Cheap-ish mods

[NoSkill]

Hi, I've just started racing my nc30 (had my first race at brands last weekend), and I'm completely hooked already.

I've got a problem with a sheared bolt for one of the front downpipes and a broken bolt on the link pipe for the rear pipes, so the exhaust is blowing and I think I'm going to need to take the engine out and possibly/probably even the head off in order to get that damn bolt out. But when racing I noticed I seem to have an annoying lack of power, I can keep up with some other riders round the corners but as soon as they hit the straight they just ride away from me, so I'm thinking of doing some mods (on a limited budget) to eek some more power out of the engine.

Just fixing the exhaust so it doesn't blow should give me a bit, and I'm also going to get it to a dyno and get the carbs setup better but I was wondering what else it was worth doing, especially seeing as the engine is coming out.

First thing that came to mind was exhaust, Tyga do the full system and should come to ~£480 with the maggot can, or £530 ish with the normal can, expensive but I'm thinking worth it (seems to give a reasonable power increase and might/should put me at least closer to 60 which should help and weighs a chunk less than the stock one).

But there are other things I've read about but don't have much info on:
Removing the quietening gears? guessing this is more quicker revving rather than outright power?
Airbox mods? how much does this help and whats the best way to go, Tyga do a carbon box which isn't *that* much...
Porting/Polishing, dunno how much this would cost or even if it's worth doing, but if the head(s) are coming off anyway?
Skimming the head for higher CR? same as above really...
Total Loss? does this increase power slightly by putting less drag on the engine?

Obviously I've got a long way to go both in improving as a rider and losing weight, so no point spending truly silly money now, but it would be nice to have a bit more power (in the last race I was ahead of a 61bhp nc29 cbr400 out of clearways and he went flying past me before the start finish straight, the git :p)

The bike is now a pure racebike, so emissions etc don't matter, just the 105dB limit (will the maggot can on the tyga exhaust be less than this?), also I don't notice any problems but are there any cheap and easy upgrades to the suspension/brakes?

Brakes are currently stock calipers/master cylinders, but with braided lines and EBC HH pads on the front.

Suspension is also stock, I believe it's the early type front forks and later type rear shock (external reservoir...), I have done the mod to the rear dogbone by drilling a new hole ~10mm further in to jack up the rear, but this seems mostly offset by the fact I'm running a 17" rear wheel...

Cheers, Josh.

[CMSMJ1]

Hey Josh,

I would go get it dyno'd now so you have a baseline to go from.

The fast NC30's have ram air, split pipes (a stack or SP1 style) and run total loss.

Making it lighter is always good so perhaps lightweight subframes, wheels, clipons, ally tank etc etc.

Outright power is not cheap.

I had my road bike tested with RVF carbs, open airbox and yamamoto race exhaust at 61bhp.

Where you based? Might be wrth looking at the carbs that graeme france has for sale at the minute in the sale section - ram air ready adn airbox.


At the end of the day - the more air you get in the better.

[chazmonkey]

I wouldnt bother going down the maggot route as mine came out at 111db!!!

It did look and sound good but thats no use if your not allowed out on the track

[NoSkill]

Cheers for the replies, definately won't get the maggot can then :p

I'm based in cheltenham/bristol area, had seen the carbs/ram-air and it's tempting,

Anybody know of any decent dyno places around cheltenham/gloucester/bristol area, rang one place called Race Techniques in Cheltenham, they seemed reasonably priced but they won't have the rolling road dyno set up for roughly 3 weeks (currently got an engine dyno setup instead, which is far more expensive apparantly :p), would be interesting to see what power it's putting out, even atm with the blowing exhaust, and then see how much I can improve it by :)

61bhp would be plenty really, I know it's possible to do 56's round brands with that power, which is a decent improvement on what I managed last weekend (59.3), some of that will be getting better as a rider as well of course, but 61 would do me for the season, as long as the other bikes don't just fly past me without even trying :p

Total loss seems a cheap way to get more power so it seems I'll definately do that, and subframe i'm not sure about, iirc the ally one from rick oliver wasn't too badly priced, another option is take an angle grinder to my current one, the bike was measured at 174Kg after one race, but I've currently been filling it to the brim at the beginning of the day due to a fuel starvation issue I had on the rookie training day, saw one site linking this (possibly) to the vacuum/diaphragm in the fuel tap, so I was planning to take that out and start running the lower fuel levels most other people run (after some testing to make sure I can make it for the race with that fuel of course :p)

[Smev]

Don't forget about the carb mods which are relatively cheap!!

the 2.5mm holes in the slides and th 0.5mm washers under the needles

Smev

[matty_boy]

Hello mate.

The first thing most people would say to you is to get the suspension sorted. If you are quick on the bends now you will be even quicker with updated forks and shock. Now this does not have to be all that expensive.

You can go down the route of buying a Maxton or the like rear shock, but if you are on a budget the Aprillia RS250 rear shock is a easy upgrade and a nice place to start from.

For the front end the std springs are not great for racing due to the road bounce that is built in to them, Rick Oliver does an upgrade kit for the forks which is around £200.

As for the engine work it is all about how much money you have.

The few things that you can do yourself are "engine weight reduction" Like removing the quieting gears. Doing this will drop some weight off of the cams, which means the engine power will increase due to not having to do so much work.
The same thing can be said about removing the charging system and running total loss.
Then you can fit a lighter fly wheel. All of these thing you can do with out breaking the bank.

The best thing to do is ask about for what people have done to there bikes on here.

[royster81]

suspension is always high up the list ,no point having 70bhp and not being able to corner.

then it's more of a weight saving exercise i think than a search for power,no point having 70bhp if your only going to be as quick as the next 60bhp bike cause he's 10kilos lighter.you could junk the flywheel as it's only going to be a race bike,chop the subframe to it's bare essentials,remove all road gear including brackets and fans that aren't going to be used on the track.alloy bits are a good idea bit on a budget just get the low cost things now,ricks alloy bars save a fair bit,rearsets help position your feet and are also lighter,and look out for an alloy filler cap on ebay,they are super light and look great.running the bike with only enough fuel for the race will also help.

then get the bike set up with whatever exhaust you what to use,like you said the tyga system is going to give more power but it's going to be a brave it lighter and if you go to a decent dyno the operator should know how to get the best from the bike.

[chrisja2]

I presume youre running a smaller cog on the front and bigger one on the back? Gearing makes alot of difference out of the corners.

Chris.

[NoSkill]

I agree suspension is important (and I do intend to do some work to at least the forks), but the problem down the straights was fairly bad, there was one zxr, not sure on what power it was running, but round the corners he was very slow, but even if I passed him in surtee's he was past me again comfortably before the start/finish line, even a 250 2-stroke had the legs on me towards the end of the straight...

I probably wasn't running low enough gearing (topping out 5th but not getting to 6th), but it didn't seem to be a problem just out of the corners, I could keep with the other bikes on the initial acceleration and then they took off...

[Riley]

Hi Josh,

Race developments in Gloucester have a very good reputation as far as engine work and dyno facilities go, probably your best bet in the area.
I may be able to help with some parts should you need them, including a very special exhaust system and carb combo amongst other things - I've broken a few Rvf's recently. I'm located in Gloucester, if you want to have a word or a look at anything just send me a pm and I'll forward my number to you. Good luck with the racing (which series are you racing in? South Gloucestershire or further afield?)