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Discussion Starter #1 (Edited)
Convert the fuel filter/pump assembly into a fuel pump and external low cost inline fuel filter.

A few teaser pics and text but the full instruction set is on my SmugMug site:
http://3banger.smugmug.com/Motorcycles/Triumph-1050-Fuel-Pump-Filter/3751978_xFpTu/1


The disassembly suggests the key components could simply be reconfigured with hoses and an inline fuel filter. Both the pump and pressure regulator (with out the o-ring) connections are hose barb-ish.
 

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3Banger my hat is off to you for this mod. I'm lazy so I won't be doing it but I might play around with the 1050 pump I now have laying around. Nice write up
 

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Discussion Starter #4
Bumping this back up since I've updated some of the info...

Update: The fuel filter mod has been working and reliable for about 10,000 miles now. However the bumped fuel pressure never had any real positive benefit and the bike never really idled properly. I have since installed an original OEM (no calibration dents) pressure regulator (45 Psig) and the bike now idles like it used to.

The ECU has no way to measure the fuel pressure. However, I believe it does compensate for the increased pressure and the slightly rich-end air fuel ratio with the oxygen sensor. It seems the ECU adapts and removes any potential gains in running a slightly rich mixture. The consequence is a very short injection duty cycle at idle that results in erratic RPMs. I have since gone back to an OEM regulator in my modified fuel system.

Early generation 955i motors did not have an oxygen sensor and may have benefited from this mod.
 

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missed the beginning of the post. I have a new gt and have about 1000 miles since nov. once while riding, coming to a stop the bike died for no reason but started right up. I doubt I lugged it to a stop as I had rpms. Is there a problem with fuel pressure on the 2011's.
 

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Discussion Starter #6
No problem that I'm aware of? Though haven't really paid much attraction to GT issues. Try a search on it maybe? After you ride for a while is there any suction that makes opening the gas cap difficult?
 

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3banger,

Your thread brings up a lot of valuable info.

However it seems to me that your proof of concept is biased.

You don't include the filter in it.

The regulator should be inserted after the filter. That is the filter must be in the tank. In your configuration, you don't take into account the pressure drop in the filter.

If my memory serves the flow is proportional to the square root of the pressure drop. That is the pressure drop is proportional to square of the flow!

I currently have a priming problem. When I want to start it in the morning (I use it every day) the engine is hesitating and I lust insist on the starter to launch it. Started on month ago and getting worst an worst.

Priming twice (ON/OFF/ON/START) solves the problem.

I suspect a clogged filter. But the filter can't be changed!?! Fortunately my bike is still under warranty.

Another question arise: where is the pressure releasing system?

Fred
 

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My post triggers the same emotional reaction as on triumphall: none.

I have to take the pump apart to try to understand. I may have two other culprits: breathing valve (don't understand why it works at the second priming thought) and the pressure releasing system.

Thanks for your help everybody that replied ;-)

Fred
 

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Discussion Starter #9
Sorry for the delay in reply, I just didn't see the post and this tread basically gets zero traffic.

You do bring up an excellent point and I don't recall if I considered that in my initial planning :eek:. I need to contemplate it and a post fuel filter pressure measurement might be in order.

Interestingly the fuel flow thought the OEM filter is quite high since it includes that bypassed by the pressure regulator and in my case it quite a bit lower since only the flow going to the engine passes throughout the filter. The the third party filter in my arrangement appears to have a larger cross-section then the OEM integral unit and is intended for 4 & 6 cylinder cars. These likely produce more HP then the ST and will have a higher fuel flow.

Also, I believe the oxygen sensor biases all of the fuel tables even when the engine is running open loop on a strait injector duty cycle map. So a small difference in fuel pressure would simply be compensated by a slightly different injector duty cycle.

All that being said my bike has been running well at least when it starts for over 10k since making this mod.

Here is a post concerning my latest tribulations...
http://www.triumphrat.net/sprint-forum/237024-checking-for-for-spark-on-a1050.html
 

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3banger,

I just read about your problems. I always assumed that the engine is using the rotation speed to determine the right stroke. When starting, it tries a firing configuration. If it accelerates (starts up) it's ok, if not it tries the other way around. This should be the good one.

Back to my problem, it started to show up one month ago and gets worth. Notmally If I prime twice it's OK. But this morning it was nok. It failed to start. Well it run for one turn and stops. So off/on/start and it's ok. Still suspecting something around the fuel pressure.

Note that whenever I leave the bike alone for some hours say 3 hours and then starts it up, it normally starts right away.

I'll set up what is necessary to measure the pressure at priming. If the pressure is ok i'll have to find another idea.

BTW do you have some info about the fuel pressure relief system. I know that on the 1050, the noise that we can hear 15 sec after shutting down is coming from the fuel pressure that is relieved but I don't know where is the valve. Any clue?

Fred
 

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Discussion Starter #11
I don't know about the fuel pressure relief after shutting down. On my 05 ST I don't hear any additional noises after shutting down. On start up you can here the pump cycle to prime and it dosent start running again until you crank the engine. Also in all my fuel system disassembly I never noticed any additional pressure relive valving. Also my system has quite a bit more volume after the tank disconnect and I was concerned about stored fuel pressure when pulling the disconnect. But there is just a tiny fuel dribble and I suspect the pressure quickly back feed through the pump when powered off.

The GT fuel system might slightly diffrent compared to my 05 ST?
 

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I'll find out once i try w/ the tank in the up position (pretty cool feature on the GT). I suspect it might be just reversing the pump. I would say the pump assembly is the same. I saw metal pump for sell on ebay. So there is a metal version. And the fuel filter is changeable.



This would suggest a different arrangement as shown here:
http://www.triumphmcparts.com/showAssembly.aspx?ukey_assembly=1177436&ukey_driveline=11332&modelYear=0&ukey_model=20179&ukey_modelrange=0&ukey_make=1248

W/ a return pipe (as on the 955) that would greatly facilitate the introduction of an external filter.

My connectors are on their way. Tomorrow perhaps.

Fred
 

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Discussion Starter #13
That assembly is quit a bit different then the unit on the 2005 ST 1050. And replacing the fuel filter would be pretty simple and more importantly not 300 bucks! The filter I recommend on my howto page would likely drop right in; might require a little bit of additional fuel line to accommodate the longer hose barbs. The they were still asking 50+ on your link. I don't fully understand why this assembly is diffrent across all of these diffrent models that essentially have the same engine?
 

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Some news and pictures about my problem which BTW seems to vanish. I used this opportunity to suppress the air valve which behavior seems pretty random:



It appears that when priming the pressure rises up to 47/48 psi than fall rapidly to 40 psi when the priming ends.



Here is the pressure when running that establishes at 47/48psi:



And finally my pressure measurement apparatus:



BTW as opposed to what I said there is NO pressure relief system. The pressure stays at 40 psi and decreases slowly. The noise we can hear some 10 to 20 sec after the engine is stopped is the stepper that is initializing (going to max position).

Fred
 

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3banger, is your Smugmug profile gone? I am needing to replace my fuel pump and I wanted to read your post. I know this thread is dirt old but I'm looking at ways people have fixed the fuel pump problem. Maybe you or someone else who has read this can give an update on the best way to change out the fuel pump and filter for 2006 Sprint ST. I'm really not wanting to pay $450 for an OEM unit!
Thanks - Cris
 

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His profile he was last active at the forum in 2015.
That is a shame since I was hoping to see those pictures of the pump mod as well.
 

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I ended up ordering a fuel pump kit bike bandit or one of those websites that claim to have one for our bikes but when I went to install it there were way too many modifications needed. So I sent it back so you didn't fit. I ended up buying a used one off of eBay for dirt cheap and it worked perfectly, it also came with injectors which was a bonus.
 
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I hope this thread can be of any help. It shows the guts of the pump.
I remember that he had to dremel the plastic body in order to gain access to the inside. I also remember the KL145 filter was introduced before the pressure regulator.
 

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This all seems very similar to my issues. I took the tank out yesterday to check for debris and obstruction. I found a little dirt on the filter, cleaned it and put the tank back on. Today the bake is stumbling while cruising and rolling on the throttle. I may have disrupted something inside the filter. Anyone have any suggestions for an aftermarket setup that actually fits in a 2005 sprint st 1050, or is ordering an OEM unit the best way? The original mod on smug mug is no longer available. Thanks so much. PDX
 
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