Ducar 140cc Gearbox issue?

[Kourt]

Recently done a gearbox in my ProX 140. In second gear it would slip then grab under high load, causing the bike to jolt, but it only happened in second.

Then i was doing some more testing and third went- made a rattling sound as i went from second to third, didnt sound healthly

Now some people have said that they have had this problem with the older lifans the and Ducar 125/140cc engines, and it was the selector? They have opened the gearbox and it was fine, just the selector had bent or broken? Just wondering if someone who has had this problem could let me know if its worth fixing and how they did it, or if its just more cost effective to get a new Lifan 140cc instead.

Im interested in how it was fixed and what was changed to stop it from happening again? Cheers buddys

 

[motoluver]

I'm starting to hear gearbox problems with the Ducar 140cc now. A mate of a mate of mine Ducar 140cc gearbox seized on one of his first rides... The motor was replaced for free. I don't know what went wrong with his gearbox.

 

[Cactus Jack]

Have any of you guys ever dropped the bike and bent the gear shift lever ?

 

[Kourt]

Nope i havent even come off the bike yet. If this engine can be saved for less than a new one i would be more than happy to do it, this motor has shit loads of grunt, I would hate to get anything with less power. If possible i would like to strengthen the parts that failed and keep using it, coz its really impressed me so far.

 

[born2slide1980]

Nope i havent even come off the bike yet. If this engine can be saved for less than a new one i would be more than happy to do it, this motor has shit loads of grunt, I would hate to get anything with less power. If possible i would like to strengthen the parts that failed and keep using it, coz its really impressed me so far.

Hey Kourt sorry to hear about ya problem. I don't know much about the "Ducars", but the 140 "Lifans" really do go hard ... However I think that is where a lot of the problem lies, the extra stoke of these motors and a few other changes feels to give them a lot more torque down low, but I don't think they had put much thought into strengthening the gearbox for the extra grunt.

I am currently building up one of these 140 lifan motors for motard use. I have been told by Mack the best way to strengthen the gears is either, get the original ones "back cut and treated" from your local machinist, or to buy a new "quality cut cluster"

I really don't know which will be the best option???, I still have to get a price on the back cutting etc. and have only found one place, that sells the new clusters and they are not cheap (and I don't know if they is any good or not).

OORacing - performance monkey bike and dirt bike components - Secondary Ti gear set (Powered by CubeCart)

If you have broken teeth in your gearbox, you will need to replace the cluster or the broken gears (if you have spares). If you have bent the selector forks (will probably have to remove the shift drum from the case to see) with a bit off heat and force, you might be able to bend them back so they work, but this probably weakens the metal a bit more.

Sound like it might be time to have a look inside the case and see what is going on in there.

Hope this helps

Cheers Matt

 

[born2slide1980]

and oh yeah let us know how you go and what you find

Cheers

 

[Ryzzy]

by the sounds of what you r saying i would think u have broken a tooth of your second gear. if you have i would probably have a spare gear that would fix your problem. Easiest and first thing you should do is check the internal oil filter because broken teeth usually end up in there.

 

[foxman]

this happened to my thumpstar,You have broken your selector for sure.I took mine apart after 2nd gear started to make clicking noises when dumping the throttle.The selector was stuffed biut my local shop are so useless and they said thumpstar are just so hard to deal with to get the part.Now im just buying a new lifan 125.One day i will fix it some how but giving up on it.It wont be your gearbox i promise you.The selector has rollers on it and you should see it when you split the cases.good luck you poor motorless man

 

[Kourt]

Thanks for all the help dudes, i tried to get the magneto off but i brought the wrong size puller!!! So i coundn't take the motor apart to check if it was just the selector. Is there another trick to getting it off?

I might just take it down to the scooter shop to get someone to pull it apart and diagnose the problem.

I think im going to go with a new lifan 140cc but i just wanted to know will they fit in to a AGB29 ProX frame with out any problems and are the gearboxes/selectors tougher on the Lifan engines?

Oh and where is the chepest place to get a 140 lifan in Perth? I cant find any on ebay ATM???

 

[pitmaster]

Oh and where is the chepest place to get a 140 lifan in Perth? I cant find any on ebay ATM???

eBay Australia: Lifan 140cc 4ST engine oil cooled, thumpstar pitbike (item 330146759593, end time 23-Jul-07 17:03:20 AEST)

eBay Australia: 140CC CRF50 ENGINE LIFAN INNER ROTOR KIT CRF 50 PITBOSS (item 320139251883, end time 24-Jul-07 18:31:19 AEST)

eBay Australia: Lifan 140cc 4ST engine oil cooled, thumpstar pitbike (item 330148088377, end time 28-Jul-07 09:57:30 AEST)

eBay Australia: Lifan 140cc 4ST engine oil cooled, thumpstar pitbike (item 330148088851, end time 28-Jul-07 09:59:54 AEST)

how many more do you want

MPE has them at a great price with cooler, ask if he sends them interstate, id buy from him B4 ebay,

 

[Kourt]

Got word from the mechanic said it would be cheaper to get a new motor as he cant get spares for the Ducar. Gearbox is US. Looks like im going for the Lifan 138cc for $320 bucks YEAHA!

 

[motoluver]

Get a 140cc they are around that price if not cheaper with some sellers.

 

[born2slide1980]

Definitely get a 140 lifan, I have heard they go a lot harder than the 138's

I think it is just a matter off trying to be as kind as possible to all of these gearboxes ie. not dropping the clutch, matching revs on down shifts etc.etc.

And if the 140 ducars run a similar setup to the lifans, you may also have some spare gears and parts from your old motor... For any future problems

 

[ducar.r.spec]

hmmm y doesnt any1 ever talk about having problems with loncins?
hint hint

 

[Flarry]

Have any of you guys ever dropped the bike and bent the gear shift lever ?

Broken the selector on both my engines now (lifan 125 and lifan 140), cheapest way to fix it is a new engine. The guy at the shop said it was from shifting up really hard but I never do that and havent drop it on the shifter, I think its from flat landing and bottoming out, me and my freind both hit a jump at my house and flat landed about 300 times in 2nd, next day both our gearboxes are broken in 2nd gear (friends engine is a jailing 125). On my old bike a had a jump in 3rd which I flat landed, after that 3rd gear broke (also snapped my frame) so I think its from flat landing with bad suspension.