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Post by bondekarlen on Jun 5, 2020 13:40:32 GMT 1
Hi all Im calling from Denmark, so please excuse for my english and maybe wrong spelling  I have bought a RD350R type 4CE year 1992 The bike was grounded for about 6-8 years. I can´t get it to run properly. I have done the following work on it.: New YPVS valves including all seal and bushes. Carbs ultra cleaned and new repairkit including: needle and nozzles-all size jets controlled and correct. Cylinder bored with new Prox pistons. New ignition coils-spark plugs NGK BR8ES - new caps 1K ohm. - new spark plug cables. New original Yamaha airfilter. And a lot of other stuffs, not related to the engine. The bike stand completely standard without any tuning/mods. The problem is when starting i must rev it to 3-4000 rpm to get it going, its like the more rpms the better(but i dont go high because of the new pistons) I work at an Authorized Yamaha dealer in sale and parts, but at the workshop we never see these old bikes any more, so when asking the mechanics there, they dont have an answer. They mean its about the ignition. When its cold its a little hard to start like its not getting fuel to both carburettors, but they have been checked several times, no fault there(apparantly) But when its warmed up for 1minute its going very well!!! Idle is perfect and i can rev it with out any hesitation and if i stop and restart i can do it with one hand. The problem shows when i put it in gear and starts driving. If i drive with 3-4000rpm in first and close the throttle and go down to maybe 2000rpm it can no longer go up and will stall, unless i pull in the clutch lever and rev it to 3-4000 rpm again. Carb settings are done and correct! Ypvs valve setting is checked and is correct. Does anyone have an idea of the solution? Looking foorward to hear from you. Kind greetings Jan Denmark |
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Post by marrcel on Jun 5, 2020 14:08:44 GMT 1
Do search on brass balls😉
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Post by midlifecrisisrd on Jun 5, 2020 14:54:28 GMT 1
Hopefully you didn't use a keyster kit
Personally I would clean and reuse the original jets, needles, airscrews and emulsion tubes
If the fuel levels seem ok then leave the pattern valves in
As for the starting you may have mixed the float bowls up
The LH (carb with choke knob) float bowl has a hole and choke jet in it. The other is blanked
This will give the same symptoms
Also make sure you have Refitted the choke link pipe between the carbs
Steve
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Post by Gitram on Jun 5, 2020 17:27:34 GMT 1
I've never ridden a powervalve but i think you would have to have more than 2000 revs to ride it and pull away without slipping the clutch, even in first
anyway, welcome to the forum
marti
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Post by bondekarlen on Jun 5, 2020 20:22:36 GMT 1
Do search on brass balls😉 marrcel i dont get your point? |
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Post by bondekarlen on Jun 5, 2020 20:32:36 GMT 1
Hopefully you didn't use a keyster kit Personally I would clean and reuse the original jets, needles, airscrews and emulsion tubes If the fuel levels seem ok then leave the pattern valves in As for the starting you may have mixed the float bowls up The LH (carb with choke knob) float bowl has a hole and choke jet in it. The other is blanked This will give the same symptoms Also make sure you have Refitted the choke link pipe between the carbs Steve We have now for more than 3 years used Keyster kits on our workshop, with good results. If i order Tourmax parts the mechanics will be very mad at me, they dont work, they say. The thing with the float bowl i didnt know, but was carefulle when i took them apart, i always separete the left and the right parts in their own box, before assembly. Anyway i will check it tomorrow, just in case.... The choke link, i guess you mean the little black tube 8-10 cm, its refitted? |
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Post by bondekarlen on Jun 5, 2020 20:33:46 GMT 1
I've never ridden a powervalve but i think you would have to have more than 2000 revs to ride it and pull away without slipping the clutch, even in first anyway, welcome to the forum marti Problem is , if i go below 2000 rpm, it will stall and engine shut down.(in 1st. gear) |
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Post by dusty350 on Jun 5, 2020 20:34:03 GMT 1
Hi, and welcome Marcel means the brass balls in the rear of the carbs;  20200101_161003 by dusty miller, on Flickr  20200101_104935 by dusty miller, on Flickr They block off a small passageway, and can get blocked with muck that doesn't always get shifted with an ultrasonic clean. If you partially drill through the ball and then wiggle it out, you can spray carb cleaner in the hole and see if it drains out - if not, it's blocked. You can buy a new 4.5mm brass ball in a pack off ebay to replace them afterwards. Dusty |
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Post by bondekarlen on Jun 5, 2020 20:37:05 GMT 1
Hi, and welcome Marcel means the brass balls in the rear of the carbs; 20200101_161003 by dusty miller, on Flickr 20200101_104935 by dusty miller, on Flickr They block off a small passageway, and can get blocked with muck that doesn't always get shifted with an ultrasonic clean. If you partially drill through the ball and then wiggle it out, you can spray carb cleaner in the hole and see if it drains out - if not, it's blocked. You can buy a new 4.5mm brass ball in a pack off ebay to replace them afterwards. Dusty Thats quite new for me, never heard about that before.(and im 65 years in 10 days). What happens if they are blocked? Whats the function of the passageway? |
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Post by midlifecrisisrd on Jun 5, 2020 20:43:01 GMT 1
The passageway is the air correction circuit for the main jet
If you look at the vent tube on the spigot on the side of each carb it leads to a passageway to vent the float bowl to the air
There is a small passageway off the passageway that feeds air via a small brass jet leading to the emulsion tube behind the brass ball
And yes I meant the rubber tube between the carbs
Steve
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Post by dusty350 on Jun 5, 2020 20:45:54 GMT 1
The balls hide part of the air correction circuit - there is a fine passageway behind the ball that leads to the emulsion tube, so if it's blocked you'll experience poor running. A proper clean with the balls removed may help, and then replace with either new balls, or some fit a grub screw for easier removing in the future. Or you could reuse the old balls as long as you haven't drilled all the way through them.
Dusty
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Post by dusty350 on Jun 5, 2020 20:46:34 GMT 1
Beat me to it Steve  Dusty |
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Post by bondekarlen on Jun 5, 2020 21:57:52 GMT 1
Thanks all, im really surprised for all the quick replies.
Great community!!!
I will return with updates when i have checked the passageway and if the float bowls shuld have been mixed.
I was pretty sure it was an ignition fault and was thinking of the CDI/pulse coil.
By the way any one who knows the gap between the coil and the rotor mark? on mine its 1,0mm
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Post by 17again on Jun 5, 2020 22:25:24 GMT 1
Hopefully you didn't use a keyster kit Personally I would clean and reuse the original jets, needles, airscrews and emulsion tubes If the fuel levels seem ok then leave the pattern valves in As for the starting you may have mixed the float bowls up The LH (carb with choke knob) float bowl has a hole and choke jet in it. The other is blanked This will give the same symptoms Also make sure you have Refitted the choke link pipe between the carbs Steve this comment worries me as i just fitted a keystar kit in my rg400. what is the problem with these the jets are wrong sizes?  sorry to hijack. i can start a new message or pm |
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Post by midlifecrisisrd on Jun 5, 2020 22:29:55 GMT 1
Hopefully you didn't use a keyster kit Personally I would clean and reuse the original jets, needles, airscrews and emulsion tubes If the fuel levels seem ok then leave the pattern valves in As for the starting you may have mixed the float bowls up The LH (carb with choke knob) float bowl has a hole and choke jet in it. The other is blanked This will give the same symptoms Also make sure you have Refitted the choke link pipe between the carbs Steve this comment worries me as i just fitted a keystar kit in my rg400. what is the problem with these the jets are wrong sizes? sorry to hijack. i can start a new message or pm They get some bad press from their rd kits I'm sure some must be ok Steve |
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Post by hoist1 on Jun 5, 2020 22:32:44 GMT 1
Hi all Im calling from Denmark, so please excuse for my english and maybe wrong spelling I have bought a RD350R type 4CE year 1992 The bike was grounded for about 6-8 years. I can´t get it to run properly. I have done the following work on it.: New YPVS valves including all seal and bushes. Carbs ultra cleaned and new repairkit including: needle and nozzles-all size jets controlled and correct. Cylinder bored with new Prox pistons. New ignition coils-spark plugs NGK BR8ES - new caps 1K ohm. - new spark plug cables. New original Yamaha airfilter. And a lot of other stuffs, not related to the engine. The bike stand completely standard without any tuning/mods. The problem is when starting i must rev it to 3-4000 rpm to get it going, its like the more rpms the better(but i dont go high because of the new pistons) I work at an Authorized Yamaha dealer in sale and parts, but at the workshop we never see these old bikes any more, so when asking the mechanics there, they dont have an answer. They mean its about the ignition. When its cold its a little hard to start like its not getting fuel to both carburettors, but they have been checked several times, no fault there(apparantly) But when its warmed up for 1minute its going very well!!! Idle is perfect and i can rev it with out any hesitation and if i stop and restart i can do it with one hand. The problem shows when i put it in gear and starts driving. If i drive with 3-4000rpm in first and close the throttle and go down to maybe 2000rpm it can no longer go up and will stall, unless i pull in the clutch lever and rev it to 3-4000 rpm again. Carb settings are done and correct! Ypvs valve setting is checked and is correct. Does anyone have an idea of the solution? Looking foorward to hear from you. Kind greetings Jan Denmark You mention warming it up for 1 minute, I would let it warm more. |
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Post by 17again on Jun 6, 2020 7:37:28 GMT 1
what size jets do you? and is the air filter new? standard?
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Post by bondekarlen on Jun 6, 2020 8:00:46 GMT 1
what size jets do you? and is the air filter new? standard? I use jets size 185 and 27,5 I have done a lot of research finding out what the different models use according to what Yamaha Motor says and i came up with this : 4L0 – 1982 137-14143-44-A0 220 - 22,5 31K – 1983 137-14143-48 240 - 22,5 57V – 1985 137-14143-48 240 - 22,5 1UA – 1986 137-14143-37 185 - 25 All later models up to the last "brazillian" from 1992 use 185 - 27,5 Except for the UK model that use 180 and is limited in the exhaust. |
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Post by bondekarlen on Jun 6, 2020 8:03:04 GMT 1
Hi all Im calling from Denmark, so please excuse for my english and maybe wrong spelling I have bought a RD350R type 4CE year 1992 The bike was grounded for about 6-8 years. I can´t get it to run properly. I have done the following work on it.: New YPVS valves including all seal and bushes. Carbs ultra cleaned and new repairkit including: needle and nozzles-all size jets controlled and correct. Cylinder bored with new Prox pistons. New ignition coils-spark plugs NGK BR8ES - new caps 1K ohm. - new spark plug cables. New original Yamaha airfilter. And a lot of other stuffs, not related to the engine. The bike stand completely standard without any tuning/mods. The problem is when starting i must rev it to 3-4000 rpm to get it going, its like the more rpms the better(but i dont go high because of the new pistons) I work at an Authorized Yamaha dealer in sale and parts, but at the workshop we never see these old bikes any more, so when asking the mechanics there, they dont have an answer. They mean its about the ignition. When its cold its a little hard to start like its not getting fuel to both carburettors, but they have been checked several times, no fault there(apparantly) But when its warmed up for 1minute its going very well!!! Idle is perfect and i can rev it with out any hesitation and if i stop and restart i can do it with one hand. The problem shows when i put it in gear and starts driving. If i drive with 3-4000rpm in first and close the throttle and go down to maybe 2000rpm it can no longer go up and will stall, unless i pull in the clutch lever and rev it to 3-4000 rpm again. Carb settings are done and correct! Ypvs valve setting is checked and is correct. Does anyone have an idea of the solution? Looking foorward to hear from you. Kind greetings Jan Denmark You mention warming it up for 1 minute, I would let it warm more. I didnt mean that the bike was warmed up after 1 minute, but it is idling fine after about 1 minute. Must be my bad use of the english language. |
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Post by Yogi on Jun 6, 2020 8:37:16 GMT 1
Just a thought 💭 you can put the carbs slides in the wrong carbs
Check the cutaways on the slides are at the back intake side
Also check for air leaks
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Post by bondekarlen on Jun 6, 2020 9:14:07 GMT 1
Just a thought 💭 you can put the carbs slides in the wrong carbs Check the cutaways on the slides are at the back intake side Also check for air leaks I will do that, the carb slides. No leaks, intake rubbers are new and is the airfilter and the clamps are all renewed. |
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Post by midlifecrisisrd on Jun 6, 2020 10:18:28 GMT 1
I thought all R 4ce models were restricted
They had a washer in the header and used different jetting
The pj was only a 25 I think as they were from the 250
I'd have a 210 main in that if the restrictor are removed
Try the air screws out 1/2 turn from closed
Then try 2 turns out and see if it helps
Also try the original pilots and air screws
Steve
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Post by bondekarlen on Jun 6, 2020 14:58:06 GMT 1
1st. update
The float bowl were mixed around.
I must have been like that when i purchased the bike, because i marked them so i would put them in the right side.
Så now my right float bowl is marked: left ;-)
I will now rem,ove the brass ball to see if anything is wrong there.
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Post by dusty350 on Jun 6, 2020 15:57:48 GMT 1
Try it with the float bowl swap first. Make 1 change at a time to help pinpoint the issue😉
Dusty🙂
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Post by bondekarlen on Jun 6, 2020 16:28:23 GMT 1
Try it with the float bowl swap first. Make 1 change at a time to help pinpoint the issue😉 Dusty🙂 Too late, i was thinking about it, but choose to do both. If the problem is solved i must live without knowing if it was the first or the other.  |
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Post by dusty350 on Jun 6, 2020 18:41:51 GMT 1
If it's sorted you wont care which was the issue ! Just get out and ride it Dusty |
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Post by bondekarlen on Jun 17, 2020 19:02:05 GMT 1
Update.
I have now done all the above.
The float bowl was mixed up ;-)
Now the bike starts very easy and i can start as normal.
Problem now is the goes very uneven, (dont know what english word to use) its constant 4000rpm or 5000 or 6000 same problem. its like maybe its misfiring very little.
I can ride the bike as an example with 60mph but a little "shaky" in the engine.
If you know what i mean please feel free to comment.
The idle is perfect!
When looking at the spark plugs after a trip for 10 miles they get too much fuel(is my guess).
I have tried to put
all the old stuff back in the carburettors, same problem.
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Post by midlifecrisisrd on Jun 17, 2020 19:31:49 GMT 1
Try checking the fuel level, not the float height
Take a bit of clear tube and attach it to the overflow spigots on the bottom each float bowl and tie up to the top of the carb
Then open the bowl drain screws and see how far up the tube the fuel goes
Fuel level is 26mm I think which is around the gasket level
Check for any irregularities
If the fuel level is too high it tends to run into the engine instead of out the overflow
Steve
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Post by Shytalk on Jun 17, 2020 20:10:29 GMT 1
Thanks all, im really surprised for all the quick replies. Great community!!! By the way any one who knows the gap between the coil and the rotor mark? on mine its 1,0mm Between 0.6mm and 0.8mm |
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