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Discussion Starter · #1 ·
My RD03 has either a misfire or runs like it's out of fuel around 5k rpm in 5th gear

Any ideas?

CDI's?

Pump?

Coils?

The choke cable is removed and the plungers are fitted with the springs so I doubt it's that.

I didn't notice it when I was running it in after the rebuild as I wasn't going past 4.5K RPM.
 

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Does it have the same problem in lower gears as well as in 5th as you've mentioned?
 

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My RD03 has either a misfire or runs like it's out of fuel around 5k rpm in 5th gear

Any ideas?

CDI's?

Pump?

Coils?

The choke cable is removed and the plungers are fitted with the springs so I doubt it's that.

I didn't notice it when I was running it in after the rebuild as I wasn't going past 4.5K RPM.
Does it have the same problem in lower gears as well as in 5th as you've mentioned?
Hi I’m having same problems !
 

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Discussion Starter · #4 ·
Yes, it was fifth I noticed it in at first but checked it in all gears and it's happening most of the time.
 

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Maybe first check out the fuel pump (is it OEM?). By-pass the pump so the carbs are gravity-fed, albeit to do this the fuel level has to be higher than the float bowls, which means the tank needs to be filled to suit (i.e. over half full if I remember correctly).
 

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Discussion Starter · #6 ·
I'm thinking its fuel starvation or ignition, its happening randomly, sometimes at 4.5-5.5k sometimes not until 7 or 8k, some times you can rev past it.

Original pump but the bike has only done 5,800km though it is 33 years old and it spent over 10 years dry.
I could borrow the pump from my NTV650 as its the same pump.

I haven't ordered a pump yet but I have ordered a pair of programmable CDI's from CDI shop and a pair of CR1 and CR2 HT NGK Racing HT leads as used by one of the RC31 tuners They use CR5's instead of CR2's because the coils are further away on the RC31.

I haven't ordered coils yet as I have a spare set. I fitted new NGK Iridium plugs during the rebuild.
 

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I'd be inclined to check the pump first, as said by by-passing it completely and feeding the carbs on gravity alone (ensuring the tank is filled up enough to do this). Or, as you say, substituting your NTV pump assuming it's in good working order. It may be as simple as the old pump not delivering enough fuel when a higher quantity is required at higher revs. Or check the output of the pump by disconnecting the pipe on the carb side and dispensing the fuel out of the pump into a measuring jug - I recall it should deliver a min. of around 900cc/minute, the Haynes Manual can confirm this figure. Sometimes a failing pump will deliver a reduced quantity of fuel, so everything works fine at lower revs when the amount required is less than at high revs.
If it's not a case of simple fuel starvation, then time to move on to other things. When you hit around 5000 rpm and it dies, is it both cylinders?.... I assume so, as if it's only one cylinder it would carry on running on the other, with a notable loss of power.
On the basis of both cylinders dying identically, and it's an ignition problem, it's likely to be one of the ignition components shared by both cylinders such as the ICU, as the coils/HT leads/plugs are of course individual to each cylinder. The other components which can cut-out both cylinders are the clutch/sidestand/neutral switches, but the chances of any of these becoming faulty and activating every time there's 5000rpm or more is I think extremely remote. I don't have a wiring diagram for the 650, so am assuming it's similar to the early 750 but could be wrong in this assumption.
 

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I'd be inclined to check the pump first, as said by by-passing it completely and feeding the carbs on gravity alone (ensuring the tank is filled up enough to do this). Or, as you say, substituting your NTV pump assuming it's in good working order. It may be as simple as the old pump not delivering enough fuel when a higher quantity is required at higher revs. Or check the output of the pump by disconnecting the pipe on the carb side and dispensing the fuel out of the pump into a measuring jug - I recall it should deliver a min. of around 900cc/minute, the Haynes Manual can confirm this figure. Sometimes a failing pump will deliver a reduced quantity of fuel, so everything works fine at lower revs when the amount required is less than at high revs.
If it's not a case of simple fuel starvation, then time to move on to other things. When you hit around 5000 rpm and it dies, is it both cylinders?.... I assume so, as if it's only one cylinder it would carry on running on the other, with a notable loss of power.
On the basis of both cylinders dying identically, and it's an ignition problem, it's likely to be one of the ignition components shared by both cylinders such as the ICU, as the coils/HT leads/plugs are of course individual to each cylinder. The other components which can cut-out both cylinders are the clutch/sidestand/neutral switches, but the chances of any of these becoming faulty and activating every time there's 5000rpm or more is I think extremely remote. I don't have a wiring diagram for the 650, so am assuming it's similar to the early 750 but could be wrong in this assumption.
Hi,
So after replacing new spark plugs, and feeding fuel through the the fuel line with a jug, it sounded fine, put it back together, been on it tonight, done approx 30 miles, everything fine, stopped for approx 30 mins, started it up again and Same problem, sounds like not firing on all cylinders, not much pull when going through the gears…… please help !!!!!
 

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Jav, so to get it clear.... after checking the fuel pump flow and renewing the (all 4?) plugs, the bike ran perfectly normally for 30 miles. Then after parking-up for 30 minutes it ran badly from the off? Was the bad running again only at higher revs (5k + rpm as you said in your earlier post)? And was it running badly but consistently with reduced power or was it cutting out completely (at high revs or at all revs)?
 

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Discussion Starter · #10 ·
So far I've changed the plug leads to NGK CR1's for the inner plugs and CR2's for the outer plugs and changed to my spare coils.
166416


A slight improvement but still has either a misfire or fuel starvation under load.
My new programmable CDI's have arrived. I have flashed them for 95 RON fuel as there isn't a map for 98+ fuel for the 650's, but the 650's run a higher advance curve than the 750's
166415


The CDI's have a yellow wire to be cut to use on a RD03 due to the side stand monitoring being different to the PD06 Transalp.

166419


I'm thinking of slightly altering the wiring by making a quick subloom, so I don't need to cut the yellow wire for now, until I know it works.

I only need to swap the earth from the 4 way connector to the two way connector after removing the side stand terminal and plugging the ground from the 4 pin connector where the side stand terminal was. Then run a wire to each cdi from the 4 way pulse coil connector to the four pin connector on each cdi.
166418


I've just bought a carb float height gauge, just in case the float height is wrong so its not filling the bowl enough.

If it not that either I will try one of my spare carbs though the one that is fitted has the only good set of diaphragms, I'll have to swap them between carbs.
 

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I seem to recall PaulS having similar running issues to his RD04 some years ago. After lots of testing, checking & swapping parts - new ignition pickups cured the running issue even though they tested ok.


Sent from my SM-A320FL using Tapatalk
 

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So far I've changed the plug leads to NGK CR1's for the inner plugs and CR2's for the outer plugs and changed to my spare coils.
View attachment 166416

A slight improvement but still has either a misfire or fuel starvation under load.
My new programmable CDI's have arrived. I have flashed them for 95 RON fuel as there isn't a map for 98+ fuel for the 650's, but the 650's run a higher advance curve than the 750's
View attachment 166415

The CDI's have a yellow wire to be cut to use on a RD03 due to the side stand monitoring being different to the PD06 Transalp.

View attachment 166419

I'm thinking of slightly altering the wiring by making a quick subloom, so I don't need to cut the yellow wire for now, until I know it works.

I only need to swap the earth from the 4 way connector to the two way connector after removing the side stand terminal and plugging the ground from the 4 pin connector where the side stand terminal was. Then run a wire to each cdi from the 4 way pulse coil connector to the four pin connector on each cdi.
View attachment 166418

I've just bought a carb float height gauge, just in case the float height is wrong so its not filling the bowl enough.

If it not that either I will try one of my spare carbs though the one that is fitted has the only good set of diaphragms, I'll have to swap them between carbs.
[/QUOTE

Hi I’m in the same process eliminating 1 issue at a time, will you post your progress soon as you hopefully solved it.

thanks jav
 

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Discussion Starter · #13 · (Edited)
Just fitted the CDI-Shop.de programmable CDI's with a slight change to the wiring to see if they worked, without cutting the yellow wire.

I unplugged the side stand switch terminals from the two pin CDI connectors, plugged them in to spare connectors to prevent the earthing out or anything.

Unplugged the earth wires from the four pin connectors and plugged it in where the side stand terminals went on the two pin connectors.

I ran a pair of wires up to the pulse coil connectors near the radiators/front coils and sleeved one with a blue sleeve at each end and one with a yellow sleeve each end.

I popped out the earth wires from the loom connector then ran them down to the correct CDI 4 pin connector and plugged them in.

Started the engine and it fired up straight away and both exhaust down pipes were hot.

Sometimes on start up the front pipe runs cool, although if I pull the plug lead I can hear it arcing

The lights on the CDI are flashing at idle and stay on if you increase the engine speed.
166421

Hopefully it's now fixed.

I've modified a Transalp CDI holder so the CDI nearest the Reg/Rec rotated 180 degrees so instead of the plugs being on the left side of the bike they are on the right side. This allows the plugs to be either side of the MOSFET Reg/Rec, if I placed the CDI how it was designed to fit in the holder the connectors would be pressed against the Reg/Rec heatsink
166431



I've been preparing a spare carb incase this doesn't fix it.

Might buy spare pulse coils. Transalp 600 share the same part number 30300-MS8-000 but are harder to find.

Hawk 650 RC31 and NTV 650 RC33 are a different part number 30300-MS9-000 but should fit as the RD03 has a RC31E engine code.

I'll take it out as soon as I get a nice evening where I'm free to go for a ride to test it.
 

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Discussion Starter · #14 · (Edited)
Just test rode it, it's improved a lot but still has a slight issue think it's fuel and possibly clutch related too.

Clutch is making a noise when disengaged

I'm wondering if the fueling issue may be because I didn't raise the carb pistons when I installed the ones with good diaphragms? Or if it's a float height, jet size or blockage somewhere.

Going to finish building the spare carb, I've checked the float height on the spare and it's spot on but I think it's from a Transalp. It looks very similar to a RD03 carb but it is a FOA code on it.

It has 128 and 130 main jets with 38 pilot jets.

I have one that might be the original which has a F4A code stamp but the float bowl screws have snapped. The float bowl that is removed has a 115 main jet with a 38 pilot jet.

I don't think it's a fuel pump issue as after pumping about 7.5l out of the tank it pumps about a litre a minute.

Just taken the carb off the bike it's a FOA has 128/130 main jets, 38 pilot jet s but the float heights don't match one is around 8mm the other is 7mm

Looking at the manual it should be a F4B carb with 125/130 jets and 38 pilot with a 7mm float height.

The carb I took off is dirty on the outside. The one I have been building is a lot cleaner.

Might give it a try and see what it's like.
 

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Discussion Starter · #15 ·
Just quickly fitted the carb and ran a temporary tank to the carb inlet. With the pump connector disconnected.

166432


The bike would start but wouldn't rev up so connected using the fuel pump.

Bike starts and revs up. So I let it warm up and balanced the carbs then set the idle. The manual says says set the balance to 40mm or less but I've got it down to around 10mm.

Seems to be fine, I will know better once I put the bike back together and take it out for a test ride.

Might set up the idle drop, never tried it before. I have a rally computer with a digital rev counter so might give it a try.

Just set the mixture screws to 2,1/2 turns out for now.
 
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How long has it been since the valve clearances were checked? I had a similar issue with my '03 Transalp 650. After much tail chasing I found that the valves had closed up, in less than 6000km. That turned out to be caused by stretched cam chains. It's worth checking.
 
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