mech73
L plate rider.
Posts: 45
|
Post by mech73 on Sept 7, 2016 23:06:39 GMT 1
I don't remember the Gitane, they were very rare and I'm not sure I've ever seen one. There were a few AJW greyhounds about (similar to the Gitane) as Chris Kingsland used to sell them in Mkt Rasen.
After the Tiger Cross broke one too many times I sold it and bought a fizzy from another Scothern lad -Douglas Portsmouth. I then moved onto bigger bikes - RD200, RD350, KH250 and a few others before leaving the area.
Back to the present Rd350LC F2 - I've done a bit tonight and checked the timing with a dial gauge and strobe. At tick over the pointer sits midway between the two flywheel timing marks, which the dial gauge shows is about 1.65mm BTDC. A few sums show that to be about 18 degrees. Which is pretty close to where the spec says it should be (17 degrees). It doesn't appear to be adjustable.
A very quick check with the motor running, showed an initial fairly steep advance, followed by a gradual retard, which again appears correct. I didn't want to make too much noise for too long late at night, so didn't measure the full advance or check the revs that accurately. I may do that at the weekend.
I also only checked the left side cylinder, as my dial gauge wouldn't fit the right side. It clashed with the power valve servo motor, so I need to make a slightly shorter holder out of an old spark plug. Again a job for the weekend. So nothing yet to suggest an issue timing wise, but there's a bit more work to do to make certain.
|
|
|
Post by budgie on Sept 8, 2016 7:29:14 GMT 1
Wow, Dougie Portsmouth and Chris Kingsland... All great memories.....
I too did a bit more to my N2 last night.... I changed the needles, lowered them one groove to second from top as advised in the manual, and ran it, mine seems much cleaner, although my test trip was curtailed on a quick ride out as it decided to strip an exhaust stud out of the barrel in Faldingworth so a noisy trip home was taken, stripped to find threads long gone along with stud, so will now have to install a helicoil and rebuild, was hoping to plug chop it at that point, but not enough miles on it to know....another day..... Sounds like your making progress, the timing is fixed, so unless the CDI is playing up , I may have a good spare I could lend you if required... But would need your numbers off it as there are different type....
Gavin
|
|
mech73
L plate rider.
Posts: 45
|
Post by mech73 on Sept 8, 2016 22:22:00 GMT 1
The stripped thread is a bit of a pain. Can it be helicoiled done in situ?
I don't think I have a timing problem, but I'll check The advance at different revs over the weekend to make sure it approximately matches the plot in the manual.
I've also got some caustic soda for the exhausts. I last tried this method about 40 years ago at a mates house. We initially mixed it in his mothers aluminium measuring jug with interesting results!! Eventually we got some in the silencer, but it didn't appear to do much and the carbon was eventually cleared using a oxy acetyline cutting torch. We almost certainly didn't wait long enough for the caustic soda to work. I've been told it can take up to a week to be effective, but I'm still a bit sceptical as to whether it works at all. I know it's a powerful degreaser and believe it will dissolve any oily sludge, but hard dry carbon (soot) is fairly inert and doesn't react that easily.
I've mixed up a small amount of caustic soda so far and a fairly oily and sooted up fizzy baffle is soaking, so I'll see what happens. I hope it works as I'm not that keen on taking a blow lamp to my original F2 exhausts, which still look almost like new.
|
|
|
Post by steven on Sept 9, 2016 3:05:29 GMT 1
|
|
mech73
L plate rider.
Posts: 45
|
Post by mech73 on Sept 9, 2016 17:09:19 GMT 1
Just read that from beginning to end very useful. The mix I've used for the fizzy baffle is about half the strength that you used at 100g per litre. That is what is suggested on the container for unblocking drains. Despite the relatively weak mix it does seem to be working. When I had a look this morning after 12 hours there wasn't much effect, but a few hours later some clean metal is appearing. Whilst the exhausts are still on the bike I've had a further look at the timing. I marked the flywheel at 0,5,10,15,20,25 and 30 degrees from tdc and then used a strobe to observe the timing at different rpm. It's quite difficult to hold a constant speed at high revs especially, but these are my results. Tickover - 18 degrees 4000 rpm - 28 degrees (full advance) 6000 rpm - 25 degrees 7000 rpm - 22 degrees 8000 rpm - 18 degrees 9000 rpm - 15 degrees 10000rpm - 12 degrees I'm fairly confident in the tickover and maximum advance, but there will be some error on the revs. So this looks about 1 degree advanced compared to spec and the shape is almost identical to the plot in the 1983 31k manual. I've seen it suggested that the F2 ignition retards the ignition sooner than the earlier YPVS which stops it revving so high, but this suggests not, unless the difference is very subtle. So far this is all based on the left cylinder. I will check the right cylinder as well, but first need to make a new dial gauge adapter.
|
|
|
Post by midlifecrisisrd on Sept 9, 2016 17:35:13 GMT 1
Think your timing is fine then
Think the biggest limiting factor on the f2 peak power is the pipes and the fact the power valves don't fully open till 10200 which seems strange on a bike that hits peak power at 8500
Steve
|
|
mech73
L plate rider.
Posts: 45
|
Post by mech73 on Sept 10, 2016 13:37:54 GMT 1
The dial gauge adapter on the left is one I made in the 70's whilst an apprentice. It's worked ok in every bike I've owned so far, but didn't fit in the RD350 right pot because it was too long and the dial gauge fouled on the power valve servo unit. So I've just used the Myford to make the shorter one on the right. Both are fitted in old spark plug bodies with the porcelain smashed out. One day I'll have a go at thread cutting and make one from solid. New one just fits. Flywheel marked up on bit of duct tape. When checked with the strobe the timing was exactly the same as the left pot at 18 degrees on tickover, with a maximium advance of 28 degrees. I guess that means at least the crank isn't twisted I had a look at the power valve operation. It's not that easy to look at it and the rev counter at the same time, best estimate is that it starts to open about 6000 rpm and is nearly (but not quite) fully open at 9000 rpm. They do fully open but I didn't actually catch exactly what the rpm was, but was probably about 10000. That seems to agree with what Steve suggested in the previous post. When I get the exhausts off I'll check that both power valves are in the correct orientation and rotate properly together. Next thing to try before removing the exhausts is removing the snorkel or maybe even the whole lid from the air box. If that improves things it will at least confirm that it's a rich mixture problem. I'm guessing that removing some of the air box restrictions will have more effect on fuel/air mix at higher rpm and minimal effect at low revs. If it stops raining this afternoon I'll try it later today. Otherwise it will be tomorrow when it is forecast to be dry.
|
|
mech73
L plate rider.
Posts: 45
|
Post by mech73 on Sept 11, 2016 13:22:51 GMT 1
Inner and outer snorkels removed and air box lid left off. Filter held in place with some washers. Just took it for a run. Initially riding around gently warming it up it felt little different,burbling and running a bit rough on small throttle openings. However once opened up on the bypass it was hitting 10000 rpm through the gears with no holding back or missing. I was worried it could now be too lean so didn't push it hard for too long. It feels fine at anything over about 1/4 throttle (approximately) but still rich below there and bear in mind I have the air screws 3 turns out. For me that's almost confirmed I have a carb issue. I'm almost sure now that it's not ignition or power valves. Partially blocked exhausts is still a slight possibility. Having non removable baffles (for cleaning) seems a serious design flaw.
|
|
mech73
L plate rider.
Posts: 45
|
Post by mech73 on Sept 11, 2016 14:58:28 GMT 1
I've just tried it again, but with the lid replaced. Still without both snorkels. No significant difference from above. Flies at full throttle and seems ok at half throttle as well.
It's a very pleasant afternoon here warm and sunny with little wind. Ideal for tinkering with the bike. I'm going to put the lower snorkel back now and see what effect that has. I'm also tempted to return the floats to the standard height, and try dropping the needles again, but will stick to one change at a time.
|
|
mech73
L plate rider.
Posts: 45
|
Post by mech73 on Sept 11, 2016 16:30:33 GMT 1
|
|
mech73
L plate rider.
Posts: 45
|
Post by mech73 on Sept 11, 2016 17:23:42 GMT 1
I can confirm that the upper snorkel does make a very noticeable difference at half and full throttle. Without it it will rev cleanly to 10000 rpm. With it fitted it will still get to 9000 + rpm but starts holding back slightly at about 7500 rpm and significantly holding back at 8500 rpm.
I don't think the rich running at small throttle openings is much affected. I'm thinking it's in the pilot jet/slide cut away region where it still runs rich.
I'm going to remove the upper snorkel again and put the float height's back to standard ie 21mm from the gasket face.
|
|
mech73
L plate rider.
Posts: 45
|
Post by mech73 on Sept 11, 2016 20:23:00 GMT 1
Upper snorkel removed and float heights back to as they were (21mm). No difference, which is what I was hoping.
So I've ended up almost where I started. The only difference is that the upper snorkel has been removed and the air screw is 3 turns out.
It's running pretty well now at half and full throttle, but still rich at small throttle openings ie when pulling away and accelerating 'gently'.
It's dark now so I'm not doing any more tonight, but next I will try putting the air screw back to 1.5 turns out. I expect that will not improve things and may make the small throttle running even lumpier, but I just want to check I'm not mistaking lean running for rich.
I can also try dropping the needle again, but 1/2 throttle seems ok and I don't want to go too lean on the mid range.
I'm thinking I may order some smaller pilot jets.
I was going to take the exhausts off today and attempt to clean them out. I will still do that eventually as the header ends could do with re-painting, but the bike is going so well now with a bit more air, that I don't think the exhausts are the problem.
|
|
chrisk
Drag-strip hero
Posts: 281
|
Post by chrisk on Sept 13, 2016 9:10:16 GMT 1
Hi. Interesting thread.
One thing I noticed when running too lean was that the temp gauge would be higher. I would not recommend using the temp gauge for jetting, but it can come in handy, epically at decent cruising speeds.
|
|
|
Post by neo on Sept 13, 2016 19:45:34 GMT 1
Have you pulled out your reeds and checked them man
|
|
mech73
L plate rider.
Posts: 45
|
Post by mech73 on Sept 14, 2016 7:48:00 GMT 1
Hi. Interesting thread. One thing I noticed when running too lean was that the temp gauge would be higher. I would not recommend using the temp gauge for jetting, but it can come in handy, epically at decent cruising speeds. I know someone who flies a 1940's Auster. He's told me, that has a mixture adjuster on the panel which you have to lean off as you get to altitude. Cylinder head temperature is used as the main guide as to how much to lean off. I think the motor is air cooled. I'm sure the principal is correct, however would the YPVS thermostat confuse things?
|
|
mech73
L plate rider.
Posts: 45
|
Post by mech73 on Sept 14, 2016 7:55:16 GMT 1
Have you pulled out your reeds and checked them man No, I've not removed them. I did check all of the petals best I could whilst the carbs were off though and everything looked normal. Gave each one a gentle prod and they opened and closed again. Thanks for all the replies so far. I think I'm on the right track, but am often wrong so any more suggestions welcome. I've not done any more on the bike since the last update Sunday due to work, but hope to soon. Cheers Mark C
|
|
|
Post by neo on Sept 14, 2016 7:59:35 GMT 1
Take the cages out remove the petals and look around the rubber part where the petals seal against them for any shiny spots on the rubbers these suckers open and close thousands of times a minute over the years they don't seal as well making the mixture the engine receives incorrect at certain revs it will manifest more than others you will need some gasket paper to remake the gasket seal but it's another box ticked if you really want to eliminate every possibility, good luck
|
|
mech73
L plate rider.
Posts: 45
|
Post by mech73 on Sept 18, 2016 16:28:16 GMT 1
I think the reeds are ok and are the standard metal ones, however I obviously can't be sure until I look. The gaskets are still available so I'll order a couple next time I get some more bits from Yamaha.
Tried the bike today with the air screws set to 1.5 turns out (from 3 turns). This definitely made it worse at small throttle openings and also made the tick over very lumpy and slow. It still went fine once the throttle was at least half way open. The issue is definitely throttle position sensitive and occurs at all rpm's, although there does seem to be a more sensitive spot at around 5000 rpm.
On my return I reset to 3 turns then opened them some more whilst the bike was ticking over. Initial throttle response on the stand may have improved a little at up to 3.5 turns, but after then there didn't seem to be any further effect. On the road it was much better, but still a little rough until the throttle was well open.
I'm going to order some smaller pilot jets from Allens. The ones fitted are 27.5's, so I'll go for some 25's and 22,5's
|
|
|
Post by davecroucher57v on Sept 18, 2016 20:26:58 GMT 1
make sure you have not got 31k needles.
|
|
mech73
L plate rider.
Posts: 45
|
Post by mech73 on Sept 18, 2016 21:36:56 GMT 1
make sure you have not got 31k needles. Needles are both marked as 5L20 which I think is correct for an F2.
|
|
|
Post by neo on Sept 18, 2016 21:40:10 GMT 1
I'm getting a German import this week (don't mention the war) been hankering for a f2 for a while.... photos to follow it runs but throttle slides stuck I been told... hope it not going to be a problem or to much of one like my first lc been after a valve for ages know nothing about how they work other than it's a valve that opens and closes in the exhaust port.... sorry to hijack the thread... keep us posted and good luck finding the cure
|
|
|
Post by davecroucher57v on Sept 19, 2016 21:38:56 GMT 1
dammm.
|
|
mech73
L plate rider.
Posts: 45
|
Post by mech73 on Sept 23, 2016 19:25:29 GMT 1
New 22.5 pilot jets tried today. I started with the air screws back to 1.5 turns out. The first difference, was that it needed choke to start, which I took as a good sign. As I set off it was very hesitant and wanted to stall. I rode around gently until it was properly warmed up, but it still wasn't right at small throttle openings. However not in the same way as before and felt weak. Tick over had increased by 500 rpm. It still went ok once the throttle was open a bit. Back home and I closed the air screw to 1 turn out. This felt much better, so I went to 0.75 turns out. Tick over was still a bit fast so The throttle stops were adjusted. Gave it a full test and it ran clean and happy at all throttle positions. Back home again and I put the top snorkel back in the airbox. Surprisingly everything was still ok. It needs to warm up now but runs clean and smooth and red lines through the low gears easy enough (I'm too scaredy to try it in the high gears and it would be illegal of course ) To recap, I started with a bike that ran rich and lumpy except when accelerating at all throttle positions. Flat out through the gears, it would start holding back at about 7500 rpm. I've tried lots of things, and the bike is now running as it should (or at least as close as I can tell). The only difference now from where I started from is the pilot jets. What has surprised me a little is the pilot jet change appears to have had a noticeable effect at all throttle positions including full throttle. I don't think adjusting the air screw did much except at small throttle openings, but the size of the pilot jet orifice clearly did. Whether the original 27.5's were just too big a size or whether they were worn or had been drilled I can only guess. So, I think as far as this problem is concerned I'm sorted, except I understand that the air screw setting should ideally be between 1 and 2 turns out. So I may try the 25 pilots jets. (I've had that much practice I can now remove the carbs re-jet and replace in about 20 minutes). Thanks for all the suggestions and interest. I've still got the fizzy baffle soaking in caustic soda, which did appear to be working slowly (I've not checked it for over a week). The RD's exhausts do need removing for re-painting at the cylinder end, so If the fizzy baffle trial is successful, I may try to give them a clean out over the winter.
|
|
|
Post by neo on Sept 23, 2016 19:38:23 GMT 1
Glad it's sorted, I'm still cleaning rust out of my tank with vinegar and it works AMAZINGLY well
|
|
|
Post by neo on Jan 2, 2017 17:09:37 GMT 1
How's the F2 running mech?
|
|
mech73
L plate rider.
Posts: 45
|
Post by mech73 on Jan 2, 2017 23:57:30 GMT 1
How's the F2 running mech? When last ridden it was running pretty well. I've still not got round to removing the carbs again to try the 25 pilots, but the only reason for that was to get the air screw setting into the normal range. I've got he exhausts removed at present, cleaned them up and given them a couple of coats of satin black BBQ paint. Other than that it's all ready to go in the spring. I've got an early RD200 motor to rebuild and my sons YB100/fizzy special leaky forks to fix, so plenty to do in the next few weeks
|
|
|
Post by neo on Jan 3, 2017 0:03:41 GMT 1
Nice one! I went out on y Lc today, I struggled to get any heat in the engine as was so cold!, it ran ok tho need a 350 back wheel so I can gear it correctly really I'm +1 on don't with a 250 standard rear ATM makes it hard to rev out through the gears
|
|
mech73
L plate rider.
Posts: 45
|
Post by mech73 on Oct 20, 2017 17:53:46 GMT 1
Since changing the pilot jets last year, the RD350 has run really well until about a month ago. I went out on it on a pleasant Sunday morning, pulled onto the M3 and opened the throttle. It got to about 7000 rpm and then started to gradually slow down until it wouldn't run above about 4-5000. I limped back home and started to investigate. Carbs came off a couple of times, plugs were changed, various resistances were checked and I checked the ignition advance with the strobe. It seemed to run perfectly well on the stand, but on the road, just cut out as the revs increased above 5K. After reading about stator issues on this forum and the one on the bike being about 30 years old, I though I'd better have a new one, so ordered one from Norbo with a new ignition coil as well. They were both fitted this week and tested today. The problem is fixed, but turned out not to be the stator or coil, although probably still not a bad thing they were replaced. The photos should show what the real cause of the issue was. The front of the seat was pushing the 'Optimate' connector into the air intake.This had been fitted a couple of weeks earlier when a new battery was installed. Connector now been re-located well out the way.
|
|
|
Post by lambert on Dec 27, 2017 18:32:39 GMT 1
Hi Mech 73 This sounds very familiar... what was your final carb set up? Did you go .25 pilot ? Mine seems happier on airscrew .75 turns out Thanks Lambert
|
|
mech73
L plate rider.
Posts: 45
|
Post by mech73 on Dec 28, 2017 11:25:46 GMT 1
No I haven't changed the pilot jets from the 22.5 yet, although I've got the 25 to try. It's running fine, but only having the air screw less than on turn out does suggest I should go up a size. Something to test next year.
|
|