Engine Loses Power after 1.5 miles Resolved..Float Stuck

Need advice on which oil to use or which tyre best suits you? Share your topic and get help here.
Peeb
Posts: 18
Joined: Tue Apr 11, 2017 6:07 am

Engine Loses Power after 1.5 miles Resolved..Float Stuck

Post by Peeb »

1998 VTR 1000 US Spec, non California

Hello Everyone, I've been about the forum and an owner for a couple of years now and have done all the things that needed doing. CCT Stopper Mod, Regulator, 48pilot jets, Fuel valve diaphragm, TPS adjustment, Pair delete, Fork rebuild, clutch master/slave rebuild, fluids, chain and Sprokets. All was done with your help, history and the service manual. What was a good looking but ratty running bike has been a dream for 2 years and 5000 miles.

The bike starts, runs and idles well. Voltage is good before start and while running. After 1.5 - 2 miles the engine bogs, looses power and runs just well enough to get home. I figured a clogged fuel screen or broken diaphram but both are new and I checked the flow with the tank on a bench, applied vac and the fuel gushes out as it should. I have vacuum taps connected for testing and the vac is good so I don't think it's a fuel flow problem.

But the behavior is exactly like a fuel flow problem where the flow is limited and the bike runs well until the bowls go empty. Both exhausts remain hot if I drive the mile home while bogging so I don't think it's ignition or fuel related to one cylinder or the other. It makes me think of items that are common to both cylinders. I am waiting for a peak voltage adapter to check the items in the ignition (section 17) of the Honda service manual. 17 specifies procedures for testing the pulse generator and the coils as installed. Bench test of coils is good (I actually replaced one) There is also the engine coolant temp sensor. This has an effect on timing as the bike warms but I don't think it could create such a gross loss of power. The problem is repeatable every ride and is not subtle. After a 30 min cool down, the bike runs fine for another 1.5 miles.

Normally I find ideas by searching the Workshop topics but no luck on this one
Any ideas? Peter (Peeb)
Last edited by Peeb on Mon Apr 08, 2019 5:18 am, edited 1 time in total.
User avatar
Chris58
Posts: 123
Joined: Tue Aug 01, 2017 2:57 am
Location: Canada

Re: Engine Loses Power after 1.5 miles

Post by Chris58 »

What was the last thing/things done to it before it started acting up?
User avatar
fabiostar
Posts: 7542
Joined: Sat Jun 01, 2013 3:53 pm
Location: sunny belfast

Re: Engine Loses Power after 1.5 miles

Post by fabiostar »

does the bike keep running if you pop open the fuel cap ? might be the tank breather blocked
the older i get,the faster i was :lol:
User avatar
8541Hawk
Posts: 2066
Joined: Sat Jul 21, 2012 5:21 am
Location: Bella Vista, AR

Re: Engine Loses Power after 1.5 miles

Post by 8541Hawk »

I doubt it is an issue with the pulse generator. When they go bad you usually see erratic running at higher rpms and it slowly gets worse and lower in the rpm range as the generator degrades more.

I would take the advice of trying to open the tank when it is happening and see what that does as it does sound like you either have a tank vent issue or the vacuum line was inadvertently attached to the wrong nipple. :thumbup:
Loud pipes don't save lives, knowing how to ride your bike will save your life.
User avatar
Stratman
Posts: 2656
Joined: Mon Dec 01, 2003 10:55 pm
Location: Norwich
Contact:

Re: Engine Loses Power after 1.5 miles

Post by Stratman »

Many moons ago, mine behaved like this and no-one could find the fault, until one day I started to take things apart systematically and the front plug cap/boot had a split in the rubber. Any moisture in the plug well, when warm, was "sucked" up the crack and then caused a track to earth and hence the misfire. New plug boot and no issues. Also may be worth checking that both plug caps are securely screwed into to HT leads?
Two bikes, still only four cylinders!

Image
Peeb
Posts: 18
Joined: Tue Apr 11, 2017 6:07 am

Re: Engine Loses Power after 1.5 miles

Post by Peeb »

Chris58 wrote: Sun Mar 10, 2019 11:03 pm What was the last thing/things done to it before it started acting up?
Nothing was done before the symptoms. It was 5000 miles of bliss. Several things (flow test, a coil replacement that turned out to be non related) have been tried since. Thank you for the thinking
Peeb
Posts: 18
Joined: Tue Apr 11, 2017 6:07 am

Re: Engine Loses Power after 1.5 miles

Post by Peeb »

fabiostar wrote: Mon Mar 11, 2019 9:24 am does the bike keep running if you pop open the fuel cap ? might be the tank breather blocked
Fabio Star, thank you for the reply.
With these symptoms, I was CERTAIN the vent was the problem. I popped open the tank cap during the symptoms (requires a stop because I have only one key) and even tried riding with the tank cap open from start with no change in behavior. I also flow tested the tank with lines off the bike. One thing I might try is riding with a long vacuum line from the fuel valve to my mouth in order to eliminate the vac source. I could also connect a small vacuum gauge to the Tee fitting that is already installed in the rear cylinder vac line.

I think I'm looking for components that are common to both cylinders. That would be fuel, crank sensor, ECU, Temp sender. I'm also wondering about a bad ground or some other cause that becomes worse (more resistance) as the bike warms. Truly making me crazy. The Peak Voltage adapter gets here today.
Peeb
Posts: 18
Joined: Tue Apr 11, 2017 6:07 am

Re: Engine Loses Power after 1.5 miles

Post by Peeb »

8541Hawk wrote: Mon Mar 11, 2019 3:02 pm I doubt it is an issue with the pulse generator. When they go bad you usually see erratic running at higher rpms and it slowly gets worse and lower in the rpm range as the generator degrades more.

I would take the advice of trying to open the tank when it is happening and see what that does as it does sound like you either have a tank vent issue or the vacuum line was inadvertently attached to the wrong nipple. :thumbup:
Mr 8541 Hawk. Thank you for the reply. I think you were the guy who got me going on the Pair Delete, the 48 pilots and TPS adjustments that really made this bike sing.

I did try opening the tank and tried running with it open with no change in symptoms. I was CERTAIN the vent or screen or diaphragm or vac source had to be causing a fuel delivey problem, it just makes too much sense. I also bench tested the tank and valve by providing mouth vacuum to the valve. I'm aware of the similar but incorrect nipple on the fuel valve that is the vent for the diaphram. Photos of the tank bottom and fuel valve are attached with comments. I welcome your suggestions, there are plenty of times I have missed something and the symptom is so indicative of a fuel problem.
Commented Under Fuel Tank.jpg
Commented Under Fuel Tank.jpg
Attachments
Commented FuelValve.jpg
Peeb
Posts: 18
Joined: Tue Apr 11, 2017 6:07 am

Re: Engine Loses Power after 1.5 miles

Post by Peeb »

Stratman wrote: Mon Mar 11, 2019 3:50 pm Many moons ago, mine behaved like this and no-one could find the fault, until one day I started to take things apart systematically and the front plug cap/boot had a split in the rubber. Any moisture in the plug well, when warm, was "sucked" up the crack and then caused a track to earth and hence the misfire. New plug boot and no issues. Also may be worth checking that both plug caps are securely screwed into to HT leads?
Thank you for the reply
The rear coil, HT lead and plug cap have been replaced. I have not checked the front and will do so today after removing the plastic farings. I'm also waiting on a peak voltage detector that may help eliminate other factors. My sons and I have several bikes between us and the SuperHawk is the run away favorite!
VTR1000.jpg
tony.mon
Posts: 15943
Joined: Wed Jul 25, 2007 10:46 pm
Location: Norf Kent

Re: Engine Loses Power after 1.5 miles

Post by tony.mon »

I agree that it sounds like fuelling. You could try riding it until it misbehaves then cut the engine after a couple of minutes and check the spark plug colours.
That should show which cylinder is affected or whether its both.

If so, it will either affect both carbs or only one, and you need to find out which option applies.

If both it will be either the tap, fuel filter (in the tank) or the tank breather--you have eliminated all of those.
If just one, it could be plug, plug cap, ht lead, igniter box, earth connections, battery, reg rec (over voltage causes these symptoms, so it's with metering the voltage at the battery), blocked air filter, or fuelling.

If fuelling, float level, oversize main jet, very worn needle jet, etc.

But my money is on a dodgy coil or the choke cable sticking on.
A plug chop should show which.
It's not falling off, it's an upgrade opportunity.
User avatar
sirch345
Site Admin
Posts: 21671
Joined: Mon Aug 25, 2003 10:35 pm
Location: The West Country.

Re: Engine Loses Power after 1.5 miles

Post by sirch345 »

Peeb wrote: Mon Mar 11, 2019 5:45 pm Image
Unless I'm mistaken the take off spout for the rear cylinder vacuum hose on the petrol tap is normally at 90 degrees to the vent spout, not sure if that would make any difference :eh:

Chris.
User avatar
Wicky
Posts: 7895
Joined: Sat Feb 11, 2006 2:43 pm
Location: Colchester Essex
Contact:

Re: Engine Loses Power after 1.5 miles

Post by Wicky »

Yes the angle on the reassembled vacuum spigot plate could possibly be interfering with the proper action of the diaphragm.

Definitely worth swivelling around to rule that out so its pointing horizontal. And a chance to check its sited well and doing its job.

Image
It may be that your whole purpose in life is simply to serve as a warning to others.

ImageVTR Firestorm and other bikes t-shirts
Peeb
Posts: 18
Joined: Tue Apr 11, 2017 6:07 am

Re: Engine Loses Power after 1.5 miles

Post by Peeb »

sirch345 wrote: Mon Mar 11, 2019 11:24 pm
Peeb wrote: Mon Mar 11, 2019 5:45 pm Image
Unless I'm mistaken the take off spout for the rear cylinder vacuum hose on the petrol tap is normally at 90 degrees to the vent spout, not sure if that would make any difference :eh:

Chris.
High Chris, I can clock the fuel valve so the vac is 90 degrees to the vent. I did flow test the tank on a bench by applying vac to the valve and the fuel drains out the two supply pipes so fast it's empty from 1/2 full in just over a min. Thanks for thinking and helping. Peeb
Peeb
Posts: 18
Joined: Tue Apr 11, 2017 6:07 am

Re: Engine Loses Power after 1.5 miles

Post by Peeb »

8541Hawk wrote: Mon Mar 11, 2019 3:02 pm I doubt it is an issue with the pulse generator. When they go bad you usually see erratic running at higher rpms and it slowly gets worse and lower in the rpm range as the generator degrades more.

I would take the advice of trying to open the tank when it is happening and see what that does as it does sound like you either have a tank vent issue or the vacuum line was inadvertently attached to the wrong nipple. :thumbup:
The pulse generator peak voltage checks good. So does the coolant temp sender. The rear coil is replaced and the front coil I have out for a bench test but nobody publishes primary and secondary resistance figures. The Honda Service Manual refers to peak voltage measured while cranking with a harness that inserts a peak voltage adapter inline between coil and harness needing to be higher than 100 volts. Does one of you have a haynes guide that gives the primary and secondary resistance values? I feel like I have eliminated the fuel supply. I could be wrong, it would not be the first time. I'm certain on the vent line, diaphram, vac connection and did a flow test to verify.
jchesshyre
Posts: 590
Joined: Wed Jun 15, 2016 9:09 am
Location: Chester, Cheshire

Re: Engine Loses Power after 1.5 miles

Post by jchesshyre »

tony.mon wrote: Mon Mar 11, 2019 8:27 pm ...blocked air filter...
Have you checked this? If it were really bad it would cause excessive richness which would worsen at the bike warmed up.
Post Reply