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Still no joy with my XVS


Thunderchild
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are both exhausts getting hot...yeah its a dumb question but hey!

Just checked, they are both getting hot, BUT, the back cylinder pipe you can barely touch at the top, whereas the front cylinder pipe you can grab hold of (despite being hot).

Does that mean the front cylinder is not firing properly?

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Yeah, I did actually reach around the covers to get a proper feel. The top pipe nearly burnt my hand off whilst the front, lower pipe was warm but as I said, I could hold.

So what next? Could this now be a CDI unit issue?

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dunno but at least you have a point of reference now eh?

I am cautious about suggesting you shell out on another CDI for obvious reasons!

have you tried new plugs yet?

have you looked for any tests for the ignition coil in the manual?

its a single carb isnt it so it's beginning to look like it might not be carb / fuel related

what do you mean the top pipe and the lower pipe?? I assume you would touch both pipes at the headers near to the cylinder heads!

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I am cautious about suggesting you shell out on another CDI for obvious reasons!

I found this thread by DE51GNZ which I will use to have a look at mine.

have you tried new plugs yet?

Second set, both have carbon deposits.

have you looked for any tests for the ignition coil in the manual?

I was looking at the electrics earlier in the service manual to see if there was anything else to check.

its a single carb isnt it so it's beginning to look like it might not be carb / fuel related

Yep, single carb, cleaned and checked twice now, so can probably rule that out.

what do you mean the top pipe and the lower pipe?? I assume you would touch both pipes at the headers near to the cylinder heads!

I was looking at my pic when I wrote that as a point of reference for you. Top pipe meant back cylinder, lower pipe was the front cylinder. I felt both up near the cylinder for each and behind the decorative/protective covers.

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Paul/Airhead thanks for getting back,

I've just checked the new plugs again, they both have very heavy black carbonisation (dry), on them. Could this be a weak ignition or do I need a new air filter instead of just cleaning it?

carbonised plugs = rich mixture, if you are in doubt about your ignition timing it may be best to refer to your haynes for correct timing

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since the rear cylinder seems to be the OK one, how about running the bike on the rear and checking for spark at the front

I've just had another look at her. I tested both plugs and they both bridge a good 10mm with a blue/white spark. I then left her running for a while and did the 'wet rag' test on both pipes up at the cylinder head. They both passed with a clear 'hiss', so I'm guessing that's another tick off the list.

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She doesn't cut out whilst idling, but will cut out within 200 yards once you stop the throttle.

Please explain this further

Do you mean the bike stop running? As your coasting with the bike in gear?

When you cleaned the carb did you pull the imlsuon tube out?Might have some of the holes pluged and the fuel is not mixing with enough air .Try the old sock trick rev the bike up and kill it by blocking all air from getting in the carb with a rag the eng acts like a big vacume and will suck any small stuff hidden in the carb

The rich mixtuer causing the dark carbon build up on the plugs is the key to this problem.

Can you get your hands on a timing light? I would check it just to be certian

I would also dump the gas just to be sure you can always use it later if not the problem

Will the bike rev up just stiitng not riding it? The computer maps the ign in 3d rpm load(speed) + throttle position.=ignition timing

How much voltage is getting to the tps with the bike running it should be 4-6 volts .If not the cdi is nfg

Also if you test the Tps signal at the puter does it sweep close to the same values as at the plug might have a wire rubed through to ground/broken

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She doesn't cut out whilst idling, but will cut out within 200 yards once you stop the throttle.

Please explain this further

Do you mean the bike stop running? As your coasting with the bike in gear?

She will happily sit at idle with no problems, but will cut out when you engage gear.

I can get up to 2nd (15/20mph), before she bogs. Further throttle doesn't do anything.

If I then start to slow or tap down to 1st, she will cut out completely.

She then has to be started several times before she catches (still in 1st gear with clutch pulled in).

When you cleaned the carb did you pull the imlsuon tube out?Might have some of the holes pluged and the fuel is not mixing with enough air .Try the old sock trick rev the bike up and kill it by blocking all air from getting in the carb with a rag the eng acts like a big vacume and will suck any small stuff hidden in the carb

I didn't pull out the emulsion tube but did blow carb cleaner through the air ports. The holes on the tube were not visibly blocked on inspection.

The rich mixtuer causing the dark carbon build up on the plugs is the key to this problem.

Agreed, but I'm running out of options atm.

Can you get your hands on a timing light? I would check it just to be certian

I'll see if I can borrow one.

Will the bike rev up just stiitng not riding it? The computer maps the ign in 3d rpm load(speed) + throttle position.=ignition timing

She will rev in neutral, but seems to bog at about quarter throttle (sometimes), but other times fine. If she does bog in neutral whilst revving, she will generally then cut out.

How much voltage is getting to the tps with the bike running it should be 4-6 volts .If not the cdi is nfg

5.30

Also if you test the Tps signal at the puter does it sweep close to the same values as at the plug might have a wire rubed through to ground/broken

Not checked this but will go have a look. I'm going to have a look at the CDI whilst I'm there.

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I have to say having read this thread and the manual...I'm having difficulty understanding anything about your TPS findings

blue and black = 5300 Ohms...is that what you said TC in post #8

, because next minute I see you referring to 5.3 volts in post #31

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Correct on both.

TPS resistance (disconnected) was 5.3 kOhms (5300 Ohms) on blue/black wires (multimeter set to 20k ohms).

TPS operating voltage (running) was 5,3 volts. (using two paper clips poked into rear of connector and multimeter set to 20 DCV).

TPS idling voltage (running) was (I think), 0.62 volts to (unknown ?).

Didn't have time to open throttle and check as it started raining heavy.

Have I done it wrong?

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not sure about all the voltage readings...where did that come from? ...I didnt any of that in the service manual checks

However now you have confirmed 5300 Ohms maximum resistance...

From manual

If the maximum resistance = 5.3 kW, then the

throttle position sensor’s maximum resistance

when the throttle is fully closed should be:

5.3 kW (0.13 0.15) = 689 to 795 W

Lift the carburetor assembly slightly out of the

intake manifolds.

Loosen the throttle position sensor screws 4 .

Connect the pocket tester (W 100) to the

throttle position sensor.

Positive tester probe _ yellow terminal 3

Negative tester probe _ black terminal 2

e. Adjust the throttle position sensor angle so

that the measured resistance is within the

specified range.

Throttle position sensor resistance

689 795 W

(yellow – black terminal)

After adjusting the throttle position sensor

angle, tighten the throttle position sensor

screws.

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Just to clear it up Air/TC the tps must recive 4-6 volts from the puter to send a signal back to the puter

Yep done wrong just unplug and check voltage. to the tps at idle.

The tps will only let as much voltage through as it wants based on how far the throttle is open.Hence the term VARIABLE resistor.

NOTE Tps min ohms reading must be set with the throttle plate fully closed by turning the idle screw full out (not removed but so it not holding the plate open)

Then you can reset the idle

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I hate to say this but if the tps is unpluged and it still wont run semi right it's realy looking like the puter is shot. esp after I reread you post about it take several attempts to restart after stalling. Its showing all the same symptoms as my rd 350

The puter is able to map the ign without the tps just not as well.

Just for the hell of it I just went out and unpluged mine and the bike runs fine soggy but still revs out

Try adjusting the TPS to spec and check it at the puter for the same readings......... check the pick up coil at the puter plug.... and if no fixie......... bite the bullet and put a puter on

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I'll give it all a go tomorrow and see what's happening.

If it does turn out to be the CDI, I'll use DE51GNZ guide and see if I can repair it before paying out for a new one. Electronics I can do, engines I'm still learning about.

Thanks for all the help so far, it has been appreciated and I've learnt sh*t loads so far :hyper:

I'll keep you posted.

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I read that as well great info unfortunatly most are burried in a gel and you have to soak them in ?? forgot what it is... to even get to the board. But I'm sorry to say it will be in the 8 bit processor or mabey you'll get lucky and find an poor connection :hyper: ..so unless you plan on writing the whole program your probably looking at new or used.

But let us all know I'll be watching

Phil

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