jimmyg
Drag-strip hero
Posts: 231
|
Post by jimmyg on Aug 17, 2021 22:42:38 GMT 1
Hi Guys i have a problem with my ypvs cutting out under load, runs fine revs up perfect, the second you pull away just cuts straight out, restarts easy but will not take any load,The carbs have been striped and cleaned,I'm thinking it's electrical, has new banshee coils/plug caps and plugs,checked the pulse coil that's 117.9 ohms Haynes says 117 ohms,checked the source coils high speed reads 4.3 ohms Haynes says 4.1 ohms, low speed reads 148.5 ohms Haynes says 113 ohms. Is that far enough out to be a problem or should I be looking at the Cdi? Cheers jimmy
|
|
|
Post by oldbritguy on Aug 17, 2021 23:17:21 GMT 1
If it starts no probs immediately after cutting out and revs fine while stationary then may well be electrical. Check your earth connection from the motor to the frame/loom and also coils to frame. I had a similar problem years ago and the engine was moving I the mounts. The twisting motion of the engine in the frame as the bike moved off had broken the earth wire and the bike cut out. Just a suggestion for a start. I am sure others will chip in.
|
|
|
Post by stusco on Aug 18, 2021 7:59:21 GMT 1
Try adjusting the airscrew it might be the pilots
|
|
|
Post by midlifecrisisrd on Aug 18, 2021 8:28:23 GMT 1
Few things spring to mind
Firstly which ypvs, which carbs, how/who cleaned them and is the bike standard
First thing to try is pull the choke out then try to pull away
Way lean for one reason or another will cause this but your winding reading does look suspicious
Steve
|
|
jimmyg
Drag-strip hero
Posts: 231
|
Post by jimmyg on Aug 18, 2021 22:17:49 GMT 1
Should have put its a 31k N1 with 1ua 10 carbs, I Belive ithe motors standard with f2 pipes I striped the carbs and cleaned with carb cleaner and compressed air, new needle valves and gaskets, set to 21mm till it just touchs the seat but not compressed the spring loaded bit,all jets and settings as the Haynes manual I tried the choke but that made no difference, still died when loaded I am pretty sure the earths ok but it's a easy enough job to run a couple of new ones Will wind the air screws in and give that a go when I get a chance Cheers jimmy
|
|
|
Post by midlifecrisisrd on Aug 18, 2021 22:22:26 GMT 1
When you cleaned the carbs did you remove the emulsion tubes and clean the air jet behind the brass ball
The low speed winding is a concern
Can you try pulling away slipping the clutch and holding 6k revs 😬
Steve
|
|
jimmyg
Drag-strip hero
Posts: 231
|
Post by jimmyg on Aug 18, 2021 22:51:31 GMT 1
The emulsion tubes were removed and cleaned, I didn't take the brass balls out, I can try and pull away at 6k and see what happens 😂 Cheers Jimmy
|
|
|
Post by chrisg on Aug 18, 2021 22:58:54 GMT 1
Should have put its a 31k N1 with 1ua 10 carbs, I Belive ithe motors standard with f2 pipes I striped the carbs and cleaned with carb cleaner and compressed air, new needle valves and gaskets, set to 21mm till it just touchs the seat but not compressed the spring loaded bit,all jets and settings as the Haynes manual I tried the choke but that made no difference, still died when loaded I am pretty sure the earths ok but it's a easy enough job to run a couple of new ones Will wind the air screws in and give that a go when I get a chance Cheers jimmy Has this issue just started after cleaning the carbs?
|
|
jimmyg
Drag-strip hero
Posts: 231
|
Post by jimmyg on Aug 18, 2021 23:54:47 GMT 1
I don't know, as when I got the bike it was not in a safe state to ride, so after doing the brakes/suspension etc it's the first chance I have had to ride it,test ride before booking the mot Cheers Jimmy
|
|
|
Post by JonW on Aug 19, 2021 2:22:25 GMT 1
A lot of these type of faults are down to the stator so if you can swap it out and try another i would. If its an early ypvs CDI it could be that too, but Im thinking stator.
General bike related silly thought; youre not grounding out the kill switch when letting out the clutch somehow? side stand switch issue etc.
Failing that blocked mains? I starts and runs well of pilots, but not mains... how about a forgotten rag in the airbox? A mate once asked me to diagnose a problem for him and i found what was left of a rag half blocking the intake lol
|
|
|
Post by abar121 on Aug 19, 2021 10:23:39 GMT 1
Did you use geniune needles from Allens etc? Fuel tap in prime position and the fuel runs out well?
The Low speed winding looks a little off.
You could try the standard coils if you have them. Make sure you don't use resistor caps and plugs. One or the other.
Check for loose fuses, re-seat them all and clean out all of the connectors and reseat. Add an earth point or two.
|
|
|
Post by Yogi on Aug 19, 2021 15:06:28 GMT 1
As Jon said the side stand switch could cause this problem if your using an f2 /n2 or r loom As soon as you put it in gear it earths out through the neutral switch and kills it
Matt 🐻
|
|
jimmyg
Drag-strip hero
Posts: 231
|
Post by jimmyg on Aug 20, 2021 7:42:46 GMT 1
Cheers guys, that give me pleanty to check and try this weekend, is there anything I need to watch out for with a new stator,is there any that will not fit or are they all the same? Is it worth trying a second hand one or am I just wasting time and money? Cheers Jimmy
|
|
|
Post by marrcel on Aug 20, 2021 9:11:28 GMT 1
Lots of electronic related tips. When there is load issue, i think fuel. Check fuel cap breather, tap, floath valves. I ditched the vacuum operated tap. It is a pita. Take a 8mm tap with proper fuel lines. Never ever you want it to burn lean.
|
|
jimmyg
Drag-strip hero
Posts: 231
|
Post by jimmyg on Aug 22, 2021 18:18:15 GMT 1
Well I spent a few hours on it today, checked the fuses,broke 2 of the holders so cut the box out and put waterproof blade holders in, ran a extra earth for the coil mount and motor, checked the fuel tap and fuel level in the bowls all ok,so gave it a go,seamed ok till it got hot then cut out,started up but just didn't want to pull away under load, so rolling slowly I thought of what Steve surgested and got it to just about 6k and dumped the clutch 😂 Didn't cut out or bog down then 😄 Took off like a whippet and pulled strong So what's this mean? Cheers Jimmy
|
|
|
Post by midlifecrisisrd on Aug 22, 2021 20:13:45 GMT 1
If it was running ok till hot then won't run low down it sounds like lo speed windings, especially if the readings are dodgy
Steve
|
|
jimmyg
Drag-strip hero
Posts: 231
|
Post by jimmyg on Aug 22, 2021 22:14:04 GMT 1
Cheers Steve will get a new one and see what happens
|
|
|
Post by jelstar on Mar 14, 2022 19:51:55 GMT 1
Hi Jimmy,
Did you get this problem solved? I’m having exactly the same symptoms on my YPVS
|
|
jimmyg
Drag-strip hero
Posts: 231
|
Post by jimmyg on Mar 15, 2022 0:31:01 GMT 1
Hi Jelstar Still slowly working on it I changed the stator and that made no difference, striped the carbs inc removing the ball no difference,added extra earth points etc and still the same 🙄 I am just finishing up fitting a zeetronic so hope to try it this weekend Cheers jimmy
|
|
|
Post by jelstar on Mar 15, 2022 10:53:52 GMT 1
Ah ok. I was convinced it was the low speed windings on my stator as pointed out in the above thread. Exactly the same symptoms as you have had. Bike doesn’t pull under load in the lower rev range but if you do a racing style start at say 6000rpm it takes off like a scalded cat with no issues until the revs drop to the 2000-4000rpm ish range then it feels like the ignition has been cut. Plugs are wet if you immediately take them out so it’s getting fuel. Carbs are balanced and all jets and passage ways clear. Fuel is flowing correctly from tank. Bike is bog std F2 model and the windings on low speed and high speed check out within spec at 143 and 4.4 ohms. Checked all connections and visible wiring for any shorts, ran the bike without tank fitted in the dark to check for any short circuits and all good.
Last used the bike all last season and never missed a beat, ran it up in neutral a few times over winter till warm. Went to go out on it this last week and that’s when this problem arose unexpectedly.
|
|
|
Post by jelstar on Mar 15, 2022 10:56:17 GMT 1
Oh and I’ve ruled out the side stand switch by temporarily bypassing it.
Still not pulling under load in low rpms.
|
|
|
Post by midlifecrisisrd on Mar 15, 2022 11:34:57 GMT 1
If it's pulling at hi revs but not low it can only be things that differ between those revs
Windings Jetting An air leak (small leak will have more effect at low revs)
Pull the choke on when trying the 2-4k revs and see how it affects it
Steve
|
|
|
Post by jelstar on Mar 15, 2022 13:02:18 GMT 1
Yes I meant to mention I’d tried the choke on/off and it makes no difference.
Also measured the low speed windings whilst bike cold 11C and when warmed up on the gauge and cases warmed through. Readings still within spec.
Doesn’t feel like an air leak would feel, feels like the ignition has been cut.
I’m going to send the stator away to be professionally checked just to rule that out of the equation and then go from there.
I initially thought pilot jets blocked as I’ve experienced that plenty of times but I’ve stripped the carbs twice to double check everything there and all good.
So bit more digging required but thanks for your suggestions it certainly pays to be methodical.
The bike starts very easily hot or cold, revs freely and ticks over nicely in neutral but it’s when you try and do a regular type pull away that it just won’t pull under load. Higher revs, no problem.
Any other suggestions gratefully received but I will be without the stator while it’s checked over.
|
|
|
Post by jelstar on Mar 15, 2022 13:06:19 GMT 1
steveWhen I say the choke makes no difference, I mean you can feel the mixture richen but it makes no difference to the not pulling under load situation
|
|
|
Post by midlifecrisisrd on Mar 15, 2022 13:11:40 GMT 1
Not really pointing to blocked pilots or air leak then 🤔
What year ypvs is it?
Steve
|
|
|
Post by jelstar on Mar 15, 2022 15:17:30 GMT 1
87/88 F2 1WT Bog standard spec
|
|
|
Post by jelstar on Mar 15, 2022 15:35:15 GMT 1
Meant to add compression checks out on both cylinders and power valve fully operational.
And no rag in the airbox........lol
|
|
|
Post by midlifecrisisrd on Mar 15, 2022 17:26:06 GMT 1
1ua cdi usually not problematic
Can you try a different pair of carbs (know it's difficult if you don't have a second bike)
Steve
|
|
|
Post by jelstar on Mar 15, 2022 20:42:58 GMT 1
Hi Steve, No I don’t have any spare carbs to swap out and try unfortunately. Does feel electrical to me but not ruling out other things, best to stay open minded on these things.
As it was performing faultlessly when last ridden I think it most likely that electrical gremlins are at play. Had a stator fail for no particular reason before on a different bike.
I was convinced the slow winding reading would measure out of spec as all the symptoms point to that but they also did with Jimmy’s bike and his new stator made no difference on his bike.
Need to drink plenty of tea, have lots of time to think and work methodically through it. Once the stator has been properly checked out I’ll take it from there. A bit annoying especially with the good weather arriving just now.
Thanks again for the pointers on things to check, really helps to keep motivated.
|
|
|
Post by headcoats on Mar 15, 2022 20:46:23 GMT 1
Are the reeds OK
|
|