RX4 Suspension Tuning - Page 2

Bob Kelly · 05-13-2022, 03:15 PM

Ok we got that done easy enough ! LOL Thanks a bunch Peter !
.....
I'll try posting a picture of my RX4 here again
just so you guys can see how much lower it is than yours....
to me it's the KEY to surviving a motorcycle ( being able to flat foot a bike)
without that ability you are constantly at a disadvantage when starting or stopping or trying to catch the bike when going over a curb or something
you need to be able to touch the ground GOOD... not just the tip of your toes as was the case for me when the bike first got here.
....
besides the fact that the rear suspension does not work on my bike yet
I have compensated by running 28p.s.i. in the rear tire enough to make the air pressure warning light up on the dash... but I'm working on the rear suspension right now and I contacted CSC about it and am waiting for a response.
....
Bob.....
here's a shot of "Miss Piggy"

...
Sigh..... this site SUX !!!! here's the error I got even after resizing it.
...our file of 1.52 MB bytes exceeds the forum's limit of 195.3 KB for this filetype
....
I really don't think 195.3 KB is obtainable anymore is it?

Finally I re sampled it down to 1024x768 pixels and it took it GEEZ !!!!

Bob Kelly · 05-13-2022, 06:13 PM

Just heard back from CSC about the hard ride and basically they say they only carry the stock spring.. and I am out'a luck.... I asked what the rate was of the shock spring and they didn't answer that question.... so their no help at all.
.... I'm becoming increasingly aggravated with CSC their manual is the worst I have ever seen in my entire life and if that wasn't bad enough it doesn't cover 50% of the bike...just highlights of things a owner may encounter technical information is very hard to come by for this bike. if you don't believe me try to find how to check the timing ! something as basic as that isn't there !!!!! and to top that off they don't even have replacement sprockets for the bike if you want to change the final drive ratio....
problems of dealing with a new company I guess...
but they really need to get off their butts and fill these holes in their armor or they will not sell many more... kind'a silly really !
Bob.......

Lukas · 05-14-2022, 08:02 AM

For the price you have to pay for this motorcycle, I honestly think that you can not complain about it too much, if you have higher requirements, then you can do the tuning, as I do, and it comes out much cheaper than buying another motorcycle with the parameters you get with your own improvements of the bike you have to grit your teeth and experiment you have yoycart or ali express, so the parts are easily available only on ali express the seller has gone out of business and they have raised the prices terribly, you need to look for other sources by the way this motorcycle allows you to learn a lot while working on it, and this is valuable knowledge The only thing I can advise you is to be patient, it took me 2 years to solve the shock absorber issue, and changing a cylinder required 1 year of preparation and information gathering.

Bob Kelly · 05-14-2022, 02:35 PM

I am Used to having the information at hand before I start a bit of pre-view so to speak
but I am no new comer to bike motors so the internals of the bike don't bother me near as much as the shock delima... I've not messed with shocks that much so i feel at a disadvantage here, Might I ask what you did to solve the rear shock issue on your bike ?
and what spring rate you wound up with ? right now everything I have is too strong for the bike.... I need a weaker one, I've tried a 500lb spring but I could not tell any difference between the stock and 500lb spring.... I'm thinking 400lb. next or maybe 350lb.

from what I understand there is a big bore kit available for the NC450 to get it to 498 or 500cc something like that but it is pricey ! where that kit is available at is another story completely.... if you find it please post it here !
.....
Personally I love the bike ( all but the rear suspension) everything else about the bike seems well thought out and of excellent quality .

..... I could have had any bike out there if I wanted to spend that much but they all had the same ailment way too frigging tall ! I'm a short dude and even with my boots on I barely reach a 30" inseam .... the RX4 was the Lowest bike I could find
I am a firm believer in flat footing the bike at a stop with either foot or both !
and because I lowered the RX4 2" front and rear I can do that ! I gave up ground clearance to accomplish that which isn't the best, but better less ground clearance than not being able to touch the ground easy.
I have 4 motorcycles here and I have online manuals for each of them and the RX4 is the absolute worst of the lot ! and that really bites the big one !
anyway.... what spring did you wind up with ?
........
Bob........

...

Lukas · 05-14-2022, 05:15 PM

Rx3 has a different problem spring in my opinion is a bit too soft, and the rear wheel with the facelift of the bike was changed to a bigger one which results in rubbing on the air box so I had to put a longer shock absorber, but it had too hard a spring so I matched the spring from the original shock absorber to it, but the bike is higher from that, What I understand your spring is too hard for you, the only advice I can give you is to find a company that will match the spring to your weight, in my country such a spring costs about 150$, I don't know how much in the USA and this is the only reasonable solution, experimenting with random springs can result in the same amount of money.

Bob Kelly · 05-15-2022, 02:50 AM

OK good news I think I found the problem BESIDES the spring....
I got to looking at the shock in the vice it moves up and down nicely but with alot of resistance as a shock should....
I got looking at the length of the springs and the length of the threads and it hit me..... the shock must be kept from bottoming out it's only got about
4" or 5 " of travel in the Swing-arm itself did I screw it up by taking out all the preload ? with the shock fully extended and the spring on the shock ( the stock one) there is about 1" of threads left on the bottom of the upper part of the shock when the adjusting nuts finally contact the spring and there is about 4" of threads above that..... so when I backed off the pre-load nuts to the top of the shock the bike lowered accordingly... the problem is the shock is bottomed out in this position and the spring is not being compressed at all
....and I wonder why it rides so hard !?!?! of course it rides hard the shock is bottomed out !!!!! when I lower the pre-load that action moves the shock piston closer to the bottom.... but when the shock's stroke is so short you do not have that much to play with.....
SO.... what I've done, and am going to do .... is put the preload adjustment nuts at the top of the spring (and lock them there) with the shock fully extended....that will give me MAXIMUM shock travel....and unfortunately maximum seat height too... I think the only way to get the seat height lower is a lowering kit or make up my own horseshoe/dog bone
....
....
"who would'a thunk it" that backing off the preload nuts would bottom out the shock ? that never once crossed my mind, but that is what is going on on this bike.... all this time it was My screwup of not understanding the system it's used in ! AURGH !
I have no doubt it will still ride like a truck... a tall truck mind you but still a very hard ride because before I did anything to that bike I rode it down Hoy road and it liked to beat me to death.... so I don't expect any change
but at least it won't be bottomed out all the time !
Oh well Live and learn !
....

at least I took the Triumph out for a ride today had to push it the last 200 feet to the gas pump because I ran out of gas and blew a fuze at the same time.... still can't figure that one out ! LOL....
and Yes I had to clean the pilot jets to get it to run good again....
I'm hoping the new gas and the run will make her happier now....
....
later all !

Lukas · 05-15-2022, 05:21 AM

I thought you were familiar with these topics.

https://www.chinariders.net/showthread.php?t=15599

http://www.chinariders.net/showthread.php?t=14677

If the shock absorber is running hard you should change the oil in it to a brand name I did.

pyoungbl · 05-15-2022, 07:50 AM

Hi Bob; As I recall, the shock only has about 1 1/2" actual travel before it hits the bump stop. The rest of the wheel travel is due to the linkage setup. Don't forget that you bled nitrogen from the shock. That gas helped to not only keep the oil from foaming but also added a progressive resistance inside the shock. Standard pressure is 145psi.

Progressive Suspension has a great suspension book, The Suspension Bible, that I found to be most useful in understanding all things suspension related. Many of us consider suspension to be a black art. If you break it down into the various components it's easier to digest.

https://www.abebooks.com/Race-Techs-...IaAnZOEALw_wcB

Bob Kelly · 05-15-2022, 02:38 PM

LOL yah but the funny thing is , is that I have always backed off the preload on all my bikes and never ran into the "BOTTOMING OUT ISSUE" before.... but this bike you can't do that..... the shock travel is way too short it may be a 17" long spring but the travel is really short
....
still working on it..... I'll figure it out !
Bob......

Bob Kelly · 05-16-2022, 03:48 PM

Peter ! just got the springs ! thank you very much !
I think I'll try the small one ! that should make for a smoother ride !
...I'll have to make up some extenders to use these short springs though... but that's why I have a lathe Right ? LOL
....
later !
Bob......

Bob Kelly · 05-21-2022, 03:01 AM

I just came from Advrider.com after a bunch of reading on the RX4 there... lot's of info there....and it looks like the opinion of the guys there are saying a 450lb/inch spring should give the RX4 a smoother ride myself I'm thinking that might be a bit too hard for my 180lbs....
and Sense I now have a 430lb spring that Pete gave me, but it is short !... all I have to do is make a spring extension.... which I have no material to make that out of... so I'm mulling over trying to make one from a piece of water pipe or wait and buy a slug of aluminum and cut that to fit on the lathe....
the thing is, I don't want the bike to be down real long as the weather has just turned nice for riding !
I did finally get the 1977 Triumph Bonneville 750's rear brake working right so it's ready to go and so is the Ninja 250R .... I think I should thin the hurd of bikes because I don't have enough ride time !!! LOL.
....
Bob......

Bob Kelly · 05-22-2022, 02:58 AM

I worked most of the day in making a spring extension for this short spring that will make it 11 " long and should fit on the shock perfectly....
...I scrounged up a 3" o.d. piece of tubing (old water heater flue from my years at Hoyte water heater co. in Reno Nv.)
I cut off 3.5" of the tube and squared up both ends on the lathe and then found some 1/8" plate to make the rings out of that. For the shock and spring will sit on.... that took most of the day but I have one done and the other is awaiting a measurement of the shock keeper, that you take off to get the spring off.... I need to know the lips diameter so I can make this extension stay perfectly centered all the time.
the top of the extension will have either short bars welded to it to corral the bottom of the spring or a larger ring that the spring sits into ....
the tubing I am using is fairly thin but I'm confident it is plenty strong enough for the task ( 1/16" wall)
Hopefully tomorrow I will weld the end caps on the short tube and then work on the end where the spring sits and figure out how to hold it securely....
....
if it wasn't for my treasured Logan 920 lathe that is the same age as I am, I would not be able to do this ! I love that lathe ! to me it's more important than all my bikes !
....
Bob.......

Bob Kelly · 05-22-2022, 08:34 PM

Well I just came back from a ride on the RX4.... a short ride but down my favorite bumpy road... and the bike is alot better riding now.... I can live with it that way.... it's still a tad on the hard side but so much better than it was it is unreal.... I put in a 400~450lb/in. Spring... (the smallest one you gave me Colonel Blood <grin>)I had to make a spacer because the spring was so short but I did get it to work.... and I lowered the pre-load a bit and that also helped I can touch flat footed with both feet but I have to work at it.... ( it's not like I had it before but close)....
I was hoping to hit the invisible bump that always knocks the bejesus out of me ....and sure enough I did.... and instead of launching me it was just a OOF bump.... that one gets the front and rear always... on every bike I have !
funny thing is you can't see it.... or I would go around it so I call it the invisible bump !....LOL....
all in all it is a firm ride , not squishy at all but there is give to it now instead of the bumps being volant,they are more rounded ...about like a NORMAL BIKE !!!!! hahahahaha !
all in all I am quite pleased I'll live with it this way !
so it's time to put some miles on this puppy !
.....Oh, I also put 60psi. in the shock sense I had it out and now it pushes the shock back up before it didn't .... ( all of the gas must have leaked out!)
Bob.....

pyoungbl · 05-23-2022, 09:03 AM

I was thinking that something in the 450~500 range would be correct for your spring. The 650 recommendation seemed entirely too stiff but since it came from an expert in the field.....well, worth a try.

Lukas · 05-23-2022, 05:17 PM

Quote:

Originally Posted by Bob Kelly

Well I just came back from a ride on the RX4.... a short ride but down my favorite bumpy road... and the bike is alot better riding now.... I can live with it that way.... it's still a tad on the hard side but so much better than it was it is unreal.... I put in a 400~450lb/in. Spring... (the smallest one you gave me Colonel Blood <grin>)I had to make a spacer because the spring was so short but I did get it to work.... and I lowered the pre-load a bit and that also helped I can touch flat footed with both feet but I have to work at it.... ( it's not like I had it before but close)....
I was hoping to hit the invisible bump that always knocks the bejesus out of me ....and sure enough I did.... and instead of launching me it was just a OOF bump.... that one gets the front and rear always... on every bike I have !
funny thing is you can't see it.... or I would go around it so I call it the invisible bump !....LOL....
all in all it is a firm ride , not squishy at all but there is give to it now instead of the bumps being volant,they are more rounded ...about like a NORMAL BIKE !!!!! hahahahaha !
all in all I am quite pleased I'll live with it this way !
so it's time to put some miles on this puppy !
.....Oh, I also put 60psi. in the shock sense I had it out and now it pushes the shock back up before it didn't .... ( all of the gas must have leaked out!)
Bob.....

Oil in this shock absorber is of poor quality and there is not enough oil, thus there is more air I have a bare body it runs very light it should not run like this without changing oil to KYB brand it is impossible to get the effect of a smooth ride over a pothole it is extremely important my rear end runs great but the front end very bad despite damping adjustments factory oil is too thin and you will not get high quality performance with factory oil in front and rear suspension unfortunately spring is not everything

05-13-2022, 06:13 PM	#17
Bob Kelly Join Date: Jan 2022 Location: Weed, California. Posts: 271	Just heard back from CSC about the hard ride and basically they say they only carry the stock spring.. and I am out'a luck.... I asked what the rate was of the shock spring and they didn't answer that question.... so their no help at all. .... I'm becoming increasingly aggravated with CSC their manual is the worst I have ever seen in my entire life and if that wasn't bad enough it doesn't cover 50% of the bike...just highlights of things a owner may encounter technical information is very hard to come by for this bike. if you don't believe me try to find how to check the timing ! something as basic as that isn't there !!!!! and to top that off they don't even have replacement sprockets for the bike if you want to change the final drive ratio.... problems of dealing with a new company I guess... but they really need to get off their butts and fill these holes in their armor or they will not sell many more... kind'a silly really ! Bob....... __________________ It's too late when you've gone too far !
	0

05-14-2022, 02:35 PM	#19
Bob Kelly Join Date: Jan 2022 Location: Weed, California. Posts: 271	I am Used to having the information at hand before I start a bit of pre-view so to speak but I am no new comer to bike motors so the internals of the bike don't bother me near as much as the shock delima... I've not messed with shocks that much so i feel at a disadvantage here, Might I ask what you did to solve the rear shock issue on your bike ? and what spring rate you wound up with ? right now everything I have is too strong for the bike.... I need a weaker one, I've tried a 500lb spring but I could not tell any difference between the stock and 500lb spring.... I'm thinking 400lb. next or maybe 350lb. from what I understand there is a big bore kit available for the NC450 to get it to 498 or 500cc something like that but it is pricey ! where that kit is available at is another story completely.... if you find it please post it here ! ..... Personally I love the bike ( all but the rear suspension) everything else about the bike seems well thought out and of excellent quality . ..... I could have had any bike out there if I wanted to spend that much but they all had the same ailment way too frigging tall ! I'm a short dude and even with my boots on I barely reach a 30" inseam .... the RX4 was the Lowest bike I could find I am a firm believer in flat footing the bike at a stop with either foot or both ! and because I lowered the RX4 2" front and rear I can do that ! I gave up ground clearance to accomplish that which isn't the best, but better less ground clearance than not being able to touch the ground easy. I have 4 motorcycles here and I have online manuals for each of them and the RX4 is the absolute worst of the lot ! and that really bites the big one ! anyway.... what spring did you wind up with ? ........ Bob........ ... __________________ It's too late when you've gone too far !
	0

05-15-2022, 02:50 AM	#21
Bob Kelly Join Date: Jan 2022 Location: Weed, California. Posts: 271	OK good news I think I found the problem BESIDES the spring.... I got to looking at the shock in the vice it moves up and down nicely but with alot of resistance as a shock should.... I got looking at the length of the springs and the length of the threads and it hit me..... the shock must be kept from bottoming out it's only got about 4" or 5 " of travel in the Swing-arm itself did I screw it up by taking out all the preload ? with the shock fully extended and the spring on the shock ( the stock one) there is about 1" of threads left on the bottom of the upper part of the shock when the adjusting nuts finally contact the spring and there is about 4" of threads above that..... so when I backed off the pre-load nuts to the top of the shock the bike lowered accordingly... the problem is the shock is bottomed out in this position and the spring is not being compressed at all ....and I wonder why it rides so hard !?!?! of course it rides hard the shock is bottomed out !!!!! when I lower the pre-load that action moves the shock piston closer to the bottom.... but when the shock's stroke is so short you do not have that much to play with..... SO.... what I've done, and am going to do .... is put the preload adjustment nuts at the top of the spring (and lock them there) with the shock fully extended....that will give me MAXIMUM shock travel....and unfortunately maximum seat height too... I think the only way to get the seat height lower is a lowering kit or make up my own horseshoe/dog bone .... .... "who would'a thunk it" that backing off the preload nuts would bottom out the shock ? that never once crossed my mind, but that is what is going on on this bike.... all this time it was My screwup of not understanding the system it's used in ! AURGH ! I have no doubt it will still ride like a truck... a tall truck mind you but still a very hard ride because before I did anything to that bike I rode it down Hoy road and it liked to beat me to death.... so I don't expect any change but at least it won't be bottomed out all the time ! Oh well Live and learn ! .... at least I took the Triumph out for a ride today had to push it the last 200 feet to the gas pump because I ran out of gas and blew a fuze at the same time.... still can't figure that one out ! LOL.... and Yes I had to clean the pilot jets to get it to run good again.... I'm hoping the new gas and the run will make her happier now.... .... later all ! __________________ It's too late when you've gone too far ! Last edited by Bob Kelly; 05-16-2022 at 09:57 PM.
	0

05-15-2022, 02:38 PM	#24
Bob Kelly Join Date: Jan 2022 Location: Weed, California. Posts: 271	LOL yah but the funny thing is , is that I have always backed off the preload on all my bikes and never ran into the "BOTTOMING OUT ISSUE" before.... but this bike you can't do that..... the shock travel is way too short it may be a 17" long spring but the travel is really short .... still working on it..... I'll figure it out ! Bob...... __________________ It's too late when you've gone too far !
	0

05-16-2022, 03:48 PM	#25
Bob Kelly Join Date: Jan 2022 Location: Weed, California. Posts: 271	Peter ! just got the springs ! thank you very much ! I think I'll try the small one ! that should make for a smoother ride ! ...I'll have to make up some extenders to use these short springs though... but that's why I have a lathe Right ? LOL .... later ! Bob...... __________________ It's too late when you've gone too far !
	0

05-14-2022, 08:02 AM	#18
Lukas Join Date: Jan 2021 Location: A small Polish empire Posts: 244	For the price you have to pay for this motorcycle, I honestly think that you can not complain about it too much, if you have higher requirements, then you can do the tuning, as I do, and it comes out much cheaper than buying another motorcycle with the parameters you get with your own improvements of the bike you have to grit your teeth and experiment you have yoycart or ali express, so the parts are easily available only on ali express the seller has gone out of business and they have raised the prices terribly, you need to look for other sources by the way this motorcycle allows you to learn a lot while working on it, and this is valuable knowledge The only thing I can advise you is to be patient, it took me 2 years to solve the shock absorber issue, and changing a cylinder required 1 year of preparation and information gathering.
	1

05-14-2022, 05:15 PM	#20
Lukas Join Date: Jan 2021 Location: A small Polish empire Posts: 244	Rx3 has a different problem spring in my opinion is a bit too soft, and the rear wheel with the facelift of the bike was changed to a bigger one which results in rubbing on the air box so I had to put a longer shock absorber, but it had too hard a spring so I matched the spring from the original shock absorber to it, but the bike is higher from that, What I understand your spring is too hard for you, the only advice I can give you is to find a company that will match the spring to your weight, in my country such a spring costs about 150$, I don't know how much in the USA and this is the only reasonable solution, experimenting with random springs can result in the same amount of money.
	0

05-15-2022, 05:21 AM	#22
Lukas Join Date: Jan 2021 Location: A small Polish empire Posts: 244	I thought you were familiar with these topics. https://www.chinariders.net/showthread.php?t=15599 http://www.chinariders.net/showthread.php?t=14677 If the shock absorber is running hard you should change the oil in it to a brand name I did.
	0

05-15-2022, 07:50 AM	#23
pyoungbl Join Date: Feb 2016 Location: Portsmouth, Virginia, USA Posts: 632	Hi Bob; As I recall, the shock only has about 1 1/2" actual travel before it hits the bump stop. The rest of the wheel travel is due to the linkage setup. Don't forget that you bled nitrogen from the shock. That gas helped to not only keep the oil from foaming but also added a progressive resistance inside the shock. Standard pressure is 145psi. Progressive Suspension has a great suspension book, The Suspension Bible, that I found to be most useful in understanding all things suspension related. Many of us consider suspension to be a black art. If you break it down into the various components it's easier to digest. https://www.abebooks.com/Race-Techs-...IaAnZOEALw_wcB
	0

05-21-2022, 03:01 AM	#26
Bob Kelly Join Date: Jan 2022 Location: Weed, California. Posts: 271	I just came from Advrider.com after a bunch of reading on the RX4 there... lot's of info there....and it looks like the opinion of the guys there are saying a 450lb/inch spring should give the RX4 a smoother ride myself I'm thinking that might be a bit too hard for my 180lbs.... and Sense I now have a 430lb spring that Pete gave me, but it is short !... all I have to do is make a spring extension.... which I have no material to make that out of... so I'm mulling over trying to make one from a piece of water pipe or wait and buy a slug of aluminum and cut that to fit on the lathe.... the thing is, I don't want the bike to be down real long as the weather has just turned nice for riding ! I did finally get the 1977 Triumph Bonneville 750's rear brake working right so it's ready to go and so is the Ninja 250R .... I think I should thin the hurd of bikes because I don't have enough ride time !!! LOL. .... Bob...... __________________ It's too late when you've gone too far !
	0

05-22-2022, 02:58 AM	#27
Bob Kelly Join Date: Jan 2022 Location: Weed, California. Posts: 271	I worked most of the day in making a spring extension for this short spring that will make it 11 " long and should fit on the shock perfectly.... ...I scrounged up a 3" o.d. piece of tubing (old water heater flue from my years at Hoyte water heater co. in Reno Nv.) I cut off 3.5" of the tube and squared up both ends on the lathe and then found some 1/8" plate to make the rings out of that. For the shock and spring will sit on.... that took most of the day but I have one done and the other is awaiting a measurement of the shock keeper, that you take off to get the spring off.... I need to know the lips diameter so I can make this extension stay perfectly centered all the time. the top of the extension will have either short bars welded to it to corral the bottom of the spring or a larger ring that the spring sits into .... the tubing I am using is fairly thin but I'm confident it is plenty strong enough for the task ( 1/16" wall) Hopefully tomorrow I will weld the end caps on the short tube and then work on the end where the spring sits and figure out how to hold it securely.... .... if it wasn't for my treasured Logan 920 lathe that is the same age as I am, I would not be able to do this ! I love that lathe ! to me it's more important than all my bikes ! .... Bob....... __________________ It's too late when you've gone too far !
	1

05-22-2022, 08:34 PM	#28
Bob Kelly Join Date: Jan 2022 Location: Weed, California. Posts: 271	Well I just came back from a ride on the RX4.... a short ride but down my favorite bumpy road... and the bike is alot better riding now.... I can live with it that way.... it's still a tad on the hard side but so much better than it was it is unreal.... I put in a 400~450lb/in. Spring... (the smallest one you gave me Colonel Blood <grin>)I had to make a spacer because the spring was so short but I did get it to work.... and I lowered the pre-load a bit and that also helped I can touch flat footed with both feet but I have to work at it.... ( it's not like I had it before but close).... I was hoping to hit the invisible bump that always knocks the bejesus out of me ....and sure enough I did.... and instead of launching me it was just a OOF bump.... that one gets the front and rear always... on every bike I have ! funny thing is you can't see it.... or I would go around it so I call it the invisible bump !....LOL.... all in all it is a firm ride , not squishy at all but there is give to it now instead of the bumps being volant,they are more rounded ...about like a NORMAL BIKE !!!!! hahahahaha ! all in all I am quite pleased I'll live with it this way ! so it's time to put some miles on this puppy ! .....Oh, I also put 60psi. in the shock sense I had it out and now it pushes the shock back up before it didn't .... ( all of the gas must have leaked out!) Bob..... __________________ It's too late when you've gone too far !
	0

05-23-2022, 09:03 AM	#29
pyoungbl Join Date: Feb 2016 Location: Portsmouth, Virginia, USA Posts: 632	I was thinking that something in the 450~500 range would be correct for your spring. The 650 recommendation seemed entirely too stiff but since it came from an expert in the field.....well, worth a try.
	0