Honda VTR SP1
(updated 13.01.2007)

"Special Performance 1"

I am updating this page so that the new stuff is always added on the top of the page and thus the older stuff will be pushed towards the bottom of the page

My SP1   anmisp1  disp sp1

This page is about trying to make this bike a little smarter. All mods have been marked like this.
v2tre weblog in finnish is here.

That small but important print :

These are experiments of a non-professional DIY mechanic, therefore, if you choose to follow these "teachings", you do it completely on your own risk !

Jan 2007

A few pictures from "winter service".

undertray   hugger   nicky   shark   kylki

The new undertray is glassfiber and somewhat lighter than the previous one. Most importantly, the new led back & brake light is E-approved and pretty compact unit. Also the rear blinkers carry E-mark. The rear hugger got black color and has been moved 2 centimeters upwards to allow better space for higher ratio rear wheel. Nicky mod (in the middle photo) allows to inspect and even change the front sprocket without hassle with the clutch main cylinder. Carbon fiber "shark" protector added in front of the rear sprocket.

Dec 2006

A few pictures from track activities with friends during 2006.

kollaasi   alastaro   alastaro

Aug 2006

Video : Jurvailua    
Jun 2006
This bike seems to require only driving ! About 4000 kms so far and about 500 kms of those on track. Here are some pics from Ahvenisto, Hämeenlinna

Lahi   oikea   oikea   polvi 

vasen  vasen   yla

May 2006

Do-it-yourself quick turn throttle mod. Thickness of the yellow plastic 2 mm, width 7 mm, inner diameter 34 mm. Ramps for the cable filed down into both ends of the plastic. This increases the diameter of the throttle cam (white in the pics) and speeds up the throttle response. The initial throttle "bite" remains as in original because of the ramp formed into the plastic. Original cables are ok and maximum thickness of the plastic could be up to about 2.5 mm. Original on-off rotation from about 90 degrees is reduced down to < 70 degrees. The yellow plastic part can be slipped into the place under the cables without removing the throttle handle from the bike; only the top cap of the throttle cam enclosure needs to be opened. The cables push the plastic onto the cam and it does not need to be clued, screwed or anything else because the ends of the plastic are in firm contact with the cable holder module protruding out of the cam itself (see rightmost picture).

uusi   mitat   uusi kahva   uusi kahva

April/May 2006

set   center   hrc   hrc cent   jtr core   jtr ready

JTR Slipper arrived as promised NF Racing. I also acquired a new pressure plate bearing, which proved to be a standard bearing manufactured by NTN (type 16003CS08) and obtainable from local bearing shop. The bearing dropped easily into the pressure plate after heating the pressure plate up to + 100 C degrees and cooling the bearing down to around 0 C degrees. I checked for free rotation of the bearing after cooling down and it spins like a champ.

In the above pics the JTR clutch is the one having darker greenish look (due to hard anodization ?) and the HRC original is the one with the shiny aluminum color. The only slight problem in the clutch change was the fact that the center nut requires a 30 mm 12-corner socket wrench. A normal 6-corner socket will not do here. Kari kindly provided me one and that solved the problem.

The JTR parts seem to be of very high quality and surface finish. All dimensions were accurate and the fitting with the old clutch basket and on the axis was spot on. For example, the washers on the top of the clutch springs are machined aluminum parts and not plain steel washers like in the original clutch. The JTR parts seem to be also somewhat lighter than the originals. I would say that in general the JTR clutch appears to have higher quality and finish than the Honda original one ! These are billet aluminum parts machined very professionally.

I made the following simple tool from iron plate to hold the clutch center in place when removing and attaching  the center nut. The bar of the tool rests on the right side rearset making it a simple task to open or tighten the nut. Without this kind of tool it might we rather problematic to work on the nut without damaging the clutch center.


Well, how it works in riding ? After a short test ride the first experience is as follows : Clutch seems to have a slightly softer initial bite than the original  for some reason even if I have reused the orginal clutch plates, which were not even close to the wear limit. This makes the clutch slightly nicer to use in starts. The power required to pull clutch the lever has remained as with the original. The lever needs to be now pulled maybe slightly deeper for the clutch to release compared to original. In relaxed riding the clutch behaves pretty much in similar manner than the original. Then, when pushing a little harder and downshifting with higher rpm without throttle, the slipper does exactly what it is designed to do: Gears slip right in without any violent feeling and the rear wheel stays in line without hopping around. The overall feeling in downshifting could be described as "increased smoothness". You do not really feel the clutch slipping but it clearly softens out the engine braking. Second gear can be pushed in at 100-120 km/h and clutch can be released in one go having throttle completely closed and it does not feel bad at all. RPM shoots up for a while but the rear of the bike does not do any extra moves whatsoever.

I am eagerly waiting for the first track ride to really enjoy the new clutch.

April 2006

Further transportation problem solving taking place before riding season: Stema, a german made trailer for 2 bikes, total max. weight 750 kg. Also, a car equipped with towing hook is on it's way (small but brisk turbodiesel with 90 hp, 190 Nm torque, climate control and MP3 player with 6 speakers). The idea is to use this combination for longer track trips instead of  riding the bike back and forward. Driving a car after a hot day in the track seems to be much safer than riding the bike for 300 kms and trying to obey the speed limits.

Then, maybe a little 12 V air compressor to adjust tyre pressures, a 12 V cooler pack to keep drinks cold and of course a 12 V coffee maker. Not to forget a power converter to supply the laptop so that Powercommander maps can be updated in the field.

But speaking about track driving, I really don't need this, but decided to get it anyway : JTR slipper clutch. Nordic reseller is NF Racing in Sweden. Some installation instructions can be found here and a few installation pics here. The installation by Greyhound in US in those pics was not succesfull because the clutch center was by mistake for a different type of Honda, but the pics give a good idea what needs to be done. Hopefully my clutch will come with proper parts. I promise that this is the last new add-on part that I will get for the SP. No more costly mods after this one.

March 2006
Bought BagsConnection Racepack to solve transportation problems. It sits perfectly on the SP1 tail.

Service has now been more or less completed. Nothing more to be done before the driving seasons starts. Some new pics below showing current style items.

sivu   teipit   takis   nopat

Work done during winter 2006 (at 22800 km) :

- white led illumination for register plate
- 520 chain conversion with new 15/41 sprockets
- new rear brake pads (Honda original)
- rear and front brake fluid and clutch fluid changed
- valve clearances checked
- new iridium spark plugs
- motor oil and filter changed
- air filters changed
- cooling liquid changed
- PAIR mod
- all flapper valve items removed
- new mirrors with blinkers
- electronic flasher unit
- new fully adjustable clip-ons
- new adjustable clutch and brake levers
- new front fairing bracket
- rear footrests removed + new silencer can holders
- frame sliders installed
- new fully adjustable rearsets installed
- rim tapes, side panel labels
- exhaust cans installed with self-made wire-mesh dB-killers
- top yoke cosmetic fix

Added some nice Constructors Racing Group parts to further decorate the pilot's working environment :) Well, in addition to looking rather good, those CRG levers are also highly functional. Further, preload adjuster knobs added to allow front work adjustment without tools. Yes, and the top aluminum surface of the top yoke was renewed by milling 0.2 mm material off with a Bridgeport mill in a single pass using a 100 mm diameter bit. After that the fresh machined aluminum surface was recoated with generous apply of clear coat. I also wanted to get  rid of those passanger pegs and manufactured somewhat cleaner look exhaust can holders using 8 mm thick aluminum.
levers   holder

I checked the valve clearances and those were all nicely within factory specs (after 24000 km). Honda (HRC) quality seems to be ok. Cam surfaces and cam wheels together with all other components under those MAGNESIUM (!) made valve covers appeared as good as new. In order to better access the front cylinder head I removed the right hand side radiator. The manual says that front cylinder head can be serviced without removing the radiator, but this might apply only to clever japanese technicians with very flexible backbone and very tiny hands. New air filters went in.

etupaasy   takapytty   scissors   etupytty   ilmanputs

December 2005
Frame sliders and 520 chain & sprockets  installed. All "unnecessary" PAIR and Flapper Valve items removed.

slider   chain   no tank   block

November 2005
Driving season has ended and therefore it is time to start the mods season. To start with I decided to first do some stuff in the cockpit. See below a new self made bracket to support the front fairing and mirrors. This bracket is made by bending 10 mm aluminum rod and it is supported via a bearing in an aluminum holder from the steering axle. The hollow steering axle holds inside a short sleeve that is expanded using an inner cone type bolt to get a tight hold of the sleeve inside the axle. This is kind of the old school's way of supporting the bracket. Looks very technical if nothing else :)

I have also turned the Öhlins steering damper other way round compared to the original set up, which looks to me kind of funny because the damper unit would be inclined compared to the top yoke. In this setup it is parallel to the yoke and clip-ons and at least to me it looks better this way.

bracket1        bracket2         gilles1         gilles2

The above figs also show the new clip-ons made by Gilles Tooling Germany. These are really high quality units and fully adjustable.. From the rightmost figure  you can see that I wanted to somewhat reduce the down angle of the clip-ons to make them better suited to my personal ergonomy (in the righmost fig the rightside clip-on is still original, the left-one is the new adjustable version).

Here are the new Speedzilla front mirrors with those intergrated turn signals. I needed to replace the original blinker relay with an electronic relay unit to make the blinker frequency completely independent from the electric load of  bulbs/leds. Some people seem to add some extra resistors to compensate for the smaller currents when using leds, but the electronic relay is really much simpler way to go. At Motonet, the cost of the relay unit was 5.90 EUR (Elektr vilkkurele 2-napainen, osa nro 48-1894).


October 2005
I have now experimented a little with the Accelerator Pump software. It does make a clear difference, but noticed also that when driving on the track it is wise to select a little less "aggressive" settings, otherwise taking the turns can become rather challenging due to the very sharp throttle response.

Bought some new stuff for the winter : 15/41 sprockets and 520 chain, frame sliders, smog block off plates and Sato rearsets. Could not wait but needed to put those rearsets immediately on the bike. They are very well manufactured parts indeed !


Driving season is approaching the end. Maybe one or two weeks still to go. Here are some autumn pics taken near my house. Looking these helps to survive the winter.

vesa1    vesa2    vesa3

Mid September 2005
PowerCommander is now installed and the 1st map is a slightly modified Yoshimura EMS map. Immediately noticeable is that bike came much smoother in the low rpm end. Town driving is possible from 2500 rpm up. Next thing is to throw in some other maps for comparison and also test the free Accelerator Pump software. Already now it is however very evident that the PowerCommander is a really good mod eliminating the snatchy throttle response.

Original front blinker    New blinker side    New blinker inside    New bliinker   

From the very beginning I have NOT  liked the front blinkers, which are HUGE and look very old-fashioned. In the above pics you can see my mod where I assembled miniature led blinkers into the original holes of the blinker arms. By lucky accident I noticed that the very bright led blinkers from Motorcyclestuff (catalog part nbrs 1002575 & 1000033, see catalog page 6.43) fit perfectly into the original holes. A simple aluminum holder keeps them nicely in place. The bike looks now much cleaner. New front mirrors with intergrated turn signals are also on their way from Speedzilla. These are needed to make the turn signals clearly visible when observed directly from the fromt of the bike.

 I also removed the VTR Racing labels from the side panels, because personally I think that they make the bike look like a teenager.

September 2005
Just noticed that Yoshimura provides their own EMS system for this bike. The software and maps can be found from here. I used the EMS software to open up those Yoshimura maps. After that, it is simple to key in the Yoshimura maps into PowerCommander USB softaware. Actually, before testing on bike, I like the look of the Yosh maps somehow better than those PC maps I have gone through.

Bike runs very well even without the PowerCommander.  I have made about 2500 kms with it without any trouble or problem whatsoever.

August 2005
A PowerCommander USB is already on its way. What occupies now my mind is that all the maps that are provided by Dynojet/PowerCommander for SP1 seem to have very significant negative trim values in them.Why is that ? I always thought that in most bikes the stock map needs typically some richening to soft down the coarse engine behaviour especially in the low rpms. Seems that the Honda PAIR system injecting air to the exhaust system is the reason for overly rich mixtures.  In order to burn in the exhaust properly the exhaust gases need to contain CO and HC instead of CO2 and NOx.

I will install my  wideband lambda probe ( Tech Edge : 0 258 007 057 LSU sensor + 2C0 unit + LD02 display ) into the SP1 during next winter providing realtime AFR readout. However, the PAIR system needs to go before any reasonable measurements can be made. Also, I need check/remove any air leaks in the exhaust system to ensure correct readings.

Another interesting thing is that the removal of the flapper valve system seems not to cause any special need to add the fuel injection in the 7000-8000 rpm area, even if the valve could restrict the air flow cross-section maximally 60 %.

In an effort to try to find some common trends in various maps developed by various persons for a RC51/SP1 2000-2001, I calculated an average map based on 28 individual maps. These maps were selected among those downloadable from the Dynojet site (i.e. from Maps available for PCIIIr/ III USB models & User Submitted Maps). I selected such maps where the rpm and throttle breakpoints were similar so the map cells "coincide". The maps contain maps both for US and European models and of course for a variety of exhaust and inlet options.

The average map is here (right click to save and if necessary, change the file identifier back to .djm).
Just acquired a Honda VTR SP1 year model 2001 (19000 kms) to replace the old and soulfull Moto Guzzi Sport Corsa. This bike was reasonably modified by the previous owners: Yoshimura RS3 slip-ons, rear wheel hugger, undertray with rear lights, double bubble plex, steel braided Goodrich brake lines, Öhlins rear shock with hydraulic pre-tension adjustment, Öhlins steering damper, Öhlins racing valves, springs & oil inside the original Showa front forks. Very good, I don't need to buy those expensive components :)

The engine is so far stock except that I already made the flapper valve mod removing the intake air restrictions. The front forks went through service (Penttilä Racing, Hyvinkää) to get rid of oil leak, which seemingly was due to the use of Öhlins racing type synthetic oil. Now the forks hold Öhlins Race & Track mineral based oil and do not leak and work very nicely.

Here is one test review giving impressions what this bike is like..

For the history, my old Guzzi modication pages : ECU and HW