setting idle & chain 'jumping' when riding away - 2005 s2r800

[pmazdan9]

Hi again, here to solve another issues with my duc

Bike has an open airbox, cat removed, open silmoto italia cans, DP map, 2005 with 35k miles.

Two issues as subject suggests:

1. Idle
Ever since I got this bike it's always been idling at 1000rpm. I want to set it to 1250. What I've tried so far:
- messing around with air bleed screws but that only seem to lower rpm and I can't increase it
- set the targed idle in ECU using TuneECU android app - it didn't do anything whether I reset TPS or not; I can confirm the app works as I successfully uploaded new fuel map (DP) and disabled immobiliser

In TuneECU I can set the idle in relation to temperature which is perfect as I can set it to 1500 when below 50 degrees, but agian, it doesn't really do anything.

I might have an air leak somewhere as rpm drop slowly after I rev it (needle hangs around 2-3k for a second), rpms are fluctuating at idle. Valves are a tad loose and will be adjusted soon, this year.

AFAIK there's no stepper motor on s2r800. The only option I see is to adjust throttle stop screw, but It's quite hard to reach, also I'm not sure what tool I need as security torx doesn't seem to fit very well and it's similar shape IIRC. Also almighty google says this screw shouldn't be touched and it's factory set, IIRC it closes butterfly valve in throttle body, right? So if it doesn't close all the way once 'adjusted', yes it will change the idle, but might affect performance.

There must a way to set the idle though!!

2. Drive chain
It seems that the chain 'jumps' occasionally when I drive away (when slipping clutch in 1st). It only happens occasionally and I mean it, maybe 1 in 20 times, but it doesn't sound good. It's like metal to metal grinding, hard to tell where it's coming from. My friend saw it once as I was riding away at traffic lights and it looked like the chain was jumping.

Few facts:
- I've had a problem with a clutch before (chain issue might not be clutch related but I want to provide as much info as I can) - retaining nut became loose, damper springs broke) - I ended up replacing the whole clutch bit by bit (expensive), only thing I didn't replace is the clutch pack - all discs are within spec, not warped or burned, clutch pack has correct height; clutch does not slip but drags a little bit and neutral is hard to find when engine hot (still it's million times better than before); new clutch basket is off another monster and doesn't have damper springs or dual mass drive gear, retaining nut was torqued to spec and I used loctite - it's still torqued as I've recently checked it
- clutch pushrod is straight, lubed with moly, orings in good shape and I have spare new ones, angle between rod and lever is 90 degrees, slave cylinder replaced as mine was leaking (OEM, nearly new)
- chain never jumped prior to replacing the clutch; it first happened when I replaced inner clutch basket (my old one was notched and was causing drag), with this it was happening almost every time unless I applied very little throttle (so bike was almost stalling) - I ended up buying a brand new one and it improved a lot
- chain is perfectly clean and lubed all the time (I'm using scottoiler), slack is 30mm as per manual
- front sprocket is a tad loose - I think it's supposed to have a little play?
- I am yet to properly inspect both sprocekts teeth and chain wear (I've a right tool for it somewhere) but let's assume it's all in good working order for now
- it never happens in other gears or when I'm riding, it only happens when I ride away from standstill

What can possibly cause that?

/e: you know what writing this thread made me realise I have and had so many problems with this bike, it's unbeliveable. If I stop posting one day it's probably because I've had enough and set the thing on fire

[pmazdan9]

As ducpainter said in my other unrelated thread:

Your ECU is capable, but without a stepper motor there's no connection between the ECU and the throttle bodies, other than the injectors.

This is a very good point and makes me thing the only way to set the idle is to give it more air. I've to say I have not tried adjusting air bleed screws AFTER installing new fuel map with target idle set to 1250. I will try it but don't have any hopes, my current map (DP) has a target idle of 1500 when cold, 1250 when warm, and it doesn't change at all.

[Howie]

As far as your chain goes, start with the basics:
   Tension properly set
   No frozen links
   Not excessively worn
   Sprocket teeth not worn

If you play with the throttle stop screw you will be messing with a base setting and (assuming TPS is correct) messing up the TPS setting.  First you want to check all base settings following the method in the repair manual.  You might want to consider getting that bike to a good shop.

[koko64]

What I do on a 620 with no stepper motor/air valve control. FWIW.

Open the air screw 1/8 at a time on a hot motor until you get the rpm you want. If the idle hangs back off (turn in 1/8 - 1/4). I use a manometer to check idle synch as some TBs want slightly different air screw settings for best, strongest, most even idle. Note any effect on synch thru the rpm range as that may be another service item to deal with. Badly adjusted valves impact idle and low rpm running and adjusting them is also part of setting the baseline.

If its all over the place and uncoperative then give the bike to one of the Speeddog's of the world for a thorough service. They will adjust the valves, set synch, set tps and set idle speed which all can interact.

Some thoughts on how to get a stubborn set of throttle bodies to idle above 1000 rpm.

You can try adjusting out the air bleed screws until the throttle just starts to hang then turn them in 1/8 - 1/4 turn to avoid the rpm hanging after you blip the throttle.

See where idle sits when hot and adjust for that, not when cold, or the rpm will get too high when properly warmed up.

Turn in the air bleeds 1/8 at a time once hot to get the idle back down to 1100-1200ish rpm if it is too high..

Remember, turning the air screws out raises the rpm and I find I cant go out too far until the throttle hangs, maybe 11/2 - 2 turns before it starts to hang.

Speeddog will have a better process I'm sure (Im a carb guy that also has to deal with efi).

Dont be too proud to work some extra shifts to pay someone to tune it to perfection, it could be more time/cost effective.

[pmazdan9]

Thank you howie I'm gonna check it all this weekend!

You might want to consider getting that bike to a good shop.

I'd love to take it to a good shop, but there aren't any in my area and I'm struggling with money these days. I'm getting my dash sorted (fried in the rain) and will take it for re-shimming valves, can't afford anything more at the moment

What I do on a 620 with no stepper motor/air valve control. FWIW. [...]

Thank you koko64 that's exactly what I'm gonna do (again)! However I think this isn't gonna change anything because the screws are out quite a lot already, iirc 1,5 and 2,5 turns out and any more than that doesn't do anything, it idles at around 1000rpm with this setting and stalls otherwise. Currently I don't have a dashboard so would be difficult to do it, I think I'll just wait till I get it back from electrician first. And if that doesn't help, I'll try again after doing valves.

Dont be too proud to work some extra shifts to pay someone to tune it to perfection, it could be more time/cost effective.

I couldn't agree more, I just can't afford to spend any more money on the bike for now so I'll do what I can to fix things myself.

[koko64]

Do you have a manometer/synch gauges?

[pmazdan9]

Do you have a manometer/synch gauges?

I don't (yet) but will get one at some point. I've never balanced throttle bodies in my life but I know how to do it and feel confident. I can do stuff as long as I understand what I'm doing or/and follow the instructions.

From what I remember:
- bike needs to be warmed up to the operating temperature
- connect manometer to each throttle body
- close air bypass screws
- run engine
- turn screw on the TB (under airbox) to balance vacuum
- adjust air bypass screw to set correct idle

This should be easy for me to do. I've tried setting the idle without balancing TB - I assumed they were balanced 1000 miles ago (at the time) by the dealer. I had no success adjusting the idle then.

I will definitely try it again, without balancing TB for now. I can always go back to stock setting if it's bad, just want to see if I can increase the idle.

About the TB balancing. I'll either buy a manometer, or (more likely) make one myself. There are some DIY tutorials. It'd cost me next to nothing, I can use scottoiler spigot to connect to TB (I've got one already), some clear tubing and engine oil. I'll do it after the valves.

/e: for a record, my previous OEM (?) fuel map had target idle set to 1000. Perhaps that was the reason why I couldn't go above it when opening the air bypass screws. My new DP map has 1500/1250 (depending on the temperature) so I hope adjusting air bypass screws will work this time.

[koko64]

You may find one tb air screw is set to slow keeping the overall idle rpm down. So theoretically, one  may need 1 turn out and the other 2 turns for example to both be at the highest idle speed. Look for each manometer tube to be at its highest position and and not just equal to each other.

[pmazdan9]

You may find one tb air screw is set to slow keeping the overall idle rpm down. So theoretically, one  may need 1 turn out and the other 2 turns for example to both be at the highest idle speed. Look for each manometer tube to be at its highest position and and not just equal to each other.

That's a very good avice, note taken. I can't wait to get my dash back now!

[koko64]

 

[pmazdan9]

Right, I checked my chain earlier today. It looks perfectly fine. It's not stretched, it's tightened properly, sprockets are not worn. I didn't check for tight spots yet as I'd need to put it on a stand and didn't have time for it.

Anyway, here's the video that shows what happens. I took it in July so while ago. It started happening when i changed clutch inner hub, every time i took off. I went back to old one and it stopped. Now i have recently changed this hub again to brand new one and it's happening again just not that bad, chain "jumps" and clunks usually once and not often, only when i take off. It sounds like a loud clunk in the video but really it's more like a grinding noise I think.

https://youtu.be/NgARvv8xjys

[DarkMonster620]

Have you cleaned your TBs with Air Intake Cleaner or Carb Cleaner?
If not, do it, engine will be hard to start, but, will expel all or most of whatever gunk was gunked in the intake; then, with engine running, give it a little gas, keep spraying into each cylinder so that tb blades and any rest of gunk gets cleaned.
After that, long thin Phillips or flat screwdriver get to the adjust throttle stop screw in the middle of both intakes holding the throttle cam shut turning NO more than 1/4 to 1/2 turn at a time . . . start engine again, idle should be around 1500, now since engine IS warm, adjust to 1100 . . . if not, then, more adjusting will be necessary

[koko64]

Id be taking that clutch cover off for a good look in there. Something may have come loose. Check the oil for debris too.

[pmazdan9]

Good idea with cleaning, it's a 14 years old bike so I'll give it a go I guess.

Koko64 pretty sure everything is torqued to spec, oil was changed 3000 miles ago; anyway, since I cleaned and adjusted the chain it doesn't happen anymore. I tried to replicate this issue but I couldn't. It's strange though cos my chain was only a tad loose, maybe 50mm slack and it's 30mm now. It was a bit dirty but lubed. I'll keep an eye on it and if it happens again, I'll check the clutch.

[koko64]

At 50mm you can hear the chain slap the swingarm chain guide under power pulses. I have seen very loose chains jump and strip sprocket teeth.