moby troubles got me blue!

so i got my ninja g2 and dellorto 15.15 on my stock av7 (until june when i buy the doppler er1 cylinder and high compression head) and it goes SO. MUCH. SLOWER. seriously, i was barely doing 20. i upjetted to a 68 and it barely made 15mph. so i went down to a 59 and now i'm doing about 25.

Now my bike stock went over 30 easy. can anybody tell me what's going on? i think i'm running rich too.

should i just go down another jet, or what?


Re: moby troubles got me blue!

You have to take some weight out of the variator, that will get the RPM's up enough to let the power kick in. Moby pipes tend to murder the lowend because you can make up for it with the variator. Also check for air leaks they might cause similar problems.

Re: moby troubles got me blue!

Check your spark plug... what does it look like?

Also, you should try changing just one thing at a time. That makes it easier to figure out what's going on.

You might be running too rich, but you'll just have to check.

How does it run on the kickstand? Can you rev it all the way up to like 10k rpms?

Re: moby troubles got me blue!

Also check to make sure the throttle cable opens the carb all the way. The dellorto will have a longer travel then the stock carb and it may not go full throttle... Take the carb off, look down the barrel and pull the throttle to make sure...

Re: moby troubles got me blue!

Seriously if you put your stock exhaust back on and tune the carb by itself first that would also help a lot. Also on my ported av7 i ran a 57 jet, with my doppler pipe I ran a 62 jet for reference.

Re: moby troubles got me blue!

🇮🇹💦 Of the Loin /

the g2 wont even kick in until high rpms

port your cylinder!, also tune the variator (if its 4 balls, take out 2. if its 3 balls take out 1, youll be fine on stock cylinder)

your jet should be over a 56, thats what i ran on a stock bike with a high flow air filter

Re: moby troubles got me blue!

anybody know where i can get a variator puller?

i'll get down to porting this week, but i definitely need to tune the variator (that'll get me some low end torque, yes?).

i got my throttle all sorted out, air leaks are still a possibility.

i'm still barely breaking 25 on the flat.

this is hurting my heart!

Re: moby troubles got me blue!

You can get the 2-sided puller from Handybikes. 614-299-0550.

You'll also need the long-reach pliers ( a MBK specific tool)

The bike should go well over 35 with the proper jetting.

68 and 59 are very different jets. Try something in the middle here. This needs to be exact, so do yr work.

Re: moby troubles got me blue!

i have tried jets in between and will continue to do so.

thanks a lot for the tip on the tools, i'll give them a call this week!

Re: moby troubles got me blue!

you also know that the ER1 cylinder is for an AV10 and is in no way compatible with the AV7 right?

Re: moby troubles got me blue!

yeah, i figured that out.

although on la becanerie when you search through the av07 listing it has (an out of stock) er1, so that got me a little confused.

im just gonna port it and run it without gaskets and hopefully that'll get me the rpm's i need.

Re: moby troubles got me blue!

no gaskets is a bad idea. if you run without a base gasket it'll throw off the port timing. the transfers wont open all the way, neither will the exhaust, that in turn will shorten their duration and thats no good. bottom of the piston level with the bottom of the ports = a good time. run a head too, just a pop can or something. the little losses in compression you'll get by doing that will be offset by a better running motor.

Re: moby troubles got me blue!

the clutch puller is a must, and you'll need a circlip puller as well. if handybikes charges an arm and a leg, though, for the circlip pullers, you may want to opt out of buying specialized tools and make your own. Ive found that medical scissors (pointier than the ones pictured) are perfect to get circlips out of the variator because they are super thin and super long. Get two pairs and bend the tips in and out so you can have a pair for opening and closing. I spent 30 minutes trying to get my circlips out till i started using these guys and i got em out in 4. Just an idea, and probably gonna be much cheaper than specialized pullers. usually come in first aid kits, or snag some next time you're at the hospital.

Re: moby troubles got me blue!

how will the loss in compression from not running a head gasket result in a better running motor?

Re: moby troubles got me blue!

if you run a gasket, you wont have a leak at the head. if you dont have any leaks, your motor will run better.

Re: moby troubles got me blue!

sorry, im not awake till 10 at least.

that confused me because i always sort of figured as long as you didn't mess with the timing, whatever you could do to reduce the squish zone to increase compression to the highest psi would result in a better running motor.

usually whenever i've run without a head gasket my psi is higher. I always assumed that head gaskets were kind of a factory preventative measure on low quality control and that if the head was machined not so flat a head gasket would prevent it from leaking but if you removed the head gasket and it ran at higher compression than there are no air leaks and you are way better off without it.

so what confused me was that you seemed to say running a head gasket will lower your compression and therefor make you run better.

sorry i should not be on a computer in the morning.

Re: moby troubles got me blue!

i was just thinking about running without a head gasket to up compression, not without a base gasket. i'd been told that was the way to go.

one thing at a time though. i'm porting today and i've ordered the tools i need to get in the variator. then i'll see where i'm at.

Re: moby troubles got me blue!

where did you get yr moby tools?

Re: moby troubles got me blue!


Re: moby troubles got me blue!

Did you take the restriction out of the stinger in the pipe? It's tack welded in behind the silencer.

You can run without a head gasket most of the time without a head leak. The base gasket is so thin that removing it will not help you. Use a new thin paper gasket everytime you take the cylinder off, or they are useless.

Porting a moby cylinder is a complicated process because of all the different cylinders. Be sure you know what you are doing and getting into before applying dremmel to cylinder.

Re: moby troubles got me blue!

i ordered them from handybikes.

Re: moby troubles got me blue!

what do you use for new gaskets? make your own? what kind of gasket paper?

i aint got no choice but to do the porting myself. i'll just take my time and use the porting guide in the wiki.

i have not taken the restriction out of the pipe! i will do that first.

frankly, this is over my head and i aint got nobody to lend a hand.

Re: moby troubles got me blue!

Use thin paper gaskets. I make my own out of brown paper bags while watching television. I use a 10mm wrench to make an impression in the paper of the cylinder bottom and then a razor blade from a box cutter to cut it out.

The restriction is why you are slow.

Re: moby troubles got me blue!

an everyday $2 hole punch really comes in handy with gaskets.

Re: moby troubles got me blue!

awesome. thanks.

do you do this for all your gasket needs?

Re: moby troubles got me blue!

is the restriction the thing right in the end of the pipe where the silencer attaches? with the small hole and whatnot? i should just cut that out?

Re: moby troubles got me blue!

pry it out with a screwdriver. that weld breaks super easy.

Re: moby troubles got me blue!

i got the restrictor out no problem, but the gasket between pipe and silencer got fucked up. what should i replace that with?

it's a little faster now, by the way.

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