Suspension Fix (Wannabiker for President!)

[Grub]

As many of you know, I have been bitching and moaning about my 2000 CBR600F4 and its handling. I have never been happy with it and have never trusted it. Early last month Kendog and I planned to spend a day helping each other with basic setups and "sag" settings. It's a two-biker job. Well we buggered off to Phillip Is and it never got done ... so when it was in at the Honda Service Agent, I asked them to set the sag to my height and weight. They did and I went on the Capital 1000k ride and still hated it. I didn't trust that bike as far as it could throw me. I had decided the frame was ferked and was telling Nasty I was going to sell it.

Well yesterday we were setting up the KB BBQ prior to the Cheescutter ride with the help of early arrivals Wannabiker and SweetP. Wannabiker put the new caliper on Nasty's CBR "Bumblebee" and took it for a ride - loved it. So SweetP had to go for a ride too with Wannabiker on my CBR. He came back with good news - I wasn't imagining it, mine was a pig.

So he gets me organised so we could measure the sag. This you do by one person pulling the wheels off the ground against the side stand. You then put a cable-tie around the fork tube, settle bike down and very gently sit on it. This moves the cable-tie up the fork leg so you can measure how much the suspension has settled.

The settings for my bike are 35mm sag front and back. What did we find? Front = 60mm, Rear = 2mm! No wonder it was a pig, it was standing on its nose, steepening the already steep steering-head angle and it had no rear travel at all.

Here is the lesson. The Honda Service Agent may have done the right thing by the book for a new bike but it doesn't work on a used bike. If you think about it, it could never work. Things age, people fiddle, wankers chuck 'race gear' on a bike without knowing what it might possibly do (like kill ya 4 corners from the top of the Takas)

So on my bike, the front springs have gone soft so the adjusters needed to be screwed full down to get 37mm front sag. I don't think we could have got less.

The rear has 6 positions with the factory recomendation being setting 3. Until we set it to 1 (full 'soft') we couldn't get any measurable sag at all. This means some wally has changed the back spring for a bloody hard one. So the setting where Wannabiker could measure any sag ended up with 40mm. Front and back now had settings perfect to the factory specs. Once you have set the sag, you don't need to change it (unless you put on the beef!). It should always be 35mm front and rear.

The CBR600F4 has fully adjustable compression and rebound front and rear. These can make a difference, but they are subtle and you can play with them for ages to get them to your liking. On this bike there are no 'clicks' for adjustment, just 5 half-turns stop-stop. So we set all the adjusters at + 2 half-turns as a starting point which is almost exactly midrange.

The bike is bloody AWESOME. It's not perfect yet but it is now rideable and it will go where it is pointed! It was noticable by the end of our road and so I had to go do my benchmark road Paekakariki Hill Rd. From not being able to tell what it was going to do or having it wallow or bump-steer or just throw itself off-line for no reason - it now did none of those things. I was able to feel what it was doing and was even able to come back and say it needed a 1/4 turn of extra rebound. It is like being born-again.

Wannabiker for President!

[cowpoos]

it acctually sounds like your honda service agent was lucky you didn't bin...because they fucked up!! very irrisponsible of them!

[Wannabiker]

Well, maybe not for president... Yes, this bike felt awful by the time got to the end of the road...there was something not right. Ok dont profess to hav fixed it to perfect...but I am pleased its a lot better now, coz it really couldnt have got worse...well almost as bad as the ducati front suspension story....but thats best told over a few beers!!!

[James Deuce]

Good work indeed. Sounds to me like something STILL isn't right though. I wonder if the spacers have been left out of the forks legs when someone has swapped the springs. Or didn't put the right amount of oil in.

I reckon a visit to Robert Taylor is in order. Ola and I were looking at your bike this morning and wondering if perhaps it hasn't been lowered at some point.

[nudemetalz]

Hey, how did the dude with the GSX250S Katana get on with his chain and sprockets in the end?
They were both so shagged.

[Mom]

it acctually sounds like your honda service agent was lucky you didn't bin...because they fucked up!! very irrisponsible of them!

Hi there, you sound like you know something about this sort of thing :cool:.........I hear you love caramel slice....:whistle:

When are you next up our way?

:love: Mom

PS: I have been told I am about as subtle as a sledge hammer sometimes :hug:

[nadroj]

Hey, how did the dude with the GSX250S Katana get on with his chain and sprockets in the end?
They were both so shagged.

That bee'd McDuck & he should be back in Whakatane very soon on the adjusted to the limit chain & alloy motorcross toothless sprocket his personal mechanic checked for him.

[RantyDave]

The Honda Service Agent may have done the right thing by the book for a new bike but it doesn't work on a used bike.
Ahhh, now that would explain a thing or two. The "book" settings for my bike are shite. Real hard to turn in. Some bravery and fiddling later and it rides like a demon. Of course, it's because the suspension is starting to get shot.

The bike is bloody AWESOME.
Adjustable factory suspension, much maligned as it is, is a shitload better than the alternative.

Dave

[nudemetalz]

Ah yes McDuck, forgot his name.
Glad to hear that, nice fellah he is.

I still can't believe a bike shop said it was okay for the trip !!!!

[Wannabiker]

Mcduck left my place at 3pm, headn over ther takas to napier, taupo and home. I put a second hand chain on ...one that wasnt soooo stretched, and wa able t o get it adjusted a bit better... the axle was in the back of the slots and the chain still slack last night. Skunk lent a couple of sprockets (but wrong mounting)...so just had to go with what he had.

[Clivoris]

Ah yes McDuck, forgot his name.
Glad to hear that, nice fellah he is.

I still can't believe a bike shop said it was okay for the trip !!!!


Mcduck left my place at 3pm, headn over ther takas to napier, taupo and home. I put a second hand chain on ...one that wasnt soooo stretched, and wa able t o get it adjusted a bit better... the axle was in the back of the slots and the chain still slack last night. Skunk lent a couple of sprockets (but wrong mounting)...so just had to go with what he had.
Also bled front brake...as lever was coming back to handlebars!! He should notice the difference now!! But....it wasnt that easy (it never is). The screws that held the cap on the M/Cyl were siezed into the resivior, and the phillips screws pretty stripped....So, Drilled and tapped a hole in the cover, and after bleeding the brakes, put a screw in to seal the resivior!!

Yous twos is legends. I have no doubt that it made the ride home much better for him.

[nudemetalz]

Bl000dy hell !!!
However these things always happen when you buy a second-hand
XR250R.......

Yeah that front brake need a bleed alright.
Hope he gets the final drive sorted once he gets home.

Oh, and no worries, Clivoris, like to help out virginal motorcyclists where I can. :)

Sorry to invade your thread, Grub.

[Grub]

Sorry to invade your thread, Grub.

No grief about that here ... it's so good to see people get sorted. We learn stuff, we screw up, we learn from that .. and we pass it on. You gotta love it :)

[chanceyy]

Always great to see those in the know helping us that dunna know any better & when we rely on the word of "experts"

gotta love the spirit of bikers in general .. seen it operation this weekend for sure ...

Great job guys .. you know its appreciated :yes:

[Robert Taylor]

Ahhh, now that would explain a thing or two. The "book" settings for my bike are shite. Real hard to turn in. Some bravery and fiddling later and it rides like a demon. Of course, it's because the suspension is starting to get shot.

Adjustable factory suspension, much maligned as it is, is a shitload better than the alternative.

Dave

It must always be remembered that improvement is always a term of relativity, although it does sound as if the settings were seriously imbalanced. Also, external clickers only adjust bypass bleed and NOT the basic character of the shock. In this instance a very progressive piston design that has rather average square edge bump compliance and too much bypass bleed through the shaft. Not to mention excessive friction and fast fade when hot. The fork springs are usually too light in weight for the average rider requiring excessive preloading. There is truth in what Paul Thede ( Mr Race Tech ) says, ''the best youve ridden is the best you know''

Those that think there wont be a significant improvement in fitting well sorted quality aftermarket suspension are in fact in denial. BUT, this is the flipside.....there is so much used aftermarket stuff out there on offer from private onsellers. And frankly many of these resellers care little whether the shock set up is correct for the new prospective owner or indeed if it is the correct shock for the bike...''yeah itll fit okay'' Interpretation, the spring rate is wrong for you, the internal valving doesnt match the motion ratio of the linkage, the length is wrong giving incorrect geometry. Every day I get phone calls ''Ive just bought this shock and it doesnt work'' Well youve just been ripped by an unscrupulous reseller....

So I have to wonder aloud if circumstances beyond the control of manufacturer / distributor ( i.e proper knowledge and back up base ) often colour peoples thinking.

What I therefore personally malign is ignorance and the inability of people to seek advice from the people that actually are fully conversant with the product concerned. That includes sifting through those who have enough knowledge to be dangerous but not enough to give the correct answer.

Note that the quality aftermarket shocks on the market are delivered from the factory with road specific settings, they are NOT built primarily as a race shock. For racing we internally respec. When they are not respec'd for road and onsold therein does lie a problem

[F5 Dave]

Thinking outside the suspension units themselves as well Robert will probably be able to write a book on the dredgy setups he's seen; but to give anything a chance there need to be no external factors screwing the pitch. We tend to get focussed on the problem as being a symptom of just one offending article.

Sorry this is going nowhere, I'll start again. :weep:

Start off with making sure that the rear suspension linkages are not seized or worn, have to whip the shock out to try it, but should become evident. Even the best Ohlins won't stand a chance with knackered pivot bearings. The forks of course need to be properly assembled and steering brgs top notch. Tyres matched & decent.

Maybe many of these things have been done, but wurf a mention.

[Robert Taylor]

Thinking outside the suspension units themselves as well Robert will probably be able to write a book on the dredgy setups he's seen; but to give anything a chance there need to be no external factors screwing the pitch. We tend to get focussed on the problem as being a symptom of just one offending article.

Sorry this is going nowhere, I'll start again. :weep:

Start off with making sure that the rear suspension linkages are not seized or worn, have to whip the shock out to try it, but should become evident. Even the best Ohlins won't stand a chance with knackered pivot bearings. The forks of course need to be properly assembled and steering brgs top notch. Tyres matched & decent.

Maybe many of these things have been done, but wurf a mention.

Ive got to concur with that, sometimes its too easy to overlook the basics.

[Grub]

Thanks Dave and Robert, valued thoughts.

I think the purpose of this post was not to applaud the perfect bike (now) but to just show how easy it is to be stuck in a place of ignorance and not know what to do about it. The bright side is finding out how every one of us could and should get with a buddy and perform these basic checks - and what a difference they can make.

Robert is surely right about all the things that one should do to get the perfect bike. My point was that you could believe someone has done a good job (surely you can trust the franchise service agent - right?) but in fact have a really bad bike and that there are ways of checking for yourself.

If I had not had a perfect handling bike in our '90 CBR600 then I would not have known that the 2000 one I was riding was a dog .. and I would not have kept questioning it.

We can all do this, get huge benefits and spend nothing. It's not over yet and I will get good gear and make improvements but at least I have a basis to work with now.

[McDuck]

Mcduck left my place at 3pm, headn over ther takas to napier, taupo and home. I put a second hand chain on ...one that wasnt soooo stretched, and wa able t o get it adjusted a bit better... the axle was in the back of the slots and the chain still slack last night. Skunk lent a couple of sprockets (but wrong mounting)...so just had to go with what he had.
Also bled front brake...as lever was coming back to handlebars!! He should notice the difference now!! But....it wasnt that easy (it never is). The screws that held the cap on the M/Cyl were siezed into the resivior, and the phillips screws pretty stripped....So, Drilled and tapped a hole in the cover, and after bleeding the brakes, put a screw in to seal the resivior!!

Thanks soooooo much for the help. In the defence of the brake, it was not that bad when i left home and it is now worse than that in that the lever gets all the way to the handle bar without resistance. AKA a leak in the system (bugger) so i will be have a close look when i re do the lines for the front brake. Could the air problem be the screw letting air in? (i dont think so but best to ask) I guess i have a few weeks of playing with the bike ahead.

Thanks again (and again) so much.

[Robert Taylor]

Thanks Dave and Robert, valued thoughts.

I think the purpose of this post was not to applaud the perfect bike (now) but to just show how easy it is to be stuck in a place of ignorance and not know what to do about it. The bright side is finding out how every one of us could and should get with a buddy and perform these basic checks - and what a difference they can make.

Robert is surely right about all the things that one should do to get the perfect bike. My point was that you could believe someone has done a good job (surely you can trust the franchise service agent - right?) but in fact have a really bad bike and that there are ways of checking for yourself.

If I had not had a perfect handling bike in our '90 CBR600 then I would not have known that the 2000 one I was riding was a dog .. and I would not have kept questioning it.

We can all do this, get huge benefits and spend nothing. It's not over yet and I will get good gear and make improvements but at least I have a basis to work with now.

I hear exactly what you are saying. Also, in real terms the whole suspension thing ( even basic set up ) has become a whole specialised field in itself. The motorcycle engineering trade has always been a VERY wide field meaning no-one person can be an expert in every aspect of it. And because of many negative factors just how many older very experienced and qualified motorcycle mechanics do you see practicing in the trade? That is one of our historical problems, previous Governments messed with the training system and the chickens have come home to roost.

[Katman]

But....it wasnt that easy (it never is). The screws that held the cap on the M/Cyl were siezed into the resivior, and the phillips screws pretty stripped....So, Drilled and tapped a hole in the cover, and after bleeding the brakes, put a screw in to seal the resivior!!

That would be one of the most irresponsible 'repair' jobs I have ever seen. When you drilled through the cap, did you drill through the rubber bladder under the cap as well? If so, what's to stop metal filings from the drilling and tapping of the thread getting into the master cylinder (and also moisture from the atmosphere - which the bladder is there to stop) and causing a brake failure (which sounds like might have happened)? If you didn't drill through the rubber bladder where did you think the brake fluid you were pouring in was going?

The correct procedure is to drill the heads off the two screws (no chance of filings getting into the cylinder), remove the cap and get vise grips onto the remainder of the screw sticking proud of the m/cyl body.

[F5 Dave]

oouh, I never even read that as it was off topic, but if that is indeed what was done then it is truly nasty. Well spotted Katman

Sometimes you can remove the screws by dremeling in a flat blade slot. On occasion I have used a tiny sharp chisel to make a groove on the perimeter & tapped with a sacrificial screwdriver in an arch to rotate it. The best start (if screws not too bad) is to tap the top of the screw with a punch to smear the damaged edges in & then fit a impact driver bit in with a bit of a tap. Always press down when removing. Some valve grind paste sometimes helps 'bite'.

Then when none of the above has worked reach for the drill.

I'd def remove this cover & assess damage straight away. Well possible the master cylinder has swarf in it. You'd want to take the seals out and check for damage & the bore.

[McDuck]

yep it is heading over to katmen tonite. At least it got me home safe (even if that was more to good luck than good managment). No hard feeling (as long as it dosnt cost to much ;))

[Katman]

Just pulled the master cylinder apart - sure enough, full of metal filings right down between the bore and the seals. Perhaps Wannabiker might want to thank his lucky stars he doesn't have a very serious issue on his hands right now.

(Clearly, green rep is given out way too easily on here).

[McDuck]

Just pulled the master cylinder apart - sure enough, full of metal filings right down between the bore and the seals. Perhaps Wannabiker might want to thank his lucky stars he doesn't have a very serious issue on his hands right now.

(Clearly, green rep is given out way too easily on here).

And red to IMHO

[nudemetalz]

It was good to see you got home okay, McDuck. That was the main thing here.

[Clivoris]

It was good to see you got home okay, McDuck. That was the main thing here.

Hear Hear. Well ridden young man.

[MSTRS]

Obviously, it is wise to have suspension optimised - but whether it is 'right' in terms of static sag etc, the front and back must still work together . Ie, if you stand the bike up and press down on the tank, the front and rear move the same amount at the same time. A see-sawing action is baaad

[Katman]

It was good to see you got home okay, McDuck. That was the main thing here.

I totally agree. It was good to see he got home safely - because, quite realistically, that abortion of a repair job could have had fatal consequences.

It's a timely reminder to all that half a clue can sometimes be all it takes to get someone in deep shit.