Tuning hell, slight bog PLEASE HELP!!!

[robotguy]

Hiya guys. Going crazy here.
I'm getting so close, but something still isn't right with my carb.
Transmission is tuned pretty well, got it tuned in before swapping the 19mm for the stock 12mm carb.
This is a prebug with a 70cc Malossi MHR rep kit.

I'm running a 19mm Dellorto PHBG with a W7 needle, stock airbox.
Right now optimal main jetting seems to be right around 80-82
Running great for the most part, good plug color, feels very fast.
The problem I'm having is when I slam the throttle from idle to WOT fast
on the stand or on the road, it bogs and dies.
If I slow the opening of the throttle just in the beginning,it runs like a bat outta hell.
Then I can ride and to full speed with no hesitation.
The bogging problem only happens if I flip the throttle too quickly from 0-WOT.

I used to be able to just bury the throttle to WOT quick, and I would just take off with my 12mm carb.

I am using a 45 idle jet now, tried 50, and the bog went away when slamming the throttle
but then the pilot screw would not function.....
I could turn it in all the way and the motor would not die.
Should I try a 48 idle jet?

I tried all clip positions for the needle, and it does best with the clip in the lowest position.
It seems to be a lean condition, as when I activate the choke #60 starting jet,
the bog goes away as well..but of course then it won't run right on the road.
I tried going up in main jet sizes as well, but then it just ran poorly at WOT,
all sputtery over an 85....


So... I'm wondering if the W7 needle taper is a short taper,
and I could use a more narrow needle.
Should I go down to a W6 needle?

So, what should I do here?
Any ideas?

Thanks,
I feel like I've pulled this carb apart 20 times today,
trying different variables one at a time.
I could do it blindfolded now.

[X7rocks]

what pipe are you useing in conjuction with the parts?

sounds like its lean when you WOT it any open air mods?

[robotguy]

Modified goped pipe, works excellent.
Nope, the airbox and tube all are intact.

It does sound lean, that's why I was asking what to do...
Everywhere else in the the setup is running smoothly.
The only issue is the fast wot blip of the throttle bogging it out.

[X7rocks]

switch the pipe out...

you think it works excellent but your talking about a pipe thats made for rpms well above 10 k and for 23 to 31cc engines (or in some cases the 460 engines or the pro 60 motors)

get a real pipe for it then try tuneing it,theres a time and place for ghetto rigging.

switch your pilote up one number put the air/fuel mixture at 1 1/2 turns out from turning it all the way inside.

do you have any pictures of this thing?

[robotguy]

I hate to disagree but.....
There is always a time and place for making stuff yourself if at all possible.
That's what I do all the time.
I'm pretty good with reshaping/resizing pipes. This pipe is meant for peak power right around 8k.
This thing performed great with the 70cc kit before I swapped the carb.

I will try to raise the pilot up,
I can't drill it like I usually do, as the drill set I have only goes from a
#45 jet up to a #50 jet.... Have to buy a few pilots I guess.

Thanks....

[X7rocks]

unless you have tryed a different pipe then you cant really compare

raise the pilot up slightly. and take it from there,

any pictures of this pipe

[robotguy]

I've tried another pipe I made as well.
(Larger belly, more torque-y...) But it didn't rev quite as well.
I'll try to get a picture of it soon for ya.

I did an order for a #6 needle to try, 48 jet, and a few mains in the low 80s.
We'll see what works....

[zeonsredcomet]

Get a real pipe! Thats all i have to say. Get an RSII its a great pipe or maybe an athena pipe

[robotguy]

Originally Posted by zeonsredcomet

Get a real pipe! Thats all i have to say. Get an RSII its a great pipe or maybe an athena pipe

I got this fixed, just haven't posted here as I'm not enjoying the hating on my pipe.
I raised up the idle jet to a 48 and dropped the main to an 80 with a W7 on the
2nd clip up from the bottom and it's running so fast it's frightening.
Running 33G rollers for now.

I do not agree with your assessment of my pipe.
Matter of fact, it makes you guys look pretty uninformed.
Just because you don't have any desire or capability to build your own stuff,
don't try new things and must purchase all your goodies,
it does not mean what I build does not work.
Part changers...pffftthh...

I was having some trouble getting my scooter tuned,
it does not mean that the pipe does not function well.

It was just tuning, and I just needed a slightly larger pilot jet to
get it slamming when I flip the throttle hard.

This homemade pipe performs great.
It's quiet, has smooth all around power, and has great bottom end.

Here's a picture, though I don't even know why I'm posting it for you naysayers.

[Blackbomber]

Many people bolt on proven parts, and can't get them to work, either. Glad to hear it's working to your satisfaction.

[X7rocks]

yeah that post was utter ignorance, you tuned the motor for a goped pipe..and i dont expect you to be really exceding that much potential with it.since its made to work for a gopeds engine

why not stick a Yz pipe on a scooter? is what im trying to say.it may be a tuning hell to get it to work decent..but wont work right .

[robotguy]

Originally Posted by X7rocks

yeah that post was utter ignorance, you tuned the motor for a goped pipe..and i dont expect you to be really exceding that much potential with it.since its made to work for a gopeds engine

why not stick a Yz pipe on a scooter? is what im trying to say.it may be a tuning hell to get it to work decent..but wont work right .

You are sounding more ignorant every post, man.
That's why my motor rips now. Because my pipe don't work right?
You're a mod...?

Do you even know how pipes work? lol.
You "can" get fantastic results for a pipe that is designed for a different engine. One just has to experiment with length,
stinger size, etc....
I have tried pipes designed for a 125CC on a 50cc with incredible results.
The larger belly just gives it so much oomph in the low to mid range
if that's desired.

There are pipes for gopeds, let's say an ADA S2, that surpasses the belly size of many of the pipes most of you are running and the length of the cones are similar.
Sure, it will be curved, and not hand crafted by Leo Vince himself,
but who cares? If it works it works.

You make so many assumptions...
The belly and most of the dimensions of the cones (though curved)
are incredibly similar to many scooter pipes on the market today.
I know, I measured a few....

A pipe designed for 50cc can run well with a 70cc too,
just might have to make some modifications, or maybe none at all.
It all depends on the tuning and the pipe's dimensions.

All I'm saying here is that it's very short sighted of you 2 to
say ditch the pipe before adding anything else when I was having a simple tuning issue.

And to answer your question about running a YZ pipe,
I bet it could be great if it was installed correctly.

[Blackbomber]

Robotguy - I think if you are happy with the setup, that's what matters.

I hope noone misconstrued the intended sentiment of my prior post. When I stated that many people bolt on proven parts and can't get them to work, I was trying to reinforce what you said about tuning making or breaking a setup. I'm going to withold my oppinions on home crafted versus "real" parts here. I think that topic doesn't require any further discussion, and I haven't had much experiance in that area. Good luck with your bike (that wasn't said sarcasticly).

[robotguy]

Originally Posted by Blackbomber

Robotguy - I think if you are happy with the setup, that's what matters.

I hope noone misconstrued the intended sentiment of my prior post. When I stated that many people bolt on proven parts and can't get them to work, I was trying to reinforce what you said about tuning making or breaking a setup. I'm going to withold my oppinions on home crafted versus "real" parts here. I think that topic doesn't require any further discussion, and I haven't had much experiance in that area. Good luck with your bike (that wasn't said sarcasticly).

Not at all sir,
I was not referring to you at all that last post.
I understood exactly what you said, and have no quarrel
and agree 100%. Tuning will make or break a setup,
and sometimes you get everything really close,
and just need that one extra little jetting change or needle adj to make it perfect. That's with the off the shelf parts like you said.
Many can't even get those to work easily.


It was the 2 guys X7 and zeon who say get a new pipe
right away....that's what I was offended by.
"get a real pipe" yeah, whatever.
I'm done, don't have anything to prove here.

[Blackbomber]

Robotguy - You have been on this forum for a while, so I probably don't need to tell you that X7 and Zeon tell EACH OTHER which real parts the other should have on a regular basis. They have both told me that my pipe is holding my setup back (which I agree, but peak power is not my ulitmate goal). They are both enthusiastic scooterists and tuners who are passionate about their setups. In addition, I believe X7 works in a shop, and has experiance with many setups, not just his own. I liken the rivalry to that of sports fans. Opinions aside, they have each given me helpful advice.
I read this thread from the beginning, and I have to admit that my first thought was to try a, let's just say, "conventional" pipe. But I stood in the background, because I have little experiance with two stroke tuning. I do believe that it's unlikely to find a mix and match of components designed for completely different engines, weld them together, and expect to exceed the power potential of something that was researched and designed from the ground up for a particular application by a reputable company dedicated to that field of work. Nevertheless, every pipe design started somewhere, and I admire anyone who wants to challenge themselves, and the laws of convention, and fabricate one's own components. I'm working on a homebuilt air ride suspension for my VW Beetle. Yes, kits are available. But they cost more than the car is worth and the rear still needs to be welded in. I have access to welders suited for the job, but can't get my car there easilly. I'm going to design an upper bar that bolts in to the cast shock mounts on the frame horn, and tack it all together in place with my 100amp mig. Then take it to work, and finish the welds. I bought generic bag mount plates from a lowrider supply place - they were only $13.00 each (x4). If you go to my profile, I have a pic there of the car. The front is done, rear is still on torsions, but was lowered 5 /12".

Now on to what should be the next question: Has performance improved from the 12mm to the 19?

[robotguy]

Thanks for being so nice BB,
I just build almost all my own stuff and sometimes take offense when people shoot down my ideas right from the get go.
****, if I listened to the naysayers,
I would have never built my rock band of real pneumatic robots which has kept me employed for the last 12 years.....

Back to scootering though,
The performance did improve,
noticeably so, to the point where the brakes can't stop me quickly.
Even when adjusted, the brakes will lock up the wheel and I'll just skid
if trying to stop very very fast from a high speed run.
That's the price one pays for a very light scooter....

However, gas consumption has gotten much worse.
I'll run it this way for awhile, and if the consumption is too bad, I'll switch back to the stock carb jetted a bit rich. I do not believe that the stocker
jetted correct with airbox intact will kill this topend.
Especially with me running good synthetic oil premix at 32:1.

I really only got the 19mm as an experiment.
Now I need to run it for a few months and see what I think of the setup
before changing.

[robotguy]

Spent a little time on it again today, after riding it yesterday and not being happy with it's running.
Found that lighter rollers were needed, went down from 33G to about 31G
(3 rollers drilled to be about 10.3G each)
Might try 30G tomorrow, what's 1 gram anyways????

Then I tried the 1500rpm clutch springs, and they were great.
I hadn't tried them since I deglazed the clutch pads and added the 2000 rpm contra spring.
They rule now that the clutch and belt is not slipping like they had before with a lighter contra and glazed pads.
Might try the 2000rpm clutch springs next, but it might be too impractical.
It's so awesome when everything starts to come together after looking for that sweet spot in carb and tranny tuning....

[zeonsredcomet]

I wasnt trying to be a "naysayer" I was just trying to get the point across that if you use a pipe that is not even close to being built for your engine ESPECIALLY an MHR rep that puts out around 10HP out of the box then you will have NO OFFENSE as you stated "tuning hell" Yes it is good to fabricate and customize things, that has a certain "engineering" appeal to it but if you want POWER and smoothness then leave it to some people aka malossi athena and whatnot who have 1000's of R+D hours.

Also x7 and myself are friends and rivals in a sort of friendly way and we ALWAYS talk about our setup and always want more of what we have and plot new builds. X7 has had countless pocket bikes (hence his name) midbikes and so forth. I myself Have a strong background with 302 mustangs and some good time in with small block chevy's. I have also gotten a moderate amount of time on some GY6 on the side and other minarelli horizontal and one vertical pre bug and Piaggio LEADER engine on a Fly 50 4t. point being x7 and myself are bluntly.....obsessed and make some of our living off scooters so we know our stuff. I can speak for me when i say i didnt mean to offend but when you use a Goped pipe for a MHR rep......it will be hell to tune and NOT recommended. However im glad your happy and i do think its cool to engineer things.

[zeonsredcomet]

Originally Posted by robotguy

You are sounding more ignorant every post, man.
That's why my motor rips now. Because my pipe don't work right?
You're a mod...?

Do you even know how pipes work? lol.
You "can" get fantastic results for a pipe that is designed for a different engine. One just has to experiment with length,
stinger size, etc....
I have tried pipes designed for a 125CC on a 50cc with incredible results.
The larger belly just gives it so much oomph in the low to mid range
if that's desired.

There are pipes for gopeds, let's say an ADA S2, that surpasses the belly size of many of the pipes most of you are running and the length of the cones are similar.
Sure, it will be curved, and not hand crafted by Leo Vince himself,
but who cares? If it works it works.

You make so many assumptions...
The belly and most of the dimensions of the cones (though curved)
are incredibly similar to many scooter pipes on the market today.
I know, I measured a few....

A pipe designed for 50cc can run well with a 70cc too,
just might have to make some modifications, or maybe none at all.
It all depends on the tuning and the pipe's dimensions.

All I'm saying here is that it's very short sighted of you 2 to
say ditch the pipe before adding anything else when I was having a simple tuning issue.

And to answer your question about running a YZ pipe,
I bet it could be great if it was installed correctly.

Also i have to say this x7 is not a mod and he did have a point as i did about not running a pipe designed for a drastically different motor. Yes you can run a 50 pipe on a 70 but you dont get the powerband that its made for.

Also your version of your motor ripping is probably (no offense again) nothing compared to our set ups. x7 runs in the upper 60's and i run an honest 65 mph. If you were to run a pipe engineered for a proper powerband then you would get alot more out of your MHR rep. I meant no offense again just had to get that off my chest. See previous post as well.

[robotguy]

Originally Posted by zeonsredcomet

Also i have to say this x7 is not a mod and he did have a point as i did about not running a pipe designed for a drastically different motor. Yes you can run a 50 pipe on a 70 but you dont get the powerband that its made for.

Also your version of your motor ripping is probably (no offense again) nothing compared to our set ups. x7 runs in the upper 60's and i run an honest 65 mph. If you were to run a pipe engineered for a proper powerband then you would get alot more out of your MHR rep. I meant no offense again just had to get that off my chest. See previous post as well.

Are you getting 65 out of a prebug vertical motor?
Big difference, as Prebugs cant even get close to the RPMs that any horizontal min can get.
I know what a fast motor is, and what it can do.
Yep, my setup is nothing compared to yours....lol.
I didn't know this is a contest.

I had problems tuning because I hadn't played with the low jet enough, big deal.
I just had to split the difference between the 45 and 50 jets I had.
The 48 worked fine. The "Hell" I was experiencing was not because of the pipe,
it was because of missing the proper jet at the time.

You're comment of "no offense" just offends again.
I'm done talking to you about my pipe, as I said before.
Keep bringing it up, it's great fun.
Is this what Provo has come to?

What do you need so you can shut up about my pipe?
a speed run? A race? lol....
Got nothing to prove to you.

My motor does rip now, for a prebug minarelli.
See you guys.
I'll be moving on....

[zeonsredcomet]

Originally Posted by robotguy

Are you getting 65 out of a prebug vertical motor?
Big difference, as Prebugs cant even get close to the RPMs that any horizontal min can get.
I know what a fast motor is, and what it can do.
Yep, my setup is nothing compared to yours....lol.
I didn't know this is a contest.

I had problems tuning because I hadn't played with the low jet enough, big deal.
I just had to split the difference between the 45 and 50 jets I had.
The 48 worked fine. The "Hell" I was experiencing was not because of the pipe,
it was because of missing the proper jet at the time.

You're comment of "no offense" just offends again.
I'm done talking to you about my pipe, as I said before.
Keep bringing it up, it's great fun.
Is this what Provo has come to?

What do you need so you can shut up about my pipe?
a speed run? A race? lol....
Got nothing to prove to you.

My motor does rip now, for a prebug minarelli.
See you guys.
I'll be moving on....

I dont want anyone to leave and iam truly sorry if i offended you. I just want people to ge the most and if i came off overbearing im sorry.
You have alot to offer the forum and community i dont want to see someone leave.

[Blackbomber]

I think it would be pretty cool if we were all in close enough proximity of each other to meet up. I'd like to ride with all of you, and see how our different approaches to tuning the Minarelli function.

Robotguy might not be moving on from our forum. He might just be moving on from our deadlocked debate over the goped pipe. I hope that's the case.

Two of the members I admire the most on Provo are Gabe and Skuuter. When they post, it's often about riding. And THAT is what it's all about.

[zeonsredcomet]

Originally Posted by Blackbomber

I think it would be pretty cool if we were all in close enough proximity of each other to meet up. I'd like to ride with all of you, and see how our different approaches to tuning the Minarelli function.

Robotguy might not be moving on from our forum. He might just be moving on from our deadlocked debate over the goped pipe. I hope that's the case.

Two of the members I admire the most on Provo are Gabe and Skuuter. When they post, it's often about riding. And THAT is what it's all about.

I would have a blast riding with you and plenty of others on this site. You do have a point about skuuter and Gabe they do always post about riding,and that is what its ALL about.

[robotguy]

chin iriyou dzuki shuushi shura kyaku yaku damu kuso

Wow, even in the Japanese language you're still a d-bag.
Impressive.

I think we've got this ironed out now.
I won't make any claims that anything of mine is the best ever
(like I never did anyways)
and no one will bust my b@11$ about my DIY projects, deal?

[zeonsredcomet]

Robotguy im glad to see your here, I think the japanese is aimed towards me however since his innappropriate posts caught him a banhammer (x7) Iam again sorry if i was hard on you with my comment.
I dont want anyone to feel alienated this isn't zumaforums....lol

That is why i dont like that site since they are hostile and curse and scream at will

I like my scooters light hearted and fun not hostile and ridicalous.

Glad to see you here have fun and keep posting.

Now tell me more about your pipe since i do want to learn!

[Blackbomber]

Originally Posted by zeonsredcomet

That is why i dont like that site since they are hostile and curse and scream at will

Let's be careful not to disparage other forums here, I don't want to have to edit YOUR posts, Zeon. Just kidding! Truthfully, with the occasional exception, we do a fair job of keeping things civil here.

Originally Posted by robotguy

I think we've got this ironed out now.
I won't make any claims that anything of mine is the best ever
(like I never did anyways)
and no one will bust my b@11$ about my DIY projects, deal?

Robotguy, I think the fact that you stuck around in spite of all this speaks volumes about your character. No "deal" required. We can all learn a lot from each other; be it about innovation and fabrication, what parts are best, and should be combined together, or just when to shut up and listen (or ignore).

[zeonsredcomet]

Originally Posted by Blackbomber

Let's be careful not to disparage other forums here, I don't want to have to edit YOUR posts, Zeon. Just kidding! Truthfully, with the occasional exception, we do a fair job of keeping things civil here.


Robotguy, I think the fact that you stuck around in spite of all this speaks volumes about your character. No "deal" required. We can all learn a lot from each other; be it about innovation and fabrication, what parts are best, and should be combined together, or just when to shut up and listen (or ignore).

Yeah i besmirched "another site" lol JK dont ban me

[Blackbomber]

Zeon, what you said is totally true about a LOT of sites; one of the reasons I spend so much time here. The most I have EVER posted on a single forum is 27 posts, and that was on thesamba.com. This is post #651, so that says something.

[zeonsredcomet]

Provo=FTW