2010 CFMoto Jetmax 250 Scooter

[bikerdoc]

Dear Bikerdok,
Have you reached 30000 km on odometer?

Have completed approx. 28700km and about to fit my third rear tyre with the last rear tyre being a Kenda (from Taiwan) performing quite well but only lasting 6000km - around half that of the standard low profile radial tyre supplied by CFMoto. My front wheel is on it's second tyre. Have been having some issues of late with starting from cold, but not sure if its the high humidity or high temperatures causing some issues with EFI/ECU, the air box/filter, or it could be just the higher moisture content in the humid air allowing for my condensation and therefore water to collect in the fuel tank/system although I think it's related to an after market muffler I've fitted bought via taobao for cny100 which also backfires through the exhaust a lot on deceleration (indicating that fuel/air mix is running to lean - which given fuel injection and ECU management I'm not worried about playing around with). The muffler is louder and thus provides less back pressure, and since I doubt that there's any decent motorcycles mechanics with a dyno-jet or the like to calibrate the new muffler to air/fuel mixture and the EFI wizardry -it's a no brainer.
Am looking to have a better after market exhaust fitted, perhaps a Lazer muffler for a Tmax, though if the gains are not worth it, I might just go back to the standard muffler.

I'm still fairly happy with the scoot.

[bikerdoc]

The CFMoto Jetmax has just been released into the Australian market for AU$3995 (plus applicable taxes & dealer charges depending state). Expected availability if middle of July (now). Scooter sales will be doing a review in the near future, which can now be found here. CFMoto Australia have a basic challenge review on their website, where the Jetmax was compared with two other maxi scooters

[eldarcom]

Dear bikrerdoc,

Do you know the size of CVT belt? Belt is kevlar or not?
Did you change belt? If yes in which run?

[lipsee]

Hi ,I thinking very much of buying a Jetmax,here in the UK its know as WK jetmax,,,Bikerdoc any chance of an update on your Jetmax???? all the best Lipsee

[bikerdoc]

Dear bikrerdoc,
Do you know the size of CVT belt? Belt is kevlar or not?
Did you change belt? If yes in which run?

I've replaced my Jetmax drive belt one time only, at 12600km although manufacturers recommends service at 3000km & replacement at 10000km. The belt I changed out I did myself, and aside from slight loss of diameter of the belt itself, it appeared in very good condition. No fraying or cracks between the 'teeth' so to speak. The second belt should have been replaced at the 20000km mark, or since I'd changed the first belt at 12600km then add 10000km to that. I've done a few hundred km short of 30000km and have not swapped the belt yet. I have had the drive/belt covers off and had to check out the variator as I had a problem with one of the CVT roller weights. The roller weight is a pressed two section weight, and the inner metal core had separated from the outer material. I've removed the offending weight, and looked to replace it ex-manufacturer, but CFMoto sell the complete front section variator pulley assembly and roller weights as a complete unit. I will attempt to buy a set (6) of roller weights from an online source, rather than spend the CNY900 for the complete front assembly which is not needed (incidentally roller weights weigh 11g). Have found a few online merchants that supply roller weights, so just need to check the specs on mine which will require me to take the said measurements from those weights installed, something I overlooked to do when I had it apart last time.

I ran into this issue around 28000km, give or take a few hundred kilometres, when I tried to ride from a standing start the CVT felt like it was stuck in a top/high gear. Pulling the CVT apart, which requires a pneumatic impact driver for the removal of the two pulley nuts, revealed the cause. I simply removed the offending the roller weight and reassembled minus the broken weight. After an additional 2000km the aforementioned problem has started to reappear intermittently. When I pulled the assembly apart at 28000km the second belt installed at 12600km still looked good, with little signs of wear so I didn't replace it at that time. Planning to do so when I replace the roller weights with a new set.

The CVT drive belt, is a Mitsuboshi 226 x 903 (check under variable speed belt on manufacturers website for information).
I'm guessing the 226 (?22.6mm) likely might be the belt width while the 903 (?90.3mm) might be the belt length? At least that's my guess. I'll have to measure one of the new belts to check this theory.

[bikerdoc]

Hi ,I thinking very much of buying a Jetmax,here in the UK its know as WK jetmax,,,Bikerdoc any chance of an update on your Jetmax???? all the best Lipsee

If you see my reply above to eldarcom, concerning the CVT drive belt and more importantly the roller weights, then that aside there's not been any major problems as such. The few problems there have been are minor in nature and have as much to do with typical manufacturing and designing that involves typical Chinese characteristics as anything else. I made mention a few posts ago about some problems intermittently with cold engine starts in hot humid weather, not helped by the fact that my battery had run flat some time ago when I was away for several weeks, and the anti-theft alarm system drained the battery leading to premature battery demise. The battery was never good after that. I've since replaced the battery with a new one, and combined with lower humidity and seasonal temperatures overall, have had less issues with starting. I had noticed that there was some backfiring or popping which can be heard at very low revs on deceleration. I'd not noticed it before, or perhaps never paid it any attention since the standard muffler (which is probably way over baffled for Euro3 compliance) is so quiet. The last several months though I played around with a couple of after market mufflers I bought of a dealer on Taobao (China's equivalent to the likes of 'eBay'). Since the muffler was louder I began to notice the back firing, which only occurs at around 1500 RPM. I liked the sound of the second of the two mufflers I installed, but got so frustrated with the low rev popping sound, changed the muffler back to standard, thinking it was a muffler issue. The backfiring/popping is still there.
In the attempts to fix the backfiring issue, one of the certified CFMoto mechanics who has a little dirty grimy workshop space in Zhenhai spent some time trying to find the culprit, checking air, ignition, ECU mapping etc. He even cut the end of the small engine breather hose, which now means I get 20-30mm of oil on my garage floor after I've taken the scoot for a ride, or any other parking space I might park in. As is typical here, he didn't even ask me, he just cut the end of the breather tube which proceeded to dump 50-100ml of oil on his floor from the get go. It wouldn't piss me so much except getting into the hose and replacing it, is not easy. Either a under seat storage removal or rear wheel removal to get into the hose and replace it with a new sealed one. Besides it didn't remedy the backfiring one iota!
Typical TIC (this is China - bull faeces).

Other than that lipsee, I think it's a great scoot, and worth the money I paid here. The other issue, is that there is limited choices here, or let me rephrase that as there's lots of choice, but lots of those choices suck!

Would I buy one of these in my home country, yes - if I was on limited budget, which I'm not, so unlikely as I'd buy something that has all the little extras that I wish this scoot had. One omission is the absence of a park brake, which I think is an oversight. Aside from wanting a 500cc engine - that's just me!

[lipsee]

Thanks for such an informative review,I contacted the importer with a view to a test ride(its a house about 10miles from my place) but they pointed me in the general direction of some scooter shop in town(that sucks) Choices,,here there are loads of choice,,infact I am thinking I have 3 choices,, this will make you laugh,,,1st Cf moto jet max its frugal ,good weather protection,good storeage,good in for commuting to work,,,2nd My mate has just bought a really nice Honda Africe Twin for just a few hundread more then a jetmax,,and I also fancy one of those,of course it will be a few years old and been to Hell and back,but its an awsome bike,,,3rd I have my old 1975 Gold wing,its a great bike,except in London,and MPG is between 30-35 a gallon(not good) ..Another thing here.Riding chinese you have to put up with remarks about where the bike has come from(China)people can be quite racist about Chinese things,and if the bike(scooter) proved a lemon I would have a lot to live down,,you are not alone in fancing a 500cc version,,(nothing beats cubes),,,,,Last thing the right bloke won the japan F1,,hopfully next year he,ll win the championship...All the best

[lipsee]

Thanks for such an informative review,I contacted the importer with a view to a test ride(its a house about 10miles from my place) but they pointed me in the general direction of some scooter shop in town(that sucks) Choices,,here there are loads of choice,,infact I am thinking I have 3 choices,, this will make you laugh,,,1st Cf moto jet max its frugal ,good weather protection,good storeage,good in for commuting to work,,,2nd My mate has just bought a really nice Honda Africe Twin for just a few hundread more then a jetmax,,and I also fancy one of those,of course it will be a few years old and been to Hell and back,but its an awsome bike,,,3rd I have my old 1975 Gold wing,its a great bike,except in London,and MPG is between 30-35 a gallon(not good) ..Another thing here.Riding chinese you have to put up with remarks about where the bike has come from(China)people can be quite racist about Chinese things,and if the bike(scooter) proved a lemon I would have a lot to live down,,you are not alone in fancing a 500cc version,,(nothing beats cubes),,,,,Last thing the right bloke won the japan F1,,hopfully next year he,ll win the championship...All the best

I must just add,I want the bike/ scoot for commuting 10miles across London,and when ever a 3 hour trip up north,,so my choices are not so wild after all,,They are!!!!

[bikerdoc]

So an update is due now that I've hit the 30,000km mark, I've had a couple of issues of late in regards to the CVT (constant variable transmission) which I've mentioned in posts # 57 and 58. I'd noticed at around 27,000km that the Jetmax had a tendency to have less than ideal take-off from idle, as though it was stuck in a higher gear. At first I thought this was an issue with the CVT drive belt wear, however upon CVT transmission disassembly I found that one of the roller weights within the variator has separated, and consequently was stuck within the outer most position of the variator ramp. For an explanation let me briefly explain how a variator and roller weights work.

Jetmax_Variator02.jpg

The CVT system works through the changing of the distance between the plates on the two pulleys. Basically, when the plate width on the variator pulley decreases. the clutch pulley plate width increases, and vice versa. This creates an infinite number of possible gear ratios, as the transmission is altering itself on the fly to adapt to the current driving conditions.

The variator is driven directly by the engine. Inside the variator are 6 rollers (some variators have 8) that are positioned in individual slots (called ramps) with rollers that they move along outward when centrifugal force is applied. Sometimes rollers can be replaced with sliders which suffer less from the friction against the variator and ramps. As the rollers move outward, they press against the ramp plate which causes the pulley plates of the variator to move toward one another, compressing the belt. This "V" shape created by the pulley plates pushes the belt outward, which draws the belt inward on the driven (clutch) side, increasing the gear ratio.

At idle, the rollers are at their innermost position within the slots/sliders, while the variator pulley plates are at their farthest apart, and the CVT belt is low on the variator side and high on the clutch side . With increasing RPMs, the rollers move outward along their ramps applying pressure to the ramp plate, which compresses the variator pulley plates and squeezes the CVT belt outwards.

Jetmax_Variator01.jpg

The roller weights used in the Jetmax are a two part item, having a alloy cylindrical centre and a type of synthetic material outer layer (unsure what material is used). There are 6 roller weights which weigh 11g each. These two roller weight materials are where one of the roller weights had separated and then the roller weight had become stuck in its individual slot at the "top" of the ramp. I simply removed the offending roller weight as an interim measure and reassembled the CVT. The consequences were that I found the Jetmax had slightly better "take-off" from idle since there was 11g less inside the variator, but lost just a little in the top end speed.

I'd contacted CFMoto for warranty information (which turns out was 6 months or 3000km), as I felt the roller weight separation was a little premature. Since my Jetmax was outside warranty I then enquired about getting a set of replacement roller weights, which as I found out only come as a complete set with the CVT variator front pulley assembly. In other words the roller weights have to be bought with the variator and are not supplied as stand alone parts. It should be noted in some overseas markets that the Jetmax is offered with a 2 year unlimited kilometre warranty.

I'd planned to buy a set of roller weights either from Taobao or from overseas, but finding roller weights on Taobao is really quite difficult as the Chiense use some really odd names for items at times, and I also needed to get various dimensions of the roller weights to be able to order, since roller weights come in many sizes etc. Roller weights can also be interchanged with roller sliders.

Getting into the CVT requires the use of pneumatic impact driver. A manual impact driver that one hits with a hammer, does not work - tried that!

The Jetmax variator assembly costs rmb1475 here in mainland China compared with CFMoto 250cc scooter models (CF250T-F, CF250 V3/V5) variators which are between rmb140-150. Since everything had been working fine for the last 2000km it had not been a pressing issue to deal with, and I had held off buying a replacement variator, as I'd planned to pull the CVT apart after the Chinese National Day holidays and measure the roller weights. However just before the recent public holiday, I'd started to experience intermittent slow take-off's as before. This time I knew what it was, and so yesterday I took the CVT apart again to find that another roller weight had disintegrated (separation of the two materials used) much in the same way as the last roller weight had. What I also found though was that many of slot/slider walls had actually worn so badly that many of the final two-thirds of said walls were almost non-existent, which would lead to two failures 1). the roller weight could become trapped at the end of the ramp, 2). roller weight could experience premature wear caused by friction against the sharp fragmented slot/slider wall. This also indicates that the roller weights are causing a large amount of friction on the slot/slider walls during the acceleration/de-acceleration phases, causing significant wear to the ends of roller weights external layer leading to outer layer/material separation.
Photos to come.

Such failures seems somewhat premature to me and I would guess that both the roller weights and variator ramps are made from too softer materials (alloy) and are prone to premature wear. One way to prolong such wear would be to use roller weight sliders which have a flat surface on one side and therefore do not spin as opposed to the cylindrical 'spinning' design of roller weights and consequently do not cause as much friction on both the roller weights themselves nor the slot/slider and ramp surfaces.

[jefkazac2000]

Hi Bickerdoc

Thanks for all your precious information this year.
I wish you a happy new year and many good thinks with your Jetmax