Project "walrus" Yam XS 750

Re: Project "walrus" Yam XS 750

Hi Ryan
Without having a good power supply (battery at 13v), you are not going to get any reliable results. Start with the basics and get a good battery, then you can start your fault finding.
Regards
Tim

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Re: Project "walrus" Yam XS 750

My regulator unit is sending 18-19 volts at 3k rpm with a busted battery. I think at least one cell is dead because even if it sits at 12.7 it drops to 6 volts immediately when i engage the starter.. running these systems with broken batteries seems to overload the charging circuits.
About your electrical troubles, go through every single connection and clean up All grounds, i bet you will have nice charging voltage along with a good battery. Also its a good thing that only 1 cyl has no spark, just need to check that coil and all leads. On my previous 750 all 3 pickup leads shorted on each other so all cylinders were firing simultaneously!
Bike was still rideable up till 5k rpm when all hell broke loose with that fixed i only needed to repair the advancer mechanism and it was flying!
 
Re: Project "walrus" Yam XS 750

Thanks guys for your help,I will get a new battery as soon as I habe the funds,next weekend I will try it with a car battery.

Do you have any recommendations on batteries?
I know that I need cold cranking power and Ah...which types would you recommend?
Dont want to buy a lead battery..the bike will sit for a few months this winter so I need to keep this in mind.

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Hi Ryan
Most batteries these days are reliable just a matter of what what you want to spend!!!
On the XS750 I am running a gel, 240 CCA and it is OK - cannot crank the engine when hot (well lubed hot pistons have higher compression, I think) but good at cold.
Husaberg is running a 210 CCA lithium Ion, very good but does loose charge after a month sitting.
TT250 - no battery at all just runs straight off the alternator - bloody reliable as it only has a kick start!!!!!
IT200 - 6V lead acid - difficult to get and a pain in the.

XS896 I am thinking a 240CCA lithium due to their small size. Probably will mainly kick start.

Don't think it is going to make any difference over winter which battery you get - they all need some trickle charging over winter.

Dave 19V from your regulator is way too high and will fry any battery.
Cheers
Tim
 
XS750AU said:
Hi Ryan
Most batteries these days are reliable just a matter of what what you want to spend!!!
On the XS750 I am running a gel, 240 CCA and it is OK - cannot crank the engine when hot (well lubed hot pistons have higher compression, I think) but good at cold.
Husaberg is running a 210 CCA lithium Ion, very good but does loose charge after a month sitting.
TT250 - no battery at all just runs straight off the alternator - bloody reliable as it only has a kick start!!!!!
IT200 - 6V lead acid - difficult to get and a pain in the.

XS896 I am thinking a 240CCA lithium due to their small size. Probably will mainly kick start.

Don't think it is going to make any difference over winter which battery you get - they all need some trickle charging over winter.

Dave 19V from your regulator is way too high and will fry any battery.
Cheers
Tim
Click to expand...

thanks tim for the insight, would you recommend running a bigger battery than the 240cca to cure the cranking issue?how do you start your engine when hot now?
 
Not sure if a higher CCA would help my issue. From my understanding a higher CCA allows you to crank for a longer time. For me, when the engine is cold, it will crank it for a reasonable period. When hot, remember the battery is warm and absolutely fully charged and it will not turn one revolution! Wait 10 minutes and it will crank and start??? So when I need to start with a fresh hot engine I use the kick starter. My bike is always easier to start with the kick starter.
I chose the 240CCA as it was a little smaller and lighter. For me I quite like the look on peoples faces when you kick start a full sized road bike.
Sorry to say that batteries really do follow the rule - to more you pay the better the performance.
Cheers
Tim.
 
Re: Project "walrus" Yam XS 750



XS750AU said:
Hi Ryan
Most batteries these days are reliable just a matter of what what you want to spend!!!
On the XS750 I am running a gel, 240 CCA and it is OK - cannot crank the engine when hot (well lubed hot pistons have higher compression, I think) but good at cold.
Husaberg is running a 210 CCA lithium Ion, very good but does loose charge after a month sitting.
TT250 - no battery at all just runs straight off the alternator - bloody reliable as it only has a kick start!!!!!
IT200 - 6V lead acid - difficult to get and a pain in the.

XS896 I am thinking a 240CCA lithium due to their small size. Probably will mainly kick start.

Don't think it is going to make any difference over winter which battery you get - they all need some trickle charging over winter.

Dave 19V from your regulator is way too high and will fry any battery.
Cheers
Tim
Click to expand...

Yea i know, cant really figure out why a brand new electrosport reg/rec would do that, except because of a broken battery.. my 30+ year old regulator does the job perfectly. Something to think about.. will try with a new battery.
 
Yep I had the same experience. I bought a new rectifier/regulator when I had my charging issues. The auto electrician went back to the original OEM unit as in his opinion the OEM unit had much better quality diodes . The modern "replacement" units use Chinese components.
My system is working well with the original OEM unit.
 
I use a sealed AGM 200 CCA, plenty to turn the motor over cold to burn up your starter. They say these are plug and play but I still gave it a bump with 10 amps for several hours, the battery voltage should be 12.5-13 sitting. I'm seeing 14+ above 2K rpms with the charge system.
What is your key on/starter draw?

And yes, these bikes are easy to kick over if you have enough voltage to make good coil spark. I've build a high comp 2t 70 cc moped that was more difficult to kick, but the lever size obviously played a factor.
 
Hi guys!

So I retested my Battery once again yesterday, made a little video that shows cold, starter draw and when the engine is cranked over.

VIDEO https://www.youtube.com/watch?v=fQ2Bu1-Wgzc

I guess I need to test that thing with a car battery to make sure it really gets enough voltage, no budget at the moment for a new battery.

As for the spark issue, i dont really think that a weak battery can cause 1 cylinder to have zero spark or can this be caused be the weak battery?

Thought about swapping the wiring of Cylinder 2 and 3 coils over to Cylinder 1 to check if the problem is the CDI box...would you try that?

thanks!
 
Hi Ryan
Your video shows exactly the same sort of readings I was getting with a non working charging system and a spent battery. A healthy battery should be much closer to 13 volts. My bike would start and run though, but very rough as it was dropping spark on cylinder #1.
Assume you have fitted the new carbi boots and the are no vaccum leaks? The vacuum ports for the petcocks and the centre cylinder are blocked. In my excitement I have sometimes forgotten to block the vacuum ports!
With your spark, if 2/3 cylinders have spark and share the CDI unit then I would investigate the components unique to the cylinder without spark, starting from the plug and working back.
Good luck
Tim
 
Its aaaaliiiiive!!

Had some time today to investigate.
Unscrewed the sparck plug cable at cylinder 1 took 2cm of and reassembled....i got spark...then put the tank back on started that damn thing :-)
It runs really rough.i need to fas it to keep it alive,no idle,in the beginning only cyl 3 got hot the other ones were cold...got a little brake cleaner into 1 and 2 and got them running too...
I used the 'old' battery (already have a new one charging).
Cold 12.4 volts,starting it went down to 11 volts when I revved the engine it got up again to 12.2...thats not enough?
could the dead battery cause this bad idling issue?

Really intense popping from the exhaust and carbs (no air filterd yet).

Will post a video tomorrow!
 
Re: Project "walrus" Yam XS 750

Well done.
Definately not charging, and the low battery can affect the running. Try tomorrow with new battery. You need to test the alternator coils with your multimeter to see if OK.
Popping could be air leaks on carbi side. Sounds like carbies need cleaning with carbi cleaner NOT brake cleaner.
Major step ahead, well done.
Cheers
Tim

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Re: Project "walrus" Yam XS 750

XS750AU said:
Well done.
Definately not charging, and the low battery can affect the running. Try tomorrow with new battery. You need to test the alternator coils with your multimeter to see if OK.
Popping could be air leaks on carbi side. Sounds like carbies need cleaning with carbi cleaner NOT brake cleaner.
Major step ahead, well done.
Cheers
Tim

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Click to expand...

Here are three videos showing my efforts to start the lady.I tried tried to adjust the mixture screws (from Video 1 to Video 3 i´m going in with the screw,cuz it was popping like crazy, thought it was getting too much gas).

https://www.youtube.com/watch?v=ixEPmk-s7qo

https://www.youtube.com/watch?v=qbQmE898vlA

https://www.youtube.com/watch?v=a8oPtxlb9CY
 
Re: Project "walrus" Yam XS 750

Screws should be around 2.5 out. If they are, then it is something else. Can you post a photo of the carbies looking from the top towards the cylinders, include the boots and cylinder in shot.
Tim

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Re: Project "walrus" Yam XS 750

XS750AU said:
Screws should be around 2.5 out. If they are, then it is something else. Can you post a photo of the carbies looking from the top towards the cylinders, include the boots and cylinder in shot.
Tim

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Click to expand...

thanks!will do when I´m back on the bike!

The middle carb boot inlet is blocked with a rubber thing, boot of Cylinder number 1 and 3 have a hose going to the petcock.
When I will run pods I guess I will need to block all 3 of these dont I?
 
Re: Project "walrus" Yam XS 750

Yes that answers my question. Just make sure the hoses are not leaking.
Could not hear the videos too well as I am out on date night.

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Yes agree with Nano about getting the pods or airbox on.
It does sound like it is lean and when you open the throttle it dies rather than accelerate. That means the fuel is not getting through. Clean clean clean those carbies with carbi cleaner. You must be able to see through all the jets. Check that the diaphragms are OK and the slides are raising and lowering.
Cheers
Tim
 
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