main jet advice Mikuni BS38

[peanut]

can't seem to find a consistant size for a standard main jet in a 79 BS38 carb?
Mike says 132.5 another seller says 135 ?
What should it be and can someone please confirm that this is the correct part number
YAMAHA-620-14231-99-A0
http://www.ebay.co.uk/itm/NOS-YAMAHA-620-14231-99-A0-CARBURETOR-MAIN-JET-132-5-XS400-XS650-/251863538397?hash=item3aa43c9add

 

[weekendrider]

peanut the problem is both are correct . . . depending.
If you look at the schematic for the '79 SF it says the carbs were 34's and the main jet size is 132.5.
If you look at the schematic for the '79 F it says they were 38's and the MJ is a 135.

I could prtscrn/ crop selection and post as a jpeg if you need but you could check the schematics just as easily.

That is the correct part# for the main jet in the '79 34's.
The part number for the 38's is 256-14944-27-A1 JET, MAIN (#135)
That number is superseded by part# 3G2-14231-27-00 when they started using that jet as an air jet on the 34's.

 

[5twins]

But ..... you shouldn't be buying your jets from Yamaha any way. You pay 2 to 3 times the cost of a Mikuni jet when it has the Yamaha part number attached. Peanut, in your case, I'm inclined to let you do that. But for anyone else, I would advise buying from a cheaper aftermarket supplier. It's the same part just without the Yamaha price mark-up. As to what is correct, well, that's been well documented, but you have to know what carb set you have. BS34s differ from BS38s.

 

[peanut]

But ..... you shouldn't be buying your jets from Yamaha any way. You pay 2 to 3 times the cost of a Mikuni jet when it has the Yamaha part number attached. Peanut, in your case, I'm inclined to let you do that. But for anyone else, I would advise buying from a cheaper aftermarket supplier..

fcuk you...fcuk very much 5twins

I always buy generic parts. I only buy OEM parts when there is no other option or there is a quality issue with aftermarket parts.

I've sourced and listed dozens of generic metric Oil seals and bearings and other parts for cars scooters and bikes over the years. Remember I have been at this an awful lot longer than you have

In this particular case if you had bothered to check you would see that the part is only $5.0 ! how much cheaper do you think you can buy than that ?!

Now exactly what was your helpful advice that addressed my question 5twins ??

 

[peanut]

peanut the problem is both are correct . . . depending.
If you look at the schematic for the '79 SF it says the carbs were 34's and the main jet size is 132.5.
.

thank you weekendrider for your your helpful response its much appreciated. last night I did not have a schematic to hand and I wanted to try order some jets before hitting the sack after another 17 hour working day. Unfortunately all the manuals I have do not show the jet in sufficient detail for me to identfy the shape and pattern sufficiently to order some main jets.

I just do not understand the current trend by a certain few long term members that seem to be determined to offer advice on the back of a sarcastic or derogatory remark. How is this helpful ?
..its the reason I mostly stay away from this site these days.

It has been raining solidly without a break for the past 48 hours now so I have had no opportunity to remove my carbs and check the main jets . When the rain finally stops I'll post a picture and part number for the benefit of other members that like me are unfamiliar with these BS38 carbs .

 

[peanut]

here are the top 8x Google listings search for part number 256-14944-27-A1

Not one of them show the actual jet and all of them are out of stock/obsolete part.
http://www.boats.net/parts/detail/yamaha/Y-256-14944-27-A1.html
http://www.kawasakioemparts.com/oemparts/p/yamaha/256-14944-27-a1/-jet-main-135
http://www.cmsnl.com/products/3g2-14231-27-jetmain_2561494427a1/#.VbSPH-GUmUk
http://www.stadiumyamaha.com/oemparts/p/yamaha/256-14944-27-a1/-jet-main-135
http://www.amazon.com/Yamaha-256-14944-27-A1-Main-3G2-14231-27-00-Made/dp/B005C59LLC
http://www.yamahapartsmonster.com/oemparts/p/yamaha/256-14944-27-a1/-jet-main-135
http://www.ebay.co.uk/itm/NOS-Yamaha-135-Main-Jet-1974-1984-TX650-XS650-256-14944-27-A1-/191138950044
http://www.nwvintagecycleparts.com/search-results.php?q=256-14944-27-A1&st=spart

If there is anyone that can help me with an image of a main jet and the thread size (6mm??) of a main jet for a BS38 1979 2F model I'd very much appreciate it .
I can then search for some generic jets and order up a couple of pairs ready for chopping over and testing when this infernal rain stops.

 

[peanut]

ok here is an image of the correct pattern Main Jet for a 79 XS650 2F with orginal BS38 carbs.Fortunately it is possible to see the part number with the jet for verification .

Hopefully it will be helpful to others so I'll amend the thread title to help with future forum searches.

This looks to me to be a standard 5mm thread jet available everwhere so I'll go ahead and order a pair of 140 and a pair of 137.5 so I can swop them and do some testing as soon as the rain stops and the roads dry out a bit.

For Brit owners these generic Delortto copies should do although the OEM part is no more expensive http://www.adrenalin-pedstop.co.uk/p/Dellorto_5mm_carburettor_main_jet__sizes_52_up_to_100-1049.aspx

If owners are at all serious about rejetting and accurate reliable testing I would recommend that they obtain a set of jet Guages for accuraely measuring your jets. All jets ain't created equal

 

[XS1961]

Buy the jets from Allens R&D or MOTOWARD , Peanut, top quality , Ive used them both since the 80's

 

[peanut]

thanks XS1961 I've not come across either of those Companies. I'll check them out.
I found a bike shop selling Main jets for £2.50 ea so ordered some this morning.
I'll update this thread when they are delivered

 

[650Skull]

The reason i created the "XS650 Model Identification/Year/VIN, Workshop Manuals, and Other Information", that is sticky'd in the garage, was to have all of the information, like in this thread, at your fingertips and save a lot of tech searching.

There is a link to the 5Twins and Grizld1 Carb Guide, and Gene Akkers site, "data extracted from Yamaha microfiche 1962-1986 Motorcycle Model ID, US only; and Yamaha model history documentation)", that has the best Parts list for the XS650. These parts fish files have all the relevant information relating to the jet sizes for the Model year and carb variations relating to the different models.

Peanut you have been around a long time now and i thought you would have known about this. Sorry i didn't post earlier

 

[peanut]

all I really needed was a picture and dimensions of the part... not the part number so that I could identify and order some generic jets.
I didn't think of looking through the carb guide because as far as I could recall the information that I was asking for was not in the guide.?I've since checked and it isn't there!

I have just spent half an hour looking through your excellent ID thread in the tech section and I have been unable to find any specification and image of the main jet there either?

As you are familiar with the thread perhaps you would know where it states the main jet standard size for a 78/79 BS38 together with the Part number and a pattern image and specifications of the jet ie thread length, head width, overall length of jet screw thread size etc

 

[Paulrxs650]

Hi. This is the link to Allens with pictures of the jets. Hope it's helpful. If not give them a buzz. Really helpful guys.

http://www.allensperformance.co.uk/mikjets.html

 

[weekendrider]

all I really needed was a picture and dimensions of the part... not the part number so that I could identify and order some generic jets.
I didn't think of looking through the carb guide because as far as I could recall the information that I was asking for was not in the guide.?I've since checked and it isn't there!

I have just spent half an hour looking through your excellent ID thread in the tech section and I have been unable to find any specification and image of the main jet there either?

As you are familiar with the thread perhaps you would know where it states the main jet standard size for a 78/79 BS38 together with the Part number and a pattern image and specifications of the jet ie thread length, head width, overall length of jet screw thread size etc

Bull Shit peanut. That isn't what you asked at all. If you had asked for physical dimensions I wouldn't have answered because I'm to lazy to walk to the shop and do the measuring AND it wouldn't have done any good cause I have no way to confirm the size of the hole.
You asked about the part number and that is what I tried to help you with.

can't seem to find a consistant size for a standard main jet in a 79 BS38 carb?
Mike says 132.5 another seller says 135 ?
What should it be and can someone please confirm that this is the correct part number
YAMAHA-620-14231-99-A0
http://www.ebay.co.uk/itm/NOS-YAMAHA-620-14231-99-A0-CARBURETOR-MAIN-JET-132-5-XS400-XS650-/251863538397?hash=item3aa43c9add

 

[peanut]

Bull Shit peanut. That isn't what you asked at all. If you had asked for physical dimensions I wouldn't have answered because I'm to lazy to walk to the shop and do the measuring AND it wouldn't have done any good cause I have no way to confirm the size of the hole.
You asked about the part number and that is what I tried to help you with.

and there was I thinking you were one of the nice guys weekendrider...

I asked for the part number because I would then be able to look the part up on Google or elsewhere and see the part for myself and hopefully ascertain the dimensions . I could then compare the pattern and shape of the part with various generic jets on ebay and elsewhere so that I could order them up with reasonable confidence.

I am very sorry that I did not explain my intentions to you fully....... I expect I was tired as I was just about to go to bed after working another 15 hour day as I do every single day of my life.!

Thank you for your detailed answer ....have a nice day

 

[peanut]

Hi. This is the link to Allens with pictures of the jets. Hope it's helpful. If not give them a buzz. Really helpful guys.

http://www.allensperformance.co.uk/mikjets.html

thank you Paul an excellent informative link thats much appreciated ..however I had already found the information I was seeking (together with some details that a member kindly PM'd to me )and posted it for reference for future enquirers,.. in post 7 of this thread.

That is... if anyone can find it.... amongst all the usual crap and invective people have to suffer every time they ask for advice and help on this forum