YAMAHA 2001 R1 engine head modification

[Lespaul66]

Some of you are asking more photoes and information from my 2001 R1 engine head work...I have already sent some photos and stories earlier...Please find the whole story published in Finnish motorcycle magazine on spring 2002 once more: I am sorry because of my poor translation....



YAMAHA YZFR1 2001 FINISHING WORK

Past four years – as long as Yamaha YZFR1 has been on the market – there have been written a lot from this motorcycle. Mainly those articles have been written from the introduction of the bike or test runs and comparisons with competitors. All the YZFR1 owners are interested from the engine improvements and this time we show how you can get the engine power up over GSXR 1000 level quite easily.

When I took the new YZFR1 motorcycle to my use on spring 2001, it took some while to get used to it’s big power. All the articles from the overpowered and poorly handling motorcycle turned out to be wrong. The motorcycle indeed is - by reasonably driving - very well under driver’s control. You can adjust the steering geometry to razor sharp, even tough, but with suspension and steering geometry factory settings the motorcycle encourage your confidence on the road. My opinion is that there is no need to install steering damper on the road. On the racetrack with extremely conditions the situation may be different especially after adjusting the steering geometry.

After the press test drive Suzuki GSXR 1000 motorcycle on spring 2001,I got an idea to rise my YZFR1 motorcycle power up to same level or even a little bit higher. The clue for engine tuning work was still to keep the strong bottom power and suitability to normal road use but get a strong boost to middle and high end. Already from the beginning it was very clear that in this tuning work it is better to use the professional tuning company help only. By that way you can avoid wrong component choosing and you can be sure that machining will be done from the correct engine pieces only. By using real professionals you can be also sure that the power goes up, not only the noise. Near my neighborhood (in Finland) located professional race motorcycle tuning company, Siukola Motorsport OY. I decided to use their years of experience in this project.

I got the suggestion for mild professional engine tuning work. The cylinder head will be ported and the valves reshaped. Combustion chambers will be also reshaped and the compression ratio will be slightly higher in tuned engine. New camshaft timing as well as new dynojet needles for carburetors will be needed. Also the standard air filter will be changed to more easily aspirate one (BMC). The best advantage from the engine work will be achieved by using new and better exhaust system. The whole work will be finalized by dyno-run trying to find the whole potential available. In other words the question is only from the original engine parts reshaping and retiming in a way that the “hidden and available power” will be searched out. The standard engine has been assembled by using certain tolerances taking account the serial production requirements. The choosing of the new exhaust system was the question we discussed a lot. One over others is Yoshimura Tri-Oval limited edition 4-1 (hand made in Japan). This is full exhaust system, not only slip-on. This hand made limited edition Tri-Oval system is different than Yoshimura USA made. By using this system it is possible to keep the bottom power in spite of the fact that EXUP valve will be removed. The only disadvantage is it’s very high price and difficult availability. The importer in Finland had got only five (5) Tri-Oval exhaust pipes during spring 2001 to YZFR1 motorcycles from Yoshimura Japan. Three were already sold and two were still remaining. I did not wondered any more, I wanted it. This exhaust system material is very thin stainless steel and we saved around 2 kg weight if compared to STD exhaust system.

Finally the work begins:

Before tuning work we made comparable dyno-run (STD bike). The dynamometer gave us luckily from the rear wheel the figure 140 hp. It seems that this one is even a little bit better bike than average. Normally the average YZFR1 back wheel power in this dynamometer has been around 135 hp. I heard also that normally 2k models have given around 5 hp more than 1998 and 1999 models is spite of the fact that the Yamaha factory has informed that the power is equal (150 hp).

[Lespaul66]

YZFRI has been washed and the engine is now missing ( the blue bike behind of the yellow R6 ). The red device on the right hand side is dynamometer which tuning company use for bike adjustment. The front wheel of the bike will be put to the groove, the bike will be supported by straps and the back wheel rotate on the dynamometer back roller. By using this device you can ride your motorcycle legally over 300 km/h even daily.

[Lespaul66]

The engine on the table and the cylinder head has been taken off. From the lower photo you can see that the protractor for engine timing has been fixed already to crankshaft.

[Lespaul66]

The engine was like new one…very clear. It has been driven only 4010 km before tuning work.

Siukola Motorsport informed that they are normally using a lot of time for cylinder head preparation. The hurry must be totally forgotten in this work. The work must be started with fresh mind and it must be the also the first work in the morning. ”Every time when you come back to work you can see the quality by different way”. The low flow resistant is not the only beatific matter, even more important fact is the absolutely correct suction and exhaust duct shape. Standard twenty valve YZFR1 cylinder head is even a little bit too open and favorable effect can be achieved by putting the small filling to certain parts to the duct. In this case the ducts will be reshaped. The valve stems will be reshaped and shortened slightly. Also the valves itself will be reshaped in a small way. They are not doing proper duct polishing but better we can say that the question is from the surface satin finishing work. After cylinder combustion chamber reshaping the cylinder head will be machined and the compression ratio rises slightly. High octane gas will be needed now.

[Lespaul66]

In some cases especially when the race engine is under tuning work, a chemical metal is used to fill and reshape suction ducts. This will improve the engine torque and power slightly. Because of the different coefficient of heat expansion between cylinder head material and filling chemical metal, there is a small risk that at the worse case the filling material may crack after some years of use. From the suction duct this may go directly to the cylinder. After all this is yet very unusual situation and because the chemical metal is very fragile it will not cause normally any bigger damages. Also in R1 cylinder head a small advantage could be achieved by slight filling work. Because the power increase should be only relatively marginal and those two or three extra horse power -which are so important during race competition- will be not needed on the road, we decided to invest directly to reliability now. The suction duct reshaping will be done without any filling material.

The BMC air filter will be installed to the bike. Normally the service interval with this filter in normal conditions is around 10 000 km. In Ram Air engine the service interval is much more shorter. Brand new filter is ready oiled. Air filter cleaning maneuver: Wash with warm water. No pressurized air or brushing! After drying add special oil to the each air filter pleat (only small amount is needed). The oil will soak to all over the filter and the filter color will be slightly red.

[Lespaul66]

Finally the engine had been assembled and the motorcycle was ready for dyno-run. After careful mixture adjusting work the dyno curve shows that the rear wheel power has increased 16 hp. It is remarkable that already after 3700 rpm there is more power and torque by all revs compared to STD engine. STD engine maximum power (140 hp/ 10150 rpm) can be reached from tuned engine already from 8300rpm. The maximum power from the rear wheel is now 156 hp / 10650 rpm. The torque increased strongly by almost all revs. The real engine power has been estimated to be now near 170 hp. We managed to beat the Suzuki GSXR 1000 engine power very clearly. The original goal has been reached.

[Lespaul66]

Limited edition Yoshimura Tri-Oval exhaust system is like artwork. The fabrication tolerances are so tight that the header is attached to silencer by slide attachment only. No any fixing springs and welds are needed. The sound wake up your respect but is still relatively quiet.

YZFR1 motorcycle looks now very light and fresh. It is ready for action!

[LDHR1]

great write-up and photos, how is the throttle response in the low/mid rpms? what were the costs related to the work done.

[turd1]

lespaul66, yes great story and photos. congratulations on a nice bike. have you modified the suspension?

[Lespaul66]

The throttle response in the low/mid rpms is great...I dont even feel that the EXUP has been removed...very strong bottom end.. not at all pop ups in exhaust system during engine braking because the AIS system has been blocked...

Last summer I visited twice on a race track and it feels that after 6000 rpm the engine starts really to scream...and the power punch is very strong ( you can see that also from the steep new power curve after 6000rpm ). The engine pulls also longer.....the standard engine started to loose its power after 10000 rpm - now the power is very strong up to 11000- 11500 rpm

I have not yet modified suspension but have ordered Scotts steering dampper from USA couple weeks ago...I suspect that this new dampper may be one ofthe rare Scotts damppers in Europe- we dont have agent here....The bike feel a little bit nervous on the track after front wheel power wheelies in second gear...

the costs

-engine head work costs were around 1000 USD= EUR (Dynojet + BMC air filter and all the dyno runs included)
-Yoshimura Tri Oval Limited edition Japan exhaust sytem was very expensive ( around 1500 USD)

My bike sound sample...I am accelerating on the track from the second gear to fourth one before tight curve....top speed around 215 km/hr...

http://www.r1-forum.com/forums/showt...threadid=16085

[Oliver]

Very interesting review. Thanks mate...

[Limited R1]

Nice write up. Sounds like the bike really screams now, great torque increase too.

[Lespaul66]

Thanks guys...

My next 2001 YZFR1 modifications before driving season 2003:

- Scotts steering dampper (I purchased it already)
- steel braded brake lines for front and rear brakes
- maybe smaller front sprocket (15), I am not sure yet...maybe 156 RWHP is too much for that ...