650 rod length?

good observation.i see your point taffy on the conrod angle,but i've never had that problem with mine,only the mains failure,when the bore & rings went from good to ratShit in a few seconds.
have you had problems with the 644's seizing :?:
dunno? maybe i just don't ride it hard enough chrome bores should take a fair flogging being 10 times harder than cast iron.certainly if we had the cast bore it really could be a problem.
probably one thing we all should be weary of, is replacing (or washing out the stainless one) the oil filter every time the oil is changed.of couse,soon as there is any restriction, that weak oil pump relief spring will bypass all the oil back to the sump(no oil getting to crank pin,oil squirter for piston/bore or top end).from memory, i think it bypasses at 8-9 psi. running an oil additive like moreys that thickens the oil,will only make it bypass worse if a heavier spring is not installed.thats more of an issue for my way of thinking.
whats the use of running the best oil, if only a fraction of that "fantastic oil "is getting there, & vital engine components are getting starved.
i bet that has shortend life of many a motor,its just that without glass engine cases, we have no idea whats really going on.
..weed..

Taffy said:

people have had rods exit the front, pistons seized with great regularity etc etc.

Click to expand...

8O
Are those sumo riders or enduro riders?

I'm at about 150 hrs on my piston and mains.
but my balancer and big end is at around 300+ hrs.
I own a brand new 80mm crank and i was thinking about when to put it in.

whats wrong with the husaberg cam chain? its just a bit of 3/8 chain simple & cheap.just what i like.
what sort of chains has ktm & huskys got?
can't say for sure where i got that relief spring pressure from.it might have been off something bushy wrote.
i'm going to take the motor out of my big girl in another month or so,so i will do the pressure test on that spring & confirm the pressure.
don't know what you are on about when you say they shortened the stroke & increased the oil feed later?
as far as i knew,they shortened the stroke & cut the oil feed to the top end.pressure fed crank pin & piston/bore squirter still remains the same as the 644.
i still think if the 644's are seizing,thats a lack of lubrication issue,either there is too much oil bypass back to the sump & the crankcase components are getting starved ,or the oil pump is worn & will not hold pressure for the piston squirter to squirt,rather it just dribbles down in that side of the crankcase.if that happens like i believe,the only lubrication the bore/piston/rings is getting is just from splash feed. plus i think a bell crank would tend to splash feed better than a circular shaped crank. conrod angle just makes the situation a little worse.
..weed..

Regarding the oil relief valve, I'd like to know why they shifted its location from inside the LHS case on the 644s engines to being externally accesible on the RHS cases on the 628s- did they also change its path in the oil circuit??
The 644s dumped excess pressure prior to the filter straight back into the gearbox- do the 628s do the same???

Regarding the oil relief valve.
My bike is 2004 644 with the external oil relief valve.

But it looks as it is the first year to get it. according to the 2003 part manual that dose not have it.

regards

AUSBERG said:

Regarding the oil relief valve, I'd like to know why they shifted its location from inside the LHS case on the 644s engines to being externally accesible on the RHS cases on the 628s- did they also change its path in the oil circuit??
The 644s dumped excess pressure prior to the filter straight back into the gearbox- do the 628s do the same???

Click to expand...

the 2006 550 cases I have and "628" cases both dump the excess oil over the input shaft, nice way to add lube to the gears

bushmechanic said:

AUSBERG said:

Regarding the oil relief valve, I'd like to know why they shifted its location from inside the LHS case on the 644s engines to being externally accesible on the RHS cases on the 628s- did they also change its path in the oil circuit??
The 644s dumped excess pressure prior to the filter straight back into the gearbox- do the 628s do the same???

Click to expand...

the 2006 550 cases I have and "628" cases both dump the excess oil over the input shaft, nice way to add lube to the gears

Click to expand...

So, the different relief valve locations accomplish exactly the same thing (prior to filter, excess over input shaft)- although it would be interesting to know what pressure difference between the 2 they begin to relieve at- theres gotta be a reason why they shifted its location...

Weed I measured the force of the relief spring as installed and worked out 9psi as the cracking pressure for the ball valve, I asked some mates though and looked in a book so its probably wrong no way to tell for sure without a see through case.. like you said hey that would be interesting :twisted:

I measured the oil pressure after the proper filter through the filter cap and increased it by adding preload to the spring. when running it was higher than 9 psi.

you would imagine the ball opens a little and the whole things sits there dumping oil at a higher pressure than the valves initial cracking pressure. running it was 15-20 I think

it was about 28psi with increased preload before I added the oil feed to the exhaust rocker.

FWIW I have seen a discussion in the RFS forum on KTalk where GWR mentions you are unlikely to be able to run smaller than a 170 main in a high load big bore RFS sidecar engine and have the engine last.

read what you like into that ... Im pretty sure the big bore katooms they are talking about have even worse stroke/rod lengths.

the 2008 and up rmz450s have a habit for eating big ends I wonder what their ratio is.

so what are you saying taffy? that hole in the centre of the picture is not suppose to squirt?
whats the 628 one look like & where is it situated?
..weed..

Yep, my 644s got exactly the same drilling, just above WP/CB drive shaft.....its a piston squirter to me.....

I think the later case oil squirter is in the RHS

Rod length on the RMZ 450 105.5 stroke 62.1mm ratio 1.6988

Yz450 63.4mm stroke, rod length is 103.5 ratio is 1.63

09 kx250f stroke 53.6 mm rod length 92.5 ratio is 1.72

09 570 berg 72mm stroke 120.8 rod ratio is 1.678

XR650 stroke 86.2mm rod length 140.3 mm, ratio is 1.627

KTM 610 crate engine and stroker crank 78mm stroke 126mm rod ratio is 1.615

Ktm 560 72mm stroke and 121mm rod ratio 1.68

Generally 1.5 is considered low and most builders prefer 1.7 to 1.9

Higher mean piston speeds and piston mass increase inertial thrust loading on the cylinder, lighter piston, rod and pin are always good.

Some reading


http://www.speedtalk.com/forum/viewtopic.php?t=406

http://www.stahlheaders.com/Lit_Rod%20Length.htm


Question is though, assuming that the rod is too short on the 644 what are we going to do about it? Make a head packer, a longer cam chain, a special second gasket for the packer and a custom rod? or a custom piston with reduced compression height, you'd need 5mm+ on the rod to get to 1.70

I think there would be a lot to gain for far less work and expense re seizures by using an LC4 oil pump, drilling an oil gallery in the RHS case and adding a second piston squirter to keep the piston well cooled. You could also use this gallery to feed the RHS main.

its generally accepted that on large singles jetting for peak torque rather than peak power (bigger main) makes the big end last longer and the engine runs cooler, i know what Id be doing.

why not run this rod length for the 644/628 stuff by Glen Woodman? hes tried more configurations on these and RFS/rf4 engines than anyone else you'll be able to reach on the net.

theres also Thomas of engine hardware with the 85mm strokers and Ben Ballards experience with his, how do they get theirs to last? Youve posted before Taffy, that you were organising your own strokers, how did they go?

yes i agree bushy.
the subject matter of the 650 rod length to crank ratio is dead.
sorry taffy ..."you" are getting bogged down with it.
"it is what it is".... & it's not really that abnormal comparing it to other dirt bike motors,but it is "not" the reason why you have seen seizures or are having seizures with the 644's.
am i reading between the lines too much?, or are you having trouble with your sidecar motors?
to start with,i would not be using those 04 model cases if they do not have a piston/bore squirter.
obviously the 01 to 03 cases does have a piston/ bore squirter.
trouble being, the relief valve spring is on the marginal side,the oil pump is also on the marginal side & is the only models to run the rockers,crank pin & bore/piston squirter all from a 20mm oil pump impellor.
why do you think they put such a small restictor in the end of the crank to lube the crankpin,by memory it was rediculously small ,it was something like a .5mm to .7mm.the "wr" that we had pulled appart had no restrictor just a 5mm hole in the crank end.the restrictor being the 2mm hole in the crank pin itself.
obviously,the restrictor is to get pressure to the pressure fed rockers & to get the piston/bore squirter to squirt(not dribble from lack of pressure).
pressure fed rockers are a "luxury" not a "neccessity" husaberg realised this & cut the oil feed to the rockers for the 05-08 models,the extra oil & pressure getting redirected to the crank pin/balancer and piston/bore squirter.
hey...thats no big deal,in therory ,not as good.... but pre 2001 huskys & bergs all ran splash fed rockers with no great problems.
it's only common sense to me, to cut the oil feed to the top end,drill larger splash feed holes in the top of the rockers (like the old 600's) so that the extra oil gets redirected to the crankcase,then drill that crank pin restricter out & preload the relief valve spring or stronger spring.
i have never heard of this upgrade to a lc4 oil pump fitted to a berg? sounds good!
i take it,it is a larger pump bushy? whatdya do? machine the cases out a bit to fit the larger pump in?
learn from what husaberg has upgraded.the writing is on the wall.
think about it.
merry chistmas & happy new year to you all
..weed..

yes larger pump, dunno how you'd go fitting it, some guys use it on the RFS

from speedtalk

This subject was brought up & was summed up pretty good at the Advanced Engine Technology Conference a year or two ago in a round table discussion with some of the very best in the business of engine design in NASCAR.

This ain't a direct quote but I believe it went something like this:
[quote:7joviwkt]You decide on a stroke, design a piston to fit your needs, measure the deck height of the block & then make something to hook them together

Click to expand...

As I recall, that was pretty much the consensus on the importance of rod length in overall engine design[/quote:7joviwkt].

Merry Christmas happy/new year to ya as well Weed ccasion5:

have you had to get the tinny out to get to the shops ?

Ben Ballard has a new pump for 40% more flow. i'ts a direct fit.

can the piston oil squirter be added to the 2004 cases?

Regards

merry christmass