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Post by neilrowe on Mar 8, 2022 13:53:30 GMT 1
My 4L0, bored out to 66.5mm, is currently fitted with a set locally made expansion chambers. These are extreme top end race pipes and not suited for road use. I have been offered a set of 29L pipes (the ones with the end cans).
Any comment or ideas about using these? I am looking for a rideable bike and basically want to move the powerband back down the rev range.
Bike setup:
1981 4L0
Bore: 66.5mm
Squish: 1.6mm
Cyl pressure (measured): 130psi
Zeeltronic
01 Carbs
Std reed block with Hytec Carbon reeds
The bike comes on to the pipe at about 8000rpm and revs rapidly to 11000. (And probably more). Obviously this is not where I want to live whilst road riding.
I also do not have stock pipes or easy access to the selection of spannies you chaps in the UK have available.
A mate has a 31K fitted with the same 29L pipes and his setup works well. This has got me thinking that the 29L pipes might be a viable option for me.
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Post by JonW on Mar 8, 2022 14:24:07 GMT 1
29L pipes with end cans? there isnt any of those. 51L maybe?
Ive never tried either on an 350 Lc tho, but im going to say 'you'll run out of high end puff'
Where are you based then?
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Post by neilrowe on Mar 8, 2022 14:26:08 GMT 1
Jon
I am based in Cape Town, South Africa.
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Post by neilrowe on Mar 8, 2022 14:33:00 GMT 1
29L pipes with end cans? there isnt any of those. 51L maybe? Ive never tried either on an 350 Lc tho, but im going to say 'you'll run out of high end puff' Where are you based then? Jon Not sure about the 29L myself. The seller told me they were the pipes with the end cans and he thought they were 29L. As you say, they will be more restrictive than the spannies I have. I guess the question can be rephrased as to how good those stock pipes were. (the ones with the end cans, I mean). |
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Post by JonW on Mar 8, 2022 16:12:15 GMT 1
ok, but there were 250 and 350 pipes with end cans. What are the part numbers? if its 51L its a 250 and your bike wont rev all the way up probably.
The 51L is a great pipe on a 250... you want a 350 pipe tho.
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Post by tony2stroke on Mar 8, 2022 17:23:50 GMT 1
My 4L0, bored out to 66.5mm, is currently fitted with a set locally made expansion chambers. These are extreme top end race pipes and not suited for road use. I have been offered a set of 29L pipes (the ones with the end cans). Any comment or ideas about using these? I am looking for a rideable bike and basically want to move the powerband back down the rev range. Bike setup: 1981 4L0 Bore: 66.5mm Squish: 1.6mm Cyl pressure (measured): 130psi Zeeltronic 01 Carbs Std reed block with Hytec Carbon reeds The bike comes on to the pipe at about 8000rpm and revs rapidly to 11000. (And probably more). Obviously this is not where I want to live whilst road riding. I also do not have stock pipes or easy access to the selection of spannies you chaps in the UK have available. A mate has a 31K fitted with the same 29L pipes and his setup works well. This has got me thinking that the 29L pipes might be a viable option for me. How about extending the front pipe, can't be exact but and inch extra front pipe should in theory move the power down by 500 or 1000 rpm, can't be more specific about that, I can't quite remember what the workings out would be to drop the power band to where you want it, but it would be worth adding an extra inch to see exactly where the power band is then, this would allow you to work out the extra length needed, the longer the pipe the lower the power band comes in (in theory) this would allow you to keep the 3000 rpm of power you have now, should just drop where it comes in. |
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Post by midlifecrisisrd on Mar 8, 2022 18:15:34 GMT 1
I fitted the 51l pipes to a 350 ypvs
It ran well with plenty of midrange but as Jon said it ran out of puff at 9k
Now am I right in thinking LC pipes are thinner than ypvs and if you fit of pipes on a ypvs it doesn't perform well
I wonder if 250 ypvs pipes may be nearer a stock 4l0 pipe performance wise 🤔
The 51l pipe is quite like the 350 1ua pipe size wise but where the 1ua is straight through to the stinger before the can the 51l has a plate just before the rear cone with 2 tubes approx 15mm diameter and 100mm long
If cheap enough I'd give it a bash but check what they are first
51l pipes are marked with the part number on the pipe at the hanger bracket and on the end can
Steve
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Post by neilrowe on Mar 9, 2022 9:38:29 GMT 1
Thanks for the replies chaps. Much appreciated. I did try and extend the existing spannies by adding a 10mm spacer to the exhaust spigot. This made no appreciable difference. A different thought:
I have a set of JL Race pipes which are for a RD350 air cooled. (They worked well on my AC bike but I converted the bike back to stock). I might be able to MacGyver these pipes to fit the LC.
Think this might be worth a shot?
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Post by neilrowe on Mar 9, 2022 9:48:28 GMT 1
Seller has confirmed the pipes are 51L - so worth a trial?
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Post by Norbo on Mar 9, 2022 9:52:10 GMT 1
I know the ones yopur talking about end cans that can be removed but look like F2 ones right .You can use them
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Post by JonW on Mar 9, 2022 12:42:10 GMT 1
The 51L as norbo says do have removable end cans. They work very well on the 51L cylinders, but as Steve (midlife) has said they work less well on 350 ypvs units as they wont rev out.
However I have no idea on a 4L0 cylinder, if that is something Norbo has tried and hes saying you should use then go for it. Worth dropping him a PM and checking perhaps to be sure... or borrow them and try maybe?
The 51L pipes will fit on an LC with a slight elongation of the holes and the bolts of the passenger footpegs replaced for ones with a less thick head. I have them on my 251LC... thats an LC with a whole 51L ypvs based setup.
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Post by tony2stroke on Mar 9, 2022 13:18:11 GMT 1
Thanks for the replies chaps. Much appreciated. I did try and extend the existing spannies by adding a 10mm spacer to the exhaust spigot. This made no appreciable difference. A different thought: I have a set of JL Race pipes which are for a RD350 air cooled. (They worked well on my AC bike but I converted the bike back to stock). I might be able to MacGyver these pipes to fit the LC. Think this might be worth a shot? You need a lot more than 10mm extra, may be your cheaper option to try and lengthen the front pipe around 50mm, that would make a big difference, about 5x the difference, just trying to find a practical cheap solution for you. |
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Post by neilrowe on Mar 10, 2022 9:56:30 GMT 1
Tony
Thanks for that. I did contact the designer of the spannies to discuss and he is running this through his design calcs.
I have another friend who has the 51L pipes on his 31K. He had them gutted though. Apparently the 51L pipes have a restrictor plate at the rear end of the divergent cone, just before the stinger. This has either got 4, 6 or 8 holes depending on the degree of restriction for various countries. The trick was to remove this and my friend has done this. His 31K is an absolute midrange monster, he says. but it does not rev past 10000rpm, which is ok with me. So I will try this and see how it goes. At least I know the gutted 51L pipes work well on a YPVS and I have the option to fir these to my own 31K should they not work on my LC 4L0.
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Post by JonW on Mar 10, 2022 13:02:30 GMT 1
Cool. let us know how you go. No many people have access to the 51L pipes so not much is know about using them as you can tell on here.
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Post by Tobyjugs on Mar 18, 2022 18:17:06 GMT 1
The tuner I used did just what Tony suggested.
He was explaining some of the principles of how the exhaust works.
He turned up two extension pieces to add to the front of the exhaust pipes.
He put it on the dyno and measured the difference.
The spacers were 28mm long, it dropped peak power down roughly 600 rpm and made 3 or 4 pk in the midrange section.
If I get a chance I will post the dyno readout. It could be in my tuning thread.
I have to say that Pieter the tuner did this just to explain some of the principles after the workshop was closed.
I would look at that option although I do think it's a bit of a band aid.
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Post by jon on Mar 18, 2022 18:30:04 GMT 1
The tuner I used did just what Tony suggested. He was explaining some of the principles of how the exhaust works. He turned up two extension pieces to add to the front of the exhaust pipes. He put it on the dyno and measured the difference. The spacers were 28mm long, it dropped peak power down roughly 600 rpm and made 3 or 4 pk in the midrange section. If I get a chance I will post the dyno readout. It could be in my tuning thread. I have to say that Pieter the tuner did this just to explain some of the principles after the workshop was closed. I would look at that option although I do think it's a bit of a band aid. I don’t quite see what these exhausts have in common with a charity supergroup? Jon |
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Post by Tobyjugs on Mar 18, 2022 18:39:32 GMT 1
The tuner I used did just what Tony suggested. He was explaining some of the principles of how the exhaust works. He turned up two extension pieces to add to the front of the exhaust pipes. He put it on the dyno and measured the difference. The spacers were 28mm long, it dropped peak power down roughly 600 rpm and made 3 or 4 pk in the midrange section. If I get a chance I will post the dyno readout. It could be in my tuning thread. I have to say that Pieter the tuner did this just to explain some of the principles after the workshop was closed. I would look at that option although I do think it's a bit of a band aid. I don’t quite see what these exhausts have in common with a charity supergroup? Jon Explain as I'm a bit sluggish this morning |
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Post by stusco on Mar 18, 2022 18:44:54 GMT 1
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Post by midlifecrisisrd on Mar 18, 2022 18:54:46 GMT 1
Wrong band aid 🤣  |
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Post by jon on Mar 18, 2022 18:57:32 GMT 1
Don’t be ridiculous, they are plasters 😂
Jon
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Post by Tobyjugs on Mar 18, 2022 18:59:05 GMT 1
Ha ha I'm a bit slow today.
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Post by tony2stroke on Mar 18, 2022 19:38:23 GMT 1
The tuner I used did just what Tony suggested. He was explaining some of the principles of how the exhaust works. He turned up two extension pieces to add to the front of the exhaust pipes. He put it on the dyno and measured the difference. The spacers were 28mm long, it dropped peak power down roughly 600 rpm and made 3 or 4 pk in the midrange section. If I get a chance I will post the dyno readout. It could be in my tuning thread. I have to say that Pieter the tuner did this just to explain some of the principles after the workshop was closed. I would look at that option although I do think it's a bit of a band aid. I did try to explain enough without writing a small book on it, but yes, the tuned length is all important to where power is. Judging by your calcs, 100mm would drop powerband by 2000Rpm, putting the power in a nice, more normal place. Just thought I would add, this is in theory, and sometimes the theory does not work out in practice quite how you thought it would. |
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Post by Tobyjugs on Mar 18, 2022 22:18:33 GMT 1
Yes it's a bit more involved than only the length.
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Post by tony2stroke on Mar 18, 2022 23:23:44 GMT 1
Yes it's a bit more involved than only the length. Oh yes!!! very interesting subject to read about. |
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Post by neilrowe on Mar 25, 2022 9:51:37 GMT 1
I fitted the 51l pipes to a 350 ypvs It ran well with plenty of midrange but as Jon said it ran out of puff at 9k Now am I right in thinking LC pipes are thinner than ypvs and if you fit of pipes on a ypvs it doesn't perform well I wonder if 250 ypvs pipes may be nearer a stock 4l0 pipe performance wise 🤔 The 51l pipe is quite like the 350 1ua pipe size wise but where the 1ua is straight through to the stinger before the can the 51l has a plate just before the rear cone with 2 tubes approx 15mm diameter and 100mm long If cheap enough I'd give it a bash but check what they are first 51l pipes are marked with the part number on the pipe at the hanger bracket and on the end can Steve Steve Your post got me thinking. I had the 51L pipes gutted (removed all the baffle plates and pipes in the rear section before the stinger) and fitted them to my YPVS. Noticeable improvement over the stock pipes. The YPVS has a "hit" now at around 6000rpm, bit like an LC. Much throatier sound too. A friend of mine had done this previously and recommended it. For info |
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