Hesitation before scooter picks up speed (Bogging Down) + Rattle

[PaulMcintyre]

Hi there,
This is my first post on any type of forum so please take it easy on me if i miss any details out.

I recently bought a used Kymco Agility 50 4 stroke on a 2009 ( 59 ) plate in the uk and it was fully restricted. The bike Has 8000km on clock and has recently had a service. After reading many of the positive reviews that people had posted after they had de-restricted their scoots I decided to go ahead and do mine.

this is what i have done in order since owning the scoot

i cut the CDI
installed new de-restricted drive boss
K&N free flow air filter
88 main jet
malossi multivar variator
Malossi kevlar x belt
5.5 gram dr pully slider weights

i have purchased clutch springs and also have the white malossi contra spring but im waiting delivery of a socket big enough for my impact wrench so i can remove the nut on the clutch, think its 34 or 33mm.

the scooter drives well and feels smooth once going but is quite slow from a start and when i rev it tends to bog down for a second or two and then picks up. my top speed is roughly 45mph shown on the clock but i highly doubt the speedo is accurate, feels more like 40mph tops.

My aim is to get rid of the bogging and get a quicker acceleration but maintain the same top speed.

Am i right in thinking the main jet might be too lean or too rich? its hard to get parts for the agility here in the uk but i managed to get a naraku main jet kit which has sizes from 80-98. could you recommend if any of these?
im also  thinking of putting the standard air box back on and putting a 84 main jet in as a friend has same scooter but with only new belt, drive boss and cdi cut and his is way faster of the mark and same top end.
 On a side note i have also noticed that my rollers are getting flat spots alot, i put 6 gramm malossi ones in before the dr pulley and after only 1 week i had very noticable flat spots and when driving i hear a contant rattle, sometimes even whilst the scooter is idle. Any Ideas?

sorry about the long post and any help is appreciated.

regards paul

[blue]

you may wana try the 82 jet the 5.5 rollers should be good and also free flow filter you may be geting to much air. maybe just cover half the filter up with something and see how that works. just becarefull you dont wana burn her up keep a eye on the plug to see if its running to rich.

[PaulMcintyre]

Thanks for the fast reply

ill try that first thing in the morning its nearly 11pm here in the uk you see, i was under the impression that 88 may even be too lean as some others on the forum had jets up to 100 with a free flow air filter. i havnt got a clue about plug chops at the moment but im keen to learn as this is my first ever bike. any ideas on the rattle?
thanks again for the fast reply

[blue]

wear do you think the rattle is comeing from what side of the scoot if its by wear the rollers go in at make sure your sliders are on right and look good. and if you got the right ones if lose they well rattle.

[PaulMcintyre]

I think the rattle is from behind the transmission housing mate, and the fact that the malossi rollers have bald spots from 1 weeks light use is a bit worrying for me 2 be honest. just cant wait to get the scoot dialed in properly so its more consistent. If i have put the dr pulley sliders in the wrong way would the scooter still run and change gear? i got 5.5 gram 16x13. is this correct? and i assumed my standard variator was making the rattle last time when i saw the rollers were flat so i bought the malossi multivar and the noise is still there. 

do u think this could be the cause of the bogging down aswel? or should i still do the main jet change?

[sidthesloth]

G'day mate, by the sound of the engine bogging it sounds like you have not yet tuned it correctly to suit the air filter. I don't have a four stroke scoot myself but, other members had fitted free flow filters and upjetted to suit, but I think the exhaust was too restrictive, some had a restricter washer inside the exhaust. If the exhaust can't handle the extra flow after changing the filter, I think some people were drilling holes in the exhaust. The better option would be to buy an after market exhaust, but it is all money. Try tuning your carb and see how you go with that, it is repetetive and time consuming, but if you run the engine too lean you can do serious damage to it. If you put in a larger jet, take it for a ride and see what difference it makes, if worse try a smaller jet, if better then you know you are going the right way. Do a search on the forum for plug chops, there are explanations on the subject that are better than I can give. With regards to the rattle, first look at your variator, if the slide bushes are worn or missing, they will rattle. I replaced my variator last night, my last one rattled like it was about to drop the crankshaft. Also check your valve clearances are to spec, another source for rattles.
Stick with it and you will have a lot of fun, though they can test your patience at times

[sidthesloth]

Hmm, missed your post while I was writing mine. If the rattle was there before changing the variator and still there after, I would be looking further into it, check that you don't have too much play in the crankshaft bearings. It may be an idea to go over the variator again and make sure that it is installed correctly. I have heard about Dr. Pulley sliders being put in the wrong way and from memory the only side effect was poor performance, no mention of rattles.

[PaulMcintyre]

thanks for the replys people, your help is very much appreciated.
to 'sidthesloth'

sorry to sound like so much of a noob but what is a slide bush? is that part of the variator? the malossi one i have installed is only 1 week old so im assuming it cant be worn down yet as it has only done like 5 miles.

[PaulMcintyre]

ok will do, ill keep you posted on how everything looks, ill try and put like an 84 with the air filter on and also an 92 and do some plug chops asap.
with regards to the rattle, one thing i noticed is when i bought the variator it came with a plastic washer but no instructions on were to put it, i put it on before i put the variator on and everything worked but the scoot was sluggish and only hit 40, i then took it off and i hit 45mph. but both times the rattle was consistant especially during 1-20mph. and still bogging down for 1 or 2 seconds.

scooters are frustrating but rewarding when they work and it doesnt rain haha

[sidthesloth]

No, the new one won't be worn. With the variators, they have little plastic bushes to stop the metal parts touching to reduce wear and rattles.
No hassle, ask as many questions as you like, there will always be people to answer them. Questions always get people thinking.

[PaulMcintyre]

Thanks,
just been doing my homework on the forum about plug chops, is it neccessary to buy a new plug everytime i want to do a test run after a change. or can i buy 1 new one go round the block, if i dnt like the result, clean it change the jet and try again? or is that too good to be true haha.

[sidthesloth]

Here is a pic of the variator backing plate with a slide bush next to the slot it goes in.

[sidthesloth]

To do a plug chop, find a plce where you can hold the scoot at full throttle for about 2 kms, warm up the engine, put the new plug in, start the engine and ride at wide open throttle for aproximately two kms, then shut off engine with throttle held open. If the engine is running lean, you can use the same plug again with a richer setting. If you are going to use a smaller jet, then you won't be able to see if there is a change as the previous test would be darker.

[blue]

Good job sidthesloth explaneing that to paul its good to see people helping people out.

[PaulMcintyre]

so im probably best warming up on my plug installed now then using a new plug for the tests and starting off with lower (Lean Jets) and moving up until i get the right plug reading.

and im also gonna check my variator is installed correctly and the crankshaft bearings are ok.

i really appreciate the help by the way mate.

do u think the bigger jet and air filter is worth the hassle or should i just put the standard air box back on and put an 82 jet in, will the difference be that much as my friends is standard and his is faster at the moment.

sorry to sound like a moaning kid, im just competative and want mine to be faster haha