Modern Buddy

I have a Rattler 110 with a Prima pipe installed. In most cases it runs just fine but occasionally seems a little rich and stumbles in midrange, idle and top end are fine. I haven’t attempted to do any tuning yet, but it appears that it might be a problem with the needle. Is it a clip adjustment on the needle or are there different needle sizes available to tune out this type of problem? By the way what type and model carburetor is on the Rattler? Because of obstructions I couldn’t see the make and model with out taking it off

Make and model... good questions. It may be an air/fuel adjustment that's needed. Seems to be pretty common it needs adjustment after it breaks in a bit. The air screw is hidden behind (toward the center of the bike) the finger adjust for the idle. It's a small slotted brass screw (super easy to see if you remove the seat bucket). Clockwise to reduce the air ammount, counter clockwise to increase it.

hey nissan what size mainjet have you settled on? ive changed it out like 15 times only to find no real difference

I'm still waiting for my jets to get here Hopefully soon, with my latest airbox mod I need to re-dial in my carb settings. It's not giving me full power and stumbles a bit in the mid-range. Nothing an hour of turn-ride-turn-ride-turn type carb tuning can't cure. All I need is the time

nissan, did scooterworks supply you with extra jets along with the pipe?
i talked to adam over there and he said the pipe comes with three different jets. the weird thing is i never recieved them either. let me know what you settle on, i have a similar setup on my own and found that 86 is best with that tiny carb. any leaner its too hot any richer its not as powerful

Really, the pipe comes with jets? Maybe we should all e-mail scooterworks and get our free jets? I'm going to try some larger jets when they arrive. As it is now with the stock jet I have to turn the air screw all the way down or it'll bog. I want more fuel so I can get the air screw at least a few turns off the bottom. I had the bike running pretty darn good... then I put the airbox lid back on. Now it's off tune again. I'll find what works sooner or later

I got a 95 and 100 main from my dealer. I went to the honda shop and ordered 105-120 mains and 38-50ish pilots. I drilled 5 holes in the airbox in those little indentions. You can actually "tune" your airflow very well with a piece of duct tape covering and uncovering the holes. With the K&N cone filter direct on the carb it pulls harder on top with the 100 main, but bogs real bad down low because of the stock pilot. Should have the jets and pipe in middle next week. I will dial it in with box airboxes and report back on jetting.

Brandon

funny i did the same thing on the airbox with the divots but i used rubber plugs that fit just perfect. although even with a 95main pulling one of those plugs out and i lost power. i think i might have a new project though. a piston and rings and gaskets were shipped overnight to my work with no charge typed on the invoice. bossman said its mine cuz im the only rattler owner in town so some porting might soon be in the future.

I hear you on the plugs, that is clean for permenant use. I was just using the tape to get a feel for what it liked. Anything more than 2.5 open 3/8" holes would start to cause a bad bog at bottom RPM.

alright everyone i ive finally hit the target on tuning this pipe 99main with one and a half turns out on the mixture screw, now the air box, i took out two of the divots at their exact inside diameter. went to a 2000 rpm comp spring and upped the rollers to 9.5g.....now with just the air and fuel mods i only noticed improvement in top end but heavier weights evened out with a high rpm spring takes you to top end quicker but keeps you at stock rpms.......and im sure you all remembered that the prima pipe is tuned for most power at STOCK rpms. put it this way, im hitting 50 in an 1/8th mile up a steady hill from a complete stop. and all the while not harming the motor

Do you have to jet the carb if there is no mods to the airbox and running a prima pipe? if so, what jet?

i would jet anyway pipe or not its running lean as hell. with no mods at all 85
pipe only 90ish(probly less) and the rest, well that is for you to figure out.

The carb is a Keihin 077 B YEV. I forgot to measure the intake manifold opening side of it for the size, but I reckon it's in the 24mm arena.

Pilots and jets are available via ebay for cheaper prices.

Anyone have any other recommendation than pouring a bit of gas down the throttle cable neck for filling the float area after working on and replacing the carb?

I thought gas would pour out of the filtered line that comes off the bottom of the tank, but it didn't. Can put pressure in the tank to get the line to flow, and can blow bubbles into the tank via the line. Had trouble starting the rattler this way...once started the vacuum pulls the gas through just fine.

I'm running the Prima and spring, and my indicated top speed went from 61-62 to 50-51. I reinstalled the stock spring and there was no change in top speed, still 50-51.

I went up one on the main jet 85 to 95, no change in top speed, slight gain in pulling power from 40 to 50 mph though.

I'm going to re-install the stock pipe and see how much bottom end gain there really is, in reality the Prima may just sound faster.

In traffic there are times when a extra 5 to 10 mph in reserve would be nice.

SIEG, WHAT ROLLER WEIGHTS ARE YOU USING?

rattler350 wrote:SIEG, WHAT ROLLER WEIGHTS ARE YOU USING?

Sorry, rollers are stock.

HMMM... I THINK IF YOU ADD 10 GRAM ROLLERS WILL GET YOUR TOP SPEED BACK, BUT I HEARD THAT PEOPLE DONT LIKE THE TAKE OFF WITH THE 10G. IM PUTTING A PRIMA PIPE/JET ALONG WITH A 2,000RPM SPRING. I HAVE TO TELL YOU HOW IT WENT FOR ME.

Keep in mind the carb tuning is so important on a 2t motor. Just having the right "stuff" in there is worthless if you don't have it dialed in. Just playing with air and fuel mixtures on my Rattler (without changing any parts) I can completely change the powerband and lose or gain about 5mph. 2t motors are tougher to dial in than 4t, but when you get the right combination

Has there been anyone to get this pipe to add top end and acceleration.

nissanman wrote:Keep in mind the carb tuning is so important on a 2t motor. Just having the right "stuff" in there is worthless if you don't have it dialed in. Just playing with air and fuel mixtures on my Rattler (without changing any parts) I can completely change the powerband and lose or gain about 5mph. 2t motors are tougher to dial in than 4t, but when you get the right combination

Agreed, but all the needle profiles, pilot and main jets combinations won't give a pipe designed for torque top-end. I think fitment somewhat dictates the design with the long headpipe and short stinger, ideally the belly of the chamber would be under the scooter for performance but that creates clearance issues. A longer silencer may add a little top-end.

And no...............I didn't stay at a Holiday Inn Express last night.

the carb actually measures 19mm - not even close to 24mm.

Here's some helpful info. on jetting: http://www.keihin-us.com/tune.htm

Whatever you do...be careful not to turn the slide barrel 180 degrees and install it like my dealer did....it will have a WOT effect upon start up!

barndwellers_md wrote:the carb actually measures 19mm - not even close to 24mm.

The stock carb is 19mm, or is that Keihin 077 B YEV an upgraded carb? I thought the stock carb was something like 15mm or maybe even smaller.

Keihin 19mm is the stock carb. In some forums I've read they are putting 19mm on 70cc 2 strokes.

OK.........in an attempt to gain the stock observed 60 mph top speed, I reinstalled the stock variator spring - no change, 50 mph. Tonight I pull the PRima pipe and installed the stock sytem sans emissions - no change, 50 mph.

Only two areas are non-stock:

>Main jet is a 90 vs. 85

>Emissions controls removed.

I corked the air bleed line off the stock head pipe.

Is the lack of emission control actually limiting top speed?

FWIW - Power with the stock pipe is not dramatically different, mid-range is weaker............the quiet is nice though.

Sieg wrote:OK.........in an attempt to gain the stock observed 60 mph top speed, I reinstalled the stock variator spring - no change, 50 mph. Tonight I pulled the Prima pipe and installed the stock sytem sans emissions - no change, 50 mph.

Only two areas are non-stock:

>Main jet is a 90 vs. 85

>Emissions controls removed.

I corked the air bleed line off the stock head pipe.

Is the lack of emission control actually limiting top speed?

FWIW - Power with the stock pipe is not dramatically different, mid-range is weaker............the quiet is nice though.

After test riding the above set up I re-installed the emission controls and went back to the 85 main jet...............top speed is still around 50 mph.

Now I'm thoroughly confused.

Is there adjustment in the variator?

Probably running a hair too rich, or a hair too much air in the ratio. I seriously doubt you're running rich. With my Polini air filter on I've got to run with the air adjustment screw all the way in or I get too much air and it runs like BIG POOP! Still waiting on my jets so I can correct the lack of fuel issue...
With my current setup top speed is still the same but I've been able to hold 45-48 (indicated) on some hills that used to drop me to 38-40. In my opinion it's still got some fine tuning to do but that's gotta wait for the jets.

Finally got the jets! Went straight to the 100 and what a difference. No, top speed is relatively unchanged. However I can now maintain about 50 at 3/4 throttle not WOT and the engine response is much smooter. I still need to play with the roller weights a bit more to get the "feel" I'm looking for but overall I'm happy with my setup. (Frankensaust, Polini Air filter housed in the stock airbox with holes drilled in it, 2000rpm spring, 100 main jet and weights being finalized soon)

anyone ever change out the low speed jet with success? I think the stock was 36 or so.

Had my Prima pipe, Polini filter, Malossi MultiVar2000 and a change of clutch springs done yesterday. The clutch bell sent with my HIT clutch was the wrong fit, so we have to wait for the right one to arrive from MRP, and I'm having the Malossi 21mm carb (listed on Scooterworks for Buddy 50) put on then, too.

Multivar2000 came with 2,000 rpm contra spring and 12g weights.
While we wait on the bell, we put the yellow 1500rpm springs on the stock clutch. Rejetted to 100 main, and bored out the idle jet to 46.

Current results (I weigh 155 lbs, fwiw):
Lost about 5 mph on the top end (but I expect to gain it back, plus maybe just a little more, with the HIT clutch and the 21mm carb installed).

Rips off a standing start... I hit 28 mph indicated crossing a 4 lane intersection. Gets to 44 indicated in just under 1 city block. Doesn't dog at all throughout any of the cycle now; it accelerates fast and stays fast right up until it tops out at roughly 53 mph (58 indicated).

Sounds monstrous.

Looking forward to getting the rest of the job done in about 2 weeks when the parts arrive and I'll let you know how it turns out.

Will you have to pre-mix with the 21mm carb? I'm curious to hear how the HIT clutch works out for you.

I'm not sure about the pre-mixing. The Buddy doesn't require pre-mixing, so I'm thinking no. I'll let you know, and will hopefully be bragging about the performance of the HIT clutch, taboot. My shop's 'hot rod' mechanic said he's really impressed with the quality of the clutch's build.

Has anyone installed a pod type aircleaner on there buckten?? I have a prima pipe with the stock airbox and a 92 main jet. My question is what size slow speed/pilot do I need with this setup???

Latest update. Sealevel and winter temps in the mid 60's the scooter liked a # 92 main jet with the stock pilot jet, mixture screw 1.5-2.0 turns out.
Mind this is with the stock airbox and aircleaner. Still waiting on jets to sort it with pod filter.