1985 GL1200 LTD Fuel Smell

Classic Goldwings

Help Support Classic Goldwings:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Rednaxs60

Well-known member
Supporting Member
Joined
Dec 25, 2015
Messages
3,067
Reaction score
623
Location
Victoria, BC,
Have been researching this issue because my '85 LTD has a fuel smell on start up and while riding. Have replaced the TPS with an aftermarket TPS, still no joy.

Have looked at the plugs and see that one bank specifically #1 cylinder is wet after sitting for the night. To me this indicates that I have a leaking injector, but I don't think it contributes to a fuel smell once the engine is started. I do think this contributes to the engine not operating as smooth as it should, it's not bad, but not as per new - I know it is a 34 year old engine.

The injectors for the '85 LTD FI system are apparently rated at 280 CC/min - approximately 26 Lbs/hr. Have found a comparable injector, P/N 195500-1070 listed on: https://www.witchhunter.com/ The issue with this is that I cannot find an auto that uses this size of low impedance injector. The closest I can come to this is 195500-0456, 220 cc/min, used in a 1988 Mercury Tracer, or a similar year Mazda 323.

I have perused various web sites regarding fuel injector requirements, and it would seem that the 280 cc/min injectors are oversize for the 1200 considering a lower flow rate is used on the Tracer and 323 1.6 litre engines. The flow rate that I get using the various web sites and considering an 85% performance rating is approximately 19 lbs/hr - 200 cc/min. Considering getting new injectors for the old girl. Set of four from Rockauto are approximately $85.00 CDN plus shipping.

I have looked into the fuel pressure regulator (FPR). It is a component in the system that could contribute to this fuel smell. Found a web site that lists five issues that are a result of a faulty FPR: https://procarmechanics.com/5-signs-of- ... regulator/

Not all of these symptoms need be present, and the FPR may function, not be leaking, but have a weak spring acting on the FPR diaphragm. I connected a fuel pressure gauge to the manifold and went for a ride. Noticed a 5 lb swing in the fuel pressure between acceleration and deceleration - 35 to 40 psi. May be an indicator. Still learning about this.

The closest FPR I have found that is configured and should fit is the Tomco 21004 FPR rated at 39 psi. This should be acceptable considering the injectors are tested at 3 bar (approximately 43 psi). These are approximately $115.00 plus $26.00 shipping CDN.

More to follow.

Cheers
 
Could it be the old fuel cap venting that you smell? My 82 Silverwing does that in hot weather.
 
Honda tends to re-use parts from the autos on the bikes, particularly the GLs. If you suspect a leaky injector, I'd run some Techron or Seafoam for a tankful -+-+ according to the instructions on the can +-+-. as they both contain chemicals for injector cleaning. Mu SEi only had a fuel smell when the fuel pump was failing. Luckily, it is easily replaced with an automotive FI fuel pump.
 
Changed the fuel pump a while ago to a Spectra SP1186. Found some info in the OEM service manual for the 1982 CX500T. As mentioned Honda did not stray too far from its auto roots when it designed these FI bikes; however, the design of the CFI system on these bikes is the forerunner for the Honda FI system and most of the development back then is still being used.

The CX500T fuel pump was designed with an internal spring loaded check valve that is set to open at 64 to 85 psi. This allows the fuel to circulate within the fuel pump casing. The turbo has another issue that the '85/'86 FI bikes do not. The fuel pressure increases with turbo boost. The turbo boost pressure in the intake manifold acts on the fuel pressure regulator. When there is say 10 lbs of boost, the fuel manifold pressure must increase to 46 psi (36 plus the 10), and the fuel pump flow has to be sufficient to ensure that the fuel system manifold pressure increases accordingly. This is why the fuel pump is designed to operate up to 64-85 psi.

The fuel system pressure specs are the same as well - fuel flow is at 1.5 litres/min minimum.

The '85 LTD specs are 36 psi static and at idle 28 to 34 psi, the same.

So with all this information, I am going to look for an older fuel pump from an early FI Honda car, or a similar off shore FI model. This should be sufficient for the needs of my '85 LTD. It is possible that the Spectra fuel pump that is rated up to approximately 110 psi is overpowering the fuel pressure regulator - stranger things have happened.

I am also looking at the different injectors. Had mine cleaned and flow tested 18 months ago and should be good, but these are 34 years old. Also looking at replacing the fuel pressure regulator.

Order of priorities:

Fuel pump (easiest to do and probably least expensive)
Injectors
Fuel pressure regulator

I am experimenting with aftermarket TPS in that I have the external alt mod, space is at a premium, and how the TPS is actuated is a challenge.

More to follow. Cheers
 
[url=https://www.classicgoldwings.com/forum/viewtopic.php?p=211976#p211976:1ugooqf4 said:
Ansimp » Yesterday, 8:01 pm[/url]":1ugooqf4]
Is it possible the fuel smell is just the cold start enrichment cycle?

Thought that as well, but no. Happens when operating. Replaced the OEM TPS ith an aftermarket one and having issue with the calibration, keeps changing. Will figure out. When the calibration is just out of spec on the high end is when I get the fuel smell.
 
That makes sense. I would rather use a second hand oem than a new aftermarket one. You really need your scope to show up irregularities when cycling the tps
 
Finding a second hand OEM TPS is a challenge. Have found an air chamber assembly with a TPS still installed. May be picking it up when I get back from Ontario with the new to me bike.
 
Gerry - no worries. If an old pump kicker like myself can learn about the FI system so can you. Spent over half of my naval career dealing with high pressure boilers, steam turbines and ancillaries. Navy sent me back to school, commissioned me and made me the engineer of a gas turbine frigate - go figure. Replaced the boiler aspect of my career with gas turbines - GE FT-4 for main engines and Allison 570 cruise engines. Went from hand operated equipment, to electrically push button controlled equipment, otherwise same operation in the system.

Getting back to the issue at hand, on my way across Canada with my sister and Mother's new to them van. Going to hit some wreckers en route today - in Calgary heading to Regina, and try to find some early model Honda FI fuel pumps.

Have found some injectors from Rockauto, Beck Arnley make and will be contacting the company to try and get some specs on these injectors. The injectors fit an '88 Mercury Tracer 1.6 litre FI engine. These injectors apparently flow 220 cc/min and the 1200 FI injectors are supposedly rated at 280 cc/min. 1600 versus 1200 engine.....hmmmmm!

This trip across Canada gives me lots of time to reflect on what is happening with the bike.

Cheers
 
Resurrecting this thread because I just took the 1200 out of winter hibernation for a YouTube video. Replaced the TPS with a used OEM original. Runs very well after warm up.

When I replaced the TPS, I noticed that there is play/wear in the throttle valve arm. Hadn't noticed before, but now that I know of this, I am careful to bring the stop screw up to the throttle valve arm without taking up the play/wear. It made a difference in the setting.

Still have that fuel, carbon smell on start, and the engine idles rough, not too bad, but rougher than it should.

I was looking at an old thread by Canuckxxxx and there was a discussion regarding the 1200 hydraulic valves. Even though there is no ongoing valve adjustment, there is a requirement to check the lifters and use shims to suit.

I thought about this and think that this is something I should look into. If the valves are "sloppy" on start the engine will definitely idle rough. I'm thinking that this can contribute to the awful smell on start. These parts are some 36 years old and do get a bit of wear.

Don't know if I explained my understanding of the valves and the adjustment theory, but I know what I have to do and it is now on the infamous "list".
 
Have been doing more research. Valve adjustment according to the manual(s) is when parts have been replaced, and in my case, valve seats have been refaced because I had the heads refurbished. I mentioned in my post above that it was reading canuckxxxx's thread '84 1200 engine for a '82 GW: viewtopic.php?f=9&t=9872&hilit=1200+engine+rebuild that got me to thinking about the valve adjustment as a possible issue.

There are many web sites about this. I have noted several pearls of wisdom that corroborates my thought that I need to do this check.

This site: https://www.motorcyclecruiser.com/valve ... implified/ has a good write up on this issue and the passage; "Out-of-adjustment valves can make themselves known in a variety of ways, the most common being a distinct clatter from the valve area indicating loose valves, while tight valves may cause hard starting or a poor idle.", for me poor idle when cold - improves significantly when at operating temperature.

Another site I visited mentioned that valves not properly adjusted can also result in a bad fuel smell on cold start. I have this as well. I had this smell before the heads were refurbished as well as the poor idle with the first start of the day.

I'm thinking that even though the heads had probably not been worked on since the engine was installed at the factory, the fact that there was significant exhaust valve blowby would indicate that the valve clearance would change, but to do a valve adjustment without removing any deposits on the exhaust valve(s) and seat(s) would possibly aggravate an already bad situation. Hence the head refurbishment. When I installed the heads I did not do a valve adjustment since I was dealing with hydraulic valves and lifters, shouldn't need to do anything to these parts.

A different site mentioned that a lot of people will accept, and adjust for a poor engine start and the issues that come with this if the engine smooths out when at operating temperature. It is not recommended to do this as other collateral damage can occur. I am guilty of this and have lived with this for a long time, but in my defence, I have tried and checked everything else that could possibly instigate this situation.

Since I have dome most everything else, checked, rechecked, adjusted and such, it is now time to get at the mechanical side of the equation.

The instructions in the OEM and Clymer manual make the procedure for checking the valve adjustment quite clear. Part of this procedure is to check the tappets as well.

One site I visited made mention to measure the shims for thickness, new and old - good tip.

I have ordered 4 shims from Honda and the shim tool from a seller on eBay. Will wait until these parts come in. I'm going to wait until I have the 1500 paint project completed, then I'll do the 1200. One bike gets TLC at a time. Interesting fact is that the shims and shim tool are for the 1500 as well.

Cheers
 
This is from limited experience (that agrees with what I read) and a lot of study: The real danger with Honda valves comes from their soft seats that recede and cause valve clearance to decrease. Eventually the valves reach zero clearance and don't stay closed long enough, leading to valve burning - primarily the exhausts. I had a CB750F DOHC ("shim-and-bucket adjustments) that had two exhausts with zero clearance. Luckily I think a PO had parked it before the valves burnt, and I was able to reduce shim thickness to put them just over factory spec along with the others. Compression returned to normal. My '75 GL1000 had - in addition to rust pitting - a badly burnt exhaust valve with zero clearance. I replaced all valves and had the seats recut. This is why a little valve chatter is no issue - "noisy valves are happy valves", and the experts like Nixon recommend loosening just a bit beyond factory specs for solid lifters. For hydraulics, before the "pump up", they should be quite noisy.
 
Dan - looked at the one that you had made. Looks quite similar. Here's the one I ordered:
Shim gauge.jpg
 
I'm curious to see if you find any difference in shim thickness since they are a non-wear item. Maybe if they weren't made originally to Honda spec there could be a difference. Knock-offs?
 
Dan - The shim tool should be here this week. Will measure it and post.

The engine is operating quite well, still have that disgusting smell, but will be addressing it in the fall. I'm hoping that I find something when I do a valve shim check.

Went for a ride with Sonya today, 2 up over the Malahat, and no issues. Have been shifting in the low 4000 RPM, works well, and every now and then go higher. Did this today and Sonya commented on the old girl still having a bit of spunk left.

Long term for this engine is a rebuild this fall/winter - reviewing the forums for information on this. The heads were done last year. Changed the clutch plates and did the sprague clutch in 2016 at 115,000 Kms - just over 160,000 Kms now. Have been accumulating engine parts over the past 4 years, new water pump and gasket set, new rings, shaft oil seals, rear cover gasket, and such. Looking at the parts fiche to determine what bearings are available, and might be the subject of change. Have sourced a new primary drive chain. This is one of the sites, have others bookmarked:https://www.cmsnl.com/products/chain-prim-drive_23131463003/#.XtG2_DpKg2x Engine will be apart. Looking for a new oil pump as well. The crank bearings and con rod bearings are elusive, but there is a company up island that takes old bearing shells and does a new babbit install. Don't know what the cost will be but can't hurt to call. Will have a local machine shop hone the cylinders, if I recall correctly $100.00 for both halves. Hoping they will clean and paint the two halves like they did for the heads.

Doing this work to have a fresh GW to ride - I like my '85. Mentioned when I started working on this bike some 4/5 years ago that this is my retirement long term project. Have no intention of getting rid of it, great touring and daily rider - and Sonya likes it as well. Besides never did a rebuild of an engine like this, challenge and a lot of fun I think. Steve83 mentions in one of the threads that it is probably more economical to just swap engines, but if you go down the rebuild road it can be very satisfying. Swapping engines for the FI models is a bit more challenging than for the carb models I think.

Intend to paint this bike as well. Have all the gear now and estimate a fresh paint job will cost less than$100.00 in painting supplies. The most challenging issue when I go to paint is the pinstripe that is used to cover the interface between the gold metallic and brown accent paint. Several options, and will post when decided.

I mentioned to the fellow who is doing the YouTube video that the 1500 gets what it needs, the 1200 gets what it wants.

New thread to come when I get started on the engine rebuild.
 
Thought I'd close this thread with a comment on the fuel smell. I have been at this for the past 6 years. The primary issue has been the fault of the owner. I read how to adjust the throttle position sensor (TPS) wrong. I was calibrating the TPS such that it was over-fueling the engine. It was an understanding of the throttle linkage stop screw. I was adjusting the throttle linkage stop screw instead of bringing the throttle linkage down to the stop screw. I have adjusted the throttle linkage stop screw to where I feel the stop screw should be, and there is no more fuel smell during a ride. I will be refining the stop screw setting when I get the air chamber from an '85 Limited Edition carcass that I bought.

As for the hydraulic lifters, this is still being investigated, new lifters installed, now hear a different noise. Always something.

More to follow on a different thread.

Cheers
 
Top