An idiot and a 77 XS750

[manas]

(I debated making separate threads for each of my queries or reports of progress but figured that it would be rather annoying and almost spam-like in the long term.)

I'm a mechanically challenged individual who works with airplanes during the day. The rest of the time I read DoTheTon and lament my lack of skill as I watch the rest of you build these amazing machines.

Anyhow, last fall I purchased a 1977 XS750D. Either I'll successfully put together a motorcycle that works or learn something on the way to failure.

March 18th 2013

1 .Took apart the carburetor. From previous discussion on DTT I've learned that its a Mikuni BS Mark 1. Not particularly desirable but will have to do on my limited budget.

2. Idle jets on two of the carbs had been stripped by the previous owner so taking them out was impossible. One of our Aircraft Mechanics lended me a hand and used his Snap-On equivalent of Easy-Out to remove the jets.

3. Main jets look clean on inspection. I can see through to the other side when holding against a light source.

4. Cleaned the bowls as best as I could with a cleaner-tub filled with AVGAS. Then washed with water to ensure no 100LL residue.

5.I purchased a Wheel Cleaner that contains Hydrofluoric Acid and Phosphoric acid. From my reading this is the active compound in so-called Aluminium Brighteners. Used sparingly to clean outside of bowls. Then polished with Mother's Aluminium polish. All done by hand (and a toothbrush for scrubbing) since I don't have polishing attachments for power tools. I'm not looking for perfection, just a nice clean.

Here are some before and after comparison photos:

 

[KOCONUT]

looking good. swap out the points igniton for the 78 and later transistorized electronic setup. You'll like it better.

 

[manas]

Re: Re: An idiot and a 77 XS750

looking good. swap out the points igniton for the 78 and later transistorized electronic setup. You'll like it better.

I'm pretty sure the previous owner has already done that. I found a Hitachi CDI box underneath the seat so I presume that somebody has already performed the conversion!

The main issue that I see with that is that since I didn't perform the conversion myself - I don't really understand what's going on with the wiring.

 

[manas]

Also @KOKONUT : I noticed that you have a pretty wicked build of an XS750D/2D yourself. Can I ask you a question? Are those K&L Universal Pod Filters? If so, did you end up changing jet sizes for all the jets?

 

[frankenrat]

Here's a link that covers the conversion, found on the Yamaha triples forum. http://yamaha-triples.org/forums/thread-view.asp?tid=13573&mid=93562#M93562
l also have a '77 triple that l'll be working on this summer.

 

[manas]

Re: Re: An idiot and a 77 XS750

Here's a link that covers the conversion, found on the Yamaha triples forum. http://yamaha-triples.org/forums/thread-view.asp?tid=13573&mid=93562#M93562
l also have a '77 triple that l'll be working on this summer.

Let me know when you start a thread for your build and I'll subscribe to it

 

[KOCONUT]

I pm'd you about the carb jetting. To tell you the truth, I actually had a specialist get me the right jets and I am pretty happy with the performance so far. The guy is on ebay, you tell him your carbs, altitude, modifications and whatever and he sends you the right jets. I rebuilt my carbs and pinesol dipped them which was a night and day difference from before.

 

[manas]

Thanks for getting back to me KOCONUT. You wouldn't happen to have link or ID for that eBay guy would you?

 

[KOCONUT]

here ya go
http://www.ebay.com/itm/Yamaha-XS750-XS-750-Special-D-2D-E-6-Sigma-Carburetor-Carb-Stage-1-3-Jet-Kit-/330882486639?pt=Motorcycles_Parts_Accessories&hash=item4d0a22116f&vxp=mtr

 

[manas]

Thanks! You're a gentleman and a scholar, sir.

 

[neevo]

here ya go
http://www.ebay.com/itm/Yamaha-XS750-XS-750-Special-D-2D-E-6-Sigma-Carburetor-Carb-Stage-1-3-Jet-Kit-/330882486639?pt=Motorcycles_Parts_Accessories&hash=item4d0a22116f&vxp=mtr

I've heard mixed reviews about those Sigma kits. They are mostly instructions and drill bits for changing your original setup.

Personally I would prefer to buy genuine jets from someone like www.jetsrus.com

Might take a bit of messing around with different options but I don't think you can go past genuine jets unless you're very capable with this sort of thing.

 

[teazer]

I've heard mixed reviews about those Sigma kits. They are mostly instructions and drill bits for changing your original setup.

Has anyone tried one? I have some doubts as to their ability to jet a bike they have never seen, but I try to do that all the time, so why not. The real question is do they include needles or needle jets. If not, they are not even close to being right.

 

[neevo]

Main jet is the only jet they supply. No needles or needle jets. I think they leave you to drill out the slow/ pilot although I could be wrong. This is off the eBay description:

Kit Includes
Main Jets
Needle Adjusters
Nylon Spacers
Drill Bits for
Slide Hole Mod (some models)
Idle Mixture Mod
Bike Specs
Carb Schematic
Carb Synchronizer Tool (how to build for $5)
Step by step instructions with photos customized to your bike.
Installation Support - If you need assistance with installation or have a question we are there for you.

 

[manas]

Re: Re: An idiot and a 77 XS750

Main jet is the only jet they supply. No needles or needle jets. I think they leave you to drill out the slow/ pilot although I could be wrong. This is off the eBay description:

Wait, what? Drill OUT the pilot jet? Why? What would that accomplish..and how?

 

[teazer]

That description is generic and there's little relationship between that and any specific kit AFAIK.

Drilling the pilot jets would be remarkably silly. On some bikes it is necessary to drill the slides to change the rate at which they respond.

 

[manas]

Stupid question for the day : I've looked at a few carb re-assembly videos and write-ups and I've noticed that some recommend applying a slight amount grease to the O-ring and gaskets.

Now that I've got my carb rebuild kits here I'm planning on sitting down at the end of the week and putting it together. What kind of grease is safe for the carbs?

 

[manas]

I'm guessing bearing grease is good enough for the carb.

http://m.canadiantire.ca/mt/www.canadiantire.ca/AST/browse/4/Auto/3/AutoFluidsChemicals/LubricantsPenetrants/PRDOVR~0280421P/MotoMaster+Bearing+Grease,+400G.jsp?locale=en

 

[manas]

Update : finally have time off this weekend. Its still going to be below zero outside but I'm not going to wait till it gets warm out. Sheds suck though.

Things I have lined up for this weekend:

1. Baking Soda Electrolytic Rust Removal for the tank - mainly doing this because its fun. I've heard good things, so I'm armed with a wire coat hangar, battery charger and baking soda. Will record it for entertainment purposes in case I trap enough Hydrogen to blow something up.

2. Carb Rebuild: armed with carb rebuild kits, bearing grease, advice from 3 different forums and absolutely no experience whatsoever. Hoping it'll all work out.

3. Oil and Oil Filter change: well, not much to add in explanation.

4. New Battery: decided to buy an ordinary battery until I get the bike running reliably. Went with the low maintenance acid type. Charging at 2Amps for a few hours.

So hopefully, with everything above I'd like to hope she'll start running again. I'll also finally take some pictures to make this thread interesting. I live an hour away from my friends place where I store it so it sucks to not be able to tinker and post more often.

 

[manas]

Update with photos, and some starting problems:

First the photos :

And the wood stove that we use to heat the little shed! :

1. Got into the shed today. Drained all the oil, replaced the oil filter and added new oil.

2. Hooked up new low maint. acid battery.

3. Hooked up cleaned carburetors. Also replaced pilot jets on two of the carburetors.

4. Tried to start her up but no go. I could hear the starter motor spinning and winding down but the engine would not start. Could someone please take a look at this video and advise me on where to go from here?

https://www.youtube.com/watch?v=wgCdnE1Ol60&feature=youtube_gdata_player


Oh and I forgot my friend Jordan who's been kind enough to let me work in his shed. He's currently working on his own 78 CB 400T, and that's his KLR650 in the back.

Here he is sodomising a tube of some sort:

 

[frankenrat]

l know you've been focused on the carbs, have you looked at or tested the electrics, put in new spark plugs, checked for spark? On this era yamaha bikes one of the biggest problems people encounter is the crappy fuse box. Since its been converted to electronic ignition make sure the coils have been changed also, to the lower resistance later year coils. Just some starting points. Oh, BTW, l'm also on XS650. com, as hmusket, my alter-ego here is frankenrat.