CB1100 Idle speed instability problem

[dave]

Hi Guys. I didn't spend as much time on the IACV on Saturday as I had planned. (I did an oil change and other maintenance items to the VFR though). I also went to the dealer and ordered spark plugs and the tool to hold the cam chain tensioner, which is necessary to inspect the valve clearances (an expensive little bugger). I reinstalled the IACV, and lubed it with motor oil. Reinstalling the air box was a real challenge. Magnus - did you experience this also, or was I just doing something wrong?

When initially powered, when you turn the ignition switch on, the IACV cycles to move the piston out, or into the cylinder. It moves out, then stops.

Besides Magnus and I (and Honda dealers), are we the only ones to have performed this repair? Magnus was able to remove his rear fender without removing the rear wheel, and I was wondering how other people did this. The FSM says to disconnect the shocks to lower the rear wheel and then remove the RH side shock, and remove the fender from the RH side. I looked at the clearance available if I did this and decided to just remove the rear wheel entirely, which I believe helped to make the entire job a lot easier. I also struggled to remove, and install, one of the many sections of the multiple-piece air box - I had to force it out and then back in, distorting the plastic to get it to fit (I am lucky it didn't crack). I was wondering if Magnus, or others, found an easier way to do this.

I'll work a little each evening this week to reinstall all of the parts I removed to get at the IACV. My plan is to perform the valve inspection on Saturday (I have to wait for the cam chain tool from the dealer). If no valves require adjustment then hopefully I will be able to start the engine on Saturday and determine if the new IACV repairs the idle problem.

On the topic of valve inspection: I believe Max posted that he had to move the large, plastic (heat?) shield on the top of the cylinder head, is this correct, or do I have to completely remove it? The valve inspection looks like another daunting task (oh how I miss the old days when bikes were simple to work on).

 

[Tim_imp]

WOW Taiwan actually has real bike's! That's awesome, I live in the Philippine's, and their idea of a motorcycle is a 150cc Honda with a sidecar and 8 people on it. LOL (And no I am not kidding) I cant wait to get my 1100 home and let them all drool. There are a few big bikes there but not many. I'm glad to know that not all Asian countries ride 150's.

 

[Cormanus]

There's some pretty big bikes in Japan, methinks, and the CB1100 has certainly been exported to China for at least one of its model years and maybe more.

 

[dave]

Thing to remember is that the engine ran fine for a long time when you got it, if the piston was mis-aligned ( position-wise ) it would have shown up very quickly, so something has changed some time later.

Gentlemen. If my repair is successful and I determine that the new IACV cures the idle problem, if I send my old IACV to one of you guys could you possibly use it to determine what failed on it? Maybe you could come up with a better method to diagnose the idle problems by doing this?

 

[pdedse]

Thing to remember is that the engine ran fine for a long time when you got it, if the piston was mis-aligned ( position-wise ) it would have shown up very quickly, so something has changed some time later.

Gentlemen. If my repair is successful and I determine that the new IACV cures the idle problem, if I send my old IACV to one of you guys could you possibly use it to determine what failed on it? Maybe you could come up with a better method to diagnose the idle problems by doing this?

Yup. My issue started a year and half after purchasing, and after putting around 9k miles on it.

 

[SportsterDoc]

Dave

Sorry for the delay in response, but wife and I are helping my son move.
After riding 465 miles yesterday, it actually felt good to load and unload my truck a few times, today, between thundershowers!

I am geographically close to you, for mailing parts, but it is probably better to post close-up photos for many pairs of eyes to scrutinize. If you are not set up to post, then you are welcome to email them to me, Max, etc. and/or a moderator may post them for you.

When I managed an electric motor repair shop, we were a factory warranty station for many manufacturers, such as Baldor, GE, Toshiba, etc. but finding a smoked defective winding, versus all windings overloaded or 2/3 of the windings cooked from single phasing a 3 phase motor or defective bearing was fairly easy. It was also easy to see if a shaft broke on a belt driven application, from an over-tightened belt. However, I am not optimistic about seeing something on your IACV.

If there is no scuffing on the piston at any point, indicating possible periodic binding, I would carefully examine the threaded shaft and "nut" to see if there is any wear or damage...is it possible for shaft to turn and piston not move as it should? If the stepper windings were an issue, I would expect a DTC.

Also, due to its position upon removal, as you described, I wonder how that can be explained.

Sorry to not be of more help.

Back to moving, in the morning, but will check back as soon as practical.

 

[Cormanus]

Dave, you may be all over posting pictures. I haven't checked. If you're not, I'm happy to help out. PM me and I'll send you an email address.

 

[dave]

Thank you Doc and Cormanus for your offer to help post. I haven't posted in a while, and I will take you guys up on it. I have taken some pictures that I think will be helpful, but I have not documented every step of the way.

I've got the air box and fender section "B" installed now. Getting the middle section of the air box in and out was extremely challenging, and I bent the metallic front brake cable where it routes down to the ABS doing it. I wonder if Magnus experienced the same difficulty. I noticed he left the rear air box section pushed back into the frame, where I removed mine (I believe removing the rear wheel opened up a lot of extra space). Magnus also completely removed the fwd section of the air box, where I unscrewed mine from the throttle bodies and pushed it aside.

I cannot detect any damage to the old IACV, and I am praying that after all this work the new IACV cures this problem. I plan to inspect my valves this Saturday, and if they don't need adjusting I should be able to complete everything and fire it up.

Thanks again for all the great support from everybody.

 

[peterbaron]

Thank you Doc and Cormanus for your offer to help post. I haven't posted in a while, and I will take you guys up on it. I have taken some pictures that I think will be helpful, but I have not documented every step of the way.

I've got the air box and fender section "B" installed now. Getting the middle section of the air box in and out was extremely challenging, and I bent the metallic front brake cable where it routes down to the ABS doing it. I wonder if Magnus experienced the same difficulty. I noticed he left the rear air box section pushed back into the frame, where I removed mine (I believe removing the rear wheel opened up a lot of extra space). Magnus also completely removed the fwd section of the air box, where I unscrewed mine from the throttle bodies and pushed it aside.

I cannot detect any damage to the old IACV, and I am praying that after all this work the new IACV cures this problem. I plan to inspect my valves this Saturday, and if they don't need adjusting I should be able to complete everything and fire it up.

Thanks again for all the great support from everybody.

Dave , you did heck of a job for all the Forum members, plus bonus goes to you, cuz automotive is not your field = needles to say well done.
If there is no one nearby to exam removed IACV, I can offer my "expertise*" (will take some time) and I'm willing to pay up-to U$20 S&H cost.
Let me know, so can pm you my address (Canada)
*bench test, mechanical and electrical, will not install
:clap::beerchug:

pb

 

[pdedse]

Thank you Doc and Cormanus for your offer to help post. I haven't posted in a while, and I will take you guys up on it. I have taken some pictures that I think will be helpful, but I have not documented every step of the way.

I've got the air box and fender section "B" installed now. Getting the middle section of the air box in and out was extremely challenging, and I bent the metallic front brake cable where it routes down to the ABS doing it. I wonder if Magnus experienced the same difficulty. I noticed he left the rear air box section pushed back into the frame, where I removed mine (I believe removing the rear wheel opened up a lot of extra space). Magnus also completely removed the fwd section of the air box, where I unscrewed mine from the throttle bodies and pushed it aside.

I cannot detect any damage to the old IACV, and I am praying that after all this work the new IACV cures this problem. I plan to inspect my valves this Saturday, and if they don't need adjusting I should be able to complete everything and fire it up.

Thanks again for all the great support from everybody.

Here's hoping that the reassemble goes smoothly and the idle issue disappears.

 

[Magnus_imp]

I don't remember having too much trouble. But my bike does not have ABS so that was not in the way. I think I left one portion of the airbox loose in the frame as it was hard to remove completely.

Just FYI I noticed no change after replacing my IACV but then after a few hundred miles and one long spirited ride it seemed to fix itself. I don't know if it was related to the replacement or not. For the past year and 2500 miles or so the bike has been running perfectly.

 

[max]

Looking good Dave, is the valve check necessary?
The reason for removal of the heat shield is the space required to lift the valve cover over the cam chain guide, which sticks out above the rest of the gear.

i would have a good look under the guide before removing it to the right, to see if you clear the guide and may damage the gasket!

However since i have no wsml there may be a different procedure that i am not aware of, my little writeup was more meant as an insight rather than step by step instruction and just mentions some of the pitfalls.
Did have to bend the heatshield and it was a bit stubborn, also note the grease inside the coil terminal rubber boots, this really helped.

And yes, let peter have a close look at it, good idea, it may be very subtle but worth finding.

:clap::clap:

.

 

[peterbaron]

Looking good Dave, is the valve check necessary?
The reason for removal of the heat shield is the space required to lift the valve cover over the cam chain guide, which sticks out above the rest of the gear.

i would have a good look under the guide before removing it to the right, to see if you clear the guide and may damage the gasket!

However since i have no wsml there may be a different procedure that i am not aware of, my little writeup was more meant as an insight rather than step by step instruction and just mentions some of the pitfalls.
Did have to bend the heatshield and it was a bit stubborn, also note the grease inside the coil terminal rubber boots, this really helped.

And yes, let peter have a close look at it, good idea, it may be very subtle but worth finding.

:clap::clap:

.

Max ,
Thanks for referral, will do my best...
:worship:

pb

 

[dave]

Hi Guys. Bike is completely assembled except for the seat, gas tank, and side covers. I plan to inspect the valve clearances on Saturday. FSM suggests inspection at 6k; bike now has just over 14k. I normally go by the factory recommendations but with the feedback from this forum I figured it wouldn't hurt to wait a little longer.

Magnus: I had a really hard time removing the middle section of the air box. I did not realize it at the time, but I bent the metallic brake line leading to the ABS modulator when I forced the air box out. I did not remove the fwd section of the air box that attaches with screws directly into the throttle bodies - I was able to shove it far enough to the side so that I could remove the IACV. (this saved a lot of time).

Is Peterbaron the guy who can look at my old IACV and determine what is wrong with it? If I determine that my new IACV cures the idle problem I am happy to send it to him.

My hat is off to Magnus, who replaced his IACV. This job has been very tedious. It's been like working on a Chinese jigsaw puzzle. Even installing the rear fender was challenging due to making sure the wires are all properly tucked into the plastic cover between the fender and the frame, near the seat lock.

Max: What is wsml?

 

[max]

workshop manual, should have not used the wrong abbreviation, sorry Dave.
Ok on the valve service, i thought you had done more km's, at this stage you are more likely to do some damage than good, that was my impression when i did mine, i hope you have feeler gauges that have 0.01 mm increments, 0.05 ( the usual ones ) are not accurate enough for this kind of work and i actually got two sets because these are very vulnerable even to rotate in and out of the cover handle, they have 0.01 0.02 0.03 0.04 0.05 mm. etc.so really thin and easy to damage and i keep them well oiled to stop rust.
most important is to write the values and odometer reading down during the measurement and keep them so you can spot a trend in the future when comparing the checks and see which ones are changing values from spec.

 

[dave]

I’m reading the FSM to learn how to inspect my valve clearances tomorrow. I have read and reread the post by Max showing how he did this (thank you Max). Before I begin I have some questions – directed to Max and anybody else who has inspected their valve clearances.

1. Max stated that he did not loosen the tensioner, like Honda recommends. I do not understand why you would want to loosen the cam chain tensioner to perform a valve inspection. If the cams had to be removed to perform a valve adjustment I can understand why you would want to do this. I bought the neat little $110.00 tensioner stopper (part number 07AMG-001A100) from Honda, but I prefer to not use it, unless I have to. Can I get some feedback on this please?

2. Honda says to remove the heat shield, but Max was able to slide it back to gain access – can I get some feedback on this also please? Also, did you completely remove the coil assembly, or just move it back?

3. For Max: You stated “…I ended up greasing the little boots on the coils on the inside because it made it easy to slip them over the little plastic ridges…”. Are you talking about the spark plug wires? Are these wires removed from the coils?

4. I just discovered that Max is recommending that I use feeler gauges that have .01mm increments – this is .00039 inch! I have .001-inch increments. I have the nominal size, +/-.001 inch, which is the tolerance. You don’t think this will work? I will see if I can purchase some new gauges before I start if I need to.

Wish me luck. This looks like a two-weekend task for me (if I don’t have to adjust any valves – I’m praying I don’t), giving that I’ll probably only spend 5 hours on it Saturday, and none on Sunday.

 

[max]

Just happened to be on the page when this post rolled in, Hi Dave;

I’m reading the FSM to learn how to inspect my valve clearances tomorrow. I have read and reread the post by Max showing how he did this (thank you Max). Before I begin I have some questions – directed to Max and anybody else who has inspected their valve clearances.

1. Max stated that he did not loosen the tensioner, like Honda recommends. I do not understand why you would want to loosen the cam chain tensioner to perform a valve inspection. If the cams had to be removed to perform a valve adjustment I can understand why you would want to do this. I bought the neat little $110.00 tensioner stopper (part number 07AMG-001A100) from Honda, but I prefer to not use it, unless I have to. Can I get some feedback on this please?

2. Honda says to remove the heat shield, but Max was able to slide it back to gain access – can I get some feedback on this also please? Also, did you completely remove the coil assembly, or just move it back?

3. For Max: You stated “…I ended up greasing the little boots on the coils on the inside because it made it easy to slip them over the little plastic ridges…”. Are you talking about the spark plug wires? Are these wires removed from the coils?

4. I just discovered that Max is recommending that I use feeler gauges that have .01mm increments – this is .00039 inch! I have .001-inch increments. I have the nominal size, +/-.001 inch, which is the tolerance. You don’t think this will work? I will see if I can purchase some new gauges before I start if I need to.

Wish me luck. This looks like a two-weekend task for me (if I don’t have to adjust any valves – I’m praying I don’t), giving that I’ll probably only spend 5 hours on it Saturday, and none on Sunday.

 

[peterbaron]

Max = you are the best
:clap:

pb

 

[dave]

Max = you are the best
:clap:
I second that!

 

[dave]

Just wanted to give the team an update: Everything I need to remove from the bike to check my valve clearances, except the valve cover itself, has been removed. I actually made a flow chart, with the FSM page numbers shown, to help me while I flipped back and forth between about ten sections of the FSM to do this, that helped a lot. Working 10 and 11 hour days has reduced the time available to work on my bike, but if I can get out of work at a decent time today I plan to inspect the valve clearance tonight. I cannot find a feeler gauge with .01 mm increments, so I'll just use my gauges that have .001 inch increments. I'm praying that none of the valves require adjustment. I removed one spark plug and it looks as good as new (14,000+ miles), but I plan on replacing the plugs ayway. I ordered the spark plug socket that Ferret recommended.