Bruce

You guys got it all wrong Not me , the old dog!

Yebo nGogo! Still swinging it I see

No chance. I think you've found a kindred spirit in Drewpy The man's either a structural sedimentologist or paleontologist. Either way you old fossil, if he gets a hard on around you, you'll know why.

Your past is catching up Being a sad old greaser and a biker isn't synonymous anymore

When you say bogging, do you mean that the motor will rev highly and then start to slow down and begin labouring? If so then your high end mixture is too lean. If the motor on full throttle transitions nicely from idle to mid range and then starts to labour without getting to max revs, making a cyclic laboured sound like a 4 stroke ("4-stroking") then you are what's called "burbling rich" on the high end. Before adjusting this, check the choke mechanism as more often than not, this latter is caused my the choke mechanism being stuck on. Also if it is this check the exhaust hasn't become coked up. A restrictive exhaust on these engines can unbalance mixture tuning / timing and make settings highly sensitive.

You didn't specify year Try this manual http://moto.tt.free.fr/explorer/Yamaha%20D...tion%201988.pdf

Classic

3R1 designates the 1980 - 82 YZ80G http://www.dropbears.com/m/models/yamaha/yzseries74.htm This model didn't have a frame number.......????? Go figure?

I was teasing you that it's full of SOGs and other assorted lecherous dirty old men that will be slobbering like bulldogs before a feast. But you will, in honesty be treated like royalty, you just may not appreciate all your subjects though. Go have a look, it's a laugh.

A frame number would come in handy

Aah, dont mind Mucho, I entertained myself for the last 3 odd years trying to wind him up. But it's like stirring pigshit...it just gets thicker. Sounds to me Andy, that you got a TT600 sprocket set. Nothing really wrong with that in as much as judging from the year of your bike it is a 3AJ model which is the same engine used in the TT's relaunched round abouts 2000-2.

Oh dear, you're gonna scare them away forever . MB should be PG rated

Well I'll be sure to tell him he missed a bit

Aah yes, I thought this was The Hillbilly's doo So how is the TDM? Traded it in yet? You never should have got rid of the wee XT and GS. It's all downhill now

OMG what are you doing here? Bloody admin too! Ja, Anus, but you've been humping mine since 2004, what's new? Andy could use a 16 /42 or 14 /39 combo for the same results. More wear on the 14, less on a 16 combo's, however these changes may require a change from the 106 link 520 chain.

Seems you are not the only one. Have a look here: http://www.horizonsunlimited.com/hubb/yama...ighlight=XTZ660

40 / 15 or any valid combo giving a reduction of 2.666

Glad you sorted it out. Oil seal leak eh? That's a new one to remember.

You might also want to check your clutch cable tension. Make sure the clutch is being fully disengaged. Good check is when the bike is cold (choke is on, revs a bit higher than norm etc). Does the bike snatch when engaging first?

Oh, you dont want a wet plug. Dont use that as your yardstick. Rather look at the plug after running for a while to judge mixture. Remember these bikes run notoriously rich anyway. Are you using the correct amount of choke on cold starts?

Early kickstart TT's have a weak kick over spark. ... you generate the current for the spark on kick over not via battery. Make sure all lights etc are off. Have you got the kickstart technique right? A seemingly stupid question, but if you are new to these old 600 thumpers, they will start a dream if you kick them over right and be an absolute bitch if you get it wrong. ... feel for the near TDC compression by gently pushing down on the kickstart lever. When you reach it come back up on the kickstart and kick all the way through to the end of the stroke with firm pressure. Failing this have a look at the following to make sure you have a clean circuit: Side stand switch (if present of course) Kill switch Check all earthing points are clean and make good contact especially on any repainted surfaces Check the neutral cable (blue if memory serves) these go into the crankcase and can deteriorate and break under heat Recheck coil resistance remember a cold engine takes more electrical current to start than a hot one. If all these check out, then you need to make sure it is indeed an electrical problem. Remove the plug from the head so you have no compression when you kick her over, then remove the suppressor cap from the HT lead and make sure a bit of wire is poking out. Ask someone brave to hold the ht lead close to a exposed metal earthing point on the bike and kick her over with gusto. If the spark is orange = weak. Blue = OK. Now try it with the suppressor cap and plug in on the same grounded surface.

I take it you have correctly connected the loom and checked resistances. I would agree the coincidence of a faulty CDI unit is unlikely. Last check I'd recommend you try is check the HT lead to sparkplug suppressor cap. Trim 2mm off HT lead, re-insert the cap and try again, as the HT Lead was known to be susceptable to corrosion in these models. Likelihood is pulling it off the plug was the last straw.

That depends on what you want to do with the bike and also what you want to do with power delivery. If it is possible, this article might give you better insight. http://www.motorcycle-usa.com/Article_Page...D=68&Page=1

What happens at 4.5k rpm? Check your plug colour, it'll tell you a lot. Various checks you can do starting with easiest... 1. Check the carb inlet mainifold rubbers are not leaking through cracks etc. Easiest way to do this is with the engine idling, spray easy start around the intakes. If you notice a rpm change, you have a leak. 2. Check your filters are not dirty, and the guaze has not corroded restricting airflow. 3. Check your idle mixture pilot screw is not set too rich / lean. Should be roughly 2.5 turns out. Note, this does not adjust fuel flow, but airflow so tightening the screw will richen the mixture. Check the vent in front hasn't corroded closed a bit. 4. Use a clear plastic Tygon tube (battery overflow tube works well enough) attached to the float drain nipple and bend it back up against the float bowel. Open the drain screw and petrol tank cock. Measure the difference in fuel height from the bottom of the meniscus to the top of the float bowl. The fuel level should be within spec 5 - 8mm (check against manual for that figure tho) If you are still having problems, you'll need to strip the carb further. 5. Check and clean all jets and atomisers. DONT forget the mini guaze filter that sits in front of the needle and seat either. 6. Check against the manual that the primary cd slide closes to the correct point and is not compensating for the pilot jet ( idling issues) 7. Check secondary carb is actuated at the correct point. Roughly once 8 - 10 mm of the cd slide has been raised in the primary carb. 8. Check the fuel pipes between the carbs for integrity / leaks 9. Check all diaphrams and the free and vacuum movement of the secondary carb 10. Check the needles for wear and that they are correctly positioned with the retaining C-clip. Mechanical. Check that the valves are indeed within tolerance and that the decompression cable free play is not set too tight and then check that your cam chain tensioner has not reached it's furthest limmit introducing a mechanical timing error. If you get the chance to drop the motor check also the cam timing marks. Timing. Use a strobe and check against the manual that the timing is advancing corrrectly. After this you are pretty much into the electronic side. Check all cable connectors are making firm contact. Use contact cleaner and then use a multimeter to check against the manual the various resistance tolerances, but honestly, when you get to this point, it's often best to trial fit a part be it coil, stator etc from a donor bike to find the error. Goodluck. Edit Tufty wrote:

On the carb (ignore the float bowl line and vacuum tube from afterburner to secondary carb and all other fuel links between the carbs) there are two outlet pipes at the rear of the carb (carb intake side). I suspect the one on the primary is an overflow, but haven't a clue as to the one on the secondary. Anyway, my inclination was to let them vent freely. Is this correct or do they have another purpose / connection?