XT 600e tune up?

[banditderek]

Hi there.I'd like to start off by saying that this has been an ongoing situation for me, and I have got a lot of helpfull advice off the Hubb which has helped me chip away at my problem XT. A while back I had running problems with my 4PT, which left me stranded on the side of the road in the middle of winter a few times. I have since thrown a lot of money at it (as you do when you not a mechanic), with only a moderate amount of success. I have so far changed: the Coil, with lead and cap
cut out the sidestand switch
cut out the clutch switch
installed K&N filter, DEP silencer, and DynaJet stage 2
swopped the CDI unit to prove it
installed new chain and sprockets
all wiring checked and terminals greaced
changed the spark plug about 4 times

The chain and sprockets actually made a big difference, because they were exagerating the flat spot which has been there all along. I have had the bike at a Yamaha Main dealer, twice, and my local bike shop, twice. I would like to take this oppertunity to say my local guys were WAAAAY better than Yamaha, but still didnt get to the bottom of the problem. The bike problem is as follows. When I'm riding along at slow speed, from about 2-3500RPM the bike feels like its starving for fuel, just a little. There is a pop or two sometimes too. If I pull the choke out just a little it comes right, but the bike doesnt like this when really hot. If I give it a handfull of throttle and it shoots past this point, it seems ok, and its ok on full throttle cruising. Idling is sweet too. Its just that initial bit after pull off. Since the choke kinda fixes it, and chokes enrich the fueling temporarily, it must be starving for fuel just a bit. Is this something to do with the fuel/air mixture screw? And if so, how come the bike shops I went to didnt see this? Is there a bike mechanic in London who knows a lot about singles? Can I just turn the screw and hope for the best?

[mecca]

hi mate just check plug gap and elimanate that mine used to do that also try another garage for petrol. you may have checked these before but its the simple things that sometimes we miss good luck

[Jens Eskildsen]

Adjust you CO screw out a bit, that should richen it up a bit.

Otherwise, get it on a dyno, so you can see the fuel/air mixture over the whoole powerband..

[chucky55]

Have you checked the inlet rubbers for splits, de-lamination, pin holes yet?

It may be a long shot but easy to check.

Cheers from Oz.

[Trix]

Dyno is the way to go you may have an air leak which the dyno should spot. Gibson exhausts (see web for their address) are having a dyno day on Saturday and its only £10 a run and there is free food you could take advantage of that they are just off junction 28 of the M25 so easy to get to.

[banditderek]

Thanks for the response. I think Dyno is the way to go. I get petrol from multiple stations, plug is good. Rubbers are new looking, but that could be something to look at.
A mate at work has said something about lifting the needle one notch. Without a dyno this would be like shooting in the dark though. I need a tuner, just running it on the dyno is only half the job. Thanks again for the replies. Cheers

[wolfzero]

rule of thumb for carbs in basic terms are mixture screws are for idle to low revs, needle adjustments are for the transition from low to mid revs and the main jets are for full revs

dyna needles tend to be more tapered than standard to give that smoother transition so i'd go up 1 notch or even beter if you can go half a notch some kits have tiny washers for those .5 increments

[Trix]

Originally Posted by banditderek

Thanks for the response. I think Dyno is the way to go. I get petrol from multiple stations, plug is good. Rubbers are new looking, but that could be something to look at.
A mate at work has said something about lifting the needle one notch. Without a dyno this would be like shooting in the dark though. I need a tuner, just running it on the dyno is only half the job. Thanks again for the replies. Cheers

Any shop with a dyno will (should) be able to explain what the dyno read out means and be able to tell you what is causing the problem and how to sort it. I use the dyno at Gibson exhaust and they can tell me exactly what to change from the read out, but that should be the case with any shop with a dyno.