Track Questions

[Tdel]

Hi all,


I was able to get my cup bike out on 3 tracks the end of the season here in the east. Here's my questions for those tracking/racing:

1. I am sending out my suspension to thermos man for springing and valving but noticed a lot of chassis flex in the bike, i am not sure if that was due in part to me exceeding the suspension or if once stiffened i'll still get a lot of chassis flex. For those that have brought their suspension up to spec for their weight, are you still getting chassis flex.
2. I noticed lot of brake fade that led to an increase lever pressure, are you faster guys seeing brake fade? If so was there anything you were able to do to address this?
3. Have you been able to address ground clearance issues with ride height?

Thanks

 

[big_sur]

1. No, but I weigh 150lbs.
2. Yes, I get pretty bad fade with ABS delete lines, motul rbf fluid, pads, and 300mm PP floating rotor, which is all that's allowed in our series. I imagine a 320mm rotor and a master cylinder would help quite a bit.
3. Yes, with ride height, rearsets, and 140 rear.

 

[Treachery]

Tdel: Two things occur to me: 1) What you're interpreting as flex could be sub-par suspension performance &/or lack of cooperation between the front and the rear., and 2) as big_sur sort of indicated--what do you weigh? I'm lighter than he is, and find the chassis to be pretty solid, especially since I upgraded the rear suspension.

 

[simpletty]

Tdel: Two things occur to me: 1) What you're interpreting as flex could be sub-par suspension performance &/or lack of cooperation between the front and the rear., and 2) as big_sur sort of indicated--what do you weigh? I'm lighter than he is, and find the chassis to be pretty solid, especially since I upgraded the rear suspension.

Im 220lbs out of gear....I found that the bike is solid and has no signs of chassis flex with upgraded suspension. it felt planted and stable under hard cornering. As far as brakes go---junk the abs, lines and front rotor. Replace with sintered pads, 320 gafler and either adapt existing lines to fit, which i did, or buy speiglers. The thing stops solid with no fade whatsoever. I am also doing a master cyl upgrade this winter.

 

[mattonrc390]

1) Haven't noticed any chassis flex on the Cup bike, but tbh I'm not sure what that really feels like. I'm 150 and kept the forks stocks and swapped out the rear spring to an ohlins .75nm, feels dialed and planted.
2) Depending on the track I sometimes also get brake fade - cheap solutions that may help: Motul RBF600, new pads. You can always get a new master cylinder and/or brake remote adjuster if you're prepared to shell out the cash, those will likely solve your issues.
3) Yes, i scrapped the exhaust pipe on the akra at first, raised the rear and lowered the front (for geometry/turn in purposes) and it also solved my parts dragging issue.

Good luck! Cup bikes FTW.

 

[Tdel]

I am 200 without gear, so I far exceeded the current set up for a 140 pound rider. Regarding the brakes it's a cup bike so no abs, not sure what rotor and pads came stock on the bike and if I can upgrade without being knocked out of a stock class. What pads are you all running, I usually run the brembo super bike pads on my track model rc8, expensive but fantastic bite and feel.

 

[Eddie390]

Hey Tdel, are you also on the UK KTM forum? I'm eddie990 on there, did those RC8 parts arrive OK?

Anyway, I also have the Cup bike.

1) The Cup WP stuff is actually pretty good. Decent range of adjustment and I've found a good set-up but was maxed out on preload. Get the spring rate changed to suit your weight, I'm 75kg (165lb?) and I've ended up with a K-tech 50-150-90 on the rear and 8.0 springs in the front. Have yet to try it out on track but it feels much better supported and stiffer.
2) I've been having the same fade issues, will be trying Brembo SC pads and Motul RBF600 fluid before changing anything else.
3) Even the lightweight teenagers in the RC Cup series have problems with ground clearance, particularly on the right hand side. Mine is jacked up but still scrapes the pipe even when I'm hanging off like a demented gibbon! I'm hoping the suspension mods will help.

 

[Tdel]

Hey Tdel, are you also on the UK KTM forum? I'm eddie990 on there, did those RC8 parts arrive OK?

Anyway, I also have the Cup bike.

1) The Cup WP stuff is actually pretty good. Decent range of adjustment and I've found a good set-up but was maxed out on preload. Get the spring rate changed to suit your weight, I'm 75kg (165lb?) and I've ended up with a K-tech 50-150-90 on the rear and 8.0 springs in the front. Have yet to try it out on track but it feels much better supported and stiffer.
2) I've been having the same fade issues, will be trying Brembo SC pads and Motul RBF600 fluid before changing anything else.
3) Even the lightweight teenagers in the RC Cup series have problems with ground clearance, particularly on the right hand side. Mine is jacked up but still scrapes the pipe even when I'm hanging off like a demented gibbon! I'm hoping the suspension mods will help.

Eddie, I did get the parts this week, all good. I am hoping I can get some of the fade out of the system as I plan on running this bike in a few endurance races. The guy doing the suspension is one of the best in the USA, has handled all the AMA/motoamerica pro teams suspension for 20 years, he completely changed my rc8 track bike. He said he has some ideas for the 390 (raise the rear a bit for ground clearance, springs and valving for my fat ass) so I have no doubt it will feel great so long as I am not putting too much energy into the chassis. A racer friend of mine is recommending the vesrah rjl-zz pads so I'll try them out and put new fluid in too, may as well do a fluid change in the rc8 this off season while I am at it! Let me know how the Brembos work out.