Lightened Flywheel question.

[philhnottm]

Advice Please

Running a Sausage speed 210 , about 18 BHP on the Dyno steady but not awe inspiring performance. Everyday runner as well as used to commute .

Just had a re build and changed the JL RH for a SIP Road Race which has made it nice and smooth in 1st 2nd and 3rd and pulls ok.

Not a great deal of top end speed ( GPS about 65mph) so wondering if I fit a HP4 1kg , or the new SIP elec start Lightened flywheel 1.8KG will this make any difference at all to performance in the range .

I have a Sip dIgital Speedo which shows it revs to about 6700 in the lower gears but no where near in 4th ???


Is it worth it or is it a complete waste of money for little impact.

Also is it a straight one for one fit with no other fettling required

Cheers

Phil

[Adam_Winstone]

Fitting a light flywheel will make no difference (or VERY little) to top speed. Light flywheels help a motor to rev faster, improving acceleration, but don't really do anything for top.

I don't know what the power characteristics of the 2 pipes are like but it sounds as though the motor could be over-geared. Are you running a T5 4th gear? If not, this is the usual fix for getting tuned 210s up into the powerband to pull 4th correctly. This all depends on state of tune vs pipe characteristics vs gearing... rather than flywheel weight.

Adam

[fraserp200e]

I've had one (the lightened beedspeed one) on my Harry Barlow stage 4. Like was said above it accelerates better (quicker), I thought it added a wee bit to the top end but that might just have been my imagination (I didn't check on the GPS before and after), the only thing I didn't like was when you roll off the revs, it feels kind of "lumpy" cause there isn't the weight to keep the engine spinning like a standard flywheel does....

It is a straight swap, so easy to change back if you don't like it, I take mine off for long runs, rallies etc and put it back on for running about local.

[cezeta]

mate had a sip race pipe on his kegra malossi. it was stainless and fell apart in france. by chance popo of scooterworld had a jl left hander like the rz. transformed the bike which could then pull fourth loaded with boring northern soul records.

i would say you need to put the old pipe back on or down gear to keep it revving

[philhnottm]

Just changed the JL RH after rebuild for the SIP road as it was faster in 3rd than 4th .

Does have T5 fourth Gear . Think I will leave the flywheel at the moment . Thanks for the advice.

Its had a PM LH , SIP EVO LH & JLRH before the new SIP Race.

The SIP appears to have smoothed it out a lot but and it can be thrashed all day long which is a bonus.

May just be a slow engine, until it goes to Al Terry next year.


just interested that people with similar set ups are hitting 75=80 GPS and a lot more than my 18 BHP on the dyno