Project "walrus" Yam XS 750

[2_DONE_THE_TON]

Hi Ryan
Before you start playing with jets you need to make sure the ignition is spot on along with everything else. Otherwise you will end up chasing your tail!!!
I have attached a collection of blogs I found online which helped me understand tuning carbies - hope it helps. The theory is the same even though you are working on different model carbies.
What was with the brake light on your video? Were you grabbing the front brake when you twisted the throttle?
Great progress.
Cheers
Tim

Thanks Tim for your insight!

I can´t really remember,but I guess the bike charges pretty well multimeter reads 14.2 Volts when revved up.
What could cause this?
I will take a little spin today and then check ignition point next weekend.

 

[der_nanno]

My needles are in "mid" position right now, IIRC you had your needle clips in bottom position didnt you?
Mixture screws are 2,5 turns out.

Yep, I certainly raised the needles, but that was also (partly) because of the worn out advancer on my points ignition I used back then.

You may play with the mix screws and set them so the idle goes up and then go an 1/8th to 1/4 turn richer than that. If they don't respond to changes, then the whole setup is too far off for the mix-screws to work. Try that for a start and let us know your findings. Also take note of the stock settings.

 

[datadavid]

Re: Project "walrus" Yam XS 750

Sounds reasonable,I checked one plug after running it and it was very clean and slightly light gray (not white).so that means fatten the mains I guess.

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I dont know anything about jetting these mikunis, but go for 130-150 range in mains with full open exhausts and pods. And raise the needles 1mm.

 

[datadavid]

Re: Project "walrus" Yam XS 750

Hi Ryan
Before you start playing with jets you need to make sure the ignition is spot on along with everything else. Otherwise you will end up chasing your tail!!!
I have attached a collection of blogs I found online which helped me understand tuning carbies - hope it helps. The theory is the same even though you are working on different model carbies.
What was with the brake light on your video? Were you grabbing the front brake when you twisted the throttle?
Great progress.
Cheers
Tim

Yes and valve clearances! Always these things first.

 

[2_DONE_THE_TON]

Re: Project "walrus" Yam XS 750

Oooooh guys...whaaat a rush!

I took the lady out yesterday for a spin and nearly rode her for 1 hour.
That sound,that torque
It was really nice seeing that my clutch is doing its job,really interesting to see the shaft drive chain difference....
A few little problems arose:

-checked the igntion timing twice with my strobe gun
Even after adjusting it on the spot the adjustment seems to 'wander'....

-one of the rubber boots (intake to motor) was not properly in place and oil was leaking....smoked nearly as much as my RD on premix
--guess this is also the reason for my lean condition problem...

The plugs looked like this.

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[JadusMotorcycleParts]

Great job man, glad you got to hear it purr and pull the throttle for a while! Nice.

Just wondering how you are burning oil from the leaking intake boot? Wouldn't the only side effect be a slightly lean condition due to sucking in a little more air after the carb?

 

[2_DONE_THE_TON]

Great job man, glad you got to hear it purr and pull the throttle for a while! Nice.

Just wondering how you are burning oil from the leaking intake boot? Wouldn't the only side effect be a slightly lean condition due to sucking in a little more air after the carb?

Thanks man!Can´t wait for summer.

The intake boots have two clips.One clips attaches the boot to the motor,this clip was loose and I guess this is where the oil kept seeping out?is this possible?
Or am I´m thinking 2 stroke ?
On the other hand the motor vent on top of the gear box is also still "open"...

Why is my ingition point "wandering"?

 

[der_nanno]

Might be some oil seeping down from the valve stems or more likely just some unburnt petrol.

Wandering ignition can be down to one or a combination of the following:
* ignition base plate bent and once you tighten it down it shifts around
* advancer a bit worn out
* not always looking at the pointer from the same angle

 

[datadavid]

Re: Project "walrus" Yam XS 750

You are never ever supposed to have oil in the intakes on a four stroke! glad you get to enjoy all that work you have done! I got sideswiped by a bitch on the phone in a tunnel today on the triumph chop, second ride of the year...
Gotta bend the pegs back, nothing worse gladly

 

[Maritime]

David, glad you're ok after the crash! chicks on phones are one of the worst hazards on the roads these days. I almost got head on collided in my Car by one with my son in it, I had to go in the ditch, she didn't even look up and see she had crossed the yellow line completely into my lane.

 

[jcw]

On the other hand the motor vent on top of the gear box is also still "open"...

This ^^^^. Crankcase breather.

 

[jcw]

Re: Project "walrus" Yam XS 750

Whoa! Glad it was just bent pegs and you are still intact!

You are never ever supposed to have oil in the intakes on a four stroke! glad you get to enjoy all that work you have done! I got sideswiped by a bitch on the phone in a tunnel today on the triumph chop, second ride of the year...
Gotta bend the pegs back, nothing worse gladly

 

[2_DONE_THE_TON]

David, glad you're ok after the crash! chicks on phones are one of the worst hazards on the roads these days. I almost got head on collided in my Car by one with my son in it, I had to go in the ditch, she didn't even look up and see she had crossed the yellow line completely into my lane.

roger that!
good data that youre fine!

Just ordered a crankcase breather filter, will take a while till its at my doorstep.

This weekend I will check further on the following points:

-strange wandering igntion point-->unmount ignition and check for points Nanno wrote above
-little oil is seeping out of the left side ignition cover
-on of the rear original blinkers are out of order-->checked all the connections and cables,seems to be an internal failure in the blinker...
-change the old bent gas cable (shorten the new one at about 1.6cm to fit the mikuni slingies)
-play around with the air screws on the carbies

Oh and before I forget, I ordered a conversion kit (2 petcocks and 1 right hand conversion kit) for my stock XS 750 tank so I can get rid of the stock petcocks which are prone to fail...they come off of a XS 650 and have the classic ON OFF AND RESERVE.

My RD will need some TLC too the next weeks so I guess my tiny workshop will be cramped as hell ;D

 

[2_DONE_THE_TON]

Just out of interest,what are guys running as crankcase breather filter, can´t really find something that suits...
Might just use a piece of hose but it will look like ish!

 

[datadavid]

Re: Project "walrus" Yam XS 750

i use a crankcase breather filter

 

[datadavid]

Re: Project "walrus" Yam XS 750

http://www.biltema.se/sv/Bil---MC/Bil-tillbehor/Tuning/Filter/Vevhusfilter-2000032870/

 

[2_DONE_THE_TON]

Re: Project "walrus" Yam XS 750

As a german speaker its a always interesting to see alignments in your language is it the same with you and german?

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[der_nanno]

Just as David said... Breather filter or in German "Motorentlüftungsfilter" - plenty of them about on ebay.

 

[2_DONE_THE_TON]

Re: Project "walrus" Yam XS 750

Just had a quick rideout again with the XS with freshly mounted breather filter.
I think I found the culprit for the burnt oil.
Looks like the left side (ignition side) cylinder foot gasket is leaking :-( and dripping on the exhaust...
Is there any way to fix this without pulling the motor?

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[Maritime]

You can try liquid gasket maker. clean the spot really well, smear the gasket maker in the seam and let it dry. it might be enough and it might not work, but if it does it will save a lot of work replacing the gasket.