Urgent help!

[ronny86]

heys guys, cheers for the top advise, only reason i didnt do carbs my self is cause he said he would sync and clean them for 90quid which is cheap i thought.... anyway been round my mates whos a good mechanic and he had a good look and he told me to look at the 3rd spark plug, so i did and noticed its only been screwed in 1/4 of the way, where the top of the 4th finished is where the start of the 3rd one is so its a hell of a way out, he tried to get it in but no go!, so looks like a helicoil job!, so gonna sort that and see how she is! if still the same ill pull the carbs off and sort it...... so if hes took the plugs out to check before he synced them and put one back in wrong, does that mean the carbs will probs be out of sync once fixed? cause im in the understanding that they check air filter/plugs/fuel filter before they sync them?

edit: do i use a helicoil or a spark plug thread chaser?

[DonTZ125]

Plugs have nothing to do with sync, unless the plug is so far out it affects the vacuum through the carb. In that sorry state, no, the carbs will NOT be properly synched.

The first option is a thread chaser, certainly. If that fails, a hard thread insert would be preferred to a Heli-coil, as it is far less likely to be damaged by removal and torquing of the plug.
http://www.timesert.com/html/bigsert_sparkplug.html

Some brave souls have fixed plug threads on their engines with the heads still installed; copious amounts of grease supposedly catches the swarf and cuttings. I'm not sure I'd really be happy; I think by the time you're drilling and tapping for a thread insert it would be safer to pull the head.

[ronny86]

ill see how it goes once i get sorted, like a say the plug is a far bit out, ill get a pic tomz how how far its in now, its in a bit further now that it was but still massivley out

[ronny86]

pics:

[yamaha_george]

you provide the info & I will encourage its use LoL

[ronny86]

looks like head is coming off next wednesday, aint gonna even attempt this one so my mates gonna do it for me and put a thread sleeve in for me, might as well check valve clearance etc whilst hes in there

[ronny86]

If the latter, they probably swapped one or more sets of main jets with the starter jets - they look identical, except that one is ~ #105 and the other is ~ #30...

been thinking about this one and gonna get carbs off sunday to check, is it that easy to mix them up when hes been a mechanic for years?

[DonTZ125]

They're physically identical except for the number stamped on the side. If he lost track of which jet goes in which of two holes...

[ronny86]

ok so 105 is main jet and 30 is starter jet? deffo gonna rip these carbs off sunday (not literally)

[DonTZ125]

ok so 105 is main jet and 30 is starter jet?

Correct

[ronny86]

ok brill, do my research and think im ready to tackle this!


my plan :
float height 23mm
pilot screws - 2.5 turns
needle clip position - 2nd from top

then get a resync again

[CJD]

ok so 105 is main jet and 30 is starter jet?

Correct

Incorrect

Stock UK/European models are as follows

Main Jet 107.5

Starter Jet 52.5

Pilot Jet 30

Main Air Jet 65

Pilot Air Jet 112.5

Jet needle position 5CFZ4/2

Pilot screw 3 turns out

Stock float height is 22mm

needle clip position - 2nd from top

Yep that is correct.

Since this is probably the first time you have tackled dismantling/cleaning carbs, I thought you should have the correct info, otherwise you could get confused. Do it right first time

[ronny86]

ah rite thanks mate

[ronny86]

the guy from the shop rasng me today as he seen a post i made on another site and he said he wants me to take bike in so he can locate the problem with the bike so his rep isnt slated, he said his rep is worth more than a few hours work so hes gonna look over it for free... he also said that there is no way the main jet and starter jet can get mixed up as they are different threads

[DonTZ125]

The main and starter are the same style jet; stories of accidentally swapping them out get posted here and on the Archives from time to time. The main and PILOT (idle) jets are completely different.

When the Yamaha shop manual says "The jet with a bigger eye is main jet (1), it should be installed on (a) position. The jet with a smaller eye is starter jet (2), it should be installed on (b) position," you get the impression they were concerned with getting the jets confused...