1985 LTD Fuel Pump Replacement

[Rednaxs60]

Went for a 4 day tour of our lovely BC province with a very pleasant passenger. Took the '85 LTD of course as I have been working on it to get it so I could tour with it. All went well, bike ran well, and it was lovely weather. Went through Trail, BC then headed up the mountain to Rossland, and on to Strawberry pass that is about a mile up. All was going well but I noticed the bike was staring to run hot.

Started through Strawberry pass and lost power. Bike would start but would then quit. Baffled me and the only thing to do was to let it sit and contemplate a strategy.

I let it sit for some 45 minutes or so, but during this time I was able to start it but it would stall immediately. I noticed the fuel pump sounded different as if it was cavitating.

After letting it sit and cool down, started it up and it sounded not bad and kept running. Made the decision to carry on. Sonya was a bit stressed but not a lot we could do.

Rest of the way into Osoyoos and on to Princeton was uneventful, but I listened very intensely to how the bike was operating. Made it to Princeton for the night.

Left Princeton this morning and the bike ran well, and no more hiccups. There was a noticeable change in the sound of the bike about half way through Manning Park for the better. Ran from Hope to the BC ferry terminal at Tsawwassen. Bike also started to idle where I had set it some time ago.

Now for the mystery. These fuel injected bikes are extremely power sensitive and need a lot. I had noticed that the voltage showing on the dash gauge would reduce as the rpm got higher, but return to 13.8 VDC (14.4 VDC at battery - only look for consistency when it comes to gauges). I noticed today that it was consistently 13.8 VDC and the bike was operating well and the sound of the engine was as I expected.

I have the alt mod on my '85 with a pulley ratio of 1:2 - 4' pulley at crank and 2" pulley on alt. I have read where alternators operate in a range up to approximately 9K RPM. I also know that alternator output is not linear, in that an alternator will go to full output say around 6K to 7K RPM then start to fall off. With the charging systems designed today, if one of the components of the charging system is not keeping up then you can have issues. I'm thinking that the alternator RPM was such that I was actually discharging the battery as I was keeping the RPMs high because I was travelling two up through the mountains.

With this in mind I'm thinking of changing the alternator pulley to a 3" pulley that will drop the alt RPM because I will now have a ratio of 1:1.5. I may even go to a 1:1 with either two 3" pulleys or two three inch pulleys.

The other aspect of this issue is the fuel pump and how it sounded when the bike first quit. It was very peculiar and I had not heard it sound this way before. I will be doing a fuel pressure test and looking at the fuel return/venting system. Have a fuel pump on hand.

I also have a wish list:

Battery to be load tested
Alternator to be taken in and checked
Check to make sure cylinders are firing
Check coil resistance/impedance
New plugs
New plug wires
Check for plug cap availability

Other than this the bike ran well and took the two of us for a good tour of BC.

Question - plug wires - are these resistance type or no and what size. Will find out but thought I'd ask.

Have to get this work done. Have another tour of BC on 19 June with my HD friends.

[Rednaxs60]

I have been investigating the issue(s) with my bike and so far nothing very conclusive. I have taken the alternator in and the bearings need to be replaced, but there appears to be nothing else wrong - this was a rebuild of an older alternator last year and I suspect the bearings were not changed. The battery has been load tested and is fine. Checked the firing and all four cylinders are well and the spark plug colour is good.

.

As I had mentioned the fuel pump sounded a bit off so I installed an Airtex E3812 fuel pump this afternoon. It is a smaller profile but rated to 90 PSI.

Because of the smaller profile I used two small sheets of 1/8 inch rubber to fit the pump in the OEM holder.

The fuel line going to the fuel filter has a fitting that is much larger than the one supplied with the new pump. It is also a different design from the modern fuel pump banjo fittings.

Most newer style fuel pumps that use banjo fittings have holes in the discharge pipe of the fuel pump. The OEM Honda fuel pump does not as you can see where arrow #4 is pointing. What happens is the fuel comes out of the discharge pipe (arrow #1) and impinges on the back of the fuel discharge cap (arrow #2). The fuel is redirected back towards the fuel line through holes in the cap (arrow #3) and then on to the fuel filter. The new fuel pump has the upgraded discharge end with the holes in it.

The OEM banjo fitting is larger in circumference as well and impinges on the positive and negative terminals. This is not an issue with the negative; however, the positive is another issue. I filed the positive terminal post so it did not touch the fuel line banjo fitting and installed a connector to the 12 VDC lead so I could push it on the fuel pump terminal. Here you can see it is a close fit.

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After a bit of fiddling with the fit, I was able to get the covers and foot peg back on. Started the bike and it seems to be running a bit better. Still have to do a fuel pressure test, but need to get the pieces to do this.

Cheers

[Rednaxs60]

Got the alternator back today, new bearings and output check is good, and no charge for the bearing work. Showing 13.7/8 on the dash voltmeter - 14.2 at the battery. As long as the dash voltage stays at 13.7/8 and is consistent, I can live with this.

With the new fuel pump installed idles very nicely. The cylinder firing sound is also better. Will have it out on the road later this week for a road test. Fuel system pressure test is next to make sure it is within spec.

Checked the rad fan circuit. Appears the switch is duff, ordered a Beck/Arnley 201-0817 out of Vancouver. $44.00 CDN delivered, better than the $112.00/$118.00 I was quoted from Honda. Should be here end week, early next. This may also be the reason I was seeing higher operating temperatures last year when I finished the alt conversion. Have a manual switch that I can use in the meantime.

With what I have checked and done, I'm torn between fuel and electrical. The bike would not have started if there was a lack of fuel or not enough juice; however, the bike may start but immediately stop if not enough fuel. I did note one issue that is worth noting. The travel computer will reset if the battery voltage is too low. This did not happen at anytime during the trip, nor when I was having the starting/running issue. Load tested the battery and it was good.

I'm also curious whether the altitude had something to do with the issue considering this is a fuel injected bike and the system should compensate for altitude. I was getting a lot of fuel smell and the only way to do this is to have the fuel returning to the tank instead of going to the cylinders. This is done by the fuel pressure regulator - from the schematic I think it returns fuel if the pressure is too high. This may also explain why the tank was under more pressure than usual.

The more I do to rectify this issue, and reflect back on what happened and the number of little things to consider, I'm tending to think it was a fuel related issue.

So my next investigation will be to check the fuel system pressure. I hope it is within spec.

The fuel system has several parts that may need to be looked at. The pressure regulator, air valve, reed valve, and of course the injectors. This may be a whole new discussion.

More to follow as I wrap this issue up.

Cheers

[wmerryall]

I have the Spectra SP1186 which I will be installing when I get around to restoring my 85 Limited Edition. It is the replacement for the 1985 Honda Prelude and from what I've heard is a more direct replacement than the one you used.

http://www.rockauto.com/en/moreinfo.php ... 70&jsn=346

[Rednaxs60]

I have the Spectra SP1186 which I will be installing when I get around to restoring my 85 Limited Edition. It is the replacement for the 1985 Honda Prelude and from what I've heard is a more direct replacement than the one you used.

http://www.rockauto.com/en/moreinfo.php ... 70&jsn=346

Looks like the Airtex model. The outlet pipe is similar to what the LTD pump has whereas the Airtex is slightly different. I found it interesting how Honda designed the outlet and fuel flow. Use 1/4" rubber sheet around the pump to fit it in the OEM holder - looks better than two smaller sheets. I visited the local wrecker yesterday and automotive external fuel pumps for FI cars are not that plentiful; however, the one for a '91 Acura is an identical size and fit match. Unfortunately it was not a working unit.

Thanks for the info and will put it in my spreadsheet/data base of parts.

Cheers

[wmerryall]

You're welcome. Here is some information that may have come from Steve Sander's site. (I have no idea how much of this is still valid or available. Hope it helps.

I owned a 1985 Limited Edition a few years back and just wanted to updated a few part issues with the fuel injection parts. I have worked on a few of these rare models and if you are have trouble finding parts I hope this helps.
The fuel pump which Honda motorcycle charges $700-800.00 dollars for is the same note SAME pump that comes off a 1985 Honda Prelude. The Honda Prelude was changed mid year to EFI so make sure you ask for a efi model fuel pump. Mine cost me $90.00 at Autozone. The fuel injectors, fuel pressure regulator and sensor are also the same. Not all the sensors but most. The fuel pressure regulator will need the chrome cap off your old one.

Timing Belts
GL1000 & GL1100 (requires 2)
Honda part #14400-371-04/14400-371-14
Gates #T274
NAPA #250274
Goodyear Gatorback #40274 (AutoZone & others)
GL1200 (requires 2)
NAPA #NBH 250070
Gates - #5043 or #T070
Goodyear - #40070
GL1500 (requires 2)
Gates - #T275
NAPA - #250275
Goodyear - #40275

Radiator Hoses
Napa #7733 ($16.95) does both top & bottom
Gates - #21008 does both top & bottom
AutoZone - #B70834 ($9.95) does both top & bottom
(may need new screw clamps, my stock ones worked okay)

Radiator Cap -- Standard style with 13 Lbs pressure, any auto supply store
NAPA/Belkamp #703-1445 (2/27/13, new #703-1697) or STANT #10229
Murray #7713
In Canada, Benson Auto Parts, Stant #10229
Thermostat
NAPA #101
Stant #13868
Murray #3868

Oil Filter - GL1000, GL1100 & GL1200
Honda Part #15410-426-010, 15410-422-004
AMSOil SMF-101
FRAM #CH6009 (comes with both o-rings)
K&N KN401
Napa #PS4940
Purolator #ML16809
STP SMO-09
WIX #24940

Cam Seals Honda part #91209-371-003, Oil Seal (27X43X9)
Napa #ATM 2117994, Altrom
Beck Arnley #052-2755, AutoZone
Note: x3 on 1000s and x2 on GL1100s.
Fel-Pro #TCS 45718 (comes with 2 seals per set)

Signal Flasher
NAPA #552 flasher relay, 2 pole
Tridon EL12 at most autoparts stores ~$10 electronic flasher, stops slow/fast flashing. Try the 552 first.

Front Crank Oil Seal GL1000 & GL1100
NAPA #13954 (35x55x8)
1200 & 1500
Part #91201-MN5-003 (Discontinued #91201-MG9-005)
Numbers on the seal are "A 8 SD 35 59 8 L HS". Measures 35 x 59 X 8
Also: Crank Seal, GL1000 and GL1100:
Timken P/N 223542, tapered (self-centering), cheaper
National P/N 223542, non-taper
Used as: 1993 Infinity J30 rear differential seal. Most auto parts stores.

Rear Oil Seal for the clutch lever
NAPA #5410 Transeal, made by SKF 14x24x6

Valves, Intake/Exhaust Parts'n'More 10 and 15 bucks each respectively.

Spark Plugs - (1000, 1100) Stock is NGK D8ES.
D7EA or ND X22ES-U for cold climate
D8EA or ND X24ES-U for standard operation
D9EA or ND X27ES-U for extended high speed operation
GL1200: NGK # DPR8EA-9 (Gap .035")

Spark Plug Boots
NAPA part # NGW8072

Serviceable Fuel Filter from Spectre
O"Reilly's Auto Parts, p/n 6932, about $10
Hall's Speedshop online
chasdog says, "I wrapped a piece of rubber around it to protect it and keep it snug - works great and you can clean it AND replace the filter element ... YES the filter elements are very easy to find - (O'Reilly's) keep them in stock - 3 to a pack."