Dreaded valve clearance!

So there was something wrong with my bike. It kept shutting down at low revs and not switching back on. Then it did after a few hours. I thought it might be time to check the valves and see if that would help. To cut a long story short, I checked the valves, they were in spec, put it all back and now it's like a double decker bus. Very low power and acceleration. I also replaced the regulator/rectifier and that seems to have helped so far. It hasn't shut down again, but I haven't run it for very long.

I've checked the air filter system with a diagram and I think I've it back together right but can't be sure. I wonder what other things could be causing this. I'm missing the idle adjustment screw so it's idling low and cutting out. I've been riding for years but only recently decided to dig into the machine and get my hands dirty (all the garages are busy atm). Any suggestions very much appreciated.

VFR800Fi 2001 5th Gen

 

No idle adjuster is a problem.
Starter valve sync in order, check spark plugs and spark plug boots for proper resistance.
Might want to have a read........
https://www.vfrdiscussion.com/index...r-last-22-years/&tab=comments#comment-1111811

 

I think the problem is actually to do with the air filter. Air intake leak or wrongly connected vacuum hoses. I had to literally break off the housing due to rusted screws to get to the valves which were in spec anyway

 

Now why am I not surprised the valves were in spec.

When I sold my 6th Gen it had done well over 300,000km and it was still running perfectly. (The offer of a fully loaded 8th Gen proved too hard to resist and has proved every bit as reliable.) From the outset I only did the valve check on the 6th gen every second time, and sure enough even when I paid to have the check done by the local Honda dealership it NEVER needed any valve adjustments.

The technician did say that as the VFR is basically a touring frame with a V4 race engine the valve inspection frequency is designed to pick up problems on the assumption you are actually using that engine as regular track day hack - so bouncing off the rev limiter in every gear day in and day out. I used my VFR mostly for long distance touring around Europe and would only very occasionally hit the redline on an enthusiastic overtake. Hence if your riding style means you are not really likely to be battering the valves on a regular basis then the Honda specified inspection frequency is probably OTT.

But it is your money to decide to bother with valve clearances checks as often as specified. But if you want a reliable motorbike never cheap out on filter and quality oil changes.

 

Well, the previous owner said it needed valve clearance. That wasn't good advice. It was running well for years. So now it's been shutting down I decided to take it apart and learn something about bikes. Indeed, that hasn't helped it's made it worse but it wasn't working anyway. No one has been able to fix it or find the answer to why it was shutting down so it's likely to be broken up and scrapped.

 

sad story. some people should never work on bikes and should find someone who can before too much damage is done.

someone can surely find the bikes problem with enough effort. youd have never got an empire with a quitters attitude. think of all the brilliant pionering work on the atom done at cambridge in the twenties and consider what simple, basic faults your bike may have, electrically.

 

Perhaps - before you throw in the towel. Please remember these bikes have a deserved reputation of having very reliable engines - the known weakness with the VFR is the charging system - which was not made by Honda - sadly it was bought in to a spec/price - meaning as long as it lasted beyond the Honda warranty period any failures and all the hassle that comes with it are entirely the owners problem.

Your description "It kept shutting down at low revs and not switching back on" sounds remarkably like the symptoms of charging system failure(s). Indeed you may have done the valve check fine - but it is certainly worth double checking all the stuff you disturbed during the check.

However if the charging system is on the fritz - you could still find the engine struggling to even start or it can cut out largely without warning other than the clocks switching off and resetting. In which case you are not alone - hundreds have suffered charging system problems - and thankfully the answer is known - fit a decent Shindegen RR instead - and then check for collateral damage to battery, loom or stator. - This thread explains all you could ever want to know about this POS.

https://vfrworld.com/threads/how-to-fix-common-regulator-stator-failures.39277/

The charging system tests in post #9 should be carried out twice once with the bike cold and again after a decent ride when everything is up to temperature - as sometimes windings in the stator can test OK whilst cold but insulation on the windings can start to breakdown when hot so instead of charging the battery the stator legs short out and rapidly drain the energy left in you battery - sometimes totally killing it - so make sure you start with a fully charged healthy battery.

Thankfully Honda eventually decided to fit far better charging systems to the 8th Gen VFRs so, touch wood this saga will eventually come to an end.

Good luck let us know how you get on.


SkiMad