NC35 (re)build thread - tis the season for 400cc greybikes

[cencalballer]

HRC? or Tyga?

 

[ircsmith]

I see the Tyga sticker on the wrapping. should of asked I have a couple systems in the garage. granted there is no way they are as shiny as the you got just got

Now I want to get rid of that 100lb rear Ex manifold that everysystem out there bolts to. any ideas on that?

 

[thenewwazoo]

HRC? or Tyga?

You know, if I had the opportunity to buy an HRC system, I don't know that I'd be able to resist. Despite the fact that they interfere with the kickstand, are mild steel (rusty!), and are reportedly crazy loud. Luckily, that's not a barrel I had to stare down.

I see the Tyga sticker on the wrapping. should of asked I have a couple systems in the garage. granted there is no way they are as shiny as the you got just got

Now I want to get rid of that 100lb rear Ex manifold that everysystem out there bolts to. any ideas on that?

I probably should start posting up when I need things, but I get impatient, and my wife doesn't believe me when I tell her how much I've spent. She's convinced I'm overestimating. Maybe I'll go through my (increasingly short) list of things to buy and see what's floating around.

The only real sore spot when the bike was on display at the IMS was the exhaust. In fact, it bugged me so much that I flipped the bike around on Sunday to show off the rear wheel instead. This is what it looked like...



So yeah. That's stock piping that's clearly seen better days. Also, the muffler doesn't match the flange. It was simply slipped on, and attacked with a drill. Then, whatever bolts that were laying around were "threaded" into the body of the muffler, grabbing at whatever metal were around. It was sufficient for Laguna Seca, but the freeway was enough that the bolts started falling out on the way home, leading to the single loudest ride up 101 I've ever made. At the time I remember thinking that I didn't remember the bike being quite so loud on the way south. Little did I know the muffler was basically falling off. Oops!



Also, because the muffler wasn't right for the bike, the mount was in the wrong place, which "inspired" someone to make a hanger for it. That's about 3mm of chopped strand mat with a single layer of CF twill on top, cut in sort of whatever shape works, and held in by one of the two mount points on the subframe. *sigh*

Yeah, kind of embarrassing.

So anyway, yeah, I needed a new muffler, and look at that dent in the collector! I obviously need to replace that midpipe too and well, why not just go with a full Tyga system, right? They're very reasonably priced for what you get, IMO. I agonized a fair bit about whether to get the dual-stack system, and about which can to get. I decided to go with the single carbon can. It's not very flashy, but it is lighter than the dual-can setup. Which is admittedly an odd concession to make on this bike, given my track record so far, but there you go. Sometimes I really do value more than looks.

I don't have any pictures of assembly, but I will share this one...



That's the very most direct angle to look at the exhaust ports, btw.

Installation was not all that easy, but it was rewarding.





Oh, and also I replaced the beat-to-shit cheapo replacement airducts that were on the bike with something a bit tastier.



Vanity, thy name is carbon fiber.

 

[GPzPop]

sexay, gonna go pose at *$ now ?

 

[Brown81]

LOOKS TITS.

 

[thenewwazoo]

sexay, gonna go pose at *$ now ?

You kid, but I am really looking forward to taking it to Alice's soon. I haven't had a chance yet, but let's face it: you haven't arrived until your bike has been admired by people at the ultimate pose spot.

 

[MotorToad]

^He's had a chance now. He could land any 50+ moto enthusiast he wants! =]

 

[ohio]

Bumping this for two reasons.

First, I was so inspired by this thread, I asked thenewwazoo if we could repost a portion to our blog. Every time I read through the Laguna Seca track day, it makes me smile.

Second, I want him to write more.

 

[thenewwazoo]

Bumping this for two reasons.

First, I was so inspired by this thread, I asked thenewwazoo if we could repost a portion to our blog. Every time I read through the Laguna Seca track day, it makes me smile.

Second, I want him to write more.

w00ty. Thanks for the bump and the post. Every time I think about that track day, it makes me smile too.

I have gotten to enjoy the bike a little bit over the last couple of months. It's still got some niggly problems, not the least of which is that the shitty eBay lower radiator doesn't even come close to fitting the stock fan, which means the bike overheats without sufficient airflow. Which is basically all the time in traffic. Oh, it also loses coolant. I think it's got a pinhole leak somewhere, but I haven't gotten around to dying it and finding it. Or maybe I'm just being naive and it's a head gasket.

:|

So I do have to be careful when riding it around, but I have gotten some quality pose time in.



I do have to say, it's not as much fun on the street as I'd hoped, but for some surprising reasons. I already knew it was buzzy, regularly touching 10,000 RPM on I-280 with its +2 rear sprocket. I also already knew it was uncomfortable due to its ergonomics and size. I also knew there wasn't any wind protection, the shock is toast, and it's indiscreetly loud. Those things I expected...

Let me digress. I had a GS500 a few years ago that I'd lightly modified. It sounded like a metal stamping factory and had the suspension of a Sopwith Camel, but it was hilariously fun to ride because I could flog the everliving shit out of it and barely be breaking the law. I borrowed a friend's CBR250R a few weeks ago too, and loved it for the same reasons. I like manhandling bikes. I like to turn in late and hard, and I like to work the suspension, and I like to lean on torque that may never turn into horsepower.

The RVF really doesn't like that. I mentioned it in the Laguna Seca writeup, but it's all about slowly-building smooth speed and very fast handling limits (which I've not reached). Additionally, while the RVF400 is immensely fun to ride hard, it's not very much fun to ride at 4/10ths. The combination of those two factors means that, to get my pulse up on the street, my usual slow-in-fast-out approach doesn't cut it. The bike wants to flow fast the whole way through the turn. Which is funny, because I imagined the bike to be a thing I could flog in contrast to a 600cc supersport, where riding spiritedly meant taking serious legal and medical risks.

In cage terms, I guess I'd sort of been hoping for a Miata and ended up with an Elise.

Poor me, right?

There is one nice thing about it... my bike totally attracts the attentions of old dudes.

^He's had a chance now. He could land any 50+ moto enthusiast he wants! =]

That's right. The best way to make your trick Mille R invisible is to park it next to a grey-market 400.

 

[RickM]

Try a CB-1 man. It's like the miata. Has some torque down low to be able to ride it under 10k rpm and have fun on the street. I can run thru three gears from a stop light and not break the law.

 

[thenewwazoo]

So, as much for my own records as anyone else's interest, the bike still currently needs its coolant leak diagnosed and fixed, and a more permanent solution for mounting the race-style overflow bottle. Also, the new lower radiator is on the way, but I need to source a good top radiator. Anyone have one laying around?

I've got a stock rear fender on the way (including an un-cut plastic snow shovel license plate mount!), and hopefully that will help the problem I have of the taillight rattling itself out of place. If not, I'm going to have to make a real pitch to the Budget Committee for a CF tail section. I'll also be able to use stock taillights, which makes me very happy. I can't explain it, but I really like the stock rear end.

The petcock is still not quite right. The OFF setting isn't, though the vacuum valve is 100% perfect. Gotta fix that eventually.

Also need to disassemble, clean, and re-lube the LHS switchgear, and replace the ignition cylinder. The wiring was cut at some point in the bike's history and it makes me twitch.

All of that will happen on no particular schedule. Last Friday I buzzed around a bit to make sure the bike was ready for the NCC dyno day. It felt great.

Any bets on the number? Full Tyga exhaust w/ round canister, 112 main jets, HRC slide springs, and a stock air filter.

 

[thenewwazoo]

Try a CB-1 man. It's like the miata. Has some torque down low to be able to ride it under 10k rpm and have fun on the street. I can run thru three gears from a stop light and not break the law.

As it so happens, I'll be taking the RVF to Deal's Gap in May, and a friend is likely to bring his sorted CB-1 along. I'm very much looking forward to a lengthy compare/contrast session!

 

[Crom]

Try a CB-1 man. It's like the miata. Has some torque down low to be able to ride it under 10k rpm and have fun on the street. I can run thru three gears from a stop light and not break the law.

The CBR400RR is like that too.

 

[RickM]

As it so happens, I'll be taking the RVF to Deal's Gap in May, and a friend is likely to bring his sorted CB-1 along. I'm very much looking forward to a lengthy compare/contrast session!

stock CB-1 has lazy handling compared to RVF. So it might be a disappointment.

The CBR400RR is like that too.

In my mind both the rvf and cbr400rr are both like the elise vs cb-1 being like the miata. I thought the RR has more top end power than the CB-1 and less torque down low and needed a lot a clutch slipping for taking off from a stop.

But better suspension and the light and stiff frame got to be a lot better than CB-1.

 

[Crom]

So, as much for my own records as anyone else's interest, the bike still currently needs its coolant leak diagnosed and fixed, and a more permanent solution for mounting the race-style overflow bottle. Also, the new lower radiator is on the way, but I need to source a good top radiator. Anyone have one laying around?

Mine always smells like coolant when riding but the levels don't seem to go down much. I'm thinking it's the water pump. There's also two gaskets under the cast peices at each end the tube in between the two cylinder banks that can get nasty over the years.

A lot of people use the Chinese rads on ebay but sometimes they don't have the right threads for the fan switch on the lower. They're not too bad for the money.

 

[Crom]

In my mind both the rvf and cbr400rr are both like the elise vs cb-1 being like the miata. I thought the RR has more top end power than the CB-1 and less torque down low and needed a lot a clutch slipping for taking off from a stop.

But better suspension and the light and stiff frame got to be a lot better than CB-1.

Makes sense. Mine came with a large rear sprocket and I've never tried the stock gearing. It was a lot easier on the street than my vfr400. I haven't ridden an rvf but I will soon.

 

[thenewwazoo]

Well, last weekend was mostly fun, but a little bit frustrating.

Saturday morning, I hit Moto Shop to pick up the RVFlette, and headed over to NorCal Cycles for their dyno day. It was a lot of fun! I saw a couple of Moto Shop regulars, met a few new people, and of course, got my first taste of actual data collection. To the dude with the 1170cc KZ1000P who kept spinning the dyno... you certainly win the dB war!

Once it was my turn...

58 wheel horsepower. Not bad for a bike that's officially rated at 60 crank horsepower and hasn't been tuned.

But it's not the prettiest graph, and the power wasn't delivered in the calmest manner. The bike was sputtering and lightly popping under load, and though it didn't sound like detonation, the bike clearly wasn't happy. It was a bit surprising, because the bike feels pretty sublime on the street. Here's what it looked like:

[youtube]n5bdEz_Ei-A[/youtube]

The oil under deceleration is also a bit worrying. I have no idea what sort of history this engine has, and it could well have been raced for 10 years and never rebuilt. I just don't know. That's not a crazy amount of smoke, though, so I probably won't worry about it for now.

Clearly, the bike needs some tuning. Most importantly, I need to get a wideband O2 sensor on it. I've actually got one in the garage, but it's not set up for use as a tailpipe sniffer, so I'd really like to schedule some dyno time. At present, the bike has a full exhaust, a stock air filter, HRC slide springs and 112 main jets all around. I would be surprised if that's very far off, but I just don't know.

(If any of you, Dear Readers, have any input on tuning NC35 engines, please do speak up.)

For now, I just have to find an afternoon or an evening to take it... somewhere.

 

[aram]

Well, last weekend was mostly fun, but a little bit frustrating.

Saturday morning, I hit Moto Shop to pick up the RVFlette, and headed over to NorCal Cycles for their dyno day. It was a lot of fun! I saw a couple of Moto Shop regulars, met a few new people, and of course, got my first taste of actual data collection. To the dude with the 1170cc KZ1000P who kept spinning the dyno... you certainly win the dB war!

Once it was my turn...

58 wheel horsepower. Not bad for a bike that's officially rated at 60 crank horsepower and hasn't been tuned.

But it's not the prettiest graph, and the power wasn't delivered in the calmest manner. The bike was sputtering and lightly popping under load, and though it didn't sound like detonation, the bike clearly wasn't happy. It was a bit surprising, because the bike feels pretty sublime on the street. Here's what it looked like:

[youtube]n5bdEz_Ei-A[/youtube]

The oil under deceleration is also a bit worrying. I have no idea what sort of history this engine has, and it could well have been raced for 10 years and never rebuilt. I just don't know. That's not a crazy amount of smoke, though, so I probably won't worry about it for now.

Clearly, the bike needs some tuning. Most importantly, I need to get a wideband O2 sensor on it. I've actually got one in the garage, but it's not set up for use as a tailpipe sniffer, so I'd really like to schedule some dyno time. At present, the bike has a full exhaust, a stock air filter, HRC slide springs and 112 main jets all around. I would be surprised if that's very far off, but I just don't know.

(If any of you, Dear Readers, have any input on tuning NC35 engines, please do speak up.)

For now, I just have to find an afternoon or an evening to take it... somewhere.

The load the bike is under with a dyno is different than you get on the street or on the track (some dynos do better jobs than others I'm sure), so if it doesn't sputter and runs great on the street. Then it's probably ok.

On cars with dynojets I would get different AFR readings on the dynojet vs at the racetrack and would always tune the air fuel ratio at the racetrack for best results. Dyno was good for figuring out what AFR and timing made the best power though.

Also the NC35 is awesome and Im sorry that other 400 had so many things needing fixing, but it looks like it's in much better hands.

 

[ircsmith]

I tuned mine on a dyno (keep in mind I'm not real experienced at it) took it to the track and had to completely change it so it would run. on the dyno everything look pretty good and read 62hp. at the track I could not make it up to turn 9 @ T-Hill without down shifting!

with the help of afm199 and Zorn I got it running pretty good by the end of the day.

took it back to the dyno and it ran like crapola. turns out the dyno setup could not replicate the forced air that changed the carb feed pressure. I have an HRC airbox.

 

[cencalballer]

That is indeed an ugly graph. Have carbs been synced? If it's making close ot the rated power thats a good sign but the graph says something otherwise. Although the loading is a little different you shouldn't get anything that feels that different. That's my experience with a properly tuned engine.