Rasing the engine in the Frame

[Jota Rob]

Hi Rob

are you running 18 inch wheels or 17 inch wheels?

on my 79 1200 at our local track I ground right through the bottom edge of an original alternator cover on the right side, but I always figured if I were to get over far enough on the left side to touch anything down on the primary cover that the bike would tuck its front wheel and pitch me on my head...... Also probably partly psychological, I tossed a Benelli 900 Sei and myself away HARD after grounding the motor on the left side and levering the wheel off the ground, so I think I am maybe just a tad more cautious on left handers, memories of the pain and the slower healing process as I age have faded but not gone away completely

my local track school advocates much more hanging off than the tidy riding style shown in your photos, problem with all the gymnastics of extreme hanging off is big weight shifts and really really sore leg muscles at the end of a track day(at least in my case)....after my last full track day tossing both the 1200 and the RGS around I had trouble walking up and down stairs for a couple of days my legs were so sore.

I was also interested to see you don't apear to be running a fork brace. Are they prohibited in your race class or do you just figure the front end doesn't need bracing?

Paul LeClair

Paul
Im currently and as pictured running 17" wheels and it's roughly around 1/2" lost in height. Although the tyres are lower profile, they are wider which balance each other out.
I get exactly the same problem as you described with severely pumped up calf muscles, aching for a couple of days, even though I regularly work out with weights . I only learnt to change my riding style since riding this actual bike, it wasn't taught, well  it was but the bike taught me. I simply couldn't ride round bends with my foot on the foot rest as I'd lose my toes so went tip toe into each bend on the respective foot and shifted my arse, the rest fell into place but of course its 5 times the effort, which I guess is what you're finding too.

The primary tensioner has come out and the lower casing boilt has unscrewed itself twice on the tarmac as these are the 1st things to touvh down, but can be re worked as you see. There is no fear of the front end tucking in, but thats probably less overall weight, a stronger front end and certainly a better front tyre, than you would have experienced on the Benelli but there is every chance of a wheel being levered off the tarmac from the engine as a pivot and that scares me sometimes.

Keith, yes that's the sender to the Digital Speedo (for the oil temp of course), it cuts in at 50 deg C and is a great point of reference.


The fork brace, well I try  to be diplomatic, I dont know how much unsupported fork tube sticks out from the neck of a space frame but I'm not sure its longer than on a regular tripple frame. The neck of a Laverda frame is too short. Oz Laverda maybe be having a problem but I dont, however on my regular Jota I do...they are completely different bikes, 30 plus KG difference and an unbraced and short steering neck mean lots of flex, plus of course with an extended neck, the lower yoke sits further down, leaving even less unsupported Fork tube to flex.

So it's not that Im being bloody minded Red, I just haven't got a problem to fix in that department yet.

Boba, that gorgeous Red coloured triple racer, look like its been raised no more than 12mm at the front which could almost be done without too much re working, today Im going to see what restriction the tank imposes on the raising of the motor. The rear end is already jacked up so far this year but 30mm at the rear is only 10mm at the front of the motor so that would mean, a 10mm raise at the front of motor will level it back out to standard again, I'd like to go higher than 10mm  though. Tippie, do you have any Photos of the Jota you mention ?  

 

[Tippie]

Rob, unfortunately not any photos. I was just a mechanic at the shop and the owner did the racebike. From memory it was much like that in the other bike shown but a round "invisible" spacer to not get caught out for.
Cheers
Lee

 

[bob]

The lengthened steering head and subsequent bracing back to the frame mean a fork brace is unnecessary.
That came straight from Van Dijk when he braced my frame. Rob has done something very similar.
A fork brace is a pretty crude device at best and can lead to other fork issues as we all know.

Forgive my ignorance Grant,  (and it is ignorance I assure you)   
Why is bracing the forks detrimental?  Surely the less they twist the better?  Not?

Julian

Hi Julian,
Opinions on fork braces are very polarised, for instance Maxton, one of the leading specialists in motorcycle suspension , don't recommend them.
One of the issues is that careless installation can result in stiction created by slightly compressing the fork seals and this will create more handling issues than it solves. I have a couple of friends who are very successful racers and they swear by them, on the other hand I have other friends who have lapped the Island at 105mph without them.....on 35mm forks! These are all expert riders who think carefully about what kit they run.
Red makes a very nice fork brace which addresses the problem of compressing the fork seals and he has kindly sent me one to test on my racer [which is currently running a Tarrozzi unit] I'm going to fit during the next two weeks and start some meaningful test.
A lot probably comes down to riding style....

 

[paul-haggis]

Hi Rob, as I'm sure you know - the lower front edges of your silencers are getting damn close to the ground also.

In one way it's a shame you have to rotate the engine - your bike has a raw beauty about it and those lines might get fecked up. Still, speed on bro.

Hag.

 

[phil37]

Hi Rob - There was a Swedish triple raced in the nineties that went on to win (or came very close to) the scandinavian race series - it had the engine raised quite an amount - it was pictured on the front cover of a Swedish magazine and looked really well prepared. Perhaps someone has a copy?
         I have suggested before to run without the alternator and weld a pipe extension on a cut down original cover - engine is already raised in this frame - wheels were 17" front & 18" rear - I have made a fork brace from 8mm aluminium plate - cheap and effective and meets CRMC regs as it is counted as a mudguard support - see photos - Regards - Phil

 

[Laverdalothar]

Let's face it: installing a fork brace is possible for anyone who is able to work with a wrench or/and a ratchet spanner. Modifications on the frame are only possible with welding, which means a complete strip-down and re-paint of the frame. Not sure that everyone on this forum is able or willing to do that.

I agree, a faulty installed fork brace makes things terribly worse. But that is the same with an over-tightened head-stock bearing, a wrong spaced or square mounted wheel etc. etc.. Even a fork can be mounted with tension which leads to a bad riding.

The fork-brace on my Jota is on since 15 years and was the first modification I did to the suspension of the bike. It helped a lot I must say, but my frame is absolutely unmodified. Can't tell how much it means for a modified headstock or if there is any difference, but I still could imagine there is. And grounding a Triple is no big deal, even I can do that: just eat more.  :-[

Honestly: how about longer shocks and forks? Raises the hole bike... If you lowered it by 12mm (1/2"), you could maybe compensate that a bit with longer suspension. Especially if you raise the engine, you don't get in conflict with the frame with your chain due to the longer shocks and different angle of the swing-arm. What shock-length are you currently riding?

 

[Jota Rob]

Hag

I'll dig out a picture of the exhaust can   but I do plan to try and make a new exhaust system, still along the same lines though with same cans, just neater. Have to learn to use the Tig welder though, it's proving harder than I thought possible !

Hi Phil, thats a great photo, good times !!  But I think that motor in your Motodd? which means its probably higher, than standard. I think I'd stick that pipe into the tarmac instead, albeit slightly later, but its something I will look at doing when I get the motor built up again. It'd be great to see that copy of the magazine .. Someone ?

Lothar, I've raised the rear, keeping the same shocks, Im not saying how, but you can use your imagination, I dont want to raise the front, as I want to take advantage of the steepened rake, it was always a very stable bike at any use and will accept a steeper angle, as I did run the forks lowered, when I had 18"/17" wheels but wanted that clearance back. Modifed Headstock is a no brainer, but Grants is so much longer it must make a massive difference to closing the gap on the unsupported fork tube.

 

[XBCoupeJota]

Rob,

I reckon your coming to the end of your rather enviable road/track special. Reckon your going to have to make a decision about whether you want to race the thing, then you can get serious about throwing away the starter, alternator and trim everything back and produce a well sorted race bike.

Red's brace is now on the Spaceframe as we had real issues with the front tyre and mudguard being pushed back into the center header pipe under hard braking, It was quite hard too believe we had that much flex when you consider the spaceframe runs much shorter stanchions than any Jota (720mm from center of axle to top of top triple tree which is about 100mm shorter than my Jota). This problem was something that had to be dealt with for safety reasons, the brace seems to have helped with flex under braking which I didn't necessarily expect and has not had any adverse affects on stiction. The problems we had with suspension at Wakefield test day Vince refers too have been completely ironed out now with some additional work to seal the emulator correctly with a machined Marzocchi internal I used from another set of forks I had.

Fitting the new 17 inch Astralite wheels took me a good couple of days to measure up the correct spacers, machine and fit to the bike. The room I have clear between the sliders and the buttons on the rotors is about 0.5 mm and when I first setup the new wheels with the brace on, I was testing the stiction on the front suspension and it went from being locked without the axle done up to free as a bird with the axle torqued up.

It would be interesting to know how far from the ground the engine is on your machine (with static sag). I'll check the Spaceframe to compare, as we haven't had any grounding problems this year with engine cases (only the fairing), and I reckon geometry could well have a significant bearing as the Spaceframe has a fairly modern rake and trail setup compared to a Jota.

Cheers Crispin

 

[XBCoupeJota]

Forgot to add we did get additional clearance assistance after fitting Steve B's engineering work of art.

Beautiful isn't it 

 

[bob]

Interesting points Crispin, I used to scorch the mudguard on my spaceframe with the centre pipe but I never noticed it until I got back to the pits. I just put up with and never considered a brace would cure it, it never felt lairy so it didn't really give me cause for concern.

Racing eligibility rules in the UK are much stricter than in Oz, unless of course you want to run with modern bikes. 17" wheels are out , and some series insist on the bikes original method of starting is retained. If Rob decided to go racing he would need to identify a suitable series and then build a bike to comply. There's plenty of opportunities over here but if you're not careful with your mods you can paint yourself into a corner and end up running in an unsuitable class.

 

[Jota Rob]

The only class I could run with is the Thunderbike series and after watching them I figured it probably wouldn't be competitive and It'd be easier to start again with another frame which I do have.

Crispin, that cover is a beautiful creation for sure and I'm suitably impressed with the impact you've made with the space frame in such a short time frame..

I cant measure the sag becuase I dont have enough weight on the bike to do  a half decent job and the engine is empty and jacked up for now but the grinders coming out this pm and the engine and tank are moving upwards. It wont look obvious, because I have Paul Haggis's concerns firmly etched in my head ..... I want it to look as it did not like a Bol D'or Streetfighter   ???

 

[sfcpiet]

Rob,

The engine is raised by 12 or 15mm (don't remember, to be frank, and the bike is 550kms away, so cannot measure for you!) spacers at the bottom and positioned about 20mm forward.  Didn't want to go further forward because of clearance issues between front wheel and centre header under heavy braking.  Unfortunately, didn't think of lengthening the headstem ? la van Dijk when building the thing, would be a definite improvement, decreasing the unsupported stanchion length dramatically.  Using a fat Beemer fork, so fork flex is a lot less than with a Marzocchi or an even flimsier Ceriani.  (Ceriani stanchions are thinner walled than Marzos...)  The forks are quite long, the rear shocks have been re-positioned for more ground clearance, still on 18 inchers with absolutely no grounding issues.  The cut off alternator cover was formerly used by the Moto Witt equipe on their TT F1 RGS, they were wearing out the CroMo bottom frame rails!  

My road 3C, the yellow one, is raised completely through suspension alone.  SFC1000 M1R fork up front, re-positioned 360mm WP units rear.  Have managed only once to ground the stock alternator cover and that was after making a royal mess of a bumpy corner.... but then, I don't achieve your type of lean angles!  Did manage to ground the primary adjuster before I modified it, no longer even get close now.

Although I don't believe in the necessity of a fork brace, I must admit Reds' is a true work of art and through its' precision alone would lend stability to any fork, providing it works properly in the first place.  Braces, more often than not, are detrimental to fork action and usually cause more headaches than cures.  The flimsy 38mm forks would definitely benefit from a DECENT brace, but I have also seen forks that no longer worked at all after a brace was fitted(shitty brace, most probably)!

But the brace will not prevent the stanchions from bending under braking, it can only (help) prevent the fork from flexing within itself.  The long headstock is one clever idea!!

piet

 

[motoddrob]

Great fotos Rob, impressive lean angles!!
I have one of those telefix braces on the Motodd and never had a problem with stiction. I guess it's how you set it up that counts.

Phil, just how much higher is the motor in the Motodd frames? I seem to recollect about 2". The Alt has never kissed the tarmac but maybe I'm just chicken shit when it comes to cornering!!

I can remember following 78jotadave back in the 70s, racing from one pub to another to get the jugs in before last orders when he got very sideways at speed, me going woohoo thinking he was very lucky not to have crashed. Couple of kays later as we braked hard for the entrance to the pub carpark I was instantly on the deck thinking what the fuck happened there. Turned out Dave had ripped the primary adjuster out of the case and I lost the front end in his oil trail. I had to ride my SF2 home without front brakes while Dave's 3c had to get home in the back of a ute.

 

[RUSS]

Realising my Lav was having problems it didn't have 20 years ago, I went on a diet and now only half fill the tank. That raised the engine.

 

[phil37]

Hi Rob & Rob - the Saxon/Motodd frame  holds the engine about 2" higher than standard - depends on suspension settings. I think that to ground it out in road use would be quite drastic cornering - racing is another matter. I use "Cerrocchi" forks with Marzo stanchions as they are a bit stronger (as Piet has said)- but I hate the poor quality of the sliders and use Ceriani ones. The fork tubes were std Marzo triple length, but were about an inch (or maybe more) above  the top yoke. With the mechanical anti dive fitted, the mudguard only just kissed the centre exhaust tube on the most drastic of braking. I learnt many years ago to remove the dome nut on the chain adjuster and let the screw thread drag on the floor - doesn't rip out hole in the chaincase then. - Regards - Phil

 

[Jota Rob]

Well thanks for all the help Guys.

I've kind of made up my decision and am half way into the engine bracketry, its going up 20mm  but also at the rear so it remains roughly level but I should be able to lower it to remove the Cam cover without too much drama. I have a couple of bracing gussets that make life a little harder to get the cam cover off as standard , so they will probably affect things to more of a degree.

I didn't know about the forks qualities, I bought a pair of brand new Ceriani Stanchions Sliders (edit) off ebay for a good price (?60 I think) a couple of years back, still boxed but I think I'll save them incase I can build a brand new Jota from NOS off ebay ..hah

I think, the higher the motor sits, the higher the point of contact on the motor when it finally makes contact with the tarmac, so I expect the contact point to move up towards the end of the crank rather than at the bottom of the Alt cover.

Russ you make a valid point, even if jesting, I never run on the track with more than a Gallon and Im always on reserve taps, with a sprint I run about 2 litres or less.

Motodd Rob , yes that oil is slippy, Ive had a few near misses with my own oil so thank, you've reminded me to make a catch tank too.

I guess one thing, the ex fabricator got right was his re angling of the centre pipe, it does seem to work quite well, so if I ever get to grips with it, I'll follow his lead.

Cheers Rob

 

[motoddrob]

Here is a shot from late 80s at the local circuit in Perth. My mates on the Motodd with me following on the SFC.
Not long after he lost the rear end but managed to keep it upright with me on his tail thinking Fuck John, that's my bike there!!!

 

[paul-haggis]

Hi Rob.

[Assuming you are leaving the swingarm pivot axis wher it is].

Off the top of my head I cant remember the height relationship between rear wheel axis & drive sprocket axis (i.e. the driveline) and the swinging arm axis. A 2" move at the drive sprocket could have an impact on rear suspension squat/lift when you are giving it the berries and could have an effect on how the rear tyre digs in when rolling on the throttle quickly.

Hag.

 

[Laverdalothar]

Can add some angle-Shots from the last two SPA-Sessions:

Nice 500:

first round out of the pits (Eau Rouge); In front Peter on a 1000SFC, me in the middle on my series 2 180? Jota, rear is Jens with a 3C/1:

dito - first round, Piet on his yellow/black beast:

Jens - wild hanging off...:

and closer:

Peter in front:

Is that you, Rob?:

aaalmost touching the tarmac:

me, too... (but with the engine, not the knee...  :-[)

again:

and again:

juuust a bit more...:

and a different shot, made with a professional camera...:

a bit to much...:

the result:

 

[MarnixSFC]

Hi Lothar,

Picture where you write 'is that you Rob', that's St?phane from Belgium on his 750 SFC with me chasing him on my Egli Lav. The dice lasted the whole session, magic. Good times.

Marnix