2F4R crankshaft problem

FUracing8 · 14-08-2006, 04:05

Hey guys...... Yesterday at the track, the lower end bearing on my crankshaft fell to peices and basically trashed my motor. Through the grace of God the cylinder managed to escape with just a nick on the bottom of the sleeve next to the trasfers.

My question is, why or what causes those bearings give out? The crank is like 3 months old, has about 8 races on it around 10 hours total running time. There wasn't any real indication of a problem before it when KAAAPOOOOT, no noise, no loss of top end power, just instantaneous death. The tempreture was a little high, about 72 Celcius, but it was a hot day, and I've seen the tempreture get up higher than that before.

I dunno, I'm looking for any answers or similar experiences you guys might have had. I'd like to see if I can get the crank rebuilt, anyone got any info on that?

Thanks fellow forum members

tiba_karotsu · 14-08-2006, 06:37

saw that failure before on a 2F4R piaggio (joel) but i never thought that problem would still continue with 2F4R mina cranks, i think MT still uses the same conrods, i'll tell my friend to replace his conrod with a Ti conrod from MHR Team crank.

ex-racer#2 · 14-08-2006, 19:25

Quote:

Originally Posted by FUracing8

Hey guys...... Yesterday at the track, the lower end bearing on my crankshaft fell to peices and basically trashed my motor. Through the grace of God the cylinder managed to escape with just a nick on the bottom of the sleeve next to the trasfers.

My question is, why or what causes those bearings give out?

Thanks fellow forum members

Usually wear or over revving. I gernaded one in a 125 GP bike after over revving it only once. It lasted about a kilometer before it gave out.

There are a number of reasons bearings fail in general and all of them apply to a certain extent with a big end bearing. Heat, lack of lubrication, wear, over revving, misalignment of the rod to the bore, bore not square to the crank, too much compression or the piston hitting the head, crank twisting or the crank halves turning/twisting on the crank pin... the list can continue.

When doing an inspection of a gernaded big end bearing check the rollers for indications of over heating or lack of lubrication. Also check the rest of the motor for the same indications. Beyond that check everything you can for indications of what went wrong. Some of the latter issues I mentioned like bore off center are things that no one checks but they do happen. I have seen a head installed "backwards" so that the combustion area of the head was not centered and after hitting the head at high rpm a few times the big end let go.

VST · 14-08-2006, 19:56

picture?

FUracing8 · 14-08-2006, 20:20

I'll post a picture as soon as I tear the motor down and get it out.

Tiba : I don't think it has anything to do with the con-rod, I think the bearing just gave out for some reason or another.

I talked to Tedeschi today and I'm gonna get a new crank and send him back the old one so he can check it out himself. The motor was tuned really well, and there are no signs of the piston hitting the head or anything along those lines. What this was, was catastrophic bearing failure....and I've gotta remedy the situation so it doesn't happen again.

**Joël** · 14-08-2006, 20:55

Quote:

Originally Posted by FUracing8

I talked to Tedeschi today and I'm gonna get a new crank and send him back the old one so he can check it out himself. The motor was tuned really well, and there are no signs of the piston hitting the head or anything along those lines. What this was, was catastrophic bearing failure....and I've gotta remedy the situation so it doesn't happen again.

In my case the connection rod snapped, both needle bearings remained intact. I've sent the pictures to Tedeschi but I didn't have warranty, he could only sell me a new connection rod that is in my engine now.

Small-end bearing failure is something I've heard more with the 2Fast cranks, but I thought that problem was solved with the new bearings (those come with all minarelli cranks).

Here are my pictures:

BartR. · 14-08-2006, 22:41

I just bought me a new 2F4R crank, and you can see Tedechi modified the conrod when I compare it with my previous 2F4R Crank.

The surface is more finished/polished now.

Browni · 15-08-2006, 00:02

Quote:

Originally Posted by FUracing8

Hey guys...... Yesterday at the track, the lower end bearing on my crankshaft fell to peices and basically trashed my motor. Through the grace of God the cylinder managed to escape with just a nick on the bottom of the sleeve next to the trasfers.

My question is, why or what causes those bearings give out? The crank is like 3 months old, has about 8 races on it around 10 hours total running time. There wasn't any real indication of a problem before it when KAAAPOOOOT, no noise, no loss of top end power, just instantaneous death. The tempreture was a little high, about 72 Celcius, but it was a hot day, and I've seen the tempreture get up higher than that before.

I dunno, I'm looking for any answers or similar experiences you guys might have had. I'd like to see if I can get the crank rebuilt, anyone got any info on that?

Thanks fellow forum members

Only the bottom bearing falls apart? Or anything else?

In a very rare case the bearing was bad.

But I think if everything was new and well assembled, maybe a lubrication failure. You need better performance oil or more oil for your bike. We use Castrol K997 for the 2fast bike, with no problem.

I think the photos help a lot (the discolored/strached parts etc..), but nobody can tell you 100% sure what was wrong.

Don't you fell resonance or anything on your bike??

Browni · 15-08-2006, 00:10

Quote:

Originally Posted by tiba_karotsu

saw that failure before on a 2F4R piaggio (joel) but i never thought that problem would still continue with 2F4R mina cranks, i think MT still uses the same conrods, i'll tell my friend to replace his conrod with a Ti conrod from MHR Team crank.

Do you steal think Malossi makes Ti conrods?? I think it's machined from a billet metal it isn't as light as a real Ti conrod (Grade5 - TiAl6V4).

Speed · 15-08-2006, 00:34

[quote=Browni]Only the bottom bearing falls apart? Or anything else?

In a very rare case the bearing was bad.

But I think if everything was new and well assembled, maybe a lubrication failure. You need better performance oil or more oil for your bike. We use Castrol K997 for the 2fast bike, with no problem.

Browni is right, it's the oil that you are using that caused this problem. You guys like to use that Amsoil Oil at 50:1. You need to by Motul Oil that is supplied on the island in either 800 series or Karting. The Motul Karting Oil can handle fromm 16,000-23,000rpm's.

Speed

trueOverrev · 15-08-2006, 02:57

so whats the best solution to resolve the crank-bearing issue of the 2FASTkit?

Couple months ago i bought 2F4R Minarelli kit from MT. its not yet running but it will be used for 400m Drag Racing Only. I just dont want my crank or bearing to give up during the race!

Should i change the con-rod now or bearing? MHR TEAM rod 85 (titanium)
I will use MOTUL oil for for sure

Appreciate all concerns and answer!

FUracing8 · 15-08-2006, 04:56

Well I've come to realize that these sortsa things happen in scooter racing. Over the last 2 years I've broken just about everything else BUT a crank, so I guess it was THAT time again. I'm gonna pull the motor apart tomorrow and take pictures so that you all can give me your input.

I really don't think it was an oil problem Speed. I don't mix my fuel the same way as the other guys, it's a total different mixture....35:1 as per the manufacturer's instructions. Amsoil Dominator series synthetic oil is rated up to 20,000 rpms also, FYI of course.

tiba_karotsu · 15-08-2006, 06:11

Quote:

Originally Posted by Browni

Do you steal think Malossi makes Ti conrods?? I think it's machined from a billet metal it isn't as light as a real Ti conrod (Grade5 - TiAl6V4).

uh no, it's just i got used to typing Ti conrods when i'm referring to MHR Team cranks, it should have read Ti alloy conrods not the pure Ti stuff, my bad.

tiba_karotsu · 15-08-2006, 06:14

FUracing8,

please post pics of the crank & conrod we want to have a look as my friend trueOverrev has the same batch of 2F4R crank as you do, btw we will be using nothing but Motul Kart racing oil, IMO it's the best oil i have ever used.

Speed · 18-08-2006, 11:42

Quote:

Originally Posted by tiba_karotsu

FUracing8,

please post pics of the crank & conrod we want to have a look as my friend trueOverrev has the same batch of 2F4R crank as you do, btw we will be using nothing but Motul Kart racing oil, IMO it's the best oil i have ever used.

I agree, Motul Karting Oil is the best. We are still waiting for those pictures of your crankshaft. I beat it was that Amsoil oil you use.

Speed

Velo · 18-08-2006, 22:33

That sux. But, be glad that is was the big end. I just got a yamaha by this week where the small end looked like yours.
And cylinder, engine blok, manifold You name it, was ripped to pieces.

(It was a stage6 ø10 mm crank btw)

packman&robin · 19-08-2006, 13:21

Is there anyone who is using the FA2ST RR crank?? Or is that crank not availeble yet??

beta675 · 31-08-2006, 22:55

Quote:

Originally Posted by Joël

In my case the connection rod snapped, both needle bearings remained intact. I've sent the pictures to Tedeschi but I didn't have warranty, he could only sell me a new connection rod that is in my engine now.

Small-end bearing failure is something I've heard more with the 2Fast cranks, but I thought that problem was solved with the new bearings (those come with all minarelli cranks).

Here are my pictures:

..OMG...

**Joël** · 01-09-2006, 13:16

Quote:

Originally Posted by packman&robin

Is there anyone who is using the FA2ST RR crank?? Or is that crank not availeble yet??

It is not available now, maybe next year.

packman&robin · 01-09-2006, 15:20

Okay,

Hendrik from xsh told me he is using ona at the moment is his engine. So it must be for sale somwhere.

tiba_karotsu · 02-09-2006, 16:05

FUracing,

dude what is up with those pics? post 'em up already the suspense is killing me.

**Joël** · 03-09-2006, 12:27

Quote:

Originally Posted by packman&robin

Okay,

Hendrik from xsh told me he is using ona at the moment is his engine. So it must be for sale somwhere.

Possible, but they are not in production until next year.

FUracing8 · 03-09-2006, 15:49

having a hard time downloading from my camera on to the piece of $hit PC, but I'm still working on it

tiba_karotsu · 22-09-2006, 13:50

well you can work faster it's been weeks since you posted it, oh well i'll just have to go through with it & use it first & find a replacement conrod later.

trueOverrev · 22-09-2006, 23:01

patience tiba! patience! Rome was not built in one day! LOL

FUracing8 · 23-09-2006, 11:32

It doesn't help when I break the digital camera either..................... I will post as soon as possible

trueOverrev · 24-09-2006, 06:37

tiba whats the update on our 2FASTJOG project? keep us posted! let me know if you already had the JOG nextzone and PASSOL II.

14-08-2006, 04:05	#1 (permalink)
FUracing8 FUracing8	2F4R crankshaft problem Hey guys...... Yesterday at the track, the lower end bearing on my crankshaft fell to peices and basically trashed my motor. Through the grace of God the cylinder managed to escape with just a nick on the bottom of the sleeve next to the trasfers. My question is, why or what causes those bearings give out? The crank is like 3 months old, has about 8 races on it around 10 hours total running time. There wasn't any real indication of a problem before it when KAAAPOOOOT, no noise, no loss of top end power, just instantaneous death. The tempreture was a little high, about 72 Celcius, but it was a hot day, and I've seen the tempreture get up higher than that before. I dunno, I'm looking for any answers or similar experiences you guys might have had. I'd like to see if I can get the crank rebuilt, anyone got any info on that? Thanks fellow forum members

14-08-2006, 06:37	#2 (permalink)
tiba_karotsu OVERREV TUNING	saw that failure before on a 2F4R piaggio (joel) but i never thought that problem would still continue with 2F4R mina cranks, i think MT still uses the same conrods, i'll tell my friend to replace his conrod with a Ti conrod from MHR Team crank. __________________ 2stroke tuning the Dutch way + infusion with Filipino ingenuity = OveRReV TuNinG Rev Higher, Go Faster, Race Harder, My Desire

14-08-2006, 19:56	#4 (permalink)
VST VST Tuner	picture? __________________ Verweijen Scooter Tuning, voor info PM VST 7T AC 86cc vlinder+fluiters in bewerkingsfase VST Evo AC 70cc slider @ 19.9pk doel: 21+SAE

14-08-2006, 22:41	#7 (permalink)
BartR. Almost Retired!	I just bought me a new 2F4R crank, and you can see Tedechi modified the conrod when I compare it with my previous 2F4R Crank. The surface is more finished/polished now. __________________ 2fast zipper

15-08-2006, 06:14	#14 (permalink)
tiba_karotsu OVERREV TUNING	FUracing8, please post pics of the crank & conrod we want to have a look as my friend trueOverrev has the same batch of 2F4R crank as you do, btw we will be using nothing but Motul Kart racing oil, IMO it's the best oil i have ever used. __________________ 2stroke tuning the Dutch way + infusion with Filipino ingenuity = OveRReV TuNinG Rev Higher, Go Faster, Race Harder, My Desire

14-08-2006, 20:20	#5 (permalink)
FUracing8 FUracing8	I'll post a picture as soon as I tear the motor down and get it out. Tiba : I don't think it has anything to do with the con-rod, I think the bearing just gave out for some reason or another. I talked to Tedeschi today and I'm gonna get a new crank and send him back the old one so he can check it out himself. The motor was tuned really well, and there are no signs of the piston hitting the head or anything along those lines. What this was, was catastrophic bearing failure....and I've gotta remedy the situation so it doesn't happen again.

15-08-2006, 00:34	#10 (permalink)
Speed Registered User	[quote=Browni]Only the bottom bearing falls apart? Or anything else? In a very rare case the bearing was bad. But I think if everything was new and well assembled, maybe a lubrication failure. You need better performance oil or more oil for your bike. We use Castrol K997 for the 2fast bike, with no problem. Browni is right, it's the oil that you are using that caused this problem. You guys like to use that Amsoil Oil at 50:1. You need to by Motul Oil that is supplied on the island in either 800 series or Karting. The Motul Karting Oil can handle fromm 16,000-23,000rpm's. Speed

15-08-2006, 02:57	#11 (permalink)
trueOverrev Registered User	so whats the best solution to resolve the crank-bearing issue of the 2FASTkit? Couple months ago i bought 2F4R Minarelli kit from MT. its not yet running but it will be used for 400m Drag Racing Only. I just dont want my crank or bearing to give up during the race! Should i change the con-rod now or bearing? MHR TEAM rod 85 (titanium) I will use MOTUL oil for for sure Appreciate all concerns and answer!

15-08-2006, 04:56	#12 (permalink)
FUracing8 FUracing8	Well I've come to realize that these sortsa things happen in scooter racing. Over the last 2 years I've broken just about everything else BUT a crank, so I guess it was THAT time again. I'm gonna pull the motor apart tomorrow and take pictures so that you all can give me your input. I really don't think it was an oil problem Speed. I don't mix my fuel the same way as the other guys, it's a total different mixture....35:1 as per the manufacturer's instructions. Amsoil Dominator series synthetic oil is rated up to 20,000 rpms also, FYI of course.

18-08-2006, 22:33	#16 (permalink)
Velo 74mm bore <3	That sux. But, be glad that is was the big end. I just got a yamaha by this week where the small end looked like yours. And cylinder, engine blok, manifold You name it, was ripped to pieces. (It was a stage6 ø10 mm crank btw) __________________ If you desire special power levels and/or race engineered motors for endurance, high stress or Vmax type events, please keep in mind that the laws of physics and thermodynamics apply. The candle that is twice as bright, only burns half the time.

19-08-2006, 13:21	#17 (permalink)
packman&robin BMXfreestyle is life	Is there anyone who is using the FA2ST RR crank?? Or is that crank not availeble yet?? __________________ \| Victory is reserved for those who are willing to pay it's price \| To become your own champion, believe and achieve \|

01-09-2006, 15:20	#20 (permalink)
packman&robin BMXfreestyle is life	Okay, Hendrik from xsh told me he is using ona at the moment is his engine. So it must be for sale somwhere. __________________ \| Victory is reserved for those who are willing to pay it's price \| To become your own champion, believe and achieve \|

02-09-2006, 16:05	#21 (permalink)
tiba_karotsu OVERREV TUNING	FUracing, dude what is up with those pics? post 'em up already the suspense is killing me. __________________ 2stroke tuning the Dutch way + infusion with Filipino ingenuity = OveRReV TuNinG Rev Higher, Go Faster, Race Harder, My Desire

03-09-2006, 15:49	#23 (permalink)
FUracing8 FUracing8	having a hard time downloading from my camera on to the piece of $hit PC, but I'm still working on it

22-09-2006, 13:50	#24 (permalink)
tiba_karotsu OVERREV TUNING	well you can work faster it's been weeks since you posted it, oh well i'll just have to go through with it & use it first & find a replacement conrod later. __________________ 2stroke tuning the Dutch way + infusion with Filipino ingenuity = OveRReV TuNinG Rev Higher, Go Faster, Race Harder, My Desire

22-09-2006, 23:01	#25 (permalink)
trueOverrev Registered User	patience tiba! patience! Rome was not built in one day! LOL

23-09-2006, 11:32	#26 (permalink)
FUracing8 FUracing8	It doesn't help when I break the digital camera either..................... I will post as soon as possible

24-09-2006, 06:37	#27 (permalink)
trueOverrev Registered User	tiba whats the update on our 2FASTJOG project? keep us posted! let me know if you already had the JOG nextzone and PASSOL II.

24-09-2006, 15:08	#28 (permalink)
tiba_karotsu OVERREV TUNING