Triumph Rat Motorcycle Forums banner

trials and tribulations of the trophy!

4K views 20 replies 5 participants last post by  IWsurfman 
#1 ·
Hi all, 1st post (besides the welcome centre one!) and its a moan about the lemon ive just bought! triumph clearly werent thinking when they came up with that fuel tap design were they! the vaccume pipe has caused issues since i bought the thing a week ago now :( is there a best solution of how to route it so it doesnt kink or get wedged against the frame? and to which carb? fuel tap just got stuck open too (think i need a rebuild kit aswell as a better vaccume pipe!) and flooded about 5 llitres of fuel into my engine so now its carbs off time to check the floats pleasantly surprised at how easy they were to get out though not sure how easy theyre going to be to put back! all in all I've got to say this trophy is not endearing itself to me in my first week of ownership! but when it has worked that triple engine is awesome!!!
 
#2 ·
I didn't know there is surfing on the Isle of Wight. Cool. Looks like you got lucky and the engine didn't fire up with all that fuel in the crankcase and cylinders. They call it hydro lock and it is known to bend connecting rods. You have a couple of issues going with your new to you Trophy. The float o-rings need to be replaced. They shouldn't come out easily when the float bowl is removed, use a little grease to put them back in. While you are at it replace the rubber float bowl gaskets.
Yeah the petcock isn't the greatest design, the air filter is worse. You'll see when it is time the clean or replace the filter.
I have a fuel line that goes to carb 1 and 2 that will kink. I took the fuel line to the hardware store a found a spring that would go in snugly. The spring keeps it from kinking. You could do the same with the vacuum line to the petcock. Inside the petcock is an aluminum barrel, at the end of the barrel is two small tabs that turns the plastic barrel directing fuel in the 3 positions. If the two tabs are missing its time to get another petcock. Take the back cover off the petcock, lift off the diaphragm without tearing it. I use a thin feeler gauge to lift the diaphragm. With the diaphragm off, use a 1/4in. drive extension the push the plastic barrel free. It won't go out because of the seal. I don't know why the barrel gets stuck but it does sometimes. When it gets stuck and someone turns the fuel knob too hard, either the knob breaks or the tabs break. Much cheaper to replace a fuel knob. Sprint Manufacturing UK sells petcock repair kits, new diaphragm and seal plus a few other parts.
I leave the fuel knob on reserve and fuel up about at the 200 mile mark. Use prime if the carbs are empty.
 
#3 · (Edited)
Surfing on the island is pretty good by uk standards, not quite as good as cornwall, and certainly not as good as california! But certainly good enough :) I think something inside my fuel tap is actually broken as its a git to turn and only seems to work when in the reserve position, so maybe not worth getting the rebuild kit and just hunt down a replacement petcock then! fuel lines seem to be fine and kink free, just the vacuum line thats a git on this one, at the moment its going to the top of cylinder number 1 carb and kinks so easily against the frame, will try a spring :) checked the float heights and they were all too high guessing thats probably why it was flooding, well that combined with the stuck open fuel tap.... the seals on the floats must need doing too then as they pulled off without much pressure, handy tip that one as I had assumed the bowl held them in place cheers :) The bowl seals themselves look good and weren't leaking though so I might chance it on those.
 
#5 ·
I think the fuel knob is broken on the backside. It is weak because of the empty cavities. I filled in the cavities with epoxy glue. If the aluminum tabs are still are still on the barrel the petcock won't need to be replaced. Have you bought a Haynes manual yet? It is good to have. Maybe the float assembly o-rings are okay. It is when they fall out the o-rings need to be replaced.
 
#6 ·
haynes is on order :) just ordered the full carb seal kits in the end, dont want to have to do the job twice because its still leaking! any tips on how to get the washer and o ring under the pilot screw spring out to replace the o rings? they look pretty well wedged in there!
 
#7 ·
Straighten out a paper clip, then bend a little 90 degree hook on the end and go fishing. The Haynes manual explains how the check the float level. It is not a matter of flip the carbs over and measure. When the carbs are upside down the little spring on the float needle gets compressed and you'll get an incorrect measurement.
 
#8 ·
fuel knob appears to be intact and has already had the void filled with epoxy, just had a pile of bits land on the doormat from sprint manufacturing for all 3 carbs and the fuel petcock.... only ordered yesterday lunchtime, most impressed with the speed, packaging and price (relative to oem anyway, all bike bits are expensive really!) hopefully this will cure my problems! Thanks for the tips Greg :)
 
#9 ·
carbs all rebuilt and back on the bike, runs and rides again but seems to have a slight hesitation off a closed throttle i dont think was there before? im going to blame a slight slackness in the throttle cable and fiddle with it later and see if that cures it! fuel tap is going to have to wait until ive nearly emptied the tank as i dont have anything big enough to drain it into!!
 
#10 ·
I think i may have put the pilot screws in a touch too lean i did count the turns but could be 1/4 of a turn out or so through thicker new o rings? tweaking the throttle cable didnt change anything :( are the pilot screws adjustable in situ? and am I right in thinking a fraction too lean would cause a hesitation/bog off a closed throttle?
 
#11 ·
Pilot screws (some people call them air screws) 2 turns out from lightly seated is a good starting point. How many turns out do you have it? If you have them turned at 2 then the probable cause is a bit of junk is stuck inside one of the pilot jets.
If you have an infrared thermometer. Start the cold engine and the header pipe that is not warming up like the others, that's the cylinder with the carb having a dirty pilot jet.

MotionPro.com makes a 90 degree gear driven screw driver that will get in there.
http://www.motionpro.com/motorcycle/partno/08-0229/

Have you split the back half of the air box vertically yet? It makes it much easier to get the air box off, and the carbs out.
Looks like this. The side screws are hard to get out the first time. I don't use the side screws anymore. I plugged the holes with rubber plugs.
http://s1308.photobucket.com/user/greg96brg1/media/IMG_0003_zps8d14ea2d.jpg.html
 
#12 ·
mine were at 1.5 turns which is where I thought id re-set them, took it for a longer test ride and once fully warm its not as bad, only a very slight hesitation from closed throttle. if you whack it full open from closed at a standstill the engine bogs down then goes, All vents in the carbs have just been thoroughly cleaned so doubt I've got some crud in there, will take them off again and add another half turn on the pilot screws and see how it is. that tool looks great, but a little too expensive for me so carbs off again I think! My airbox is still one piece, took it off to check it wasnt full of rubbish before refitting the carbs but thats it. Got to say getting the carbs off and on/ air filter out would be alot easier with a bit more access! Will take a look at modding it. Cheers for your help again :)
 
#13 ·
Yeah I agree the MotionPro tool is a bit pricey, but it is the only one that I've seen that can do the job. But then I tend to fiddle with stuff trying to understand how it all works. Just because it's running perfect doesn't mean I leave it alone. So I use that tool occasionally. It sure is handy having the right tools in your tool box.
As the engine warms up it can tolerate a leaner fuel mixture. I found the middle clip on the needle worked the best. Pulling away from a stop, after its in 2nd gear and at 4,000 rpm's whack the throttle open. It is bogs for a moment then takes off, that means the needle is too low. Raise the needle up one notch.
I learned about the air box mod from the Yahoo Hinckley Trophy group. I cut the back half of the box with a utility knife. It makes the gap smaller when put together. But whatever air leaks thru the gap has to go thru the filter anyway, so it's no big deal. Did Katy Perry just enter the room?
Here's a carb link.
http://www.factorypro.com/tech_tuning_procedures/tuning_carbtune,cv,high_rpm_engines.html
 
#14 ·
well i took the carbs off again, pilot screws out 2 full turns, its better but still bogs off a closed throttle, do you think its possible I might have overdone it on lowering the fuel level in the floats? its fine at full throttle which makes me think the floats are fine but i guess it could affect low rpm too? i set them at 14mm like my newly acquired haynes said but i cant say ive always had faith in settings listed in the haynes manual! Also am i right in thinking the pilot screws are fuel, not air? or are they air screws? im getting a little confused as to what im adjusting! cut the back half of the airbox too like you sugested, soooo much easier to get it apart now! the big screws on the side needed cutting off though as they just spin, that was a pain but worth it i think in the long run :) cant see why triumph made the airbox such a pain to take apart!
 
#15 ·
Hi Surfman, The 2 parts fiche I go to, World of Triumph and 2 Wheel Pros, both call it a pilot air screw. If you take the screw out and shoot carb cleaner thru into it, the fluid comes shooting out the hole at the bottom of the venturi in front of the throttle plate. So they call it an air screw, but it is controlling how much fuel is going thru the idle circuit. I would re-name it an idle fuel screw.
It still bogs coming off a closed throttle, strange. Did you take the pilot jet out and check to see it is clear lengthwise? It isn't easy finding a slotted screw driver to fit down inside the hole. I am on good terms with my local Triumph dealer. Each Christmas I give the head mechanic a bottle of Jack Daniels Black, and the parts department gets a case of beer. They loaned me a pilot jet. I went to a store that sold good tools and found a screwdriver to fit. The jet is soft and I didn't want to mess it up taking it out. The lengthwise hole is very small .355mm, that's a #79 drill bit. I have a wire brush and one bristle fits in. First try shooting carb cleaner thru the jet, if you go the wire bristle route take any burrs off that might be on the end of the bristle.
Measuring the float level isn't as easy as flipping the carbs over. That will compress the float spring and give a false measurement. Check the Hayes manual on how to do it.
 
#16 ·
Pilot screw-Air screw? greg is right, no one really seems to know what it really is. It does control the amount of fuel going through the idle circuit. In = less fuel, out = more fuel. The Pilot jet is fixed but different sizes are available. It controls the amount of air going through the idle circuit.

The mixture screws on the bottom of Mikuni carbs are fuel screws.
 
#17 ·
I have 3 1200's, all have had this issue. The design of the petcock location is just STUPID!!!!

Couple of ways to fix it.

1) IF YOUR GOOD............the barb coming off the petcock for the vac line can be bent to 90 degree's..............takes right tools, and heat, not for the average Joe to try and tackle.

2) Go to a foreign auto parts store and get the VOLKSWAGON heavy duty FABRIC COVERED fuel line in the correct size. They make several sizes. They can be run on the vac line, and the fuel supply lines.
Hose is TOUGH, will NOT KINK making that stupid turn to the petcock.

The vac signal comes off carb 3, other ports on 3 other carbs are capped.

Run the Volks line from the petcock to the vac port, AND the 2 fuel lines..............making sure to route the lines correctly(factory routing is good) .

I also install a "balance" tube line between the two incoming fuel lines. Use a T, and run a balance line between the two fuel lines,
about at the bottom of the vac caps for height reference. This seems to help, NOT had any issue on any of the 3 since doing this fix.


As to your jetting..................follow this, YOU CANNOT go wrong.
In this you will find your answers, this is the only way to jet her correctly. Sorry it is long, but a GREAT read.

Any questions, hit me up,

Jet

Follow steps in order....First, dial in:

1. Top end (full throttle / 7.5k to redline -
Best Main Jet must be selected before starting step 2 (needle height)!
Select Best Main Jet
To get the best, most even top end power (full throttle/after 7500 rpm), select the main jet that produces the hardest pull at high rpm.
If the bike pulls harder at high rpm when cold and less hard when fully warmed up, the main jet is too large. Install a smaller main jet and retest until you find the main jet that pulls the hardest at high rpm when fully warmed up. This must be done first - before moving on to the other tuning ranges.

If the bike doesn't pull well at high rpm when cold and gets only slightly better when fully warmed up, the main jet is too small.
In order to properly tune the midrange and low rpm carburetion, THE MAIN JET MUST FIRST BE PROPERLY SELECTED after 10 to 15 minutes of hard use!

Do not pay too much attention to the low-end richness when you are changing main jets - you still need to be using the main jets that produce the best power at high rpm. You will deal with the low-end / cruise later - after step 2.

2. Midrange (full throttle /5k-7k)

Step 1 (Best Main Jet) must be selected before starting step 2!
Select best needle clip position
To get the best power at full throttle / 5k-7k rpm, adjust the needle height, after you have already selected the best main jet.
If the engine pulls better or is smoother at full throttle/5k-7k in a full throttle roll-on starting at <3k when cool but soft and/or rough when at full operating temperature, it is too rich in the midrange and the needle should be lowered.
If the engine pulls better when fully warmed up but still not great between 5k-7k, try raising the needle to richen 5k-7k.
If the engine pulls equally well between 5k-7k when cooler as compared to fully warmed up, the needle height is probably properly set.

Do not pay too much attention to the low-end richness when you are changing needle clip positions - you still need to be using the clip position that produces the best full throttle / 5k-7k power in conjunction with the main jets (Step 1) that produce the best power at high rpm. You will deal with the low-end / cruise next.

3. Low end (full throttle / 2k-3k)

Step 1 (Best Main Jet) and Step 2 (needle height) must be selected before starting step 3!
Float height (AKA fuel level & how to..)
To get best low-end power, set float height (fuel level) so that the engine will accept full throttle, without missing or stumbling, in 2nd gear from 2.5k to 3k rpm at minimum.
Float heights, unless otherwise specified in the installation guide, are measured from the "gasket surface" of the carb body to the highest part of the top of the float - with the float tang touching but not compressing the float valve spring.
If the engine has a "wet" rhythmic, soggy area at full throttle / 3k-4k rpm, that gets worse as the engine heats up, lower the fuel level by resetting the float height 1mm greater (if the original was 13mm - go to 14mm). This will lower the fuel level, making full throttle / 2k-3k rpm leaner.
If the engine is "dry" and flat between 2k to 3k rpm, raise the fuel level.
Example: change float height from 15mm to 14mm to richen up that area.

REMEMBER, since the main jet WILL affect low speed operation, the MAIN JET has to be within 1 or 2 sizes of correct before final float setting.
Warning: If the engine is left with the fuel level too high,, the engine may foul plugs on the street and will be "soft" and boggy at part throttle operation. Adjust Floats to raise/ lower the Fuel Level.
Base settings are usually given if a particular application has a history of fuel level criticalness. The Fuel level height in the float bowl affects full throttle/low rpm and, also, richness or leanness at cruise/low rpm.
Reference: a bike that runs cleanly at small throttle openings when cold, but starts to show signs of richness as it heats up to full operating temperature, will usually be leaned out enough to be correct if the fuel level is LOWERED 1mm. Check out and RESET all: Suzuki (all), Yamaha (all) and Kawasaki (if low speed problems occur). Needless to say, FUEL LEVEL IS EXTREMELY IMPORTANT!!!
If there are low-end richness problems, even after lowering the fuel level much more than 1.5mm from our initial settings, check for needle wear and needle jet (part of the emulsion tube). See Worn Needle and Worn Needle Jet diagram. It is VERY common for the brass needle jets (in the top of the "emulsion tube") in 36mm, 38mm and 40mm Mikuni CV carbs to wear out in as little as 5,000 miles. Check them for "oblong" wear - the needle jet orifice starts out round! Factory Pro produces stock replacement needle jets / emulsion tubes for 36mm and 38mm Mikuni carbs. Click here
4. Idle and low rpm cruise
Fuel Screw setting (AKA mixture screws)
There is usually a machined brass or aluminum cap over the fuel screws on all but newer Honda. It's about the diameter of a pencil. Cap removal details. Newer Honda carbs have no caps, but use a special "D" shaped driver, usually supplied in the carb recal kit. We do have them available separately, too. 800 869-0497 to order -
Set for smoothest idle and 2nd gear, 4k rpm, steady state cruise operation. Set mixture screws at recommended settings, as a starting point. For smoothest idle, 2nd gear 4000 rpm steady state cruise , and 1/8 throttle high rpm operation. (pj tuning information)
Pilot fuel mixture screw settings, float level (but, you've "fixed" the fuel level in Step 3 - which you have already done!) AND pilot jet size are the primary sources of mixture delivery during 4000 rpm steady state cruise operation.
If lean surging is encountered, richen mixture screws (turn out) in 1/2 turn increments. Alternative pilot jets are supplied when normally required.
Pilot fuel mixture screw settings, float level and pilot jet size also affect high-rpm, 0 to 1/8 throttle maneuvers. Too lean, will cause surging problems when the engine is operated at high rpm at small throttle openings! Opening the mixture screws and/or increasing pilot jet size will usually cure the problem.
NOTE: A rich problem gets worse as the engine heats up.
If the throttle is lightly "blipped" at idle, and the rpm drops below the set idle speed, then rises up to the set idle speed, the low speed mixture screws are probably set too rich: try 1/2 turn in, to lean the idle mixture.
NOTE: A lean problem gets better as the engine heats up.
If the throttle is lightly "blipped" at idle, and the rpm "hangs up" before dropping to the set idle speed, and there are no intake leaks and the idle speed is set at less than 1000 rpm, the mixture screws are probably too lean: try 1/2 turn out, to richen mixture. Be sure there are no intake leaks and the idle speed is set at less than 1000 rpm!
 
#21 ·
will give the VW fabric line a try, but it seems to have been ok for the last few weeks thankfully! squeezing the vacuum line over the wiring loom and under the main frame spar seems to have stopped the kink for now.... I've no doubt it will be back the next time i take the tank off though, ive probably just been lucky! Got a spare fuel tap now to rebuild (mine only works on reserve and leaks if you dare touch it! so I may try bending the old one :)
I have read the factory pro article many times, I'm only a little confused as i hadn't changed the pilot screw setting, I counted the turns when removing and replaced it at the same. Replacing the seals seems to have caused the issue, other than the overflowing float it had previously it ran better before i touched it! anyway its been close enough for the last couple of weeks so i will wait until i next have to take the tank off on a sunny day to fiddle with it again! Cheers for you help guys :)
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top