Derestricting my TZR 250 3XV RS

[SouthCoastRich]

The title of this post has some optimism in it. It could end up being "How I broke my bike" or "Still not running right", but I have a clear goal, which is to remove the Japanese market restrictions from my TZR, to make it the road bike that could have been sold on UK shores, maybe a little better. What I'm not doing is to get the most HP for a track day weapon.

In fairness I could have started a project thread on this bike when I got it, but I didn't know the extent of the problems I would find. Water pump issues was the first and biggest, needing a strip down to remove the gearbox and replace a seal AND set the water pump circlip AND fabricate the missing water pump washer. There's been many other issues, such as 5k idle, but that's all sorted thanks to this forum and the advice & resources section helping me get the carbs clean and back to stock jetting and there's the leaking PV seals and exhaust issue that kept the belly pan liberally lubricated.

My TZR currently puts out just shy of 44HP (see pic), which is good in one way as that's just one pony left the stable next to the designed limit of 45HP (later TZRs were restricted to 40HP). However this bike managed this by going super lean as there was a hole in one intake manifold and, as you can see from the clip, only survived this without a seize by massive over oiling.

Thanks to Gavin, who seems to be good at spotting when these things come up, I replaced the inlet manifolds which came with 2 stage TZ reeds, so I put those in too. I also sorted the oiling as there was a non-standard cable that couldn't be adjusted down correctly until I snipped out some of the sleeve.

I was really ready to say "job done" but there was a "little" niggle. The right pipe was smoking more than the left (now noticeable as I'd sorted the over oiling). Turns out my gearbox side crank oil seal is leaking. This was confirmed by a) too much smoke from one pipe, b) smoke smelt like a worn diesel, c) gearbox oil was uncontaminated but disappearing.

I have to replace this, which means strip down into unknown/untrodden areas. So pulling the crank means I'd be foolish not to have it rebuilt while it's out and an idea came to me. Why not derestrict the bike and upgrade the parts I had to take off to get this crank seal replaced? I'm quite lucky in my bike has Jackal pipes already, so that's a big part of derestriction. It also has Wossner pistons, which I'm sure helped it survive boiling over / running super lean. I'd just put in 2-stage TZ reeds, so I was already going down the path.

A rebuilt R crank would probably be just fine for derestricted power, but an SP crank would definitely be good. So as these can still be purchased, I got one of those (Thanks Andy at Webbs for the 10% forum discount!). Next I got a Zeeltronic programmable ignition (Thanks Sean from The Tuning Works /Borut from Zeel for helping me understanding this, and answering my stupid emails so quickly!!). So now I have a shift light and two switches to change PV mapping and Ignition mapping on the fly. The missing ingredient is port tuning, which we are lucky enough to have Martin J (Martin77) right here on this forum. Also to get the critical squish set right, we also have Dan the Gasket Guru (maccas) on the forum too!

Last off there's an odd restriction in the static pressure intake volume on the upper airbox. My dad helped out with this and there's a thread on a mod to resolve this. http://pure2strokespirit.net/forums/index.php?topic=7535.0 If you look at the lower airbox snorkel you'll appreciate the static volume isn't an issue for the lower carb.

So I'll have all the ingredients for derestriction to make more power,

• Jackal Pipes
• Zeel Ignition & uprated coils
• SP Porting, PV matching & Head work
• SP upper airbox lid

I also have all the ingredients to make the power safe & reliable

• Sp Crank
• Wossner pistons
• Various thickness base gaskets
• This forum 

If anyone is interested in the Wossner pistons there's a Group Buy right now, take a look - http://pure2strokespirit.net/forums/index.php?topic=7447.0

Next update will come when I start the strip down...

[41juergen]

Great setup, looking forward to your results...
Just a remark: does the dyno have a exhaust extraction system (might be good the operators health...  )? And I would recommend to do a let's say 6th gear acceleration to get the power vs. RPM curve...

[SouthCoastRich]

Great setup, looking forward to your results...
Just a remark: does the dyno have a exhaust extraction system (might be good the operators health...  )? And I would recommend to do a let's say 6th gear acceleration to get the power vs. RPM curve...

Yes, the dyno has exhaust extraction - goes to show how far over oiled the bike was 

I was going to ask the question of what gear, looking at the specs it appears that's closest to 1:1 internal ratio and going up the gears at WOT is no fun to watch or the bike to experience. Agree I'll get this done vs RPM - Thanks Juergen

I plan two runs for every run to start with (if they only have one lamda sensor) so I can see the air/fuel on each side, but any advice gratefully received. 

[Warwick]

If you'll be using the same dyno place as for the run posted, and will be testing various setups over a number of runs, it would be worth downloading the dynojet Winpep run viewer software and asking the dyno place for a copy of your dyno run files, Rich. That way you can bring the runs up again at home on your own PC and compare different runs again when you have more time to mull things over than you will have when you are paying by the hour for the runs themselves.

You should be able to download it from here. If not I can probably forward you a copy: https://dynojet.co.uk/downloads

It's very helpful indeed to be able to do that after or between dyno sessions to help keep you going in the right direction and keep a track of what worked well and what didn't work so well. 

Commercial dyno operators tend to use 4th for simple power runs I think. I've never thought to ask why? A good compromise between getting the power down without the wheel spinning on the drum and a reasonably quick run up time, maybe?

Edit. Added a few graphs to show how you can select the axis values and use the software to compare runs etc. 1st and 2nd pic are the same run file. First with just power and speed showing, then (2nd pic) with the torque added to the view, and the lower axis changed to rpm. Third pic is just with another couple of runs added to allow comparison of different setups. Really useful when doing any development work.   

[SouthCoastRich]

If you'll be using the same dyno place as for the run posted, and will be testing various setups over a number of runs, it would be worth downloading the dynojet Winpep run viewer software and asking the dyno place for a copy of your dyno run files, Rich. That way you can bring the runs up again at home on your own PC and compare different runs again when you have more time to mull things over than you will have when you are paying by the hour for the runs themselves.

You should be able to download it from here. If not I can probably forward you a copy: https://dynojet.co.uk/downloads

It's very helpful indeed to be able to do that after or between dyno sessions to help keep you going in the right direction and keep a track of what worked well and what didn't work so well. 

Commercial dyno operators tend to use 4th for simple power runs I think. I've never thought to ask why? A good compromise between getting the power down without the wheel spinning on the drum and a reasonably quick run up time, maybe?

Edit. Added a few graphs to show how you can select the axis values and use the software to compare runs etc. 1st and 2nd pic are the same run file. First with just power and speed showing, then (2nd pic) with the torque added to the view, and the lower axis changed to rpm. Third pic is just with another couple of runs added to allow comparison of different setups. Really useful when doing any development work. 

Thanks Warwick. Very nice shape power curves too! Yes, I'll be going back to DoubleTake in Southampton. I may message them to see if they can email me the last dyno run, although that was nearly a year ago but worth a shot.

I'll download the software on my windows laptop - that's got the Zeel software on it too, thanks for the link 

Maybe I'll book them for before and after lunch - so while they're munching on oil sarnies I can trawl through the event's before lunch and have a better idea of what of where to go after lunch. That said, they've done some pretty complex Zeel setups so I doubt I'll be too much help 

I did find the VAJ settings (well a close approximation) in the resources section that indicate 2 & 4 open in the early midrange and 1 & 3 open at the top end, all VAJ circuits open at full power. Interesting. (see pic)

I also thought about the gear to use for the pulls and read somewhere that 1:1 internal ratio was best as this is the least internal losses. I think that includes the primary too though, not just the gear ratios. I'll have to do some more research.

[Warwick]

I may message them to see if they can email me the last dyno run, although that was nearly a year ago but worth a shot.

Good idea. It'd allow you to get a feel for the software. Plus you can plot your runs against revs rather than speed as on the printouts, and view the torque curve yourself, too. 

Using the Sugo ECU, I never did anything with the VAJ stuff on the 3XV. 

[41juergen]

Be aware, the pic shown in the manual shows the "general" operation of the VAJ only, the detailed data you can find in the excel sheet I have uploaded when I did the CDI testing..
A dyno run should be as close as possible to the desired use of the bike (so either track or road use). For a track, the dyno pull should take as long as the longest acceleration on the track (in time). Some dynojets have an additional eddy current dyno attached. With that, the operator can add load to the inertia load and though can extend the time for a pull. If that is not available, I would use the 6th gear to get the duration long enough... The typical ex temps shall be around 630°C (with the 1,5 mm sensor approx. 200 mm behind piston face), the temp at the end of start/finish straight then will be approx. 650 - 660°C max (depending how you create the overrev with the ignition timing and the carb setup).
The 630°C also correlate well with using the bike on the raod and getting up 650 - 660 °C on the highway..

[SouthCoastRich]

Be aware, the pic shown in the manual shows the "general" operation of the VAJ only, the detailed data you can find in the excel sheet I have uploaded when I did the CDI testing..
A dyno run should be as close as possible to the desired use of the bike (so either track or road use). For a track, the dyno pull should take as long as the longest acceleration on the track (in time). Some dynojets have an additional eddy current dyno attached. With that, the operator can add load to the inertia load and though can extend the time for a pull. If that is not available, I would use the 6th gear to get the duration long enough... The typical ex temps shall be around 630°C (with the 1,5 mm sensor approx. 200 mm behind piston face), the temp at the end of start/finish straight then will be approx. 650 - 660°C max (depending how you create the overrev with the ignition timing and the carb setup).
The 630°C also correlate well with using the bike on the raod and getting up 650 - 660 °C on the highway..

Thanks Juergen. I had not seen that post - this should really go in the resources section, fantastic data!

Good to know the expected ex header temps, this is valuable safety data!

http://pure2strokespirit.net/forums/index.php?topic=679.msg49929#msg49929

[SouthCoastRich]

What's really fascinating is how Yamaha have programmed 0% TPS at high revs to open the PV on the way down, I guess (and I have little knowledge next to others) that this is to reduce CHT. Amazing work in mapping all this out!

[SouthCoastRich]

the detailed data you can find in the excel sheet I have uploaded when I did the CDI testing..

Allen keys are turning.... anyway, just thought I'd post this comparison of a restricted 3XV vs 3XV Zeel (unmodified) vs Sugo CDI, using data from Juergens testing  .

I think I'll trim off the sub 6k advance from the Zeel before I go to the dyno, just to be on the safe side.
And it makes a lot of sense to ballpark the PVs as per Phil's thread http://pure2strokespirit.net/forums/index.php?topic=5829.0 which will be a piece of cake because I can switch between a 0% and a 100% map on the fly.

[SouthCoastRich]

A good few careful hours with spanners, Allen keys, and correct type screwdrivers, plus some zip ties for ease turns this into that.

[SouthCoastRich]

I have taken loads of pictures and carefully storing everything.

Couple of tips I found useful.

• Zip ties can help remove exhaust springs and clutch plates
• Remove all the pipes from the rad before trying to get this off
• Removing the plugs means you can turn the clutch by hand
• Use a piece of card as a mounting bracket surrogate so you can remember which sides washers etc go (see pipes in pic)
• Make cardboard templates for holding fixing screws (see pic for fairing fixings)

[SouthCoastRich]

I took pictures of everything to make sure I could recall angles, routings and general fit.

However I took this picture. Ooops. I think that should be connected with a washer and circlip.... off to the resources section to find out.

[Warwick]

yes, washer, wavey washer for tension, and a circlip to hold it (and a rubber boot over it all too).

[SouthCoastRich]

yes, washer, wavey washer for tension, and a circlip to hold it (and a rubber boot over it all too).

Thanks! Notice that any part number that does not start with "3XV" is likely to not only be available but a (half) reasonable price.

Washers & clip = £2.97

Any part starting with "3XV" is likely to be GBTLO* and expensive. Oh well I guess I don't need that.

Boot (3XV-1131M-00) - £3.32

Ahem 

_{* GBTLO = Gavin brought the last one}