Linkages or Rear race shock or both !

[stu23]

Hi

A quick question re Race shocks , Do i need the linkage updating too, to an alternative to raise the rear or will a race shock with adjustable length do just as well..  Angles and such ?    I will be putting an R6 front end on ( have a complete one in the shed )  as the bike currently has a rather bent std front end on it.

Cheers

Stu

[M. Hausknecht]

The Robem linkage creates a more linear relationship between wheel movement and force (allows the shock damping to work more effectively), and it creates more swing arm angle (which results in more anti-squat in the rear). Both changes improve the bike's handling with the rider only.

Adjustable shock length can be used to make small adjustments to rear ride height (which impacts swing arm angle, head angle, trail, and center of gravity). Competitive MotoAmerica Twins Cup bikes typically have both.  I do too although I'm not near the pace of the top 10-15 MA bikes. Do you "need" new shock linkage? Well, that depends on your goals, your pace (I assume you intend to at least track, if not race, your bike), and your ability and willingness to spend money.

Ideally, you should also replace the stock R6 triples with triples that allow you to adjust trail. The stock R6 triples feature 30mm of offset, which results in very little trail, which will result in a bike that is unstable and doesn't want to go in a straight line (think tank slapper).  Raising the rear, via added shock length and/or revised shock linkage, also results in less trail, further aggravating the situation.

The stock 07 geometry leaves a lot to be desired if outright performance around a race track is your priority. Because everything is related and effects the geometry of the bike (fork height, offset in the triples, shock linkage, shock length), an integrated approach is necessary to assure you end up with something that works.   

[FZ not MT]

Just now, stu23 said:

A quick question re Race shocks , Do i need the linkage updating too, to an alternative to raise the rear or will a race shock with adjustable length do just as well..  Angles and such ?    I will be putting an R6 front end on ( have a complete one in the shed )  as the bike currently has a rather bent std front end on it.

Just wanted to mention another very well made option regarding linkage - the Extreme Creations lowering link which also has a raising options as well. I have this on my FZ and it is so well made, it's arguably artwork. Do some digging in this forum and you can learn more. BTW, the price on their website is in AUD, the US is $173 which includes the seals and bearings which I would recommend you let them do.

https://www.extremecreations.com.au/mt-07-jack-up-plates

 

[stu23]

Thanks for getting back to me    yes I intend to race it  here in Australia   I have raced for many years usually on an R6  and am near the sharp end of racing  ( but not at national level )  I thought I would enjoy racing a twin for fun so here I am .  Yes I have read articles on the forum   some say the r6 front end is fine though  even without triple mods   can be quite confusing 

[stickshift]

4 hours ago, stu23 said:

Thanks for getting back to me    yes I intend to race it  here in Australia   I have raced for many years usually on an R6  and am near the sharp end of racing  ( but not at national level )  I thought I would enjoy racing a twin for fun so here I am .  Yes I have read articles on the forum   some say the r6 front end is fine though  even without triple mods   can be quite confusing 

Getting trail numbers right is more important than whether you choose R6 or standard forks (obviously with aftermarket mods) in my opinion. Robem triples allow you to choose from a number of trail angles.

Some racers swear by the R6 forks, others view them as unnecessary. I think most would agree that 'track' trail figures are more important than fork type.

Edited August 26, 2022 by stickshift

[stu23]

Sounds good to me    let's see what we can do with this bike

[M. Hausknecht]

Just now, stickshift said:

Getting trail numbers right is more important than whether you choose R6 or standard forks (obviously with aftermarket mods) in my opinion. Robem triples allow you to choose from a number of trail angles.

Some racers swear by the R6 forks, others view them as unnecessary. I think most would agree that 'track' trail figures are more important than fork type.

Trail is arguably the single most important geometry number when it comes to getting around a race track on a motorcycle. Fork offset and front and rear ride heights determine trail at the ground. You'll want a fork offset somewhere between 24 and 28mm. The greater the offset, the less the trail. I'm  at 26mm, which seems to work well with Pirelli slicks, and higher rear and lower front ride heights than stock.

As for the forks, I've got stock forks with Ohlins cartridges, and suitable springs and fork oil weights. After running about a half dozen race weekends I've concluded that at my weight, 160lbs, they are just too flexible to provide any meaningful feedback on what the front tire is doing (I've run Dunlop and Pirelli slicks). They are sufficient for advanced pace track days and spirited riding but just too numb for flirting with traction limits either on braking or corner entrance. Right now, no one in the top 20-25 of MA Twins Cup is using the stock fork tubes.

[stu23]

Have found a company in oz that makes fork extenders for r6 forks so should be able to get to some good numbers with these if i need them   we shall see