Yamaha TRX850 Enthusiasts Forum

The Keihins are getting installed by a mechanic this coming Tues. There's something that's been bugging me since I tried (and failed) to put em on myself...
When I stuck the flatslides on the bike I was careful not to tweak the throttle until the throttle cables were set up. I then connected the fuel and breather tubes (the right way around) and tank/vac/fuel hoses and started the bike up...it would idle for a bit then bog with some carefully/slowly applied throttle. I did this a couple of times and then decided (given I know nothing about carb setup) to switch back to the standard Mikunis and call the workshop. When I took the Keihins off the manifold under the carbs was actually wet/dripping with petrol. Oh, and this was with the airbox off and ramair filter.
Should I get my mechanic to check all the settings on the Keihins before attempting the installation? TIA for any advice

Correct me if I'm wrong but FCRs are pumper carbs. Used to remember seeing them spray straight petrol when I had my set on the Guzzi.
Let us know how Lloyd goes installing them?

Bob

Yup, I knew to be careful about twisting the throttle before it was go time...then it wasn't go time Lloyd knows the whole sordid tale and is armed with pics of the tps bypass mod if required...looking forward to tomorrow arvo (hopefully)

Disaster Lloyd is away today and Cody has found exactly what I found. He changed the needle position and synced em and got them running "OK" but they make no power on the road. To paraphrase him: they might not work but he's said that before and have gotten them working great.
Goddammit Lloyd's back tomorrow...praying for a happy ending
At least I didn't do anything wrong myself that the workshop couldn't replicate (trying to look on the bright side there)

is that with the bellmouths or the airbox????
maybe paying a couple more dollars for a dyno would have solved all your problems in a jiffy and sorted your jetting out ..
Lets just hope your mechanic isn't havin a bad hair day and is relaxed,doesn't have a cold,still has a good ear and nose.
It would also put your mind to rest any doubts about lack of power with proof in the pudding in readouts of fuel/air ratios power output and torque thro the rev range.
I even got them to do a dyno run with and without the teastrainer bung they gave me for the end of the exhaust can .. It quietens the bike amazingly fairly well with a drop of just under 1 HP
It's the only time it's been used tho

Hey David..Hope all's ok after your tune up.. How did it go??????

Its gone completely to sh*t...and is really messing with my head (that's why I'm up at...what is it...4:53 am). The mechanic cannot get these things to run at all. This is completely contrary to everyone else's experience...including people who have bought exactly the same kit from the same place before (some chap in WA) and after (forum member Excalibur) me. I contacted the previous owner of the bike because he mentioned something about the fuelling but he's gotten back to me saying it was simply tuned a bit rich for the track (i.e. no messing with the fuel pump). Somewhere along the line I've allowed myself to be talked into getting a dynojet kit fitted to the stock carbs instead.
I am cranky and losing sleep over what should have been a great experience.
I'm going to allow the dj refresh of the mikunis and either sell the keihins to ahem (you know who you are ) or take them apart and see if someone (mechanic) is bullshitting me about checking the recommended settings and get them working myself.

Dav wrote:Its gone completely to sh*t...and is really messing with my head (that's why I'm up at...what is it...4:53 am). The mechanic cannot get these things to run at all. This is completely contrary to everyone else's experience...including people who have bought exactly the same kit from the same place before (some chap in WA) and after (forum member Excalibur) me. I contacted the previous owner of the bike because he mentioned something about the fuelling but he's gotten back to me saying it was simply tuned a bit rich for the track (i.e. no messing with the fuel pump). Somewhere along the line I've allowed myself to be talked into getting a dynojet kit fitted to the stock carbs instead.
I am cranky and losing sleep over what should have been a great experience.
I'm going to allow the dj refresh of the mikunis and either sell the keihins to ahem (you know who you are ) or take them apart and see if someone (mechanic) is bullshitting me about checking the recommended settings and get them working myself.

Sounds a bit like they don´t draw gas (or to little) when opening it up.
Where did the carbs came from? The previous owner didn´t crasch or something getting muck in the jets?

Shit, that's no good Dave. Lucky mine are still in the box. I'll get round to it one day.....................

Bob

Killerwhale wrote: Sounds a bit like they don´t draw gas (or to little) when opening it up.
Where did the carbs came from? The previous owner didn´t crasch or something getting muck in the jets?

These are completely new carbies...and supposedly checked by the mechanic

Dav wrote:

Killerwhale wrote: Sounds a bit like they don´t draw gas (or to little) when opening it up.
Where did the carbs came from? The previous owner didn´t crasch or something getting muck in the jets?

These are completely new carbies...and supposedly checked by the mechanic

Ok, only thing i can say then is that they are jetted for airbox with 150 main jets, i have ridden with 170´s with pods...now bigger with the TRX 900 enjun.
Could it be that the slow jets are screwed in and not tuned? ...as it bogs so down low?

Other thing i could imagine is that your inlet rubbers are old and cracked drawing air....

I know many moons ago i was booked on trackday´s and the head tuner thought the length of inlets could be optimized....we figured though the carbs would foul the oil filler
I could not get hold of new inlets so i tried do a fix meself....and it was much as you describe....and they draw air where they shouldn´t.....
If you can, get new rubbers and clips and see...not that expensive.
You have to experience the omphh of the flatties!!

first dyno reading would have shown all the probs mate .... Be a lesson to all... it's worth spending just a few extra dollars to get them tuned right from the start... Mine still has the std 150 jets with the bellmouths and just the nedles lifted 1 clip and the air jets where changed also.
But it ran fine straight out of the box new with the airbox on (just wouldn't rev right out in top gear)and even with the bellmouths on for that couple of days before the dyno it wasn't too noticable... It was running fine before you pulled the carbs off before tho wasn't it...
Are you sure your mechanic knows what he's doing????? or just taking you for more money..
Whats his name and where is he so others know to STAY AWAY
Sorry mate ...it souldn't be like that...
They should just bolt on from the factory so I don't know what the first mechanics done or hasn't picked up on...

don't forget killer has a headjob,878 kit and killer exhaust...
I think Kev from memory even with stock motor and FCR's , Over exhaust to make it breathe only runs a 156 main..
so again your mechanic shouldn't have to do anything to the carbs to just get it running ok.....just bolt them on.....it's just a matter of fine tuning...
Just hang in there mate.. stand your ground
personally I would Ring up cancel the jet kit, get your bike out of there, take it to a shop with a dyno and do it right.. He's gunna sting you at least that for the kit anyhow and tell him to shove his business up his%$#@ ...

cobbadiggabuddyblooo wrote:don't forget killer has a headjob,878 kit and killer exhaust...
I think Kev from memory even with stock motor and FCR's , Over exhaust to make it breathe only runs a 156 main..
so again your mechanic shouldn't have to do anything to the carbs to just get it running ok.....just bolt them on.....it's just a matter of fine tuning...
Just hang in there mate.. stand your ground
personally I would Ring up cancel the jet kit, get your bike out of there, take it to a shop with a dyno and do it right.. He's gunna sting you at least that for the kit anyhow and tell him to shove his business up his%$#@ ...

The tuning is not the biggie....it´s that i´m located in Sweden so i seldom ride in over 20 degree celcius...and bike need to run when only +5

so colder air being more dense .. so more fuel ..
I know once the cooler denser nite air sets it it makes a difference to frequency responce and overall body to the mix with sound