This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

644 vs 628

T

tsk

Joined Apr 2010
4 Posts | 0+
Currently looking at a fs650e 2005. This has the 644 engine correct?

And is there any difference in the engines other than the crank? Is the 628 the better choice?

Thanks in advance.
 
The 2005 should be 628 according to the spare part manual.
The 628 crank is supposed to be much stiffer and alot better than the 644 crank according to ben ballard at JBS racing (http://www.jbsracing.co.uk/). My berg had failed main bearings at about 100 hrs.
My 2004 berg is 644 and i have bought me a 628 crank which goes in to my engine next time i will open it.

regards The Force
 
The_Force said:
The 2005 should be 628 according to the spare part manual.
The 628 crank is supposed to be much stiffer and alot better than the 644 crank according to ben ballard at JBS racing (http://www.jbsracing.co.uk/). My berg had failed main bearings at about 100 hrs.
My 2004 berg is 644 and i have bought me a 628 crank which goes in to my engine next time i will open it.

regards The Force
Click to expand...

Hmm, when i look at the specs i find on the internetz it says that 2005 is 644. But even if the 628 is better, is the 644 bad?
 
the KTM rfs engine (early husaberg engine copy) builders reduce the weight of the crank to reduce deflection by cutting the full circle down to a pork chop.

husaberg crank weights:

644 circle crank weight 5kg 32mm pin
550 circle crank weight 4.75kg 32mm pin

628 forged pork chop 4.5kg 35mm pin (stiffer) = less deflection = less axial loading of mainbearings from crank flex due to its own weight

it is no coincedence IMO that the ktmtalk gallery of the guy doing most of the KTM crank work has pictures of the hberg 628 pork chop crank scanned from the workshop manual.

not having owned a 644 I can't say which is better. I like light parts. Weed has built a strong 644

I think with the 644 and the 550 you have to get it right in respect to the mains, with the 628 you can get away with more.
 
Thanks for the info bush.
Turns out the bike is a '04 tho, or at least it looks that way to me. It has a solid front brake disc and a 6 piston caliper, that should mean it's a '04 right?
At any rate should i avoid buying a 2004 model?

Here is a pic anyways:

79_-1672028128.jpg
 
i bet that this is a 2005 FE model converted to FS, thus the six pot caliper (that suits only the fe wp boot)
i concluded that from the angle of oil filler bolt , the kickstarter and the master cylinder for the brake that seems to have a separate fluid reservoir (i think the 2004 did not have this) which means that it is an aftermarket unit.
also the color of the swingarm indicates 2005.
of course this bike has a 2006 tank.
 
I own a 01 650 and an 06 650(628). All i know is my 01 is the fastest bike i have ever ridden or owned. But i trust my 06 more and ride it most.
 
Thanks for all the help but nmv now, someone bought it right in front of my face :cuss:
 
hey out of the crate,the 628 has to be a more bullet proof option,but in saying that don't be affaid to buy a 644.
i know a bloke who has a the 04 model 644 & he has had a fantastic run out of it & he has riden it quite hard.
do the usual, & see if you can pick one up with low hours ,or if not, get it cheap & rebuild it.
keep away from the 01-02 models too many minor problems to sort out.it is certainly not hard to get more power out of the 644.stocko they are a little bit average,just make the thing breathe a bit better & by cricky it makes a difference,they get up & mumbo then.it even sounds angryier.
mine is up to 130hrs since the last rebuild &i haven't exactly been playing hacky sack with it(they've been reasonable hard hours) & i haven't really had to lay a spanner on the thing.
more power & good reliablitly, what more can i really expect out my favorite dirt squirter?
good luck
cheers..weed..
 
I know a lot of people are going to give me **** for saying this but I think 644 are better then 628. 644 have more torque and they use less gas. The only good thing about a 628 is the horsepower but you can make a 644 go way faster by doing some MODS to it. 644 is 2.7 engine and 628 is 2.5 engine.
 
I always wondered if they two engines where alot different in terms of power. But In the end if you arent using 100% of the power 100% of the time it is wasted.

With that being said I think a FC628 would beat a FE644 because of the higher compression, and if you are able to run a 628 harder with out destruction then at the end of the day a bike that works makes alot more power then one that is busted. :mrgreen:
 
:idea:I would think if the 628 (80mm stroke) has Higher compression than the 644 (82mm stroke) that could give it Similar torque as the 644

just a thought :?:
 
I have a 644 crank here from a 2004. it is different to the full 360 (circular flywheel) of the other 3 years in that the flywheels appear 360 from the outside but are pork chop on the inner half. please note Damon!

I like full flywheel in sidecar application.

now this 644 has lunched itself on the big end and the mains merely laughed at it given that they are special rollers. AND AND the little end didn't snap it's little head off!

but the pin has worn the hole conical. the holes in the flywheel are larger near the rod than the outside edge. nearly half a thou.... and you can see staining across the bottom of the hole (side nearest the central axis) which i take to be some sort of oil stain or something.

the conical-ness is worst on the right flywheel and the interference fit is down to just 0.0025" (two and a half thou) on that side and back to .004" on the other. not good.

this does tell you how the pins simply move in the flywheels without actually twisting yet flexing.

I'VE LEARNT A LOT ON THIS ONE.

regards

Taffy
 
I have a 644 crank here from a 2004. it is different to the full 360 (circular flywheel) of the other 3 years in that the flywheels appear 360 from the outside but are pork chop on the inner half. please note Damon!
I like full flywheel in sidecar application.
Click to expand...

nice! so If i get hold of one I can easy turn it into a pork chop.

have you tried that yet Taffy? I'm not convinced if the full circle is really better, you'd have to try both to tell right? added flywheel effect sure be good on a side car.

this does tell you how the pins simply move in the flywheels without actually twisting yet flexing.

I'VE LEARNT A LOT ON THIS ONE.
Click to expand...

well I did try to tell you that in another thread ............. :D

just stirring you old fella, nice work!
 
yes but i didn't know that a crank could go down to those numbers and still not twist yet wear itself out flexing? almost remarkable.

regards

Taffy
 
Tis remarkable and odd that the RHS is worse

Ive heard of cranks twisting and ive seen twisted cranks come out, ive even twisted one by holding one side of the crank and tighteneing the nut on the other just to see what it did.

but FWIW none of the ones ive rebuilt and then seen later have come out twisted.

But then mine is the only "high hp" pressed single that Ive done and its welded.

it is possible I guess that the big end on that crank you have there was pressed open a couple times to replace the bearing but done from the RHS so leaving the LHS of the pin in the LHS flywheel.

tis really amazing these things work at all, great big heavy things wirring and flexing away held together by a 2 -3 thou interference fit 8O
 
good point about which side you choose but at the end of the day both sides get pressed out once and in once so....

I've just welded it up. what do you think to this: flywheels out of step in the ease to west direction by .002". anyway, hit it straight absolutely spot-on and then welded it and about to check what distortion you get welding does it!

I have a 35 year old MIG. That's all I can afford at present. does a lovely job methinks.

.....spot on!

hasn't distorted!

regards

Taffy
 
if replacing the bearing only then only one side needs to come out, usually the side without the oil gallery is best

in our cranks it also happens to be the side that doesn't have to transmit any tourque from the pin to the flywheel.

i reckon that if the LHS had a 2 thou int fit it would probably have twisted, just a guess

Mig sounds nice, the pin welds are not as effective as I first though so ive probably been over doing things a little with the preheat oven and TIG, sounds good though :D
 

Similar threads

G
For Sale FS650 2004
Replies
0
Views
437
Gyorgy
G
S
2004 650 engine rebuild questions
Replies
8
Views
373
Samuel42
S
E
1994 FE 350 carb help! I need parts!
Replies
0
Views
483
evilspiritengineering
E
T
570 engine rebuild help!
Replies
5
Views
521
TurboYoda
T
G
98' FE400 fork swap for supermoto
Replies
6
Views
302
Craig74
C

Register CTA

Register on Husaberg Forum! This sidebar will go away, and you will see fewer ads.

Recent Discussions

Recent Discussions