Running rich.

[jake]

I gave my Honda carbs a makeover and decided to give the Bulldog carbs a clean. After reassembly and a test drive after 20 minutes the dog was not responsive from standstill. It was putting out black smoke and I had to rev hard to make it move, at high speeds it seemed ok. On taking out the plugs they were very black. I adjusted the lean/rich * to 3 1/2 turns out, and left the bike to idle for a few minutes. The plugs were still black. I then adjusted the needle clip to 2 notches from the top. I left the bike to idle again and thr plugs appeared ok, I have not ridden the bike yet. Any ideas as to what may be wrong? Cheers.

[sandro]

It already happened, that main- and idle-jet were interchanged at the assembling of the carbs (!)
Engine was running, but with similar problems you told...

[Axman]

Hi Jake,

as Sandro already said, it could be that you mistook one jet for the other (they look very similar and are nearly side by side). Are both cylinders running ritch? Do the plugs on both cylinders look the same? If yes the choke might be sticking...and so on.. If you don´t approach carb-problems methodically it could be, that you are moving in the wrong direction. To solve the problem will then be more and more difficult. I know it is tiresome, but you should start again and backtrack the changes you have already done. Start with the jets... What numbers are on them? Then lets see from there...

Cheers, Axman

[jake]

Thanks for the replies, but everything seems to be in the right place
Choke not stuck on
Both plugs very sooty
Idles fine from cold

******
Now I have gone back to basics .... Original exhaust; original carb settings - that is (see attached picture ....

Bulldog Carbs (Apr 2016).pdf

(134.96 KiB) 165-mal heruntergeladen

Bulldog Carbs (Apr 2016).pdf

(134.96 KiB) 165-mal heruntergeladen

), needle setting clip 4 down 2 up; mixer * 3.5 turns out = result STILL running rich / very black sooty plugs!!!

Now running at stage 1, a lot better, but still some hesitation (de-de-de-de) on acceleration, which needs putting right for the engine to run cleanly ??

Any more ideas .. PLEASE?


Further to the last post, I now think that the TPS is at fault. Has anyone changed theirs for a specific reason?

[WullDee]

Hi Jake,
I'm sorry I can't help you, but for other potential readers: what does TPS stand for?

[ronald53]

Any more ideas .. PLEASE?
Further to the last post, I now think that the TPS is at fault. Has anyone changed theirs for a specific reason?

I tried to find a picture of an opened carburettor, to compare against yours. Found one here: https://sites.google.com/site/vstar1100 ... ure-screws
Seems you put the jets in the correct positions.

If only one cilinder is running rich (it is not likely that the following occurs at both carburettors at the same time):
- Are you certain that both needles are correctly fixed in their position by the small plastic plug and the spring?
- Did you by accident bend one of the brass tabs that set the float height?

With respect to the Throttle Position Sensor: The workshop manual has instructions on how to check the TPS for correct functioning. And on start-up there is a check on the functioning as well. At least, on the 2005- model there is, again see the workshop manual. I advise not to take off the TPS unless really necessary.

Good luck,
Ronald

[jake]

Cheers Ronald,
both carbs are running rich. As for the float tabs, I am pretty sure that the tabs have not been bent. I tried a second set of carbs and the result is the same. I really don't know what else to try, so I will be taking it to a Yamaha mechanic. Thanks.

[ronald53]

Cheers Ronald,
both carbs are running rich. As for the float tabs, I am pretty sure that the tabs have not been bent. I tried a second set of carbs and the result is the same. I really don't know what else to try, so I will be taking it to a Yamaha mechanic. Thanks.

Since both carbs seem to be affected, one has to search for faults in systems that are shared by both carbs. I can think of two (only):
- Air intake. Is the air filter severely blocked? E.g. by a piece of foam that has come off the foam pad attached to the bottom of the fuel tank? Such partial blockage could explain rich running. However, this is hard to combine with what is written in your initial post, where you mention that everything seems to be OK at high speeds.
- The ignition system. Did you check the TPS by measuring the resistance values? see page 5-8 ( section 5 - page 8 ) in the English Workshop Manual: viewtopic.php?f=18&t=16223 .

Regards,
Ronald

http://mechanics.stackexchange.com/ques ... motorcycle

[jake]

Thanks Ronald,
I have checked what you have said. The TPS R2 readings are higher than stated in the manual and out of the specified range, but I do not get a fault on the self diagnosis on ignition turn on. Cheers.

[jake]

Well that's it. Just took the dog into a main dealers to get sorted out. The bike ran great all the way, without missing a beat. It was like nothing was wrong.I don't like main dealer prices but it needs to be done.

[jake]

Further down the line........ the bike is still running rich. I thought the bike shop had sorted the problem , but only eased it. When running slow in hot weather the bike starts to die and I have to rev it hard to keep going. Everything has been checked, I think. Everything in the carb is standard, float level ok, no leaks anywhere, air filter not blocked. I have dismantled the carbs numerous times and tried different needles and jets, but it is always very rich. Got to the end of my tether and run out of ideas. On a lighter note I am looking forward to the Treffen and two mates from England are attending, unfortunately they do not ride Bulldogs, but hey, they will still have fun.