor up that high in frame?

 

[mechsmoto]

surprisingly the weight feels good.. the bike rides well and easily under pedal power as is... Im sure it will be a lil easier to pedal after the michellin tires and tubes arrive friday... they are 35 instead of 38 width... and much more agressive tread pattern... will post pics as soon as i have them mounted..

I guess im gonna end up ordering the Bills Pipe's kx65 exhaust... found it on ebay for $130 brand new.. header pipe and silencer... other sites sell the header pipe for $180 and the silencer for another $100 bucks.. The guy says its about the same as stock noise wise.. and IF im gonna beef her up later on might as well have a 65cc pipe that can handle it... says it gives 2hp off the rip...!! Im going to purchase it in the "works" as i dont want a gleaming silver pipe on the side of my bicycle riding through downtown miami!! lol!! Hope its not too damn loud... but, the stock silencer on ebay is like $60 with shipping new, and a used stock header is $50 with shipping so, before i do that might as well try out the new performance pipe for $20 more bucks.. The fmf turbinecore 2(us forestry approved) silencer is $100 bucks but MUST be used with an fmf header which is $200... and $300 is just too much money for a pipe im gonna weld and cut and what have you...

 

[itchybird]

Mechsmoto

Before you plunk down big money on a pipe, check your local craigslist. I found a nice used KTM pipe/silencer for forty bucks. Somebody also just listed an brand new KTM 85cc pipe and silencer for $45, so deals are out there.

You have so much room at the front of the motor, getting a pipe to fit should be easy. Since my bike is a vintage style, I flipped the pipe, it's now routed down under the motor with the stinger silencer following out the the rear chain stay.

Rich

 

[culvercityclassic]

Hey Rich,

You have any pictures of you ride to share?

 

[mechsmoto]

craigslist good idea... but, its too late... i went ahead and bought the bills pipes exhaust... think i got a super good deal... fought about weather to buy it or not all day long... everywhere else I found it .. it was $300 for the set.. just like fmf's fatty pipe and silencer... after i purchased it i went back to look for the add and its gone... the set i bought was the ONLY one!!! wooo hoo!!! I researched bills pipes as i had never heard of them before and it turns out they compete with all the other big name pipes... says they work best on suzuki engines and suzuki is famous for running the small 50cc morini engine in scooters and dirtbikes... will post pics as soon as it arrives... Looked up a video on you tube just to check noiselevel on the exhaust... the video i found was of a banshee(250cc 2stroke) and the bike riiiips with the bike.. they were always super fast anyway... but the sound was impressive... coming at you he was almost no louder than a car passing by... a lil more noise going away from you though... and when he opens it all the way up its loud but it hits the pipe immediately... no hesitation anywhere in its powerband... Im excited!! cant wait to get it.. get it welded up and have our first start!!!! WOOOOOO HOOOOO!!! Super good day!!!!

 

[itchybird]

Hey Culvercity,

You can see some early pics in this thread:

http://motorbicycling.com/f47/sportsman-flyer-racer-edition-23530.html

the first two pics are of my bike, but these are way early pics, before it was even done, and no pics of the current pipe have been posted. I think Pat has some pics of the bike just before I tore it down.

After tear down, I dropped off for powder coat last week, it should be done by tomorrow or Friday. I went ahead and dropped off the pipe for a high temp coating as well, I won't see the pipe until early next week.

So for now, no pictures, but I will start a build thread so you can see my interpretation of a Morini build based on one of Pat's flyers. Mine is flyer numero uno -none other like it. I added a lot of little touches to my bike to make it uniquely my own. One thing for sure, all you Morini types will like it.

Rich

ps Mechsmoto -its only money! the faster you spend it the bigger the rush.