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Post by pxguru on Jan 19, 2015 9:43:51 GMT
It will go ok with a standard inlet like everyone elses does but opening it out will make a differance. Standard inlets are tuned with just economy in mind. Measure the inlet degrees you have on your standard crank and cases and compare it to what a touring tuned scooter should have and you will see what I mean. Inlet degrees are quoted as before and after TDC like 130/70. When cases are in pristine condition its a tough decision to cut them
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Post by pxguru on Jan 17, 2015 8:14:40 GMT
The only thing you dont have is the barrel/piston. Either will be ok for your needs but the bigger bore of the 180 is easier to tune. The 20mm carb and old crank will be just fine. Using the same clutch will save some money as you would need another 21 tooth.
If you are going to open out the inlet then that old crank will need to be cut as well.
Whether its a 150 or 180 about 8000 rpm is where you should be aiming. The rev limit is 10,000rpm over that the reliability becomes questionable. Otherwise if the engine is built well, reliability is about set up of carb, compression and timing.
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Post by pxguru on Jan 16, 2015 17:51:58 GMT
All looks good. As H says about the broken circlip seat. Will be fine.
The big question is are you going to Dremel those casings or leave them totally standard? Which would really depend on what kind of engine will this be? Which will also detemine the gear cogs and primary clutch cog use.
If its going to be a standard 150 barrel then it should be tuned for 8000 rpm. Which will make it fast, relisble and go up hill. Once you make this decision then all the other decisions will fall into place much easier.
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Post by pxguru on Jan 11, 2015 7:33:08 GMT
3 hands does make adjusting the clutch easier The cable adjustment is tight enough when pulling the clutch lever disconnects the kickstart. The kickstart should press freely without any resistance. When releasing the clutch lever the kickstart should work without slipping. If yours does this then the adjustment is close enough.
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Post by pxguru on Dec 29, 2014 9:45:43 GMT
The numbers on MD and GSF may be a bit dodgy but the shape of the curve showing the power band is a big help. I think very useful. Well, from this comparison it shows there is nothing really wrong with your SIP Road mk2. The results are too similar to be exhaust pipe related. I would think it feels faster with the mk1 exhaust on? The height of the exhaust port and how well the exhaust pipe works combine together. With your below minimum exhaust port and a decent expansion pipe, your engine as it is now will have much more power than could normally be expected from just adding an expansion on another engine. The curve being much better shaped on the mk1 shows up the exhaust port issue. Do you not know anyone who could port your barrel? This will really fix it
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Post by pxguru on Dec 25, 2014 11:53:14 GMT
Vespasco, Still need to see a dyno run with a different exhaust on!
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Post by pxguru on Dec 25, 2014 11:42:11 GMT
Merry Christmas everyone! No sign of any white christmas here to hinder my lunchtime walk to the pub
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Post by pxguru on Dec 18, 2014 10:53:07 GMT
Just did an edit above
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Post by pxguru on Dec 18, 2014 4:08:36 GMT
The beer can will be ok but the SIP shims fit really well with no gaps. An exhaust leak increases the EGT which is fine if you set it up while its leaking The kind of power loss you have seems a bit too much for timing. You need to try a different exhaust. If everything is exactly the same just 2 years apart then it could be a blocked exhaust. I have seen this a few times before and would like to eliminate it from the investigation. The typical symptoms with a blocked exhaust are that, it goes great until mid range then loses power. Sound familiar? Keep the packer where it is for now. There is no issue with sanding out Nikasil ports. If the plating was going to come off with the heat it would come off anyway. Rounded into the port or not. Once the ports are sanded to shape the chamfer should be polished in (takes a while). The plating only needs to be where the rings and piston touch it. My next barrel is a chipped Malossi 210 I brought off ebay. The small chip is just below a boost port, will just be sanded smooth and left. Won't make any difference to reliability or performance. Once I have finished with it every single port will have been opened out for the most power (I have been designing this one for a while) Certainly wont be getting the bore re-plated before running it
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Post by pxguru on Dec 17, 2014 18:13:35 GMT
something to think about for when its running right. I have my timing strobed to 26 degrees on the stator and using a programable CDI (Kheper) to reduce it. Makes changing the timing really quick. USB, laptop, click, wait 5 seconds This way it is possible to have it all. The software allows the timing to be set on a curve against rpm. At the moment I run mine at 26 degrees up to about 4000rpm then on a curve to reduce it and flatten off at 8000rpm
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Post by pxguru on Dec 17, 2014 17:31:21 GMT
If we are looking at exactly the same set up but 2 years apart then its not a tweek but something bigger. After seeing this comparison and knowing all that you have done, the first thing I would do is try a different exhaust. I take it from the beer can packer it has a habit of slipping on the manifold (you know SIP sell real ones?). This could mean something. I wouldn't touch anything else until I had seen it run another exhaust.
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Post by pxguru on Dec 17, 2014 4:17:04 GMT
Vespasco, Looks like you've been pretty busy I saw the other charts on photobucket. The extra 0.5 on the packer did pretty much like expected, made the mid range better and high rpm worse. I really don't like the the comparison with 2 years ago. If everything on the whole set up is identical to 2 years ago then there is still a big problem somewhere. The 2 year ago curve is still not ideal shape but is much better. Did you show us this old data before? I must have over looked it. Do you have any other exhaust that works? Not important what it is, just to try something else that isn't your SR2 and see what the curve looks like.
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Post by pxguru on Dec 16, 2014 3:51:05 GMT
Will look forward to seeing the MD runs. Going to confuse the issue slightly with multiple variables (packer and timing) but it will be the shape that is important That timing was way to low for performance. On your set up I would say you could go a few degrees more without any worry. Some Pinasco 225s can run standard 200 timing. Just listen out for detonation at high rpm and check the plug for electrode rounding/melting after a while. This might really help your rpm like you say. We know the blowdown is under minimum but if it starts to go ok for you, then having low blowdown won't do any harm, will just be more economical/slow After you have sorted it could put some tippex on the stator pick up where it was touching. It will help next time you take the flywheel off to see if its still rubbing.
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Post by pxguru on Dec 14, 2014 5:24:33 GMT
I never noticed Vespasco's major edit either! looks like some really good work and gives the overall result I would expect. The camels hump curve is as you say. The low blowdown causes an increase in low rpm torque but a total loss of high rpm power causing the bottom end to be fatter and top rounding off too early and giving you the camels hump If the blowdown was were is should be with the exhaust port 2.5mm higher, the curve will change from the hump to a wedge shape, I would expect about 5bhp more on peak at higher rpm, slightly less torque at the bottom but the rate of rpm increase to go right up. As said a few times now will be very interesting to see on the next results with the TD higher and blowdown even lower. The camels hump should continue but me more exaggerated. Will feel like it goes better though and you might even get it where it goes good enough to stop fiddling
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Post by pxguru on Dec 13, 2014 16:37:00 GMT
I am just the same with the barrel studs. I almost never take them out. Seen to many pop out when its running. On a PX its possible. Take off the exhaust and carb box put a couple of bricks under the centre stand, undo the back shock and jack the frame up. The barrel just clears the frame without removing the studs. Not sure if you can do the same on a Rally.
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Post by pxguru on Dec 13, 2014 16:22:39 GMT
Glad you like the plan you know it makes sense! Should be able to find some barrel on ebay. better if it has a piston but if it hasnt got a piston you can rebore it with a new one after porting practice. Fine to use that old crank. Do you have the back hub with the spare engine?
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Post by pxguru on Dec 12, 2014 11:50:43 GMT
I just can't get past how expensive this is going to be to end up with the same type of engine. Once the new engine is in the old one will never go anywhere again. How about this for a plan? Your EFL engine has just been rebuilt and is in good condition. If you must have two engines economically re build/re condition the new one, as it is, as a standard 150 with a few tweeks to make it go properly (will probably perform as good as your DR goes now, if we help you with some Dremel practice on the 150 barrel). Then do all the work on the EFL engine and DR kit. DR kits can really be tuned well and reliably if just looking for a touring set up. Apart from the tuning you would only need something like a 60mm crank, seals, gaskets, fly bearing, banded basket and a proper head. Wouldn't cost so much and after you could sell the 150. Probably break even. Properly tuned and set up engines last pretty well. My approx. 33bhp high rpm Polossi has many of the same parts as your 150 and has not been split for 2 seasons and done about 8,000 miles. With the type of engine you are after you won't need a spare
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Post by pxguru on Dec 11, 2014 17:04:06 GMT
Nice idea but I think unless you are going to build a different type of engine, for a different use, it's a bit of a waste of money.
Now you have the other engine. You could just build it as a fully standard 150 (barrel tuned for torque of course) for spares or reserve to keep you on the road if something happens to the other one.
If you just put a 1mm packer on your 180 and a better head (at the same time or separately, doesnt matter), I think you would be quite happy with it. For quite a while.
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Post by pxguru on Dec 9, 2014 18:37:33 GMT
I would never fit anything but a 60mm crank in a DR kit
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Post by pxguru on Dec 9, 2014 8:10:54 GMT
When we are talking about minimum blowdown, this is the minimum for any type of exhaust. The minimum for an engine to have high power at high revs. A few degrees is a lot! The timing should always be advanced as far as possible while continuing to run well and not blow up. If you can get it running acceptably for you then you can avoid modifying the barrel but if you want it to go fast and keep the SIP road then you will need the exhaust port raised. You're going to give us some interesting results though
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Post by pxguru on Dec 7, 2014 12:53:51 GMT
What I am seeing from your power curves is exactly the shape would expect when there is insufficient blowdown.
Raising the barrel now will make it feel better. The torque will go up and it will ride better, as long as you keep it under 6000 rpm! If you want it to go better at high rpm and mid range, then you need much more blowdown.
The numbers are never that far different from the reality of how an engine actually runs.
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Post by pxguru on Dec 5, 2014 23:13:00 GMT
I'll try to get a few more wav files over the weekend and try to get a cleaner run. They are all showing near to what it actually is I guess you worked out the speeds I was doing on these runs? That last curve was from 22mph to 69mph in thrid (GPS speed), it's a 17 stone guy on a scooter not a Fireblade On the last run down the bypass it topped out at 8200rpm in 4th, took about 2 minutes to get there though!
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Post by pxguru on Dec 5, 2014 22:55:41 GMT
I think it will be an interesting experiment to fit the 0.5 packer. What I expect is that at less than max rpm it will go better than before. in third certainly rev higher but in 4th it wont rev out. Even worse than now. this will be due to the below minimum blowdown duration being even more below minimum once the barrel is raised. Raising the exhaust with the packer will increase the exhaust duration but the exhaust duration alone is of no importance to anything. The exhaust duration just provides the blowdown duration which once the barrel is raised will be even shorter, so would most likely clip the top of the power curve even more. Will make interesting results for the other thread. When you doing it? Next experiment is to get the exhaust port raised 2.5mm then it will go like a train
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Post by pxguru on Dec 5, 2014 11:56:49 GMT
Just talking about compression and totally ignoring squish band, clearance or angle. Corrected compression is sometimes called trapped compression, which describes it better. This is what actually matters. The full volume divided by the head volume gives a figure like a 4 stroke. This is a guide as a higher number will perform better until you have too much. There is also the supercharge effect from an expansion which is a major factor if you have an expansion that works over the same range as your power band (porting).
To calculate trapped compression is the same as the usual way but the cylinder volume is only measured from the top of the exhaust port. This gives a figure for static trapped compression.
The 200 standard barrel from the factory gives a trapped compression of 6.5:1. IMHO this is like the minimum for any 200 tuned or otherwise. This is not particularly high compression when compared to motorcycles but still takes some skill to set up the squish, carb and timing to avoid the dreaded pinking!
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Post by pxguru on Dec 5, 2014 8:10:24 GMT
I dont see why GSF and MD are so different. Sent you another wav file to try. On MD this one comes out at 33bhp.
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Post by pxguru on Dec 4, 2014 10:37:35 GMT
Weight: 108+107+clothes+fuel+oil&tools. I just guessed at 240kg Gear Ratio: runs were all in third so on mine thats 6.604:1 Temp & Pressure: 7 degs and 1015 Tyre Circumference: 1350mm
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Post by pxguru on Dec 4, 2014 9:03:47 GMT
Here is my best looking effort from yesterday. Not as easy as it looks getting a clean run. then finding it on the wav. Need to zoom in to actually see it. The most I saw on my rev counter was 8900 but looks close enough. I guessed it was somewhere around 30bhp so thats about right too Here is another one that looks exactly right for revs but its not that powerful!! is it?
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Post by pxguru on Dec 4, 2014 8:38:57 GMT
You're using photobucket! I'm just trying to upload into the post. Says the forum is full. Nik, Can this be fixed?
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Post by pxguru on Dec 4, 2014 8:21:14 GMT
Glad you mentioned this. There is a significant relationship between where the ports open and close and where the power/torque curves start and finish.
Like you can see on Vespascos curves how max power is "clipped" by the insufficient blowdown. Hits max power at 6000 (where there is enough blowdown) then doesnt increase. A few degrees here makes all the difference.
I cant post any pictures is something wrong with the site, or is it me?
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Post by pxguru on Dec 2, 2014 20:11:08 GMT
Was not scootering weather today. Hopefully will get a go at it tomorrow
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