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Post by themajekalbum on Aug 10, 2014 23:17:39 GMT -5
EDIT: Long story short: Wasn't running in the powerband for my carb/cylinder/exhaust set up. Stiffer contrast spring and lighter weights was the cure.
Hey everyone. Heres some back story on it first. I'm in Colorado at 5200. I bought it in 2007 from a dealership used. Only after market on it was a technigas next r pipe and a derestriction kit(85 main jet, vario sleeve, 6g rollers and unplugged cdi wire). I rode it for about a year and a half and it would do about 50mph flat ground (not gps, speedo minus 5 for error). Once I got a car again, the scoot was put away wet and forgotten about in my sisters back yard for 4 years. Now we're caught up to the beginning of this summer.
Finally decided I missed the scooter adventures I went on and decided to fix her up. Pulled the carb apart and cleaned it with carb dip and compressed air. Noted a 35 pilot and 85 main. Opened up the cvt to see what was in there, belt looked good and was with-in service specs. Found 6g rollers(stock is 8.5G, or so I read somewhere) in there. Took her out for a quick spin and couldn't get anywhere near 50 like it used to. Decided I needed a major overhaul. Heres the list of stuff I've put on/have to play with.
Stock size Kendra tires (running 30 psi f/r)
Airsal 50cc kit - stock kit was toast (90psi)
Naraku 17.5mm carb (Dellorto phva clone) (got 82, 86, 90, 92 main) Also have a "stock" ebay clone(unmarked jets) and the stock carb
Malossi shielded pod filter - still have stock air box with naraku foam filter
malossi carbon reeds (.35mm in now also have .25mm and .40mm) - still got stock
Naraku crank seals
7g and 5g rollers
Gates belt - Got stock belt as well, still good
Naraku twist control
Naraku Race CDI - got stock as well
Naraku high tension coil - have stock still
Naraku High output rectifier - have stock still
Stage6 Tach/temp gauge(temp only reads up to 230*f)
Scooter assassins startor (stock one gave up right when I did my crank seals)
Drilled out stock auto-cock to flow all the time and added a petcock at the carb along with new lines and filter (removed auto-cock screen)
After doing that I was sure that I'd be back around 50mph or better, of course not! I can only get to 35mph at WOT on a real good day. Here are some things I've noticed on flat ground testing.
CVT seems to keep the motor in between 6.5-7k when accelerating
5g vs 7g rollers dont seem to make a difference in acceleration or top speed rpm
Motor wont rev past 7k easily(when loaded)sometimes 7.3k tops (17.5mm carb and the stock/clone are the same) Sharpie test shows the cvt isn't reaching top gear when loaded(me @180lbs doing 30) at 7K (does reach top gear when reved to 10K on the center stand)
17.5mm Carb wont idle on idle screw (using throttle cable to float the slide to about 1/4 throttle, idle bounces around between 1600-2300)
Stock and clone stock carbs will idle with the idle screw holding the slide up as much as it can
Seems to run best with the 17.5mm carb and pod filter with the 86 in it(loads up an dies with the 90). Tried all carb/air filter combos I have.
The main issues I see is not reving over 7k when loaded Sorry if my notes are hard to decipher, I've been going crazy reading forums/theory and trying different things on my own. Think I burnt out my last brain cell swapping carbs, jets, and air filters today.
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Rune 75
Scoot Enthusiast
Posts: 441
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Post by Rune 75 on Aug 11, 2014 4:04:01 GMT -5
Can you make a video of the scooter's behavior ? It can make it a lot easier to diagnose.
Do you still use the same pipe (next r) ?
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Post by themajekalbum on Aug 11, 2014 8:02:50 GMT -5
Yea, still running the technigas next r pipe. I can do a video of it later on today an get it posted up. Ordered a malossi multi-var last night to alleviate my worries of a worn out variater and/or contra spring.
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Post by 2TDave on Aug 11, 2014 8:42:26 GMT -5
You might want to check that something hasn't gotten in the pipe and clogged it. Mud dauber etc.
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Post by themajekalbum on Aug 11, 2014 19:01:33 GMT -5
Forgot to mention that I cleaned the pipe as well, steel cable, few nuts and a drill.
Either why I found my major issue today, of course after I post asking for help. The drive faces in the cvt were too smooth allowing the belt to slip. The heat caused the variator to stick to it's bushing. I cleaned all the cvd bits in solvent at work, silica sand blasted the drive faces,emery clothed the vario bushing an sleeve, re-lubed the rear pulley and threw in the new gates belt. Hit 45mph GPS three times on the way home. Little more cvt tuning an it'll be better than before.
Still curious about not being able to idle on the idle screw...any ideas?
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Post by 90GTVert on Aug 12, 2014 12:06:07 GMT -5
You've probably got a mixture issue of some sort at idle. Either too rich or too lean. First I'd make sure the pilot jet isn't clogged and check the float height.
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Post by themajekalbum on Aug 12, 2014 13:45:17 GMT -5
It's a dellorto phva clone, non-adjustable float and the jets are clean. I went OCD cleaning it after I found an aluminum shaving in one of the passages. I'm just a bit stumped cuz it seems to idle around 2000rpm with the slide at about 1/5 open. On the stock carb with the idle screw in all the way, the slide is about 1/5 open as well. Just annoys me that I have to float the slide with the throttle cable on the 17.5mm carb, makes the idle slightly erratic cuz of how I had to modify my cable. Both carbs have a 35 pilot jet and turning the mixture/air screws don't make any noticeable difference. I've tried the pod filter and the stock air box. Any one else around 5200ft that can chime in on pilot jets?
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Post by 90GTVert on Aug 12, 2014 15:56:36 GMT -5
I'm at sea level, but that may be a bit large at 5000ft. There's definitely a problem between the screw way in and no response on the mix screw. If you have any pilot jets to try, do that. If you're also seeing excessive fuel going the wrong way (wet air filter) then maybe check the reeds and make sure they're sealing.
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Post by themajekalbum on Aug 12, 2014 19:16:50 GMT -5
The reeds do stay open a hair cuz of the nitrile coating(the coating makes a little lip at the coating-metal transition). I've been thinking about taking the reed cage to a machine shop to have it decked to solve that little issue.
Also wasn't too clear on the carb air/fuel screws. The stock carb, it makes a difference in the time it takes to drop from high idle to normal after running wot. On the 17.5mm carb it does nothing. It seems like the stock carb has a larger range of idle adjustment than the 17.5mm carb does. Like the stock carbs idle screw pushes the slide twice as high as the 17.5mm. Unfortunately I dont have any pilots to play with yet.
I do know that in theory my jetting correction factor is .92 comparing sea level to 5000ft at 80*F. Then my current main jetting blows that theory out of the water, I've been reading that people are using 85-90 for a 70cc BBK at sea level. I got a 90 main in and it seems fairly happy.
Another thought I've had is cvt tuning and jetting...Right now I'm running under my power band. Should I get the cvt dialed before I tune my main jet? When my tach hits 8300rpm the motor seems to really come alive. Right now it's running 6-7.1K when accelerating. Then 7-8k is kinda dead, I have to tuck to accelerate, but once i hit 8.3k I can sit up again all the way to 10k. Im hoping that the malossi multi var's contra spring will put me in the proper range as I'm a bit worried about dropping the roller weights with the belt slipping issue I just had.
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Post by 90GTVert on Aug 12, 2014 19:41:16 GMT -5
You'll need the pipe to be hitting for a good WOT tune I'd imagine. I've never had much luck tuning when the CVT is real far off and not hitting. Heavy rollers, soft contra spring, or rich tune will all make it struggle to get on the pipe. I don't look at other people's tunes as much beyond a basic starting point with jetting. A lot of times it's close, but not always. If the kit, pipe, filter, and carb are different you can be way off using other people's tunes. Even on my own tunes, at the same place, I've had one with a BBK and stock pipe and stock airbox using a 95 main and one with a BBK and tuned pipe and stock airbox using a stock main. Both stock carbs... 16-16.5mm Mikuni clones.
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Post by themajekalbum on Aug 12, 2014 20:45:50 GMT -5
I need to get myself outta that habit of comparing tunes to mine then, just gotta keep playing with it and realize there is no magic formula for my scoot or any others for that matter. Right now I think my issue is mainly a soft contra as its the stock/original from 2005. Close to 10 years and 5900Km(not much compared to some)on it.
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Post by themajekalbum on Aug 16, 2014 15:26:10 GMT -5
Did a few changes recently and seems to have gotten a little better. I swapped the 86 main(17.5mm carb) back in put the stock air box an snorkel back on, premixed 40:1(removed cable from oil pump) and put in my 5g rollers(roughed drive faces with 220 sand paper). I've now noticed my initial take off and acceleration is more what I want/remember. After the initial acceleration I seem to loose rpm and it gets worse after every take off. If I let it sit to cool for a while I get that initial acceleration back.
Notice the acceleration rpm up to the first stop sign (8200-8300) accelerating from that stop sign it's at (7800-8000) and was able to hit 40mph a few seconds before I turn around after the turn around it's (7200 -7500) and only hit 30mph (street is level) Does this seem like the contra softening up with heat?
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Post by 2TDave on Aug 16, 2014 16:53:01 GMT -5
Could be a weak contra or sometimes in my experience an exhaust leak will show itself once things get hot and expand.
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Post by 90GTVert on Aug 17, 2014 14:22:48 GMT -5
That's a bunch of changes at once, which makes it tougher to figure out. Try and stick to one thing at a time from here to make it easier to solve the problem.
A spring getting weak with heat could be it. It may also be a little lean and when the enricher stops adding fuel it slows a bit.
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Post by themajekalbum on Aug 17, 2014 15:13:34 GMT -5
I've decided to take a different route(the one I should have taken first) cuz of a few things I noticed. One of the motor mount bushings has separated and that means the others arn't far behind, gotta replace them all. I've started doubting my cylinder install as I've noticed a tiny bit of oil around the base gasket and exhaust. I've pulled the motor and I'm planning a reseal on the motor followed by a leak check. Gonna throw the stock carb back on with the stock air box and start from how it was when I got it, with the exception of the airsal jug/piston. Then I'm gonna experiment with all the other goodies.
For the reseal I ordered the Hoca Premium Kymco AC Gasket Set. Do you recommenced putting anything on them to assist sealing such as Gasgacinch or copper spray?
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