HEBO clutch tuning help

[spectroplasm]

Hello all

first time posting on the forums, i've got a question to ask;
I just bought a Hebo clutch competition version and i was wondering if anybody has any expirience with this clutch.

I would like to tune it so that i may have the best acceleration and or top speed on my scooter.

I've got a PGO big max 50 scooter with the following engine setup
Mikuni 21mm carburetor
70cc Koso barrel
koso krs variator with 3x 3.5 gram and 3x 4.5 gram weights.
Mitsubishi belt.
Koso pipe (modified for higher output)
Polini evolution air filter
Hebo clutch <---the one i'm having problems with)

so far here is the problem:
when i first mounted the clucth i replaced the 3 green springs with the supplied 3 blue ones and also replace my stock central spring with the supplied red one.

I went for a test and was able to reach 0~45kmh in 3.5seconds very very quickly (it felt like a sudden Tug) but after it takes it 5 seconds more to reach 70kmh and seems barely make it to 82kmh
i parked the scooter took the clucth out and tuned the adjustable hex screws, i turned them 1 1/2 CW). i went for a second test and i still felt the wonderfull tug and BAM 0~54kmh 3.5 seconds starts to lag once it hits 72kmh and after wont go past the 78 line

i tried playing with the weight rollers but i found the 3.5 and 4.5 mix to be suitable. any body help me cause i dunno what to do with this, i'm an avid scooter fan but i don't know how to tune this clucth.:X

 

[spectroplasm]

anybody ????

 

[narx]

This doesn't seem like a clutch problem, more like improper spring/roller combination.

I don't see a reason for changing the central spring and rollers when replacing the clutch, try central spring/rollers you used before.

 

[spectroplasm]

ok thanx for the reply narx , i have put back my original central spring and rollers and now the scooter wont tug like before and i hear the engine screaming really high altho he isn't going that fast (maxes out at 50kmh ).

 

[Rwade]

Thats heavy

This doesn't seem like a clutch problem, more like improper spring/roller combination.

I don't see a reason for changing the central spring and rollers when replacing the clutch, try central spring/rollers you used before.

Your rollers seem way to heavy wow the hebo clutch is very adjustable u can adjust the lil pivot point. This will give u a lil more slip without changing the spring by putting more tension so u can launch at the correct rpm. If your rollers are to heavy it wont work out to well that clutch is ultra light and heavy rollers wont let it take off how u want but it can give u great take off.

 

[adas]

ok thanx for the reply narx , i have put back my original central spring and rollers and now the scooter wont tug like before and i hear the engine screaming really high altho he isn't going that fast (maxes out at 50kmh ).

My money would be on your rollers being too light. Experiment!!
You should be around 100 kph with your setup.

frank

 

[spectroplasm]

thanx for all your replys , i had enough free time yesterday to play around with the clutch and rollers, i found a sweet spot i think:
5 gram rollers
red spring
1/2 turn on the pivot point and green slide springs

with this i am able to launch the scooter from 0 to 68kph in 4 seconds but after it has a hole (it stall for like 7seconds) and then begins to pick up speed slowly till it reaches 86kph no further.

what to do next in order to remove that acceleration hole ?
thanx again for all your help
oh and if you guys are wondering how am i reading the speeds on this thing i have a digital tnt speedometer hooked up to it i use my watch to do the chronometer, the local race track is just a block away from my house, and it's free to enter for scooter owners .

 

[narx]

There can be lots of transmission related problems beside rollers/spring adjustments and it's hard to know what's causing your problems, you'll have to try and inspect everything.

Do you have a belt adequate for your engine, is it worn out too much? Is variator working properly, is everythink ok with the rear pulley etc.
I would check the belt first.

I don't know what kind od power are you pulling out of your koso cylinder but I think you don't need a red spring because it's very stiff (if you have malossi one), yellow should be fine.

How did your bike run before the clutch swap?

 

[spectroplasm]

ok, after close inspection of my belt i see it's kinda worn out so i'm gonna buy one asap this afternoon any suggestions on the make of good belts? i forgot the belt legnth measurements but i'll post it up once i look at it.

for the koso cylinder it's a 47mm and comes with a two ring piston the segment rings are kinda wierd because they are thing (and i mean thing 1mm each i reckon). the ports are very close matched to that of a Polini corsa cylinder tho it's 2mm smaller.

before the clucth change the scooter was very sluggish in terms of acceleration and i had to mix my weights in order to get a good balance of acceleration and top speed. but i couldn't reach the 70kph line using stock clutch (all stock springs).

now with this new clucth the scooter flies in term of acceleration but i feel there is something holding it from going all the way to the end of it's powerband. I don't have a yellow spring but i will get one for testing if it's needed. btw are hebo red springs the same tension as malossi red? i think my red springs are 40% if i'm not mistaken, should i go for a hebo 25% spring?. I'm kinda new to english terminology for my scooter parts because over here they all speak french. I cam from the states so that's where i got my english skills

thanx a lot for all your help guys

 

[adas]

Aloha, I think you are making too much of the clutch. It is basically tuned for stall speed so your engine does not bog on takeoff by putting in stiffer springs and that is basically all it does.
Find if your engine is bogging (slowing) or overeving when you loose power after 65kph. If bogging, you will need a bit lighter rollers, if revving, go heavier. It may be a tradeoff, especially if your Variator is not a good one. I do not know your variator, but it should hold a constant rpm from takeoff to max speed.
Is your engine overrevving when you get to 86kph? If so, then you are "running out of pulley" and need an overrange (larger diameter) pulley and make sure the pulley is fully closing together and belt goes all the way to the top when at full speed. frank

 

[Thomas]

do you have a torquedriver? that will fix the problems you have with the speed stalling.

 

[spectroplasm]

thanx adas , the engine does not bog when hitting 86kph instead it sounds as if it's climbing in RPM, i verified to check if the belt is being pulled all the way to the top by tracing a thin line of on the pulley i went for a test run and parked the scooter opened the carted and checked the line was completely erased so i guess it is looking for a larger pulley.

@thomas yes i have a torquedriver, why?

does anybody else have a PGO big max scooter around these forums?
i need to know which overrange pulley will go into my scooter.

i have to admit this has got to be the best forum around man, i have been to countless ones including italian but none of them seems to understand my problems better than the pros here :0) i wish oneday i could help someone like you guy do.

 

[narx]

I'd say 86 kph is ok for that kind of cylinder if you have accurate aftermarket speedo, those stock ones are usless pieces of shit anyway showing 10-20 kph too much.

First you have to find out what's causing that rpm drop, and as I said before there are many reasons for that, check your variator, try the stock one if u have it. Your rpm MUST BE constant till variator reaches its top gear ratio.

As I know those PGOs should have kind of minarelli clone engine and maybe some minarelli parts would fit.

 

[spectroplasm]

ok this is what i have just done, i bought a new belt in place of the old one and performance is 10% better on acceleration but top speed is the same.

i don't access to any type of dyno but i do have a access to a 50kg rear wheel which i borrowed from the local race garage. i left the carter open and a friend of mine is doing WOT as i look at the belt variations, one thing i noticed is that when the engine starts to pick up enough RPMs the belt seems to float over the variator (it looks like it's gonna spin off) I heard there are "grand plage"<---(french word) variator and drive face on the market but i don't know the english equivalent of this word.

so far all HEBO parts listed in their catalogs fit my scooter fine. I'm going to switch to a malossi or a polini setup pretty soon, but i'm still waiting for someone to buy my full bred hyabusa bike, once i get that out of my garage i'll use the money on scooter tuning kits and parts

 

[adas]

Aloha, I have a PGO T-Rex. The motor is different than a minarelli, but close. The Rear torque driver is Honda, not Yamaha. The best belt is to use a Kymco 100, top boy, (there are several clones in this family). The intake manifold is completely different, you need to make your own, nothing will fit. The front vario will be from an overrange Polini for a Honda and using an oddball "boss". ie the Yamaha 50 or 90 will not work as no bosses (hubs) will fit the crank as well as the pully. You need to go to Honda parts and swap out components. CDI is Honda. Most cylinders from Minarelli will fit.
I finally just swapped over to a real Minarelli.

frank

 

[spectroplasm]

adas you're right about the honda peices going into the PGO. i remember buyng the honda Dio vario for it and the Hebo clucth was already listed in their catalog so i didn't have to use an adaptor. for the intake manifold i'm going to buy my a spare pipe and cut it to size. adas if you know of a diaphram adaptor can you post it here? the carbs on the Pgo's all have screws but i can't find a real dell'orto carb that has screws so i have to make an adaptor, for OKO carbs i have found one with a screw but it's way to big for it's size (30mm) i think my engine will be too rich with this carb no?.

I'm going to look for the Polini overrange today do you have a price range for it?. thanx

 

[spectroplasm]

ooh i forgot to mention does the Reinforced Honda Dio crank fit on the PGO? i saw it at the store and the guides were identical (i didn't take measures tho) thanx

 

[adas]

ooh i forgot to mention does the Reinforced Honda Dio crank fit on the PGO? i saw it at the store and the guides were identical (i didn't take measures tho) thanx

The PGO crank is unique. Most like a Minarelli, not Dio at all. But as I remember the Minarelli is different too.

"adas if you know of a diaphram adaptor can you post it here? the carbs on the Pgo's all have screws but i can't find a real dell'orto carb that has screws so i have to make an adaptor,"

I am not sure what you are saying... but if you mean reed block, that also is very different on the PGO. I just modified the stock one and fitted a 19mm delorto mounting bolts, but it was a tight fit.

When I got tired of the PGO quirks, I bought a LC Aprilia rear disk engine and sold the PGO engine to the local dealer who was happy to get the spare.

frank