cold starting a problem

[Bill Jurgenson]

Any idea what could be the culprit?

the much too small and weak battery. how many people must write this how many times?

[kman.45]

Hi,

Good news is that I'm off for a week and half next week, and my local bike shop have agreed to take it in while I'm away and try to figure out what's wrong. Chap there said it could be tight valves ...Doug

Doug, you should maybe investigate this further. My Baggi has gotten difficult to start and operates poorly on choke everytime the valves get tight. Each time I've adjusted valves the bike runs 5x better on start and idle. I've done valves three times at the 6K interval and it's needed it each time, and run better each time. I let it go a little too long one time and boy was it recalcitrant on startup, easy to flood and such.

Kyle

BTW, I ride my bike all year here in TN, many days in winter with temps in 20s, never had a problem strarting due to "weak" battery.

[handsomejackuk]

Bike currently done 9000 miles so valve clearances need to be done. Anyone know what recommended gap is for valves. I got the tank and the rear subframe off at the moment i see that on the rear of the engine is a oval plate what is clearance for valves under there and how many 2 or 3 and I assume that the two round plates with hex head on top is for the exhaust valves recommended clearance for these please

THanks Alun

[Bill Jurgenson]

those are the access points for the 5 valves.
0.10mm intake and 0.15mm outlet.
Careful with the left and center intake valves since they have a common rocker arm and it is easy to get it wrong.
I check each time I have the tank off but almost never have to adjust them. After many years experience with this engine, I admit to adjusting by feel without using a gauge. Check the exhaust more frequently than the intake - they are more often in need. but this is extremely seldom in my experience, even with the racing motors. Do keep an ey on the timing chain, tho. And especially, cast a glance once in a while at the woodruff key of the primary drive.
Lest anyone think I pamper the things, I routinely use an open CDI or one modified to 8400 and routinely rev them way over 7500, even occsionally to the limiter at 8400. The limiter-less racing motor over 9000. Doesn't matter. The street engines still have the original guides and valves in place at over 50000mls of such treatment. And the street engines have seen racetrack use, too. And 200km+ stretches at 8000+rpm.
The comments further up about needing such frequent adjustment lead me to believe that something is desparately amiss.
Let the thing get warm without stress, change oil more frequently than the advised 6000km or once year, always change filters (good ones , e.g. K&N which only cost maybe a dollar more) and use good oil. When you change oil, pour 1/2 quart into the head thru the oval access cover.

[handsomejackuk]

bill,

thanks for quick reply, i have got the rear subframe off at the moment so most bits are easy to get at. I will check the valve clearances now it is all apart. New air filter fitted as old one is 5 year old...

One other questi9on not sure if you know the answer to this but on the side of left hand carb is an access plate with a rubber diaphragm in it when i removed this the diaphragm fell out and i am not sure whether i got it on right way would you know if this makes much difference as it looks very similar both ways around...

THanks Jack

[Bill Jurgenson]

That should be the accelerator pump. It has been a long time since I did anything with that carb, save for taking it off the engine.
Here is the relavant page from the Yamaha workshop manual.

Picture 1a.jpg (161.78 KiB) Viewed 3715 times

you are referring to the number 46 behind the small cover number 24, aren't you.

here is what the book says:

Picture 2.jpg (34.51 KiB) Viewed 3715 times

[handsomejackuk]

Bill,

Thats the jobby the diaphragm. not sure what is the right way to fit it. I have put it back in for now but will have to evaluate it when ii come to start bike.... would good to know for definite the correct orientation as its a small item which could make a big difference....

Thanks Bill


Jack

[handsomejackuk]

Bill,

Adjusted the inlet valves today they were really tight could not get a feeler under tappet at all. set them all to 0.1mm. why would they completely close up ? put rear subframe back on sealed a small leak in exhaust between tailpipe and intermediate turned over started 2nd time sound like theres more compression there before it used to splutter and cough. Will reassemble all of rear subframe tomorrow. Then drop radiators and do the exhaust valves. think i may find them closed up to !!! I have been keeping battery on my solar charger for a couple of days so maybe this as helped as well. All in all i think it maybe lack of maintenance new air filter must all make a difference...
also put my baffle (DB killer back in the exhaut).

Just out of interest, what capacity battery are similar bikes of this capacity using would it be advisalbe for all us baghira owners having trouble to uprate battery to a better spec ?

Keep you posted thanks Bill....

[kman.45]

Adjusted the inlet valves today they were really tight could not get a feeler under tappet at all. set them all to 0.1mm. why would they completely close up ..

Jack, that is EXACTLY the issue I had the first time I adjusted valves too. Could barely get the 0.0015 inch feeler in there (spec is basically 0.004-0.006 inch). First two times I adjusted to the 0.005 inch (0.127mm) and it wanted adjustment by the time the 6k interval rolled around, had done the hard starting not running well on choke routine, valves had tighted to less than the 0.004 spec. Last time I adjusted on the 0.006 (0.152mm) gauge and I'm a couple hundred miles from the 6K interval and bike has continued to run far better than the last two times. Been considering putting in a DPR8 range plug instead of the DPR9 as maybe a hotter plug will keep shit cleaner? I dunno.

[Bill Jurgenson]

well, exhaust specs are 0.15mm (.006"), intake 0.10mm(.004").
by no means less; a wee bit more doesn't hurt at all.
by all means use an 8 plug. The 9 is too cold.
I use D8EA, even in the racing engine.

The only way valve clearance can close up is when the seats are bashed into the head or the heads deform. Once driven in, thre is no appreciable wear on either.
Seat rings driven into the head casting was a BIG problem with the radial valve Honda single but is is virtually unheard of with the Yamaha engine.
Of course too close clearance to start with can cause wear by keeping the valves from actually closing. Then the contact surface of both burns away.
So, like I said, if you need to reset valves at such close intervals, there is something very wrong.