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Hi guys, as requested, my MSX build thread...

 
***Note: I have changed to +1 on the front sprocket, hence when I say by bike is doing XX mph, it is infact going 1/15th faster, or approximately 64mph at an indicated 60mph.***
 

Firstly, I fitted this: http://www.ooracing.com/store/index.php?act=viewProd&productId=3252. Not a straight swap - you have to use a set of 8mm-to-6mm studs (http://www.ooracing.com/store/index.php?act=viewProd&productId=3342), then file out the flange holes slightly - drilling one out to 8mm did the trick.

With hind sight, drilling them both to 8mm might have allowed use of original studs, but I think it's the spacing that's out, not just the stud sizes. The flange-end of the pipe was also too long, meaning neither size studs were long enough. 20 minutes with an angle grinder shortened the end of the pipe enough to get it to fit. As you can see, it's at a true 90 degs to the head, which being slightly inclined upwards means the pipe point too far down. So later I will regrind a slope onto the end of the pipe to make it more level. Noise is a little better (fruity but not too loud), power doesn't seem better or worse yet, but only ridden a mile so far. Weight is a lot better, and looks are SHIT LOADS better (well, I think so!). The baffle is welded in. It takes the form of a tube with the inside end shut, and holes drilled in the sides. I shall be drilling a small hole in the end to let more gas through.

Pipe cost £40, studs £4ish, and postage £6ish.
  new pipe.jpg

Experience running the exhaust revealed that as suspected the restrictive baffle is stiffling the engine, and it's actually lost a few mph.

 
Now on to modifying the exhaust!

Step 1) I tried drilling through the baffle, but even cheap chinky Stainless is too hard for normal HSS drills until you've got a pilot hole. Will have to find a special drill for hardened materials. In the end I ripped the baffle out, which involved pushing it down the pipe, and dremmeling the weld pips out. Then I cut off the end with the angle grinder. To fix it back in I did try solder, but no amount of fluxing and cleaning would let me tin the cheap stainless, so I had to drill it. An hour later after much faffing with various grinders, dremmels, diamond engraves, and old darts, I eventually made two 4mm holes suitable for a pop rivet under the pipe and in the baffle. I did try the pipe with no baffle - literally as restrictive as shouting down a traffic cone! Want your MSX to be louder than a Harley with Screaming Eagles? This will do it! Luckily the very gentle valve timing allows it to run with zero back pressure. With baffle fitted it's fine, a bit noisier, and it definitely revs as per normal now.
msx pipe de-restriction.jpg
Step 2) Sorting the intake. I bought two air filters from ooracing with the exhaust, in the hope that at least one would work. BTW - the throttle body has a 38mm spigot.

The first was the PEX filter. http://www.ooracing.com/store/index.php?act=viewProd&productId=3720
BRILLIANT quality, with plenty of space to mount the intake sensor underneath. Unfortunately it didn't clear the frame. Any one want to buy a filter? £10 including p&p.

The failsafe option was the open stack. http://www.ooracing.com/store/index.php?act=viewProd&productId=3243
(The longest one). This was again lovely quality, shame about it just having a sticker on it instead of an etching or something.

This fitted nicely, but left me with no where to fit the sensor. I drilled a 9mm hole half way down for the sensor, and counter sunk it for the oring seal. I then drilled and tapped two M5x0.8 holes for a pair of stainless allen button bolt I had. These were fitted and marked flush with the inside of the stack. I removed then and trimmed to length, and refreshed the thread with a die. After a good clean I had a lovely stack complete with sensor. Assuming it's an intake temp sensor, being directly in the intake will cool it a little more and make the ECU inject a little extra fuel which will help compensate for the open intake and exhaust until the fuel injector arrives.

The last step was to cut up a plastic sieve to act as a mesh filter. I don't want it swallowing a chunk of grit etc. This was held on by a big jubilee clip. Not very neat, but works beautifully.

All this has enabled me to remove the entire air box assembly. Should help with cooling a bit. Does allow the panels to vibrate a bit as there's nothing to support them at the bottom now. But I might change to a different body set soon. In the mean time I have attached a set of cable ties to pull the panels in at the bottom. This has made them that little bit more rigid.
DSC00934.JPG DSC00935.JPG
(for some reason it always rotate the picture of the intake. You can tell where horizontal is by looking at the bricks in the background!)

Following the exhaust and intake installation and modification over 1,000 trouble free miles have been done. The engine revs noticeably better, and higher rpm power is good, with plenty of over-rev. I suspect that the dyno chart would look similar to stock, maybe a little taller at the top, but that it would continue at a high plateau for longer before dropping.

OK, injector has now arrived and been fitted. http://www.rzracing.nl/webshop/honda-msx-high-perfarmance-fuel-injector-yuminashi/ It took a while to come after dispatch - post took about a week. To fit requires temporary removal of airbox and hence bodywork. If, like me, you no longer have the air box, fitting take about 3 minutes. Unplug the electrical cable. Then undo the two 10mm bolts on the mounting. Pull out old injector and mount. Pull old injector out of mount, and replace with new one. About 1 teaspoon of petrol dribbles out, no more, so have a little rag handy. Make sure new o-ring is on injector-end of injector. Refit injector and mount, reattach 10mm bolts. Reattach electrical cable. Take for a ride...

On first firing it up it idled VERY slow, like it was about to stall (900rpm). I took it up the road but past half throttle it began to choke. I made it up to about 47mph like this. A mile up the road I turned around, letting the engine idle again. Suddenly the idle improved back to normal. On the return leg, the engine revved cleanly. Infact, I hit 62mph in 3rd!

Results for a run up a level-ish piece of road, and then return. Very windy today.
 
Stock: 3rd gear - 57 out, 58 back. 4th gear - 56 out, 57 back.
Light-bore injector: 3rd gear - 58 out, 60 back. 4th gear - 58 out, 59 back.

So it makes a tiny improvement, but not much more than say, tucking in. Fitting very low bars may have same effect. My impression is that it revs better though. In which case on the motorway tomorrow I expect it will be significantly quicker than stock. I will let you know...
 

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Stock: 3rd gear - 57 out, 58 back. 4th gear - 56 out, 57 back.
Light-bore injector: 3rd gear - 58 out, 60 back. 4th gear - 58 out, 59 back.
Is 4th gear really THAT tall with the +1 front that you can't push through it in 4th?

great write by the way!
 

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Is 4th gear really THAT tall with the +1 front that you can't push through it in 4th?

great write by the way!
I saw somewhere a fourth gear that reduced the overdrive characteristics of the stock transmission gear. It could have been 00racing. It would involve splitting the cases but I could see the benefit. I can't wait to ride mine. Great thread keep the info coming.
 

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I saw somewhere a fourth gear that reduced the overdrive characteristics of the stock transmission gear. It could have been 00racing. It would involve splitting the cases but I could see the benefit. I can't wait to ride mine. Great thread keep the info coming.
Yuminahi was the place, pretty cheap part but a lot of work involved

From Swiftys thread he said the +1 front was too much of a sprocket for the stock displacement and his weight, I'd rather go down one or so on the rear personally, even tyga mentioned a 16t front is big for these

Gavin if you like it that way then more power to you friend
 

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Yuminahi was the place, pretty cheap part but a lot of work involved

From Swiftys thread he said the +1 front was too much of a sprocket for the stock displacement and his weight, I'd rather go down one or so on the rear personally, even tyga mentioned a 16t front is big for these

Gavin if you like it that way then more power to you friend
True! The tranny gear would be work but I bet the difference is huge. It would make a bike pull harder through the gears. A big bore kit would benefit most.
 

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Discussion Starter #9
Hi guys. My bike has always been faster on the motorway ('freeway' for you foreigners!) than on country lanes, by quite some margin. On said freeway it will (with NO headwind) rev through in 4th. It's better for cruising going +1. I only need to down-shift on the worst hills. My record speed (with pipe and stack, without injector) was an indicated 76mph. Add 1/15th, and that's a mighty 81mph! That was done a slight slope, on a freeway, with a tailwind, kissing the clocks! The injector hasn't worked today, been bogging all the way to/from work - 80 bloody miles at half throttle! I've email Reggy (the owner of Yuminashi) to ask for help. I know it does work, 'cos it has, I just need to get it to KEEP working. Oh, and we Brits use both metric and imperial. We tend to match the units to the required accuracy. Some something might be about 3ft long, but if we wanted accuracy we'd probably say 955mm or whatever. We buy petrol in litres, but measure economy in miles per gallon!
 

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Discussion Starter #12
I know that parts works well, I think the problem is the ECU is playing silly buggars at the moment. On the up side, you don't need the injector, my set up seems to be fine without it. I'll wait until Reggy gets back to me.
 

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Discussion Starter #13
Oh, I weight about 13st, and am about 5ft8 high. As I said, it was a hot day (makes a big difference) with the best fuel (Shell standard 95 is the best, other brand I need to use premium 97 etc), down a hill, with a tail wind, tucked in, behind a car! Also don't forget mine has an open pipe and open stack. Normally my top speed on the level is mid to high 60s. I think if I went down a cog on the front it would be a little faster, but I'd be revving it's nuts off the whole time.
 

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Discussion Starter #15
I've seen Reggy refer to a 3-sensor race ecu, but I've not got any more details yet.
 

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Discussion Starter #17
Had a very comprehensive reply from Reggy last night. Apparently he's doing the full kit, it's just not advertised many places yet. He does have a piggy back unit that can adjust injection and ignition timing. He's also double checking how to reset stock ecu. He think's its the same as PCX but wants to check. It doesn't help that my bike worked, then didn't!
 

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The injector hasn't worked today, been bogging all the way to/from work - 80 bloody miles at half throttle! I've email Reggy (the owner of Yuminashi) to ask for help. I know it does work, 'cos it has, I just need to get it to KEEP working.
Gavin - Did you get the higher flow fuel injector to work ?

What was the problem and the solution?

Did they come back to you with a way to reset ECU?
 

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Discussion Starter #20
Yes - take the engine to 155cc! Problem - the light bore injector was too far up from stock for the FI to adjust fully I think. One in between would have been better. Solution - fit big bore kit (any excuse me....!). No, didn't hear anything back. He had a tantrum at me for saying that his first batch of kits weren't up to scratch.
 
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