81 GS 750L Bobbed

[Weeksz]

Does anyone know what the model number for Mikuni carbs are on a 1981 GS750 L?

Are any of these carbs able to run on bikes if they are a year older or newer? I was told that I was receiving the carbs for my bike but they appear to have a different throttle assembly than my set (that is torn apart so I cannot directly compare.

 

[ShadowFocus603]

Bs32ss is what I have on my L. And if your throttle and choke stays are different just use your old ones like I did when I ordered a new set. Hell mine that I ordered were even spaced a little differently overall. I just put a bit of oil on the boots and wiggled them in. Thank god for flexible longish rubber boots.

 

[Jbowles]

Does anyone know what the model number for Mikuni carbs are on a 1981 GS750 L?

Are any of these carbs able to run on bikes if they are a year older or newer? I was told that I was receiving the carbs for my bike but they appear to have a different throttle assembly than my set (that is torn apart so I cannot directly compare.

model no. for your carbs BS32SS

 

[Weeksz]

Fantastic thank you.

 

[Weeksz]

So I got my head back from the machine shop and all the sheered cam journal bolts extracted but they said that it was gonna cost me a lot to get everything jet-washed. I'm wondering a good way to ensure that all the metal flake is out of there before I start rebuilding.

My plan is to use brake cleaner and then spray out with a compressor. Or should I use a power wash? Ideas?? I'm trying to save cost too.

Also, I asked this in another thread with no response. How important is it to get the carbon deposits out of the intake and exhaust ports?? Is this something that's just going to build back up after an hour of riding it again? Or is this something that you want to spend a lot of time on? I've gotten the vavle seats and valves good with some Seafoam and i'm going to lap my valves but what about in the ports??

Thanks for any input.

 

[ShadowFocus603]

Id clean up everything you can. Better to be safe and do it now. If nothing else it can't negatively impact you so there is no loss.

 

[Weeksz]

Id clean up everything you can. Better to be safe and do it now. If nothing else it can't negatively impact you so there is no loss.

Yeah. I just havent figured out a method that will be cost effective yet. I'm thinking a copper brush that can be chucked into a drill? with some carb cleaner? I'm heading to Menards after work today.

So I was prepping some surfaces yesterday and I noticed that the two Oil jets on the outside tops of the crank case were at different heights. One was sitting flush and the other was not. I haven't moved these at all and I'm wondering why they would be like this? Should I seat this jet or is it at an adjustment??



https://flic.kr/p/o9poUF

And here is my carbon filled head. and my attempts to remove it.

https://flic.kr/p/nQ8BJA


EDIT:

I am also wondering if anyone has any suggestions for a DIY piston ring clamp for guiding the pistons into the cylinders. Is can you get them in just using your hands or is a some kind of tool actually needed. I've never attempted it before as this is my fist rodeo. I was thinking a beer/pop can split in half??

Thanks

 

[ShadowFocus603]

PVC pipe and hose clamps works well. Just split the pvc down one side and slide it over the piston then clamp it. However the bottom of the piston liners should* be chamfered or sloped to allow you to drop the jugs over the pistons without compressors. You might have to gently push each ring in with a screwdriver but they will go. An extra set of hands here pays dividends.

 

[Weeksz]

Progress. New base gasket, head gasket, and new piston rings installed. Cylinders honed and pistons reinstalled. Valve seals replaced and valves lapped.

 

[ShadowFocus603]

Looking good

 

[Weeksz]

So I ordered these wires on Z1 thinking that spark plug wires are spark plug wires. I did a search for parts by bike model and ended up ordering these wires.

http://www.z1enterprises.com/ItemDe...ires+8mm+suppression+core+(grey)&item=DYDW800

Well when I received them i went straight to splitting them to install them into my stock coils and I realized that these have a synthetic or suppression core with no actual wire inside??? Will these work for my bike? It mentions "DO NOT USE SUPPRESSION WIRES WITH RESISTOR PLUG CAPS"

 

[smooth_358]

stock wires used copper core wire with the resistance built into the plug cap

these use the wire itself to build the resistance and use standard plug caps.

only thing that might not work is that they are 8mm and not 7mm like stock wires.

 

[Weeksz]

Ok so thats good news. What issues would I run into with the 8mm wire instead of 7?

 

[smooth_358]

might not fit in the coils

 

[Weeksz]

Well they do fit in the coils so no issue there. I'm just surprised that the old coils work with the composite core wires...

 

[Weeksz]

So I've finally got a clean rebuilt set of carbs thanks to Chef1366 (Thank you). Just purchased new fuel lines and a fuel filter and some new gas and am going to finish adding oil to her this afternoon and then see if I can get her to start.

I was wondering, is there anything specific I should do before I turn it over for the first time. A friend suggested pulling the plugs and turning over the motor a few times to let some oil circulate inside before actually letting it fire. Any "do nots" other than rev it to the sky the first time it runs?

Thanks,

 

[ShadowFocus603]

I second the rolling it sans plugs idea just to get some lubrication built up. Especially if you assembled it 'dry' or it has been awhile since you put it together. Good to hear you are getting there with it. Feels good I bet.

 

[Weeksz]

Well found out that my battery is toast. With a jump it turned over just fine but I'm not getting any spark out of the second plug. 1&4 and 3 are firing but nothing on #2. I checked the connection on the coil because I put new wires in it but my guess is the coil is shot? Any recommendations for new ones or maybe any ideas why it wouldn't have spark?

thanks guys

 

[ShadowFocus603]

http://www.ebay.com/itm/171349900643?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT
If you have to replace you may as well upgrade. I'm putting these on her 750L and my 850G this winter with Dyna DS3-2 ignitions. Link is for reference. You can probably find them as cheap or cheaper from your preferred vendor.

 

[Weeksz]

Thats a bummer. $118 is more than I was hoping to pay. Is there anyway to rebuild these? or is it possible that there is another reason that the coil isnt firing that plug? Like typically when the coils go bad, do they both go bad or does just one go bad? (by one I mean a one plug at a time)

Also, I see that the coils are offered in different ohm outputs. Whats is the preferred output and is this something that you run different depending on your intake and exhaust setup? Wires too? I've got the 8mm suppression core wires.

Thanks,