I have a 300 Tyga conversion kit which I wish to fit to my MC21. At present in 250 form, it runs on 185/182 main jets with powerjets blocked off and HRC B needles on middle setting. Airbox lid is removed but filter is wired in place. It also has open pipes (Tom Crawford USA?).

Any advice / help greatly appreciated as I can't afford to blow this engine!

I live in Lincoln GB. Many thanks, Boyoink

hello mate, wellcome, I think the best thing to do is run rich to start, no one here will have settings for you as all the bikes are diffrent and require diffrent size jets etc, most advice ive seen here is start with a larger jet and work up or down according, doing plug chops have you asked Matt at tyga what they recomend? PS watch out fer Dave he'll have you for using Caps lock

I've got 198 for the front/bottom and 196 for the back/top (not sure about the back one tho, i don't have my jetting notes to hand at the moment). I haven't run my 300 yet so i don't know if these sizes are any good but they seemed big and safe to me?! As RC46 (that's the VFR800fi isn't it?) says, put big 'uns in and work from there.
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After years of moaning about immigrants now i am one...

I ran 215 top and 220 bottom and it wasnt safe for me!
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If I have to take the carbs off once more...

StephenRC45 wrote:
I ran 215 top and 220 bottom and it wasnt safe for me!

Yeah, and that was with power jets too!!
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Andy.
NSR-WORLD.COM

Please keep all responses to Forum posts on the Forum so that others may benefit.

Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.

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I can't stress enough... (as usual I know), that there is little use asking what other people are running as each bike can be considerably different. For comparison, when my 300 was running standard 21 carbs (now on PJ38's) I was running a full HRC jet kit with 'B' needles on position 4 from top and 175/172 mains, with 45 slow jets. (But this is with a premix set up) If you ask the sizes for other members with 300's, there is quite a range...

This was set up on the rich side also. (6.5% CO2 reading)

The best thing to do would be to start at 185 or 190, make sure it idles and revs once warm and run it in on a dyno, where thay can at least tell you you're safe rather than guessing. 70 quid for a session is better than a seizure!
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NSR300R - Why did i ever have a 250...

Boyoink?

Consider yerself modded! And please stop yelling at us, we're really quite helpfull if you just ask!
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball

Look at what Tyga did for a base setting;

They ran 150's in the '21 power up project and 165's in the similar spec 300 kit (both with power jets) which is 6 sizes up so if I were you I'd start at 200/198.
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Please do not PM me technical questions, if you can't find it on the Forum start a thread

This is exactly what I mean, as everyone so far has given you varying starting points... Start huge, make sure it will run, take to dyno... simple!
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NSR300R - Why did i ever have a 250...

The problem with a dyno is it isn't real, the load the bike is under sat on the dyno at room temperature isn't really comparable with hauling me up the A610, flat out, 6th gear, WOT, mid autumn early morning and it just leads to chasing top end numbers which is silly. The only way to get them to carburate perfectly is to spend time playing.

We probably really need det counters to be safe but done properly a plug chop does indeed show there and then what the bike is really doing and that's what we need to know.

Done to death(ish) here. Listen and learn with uncle Matt.

And yes I've done (probably more than) 10 second, 12000 rpm+ WOT in 6th uphill plug chops which is why I didn't worry about being flat out 200 yards before my braking marker at Donington.

Of course this doesn't help with ring locating pegs breaking
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Please do not PM me technical questions, if you can't find it on the Forum start a thread

Read this for an explanation of detonation:

http://www.jcmmachine.com/detonation_preignition.htm
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball

Have to disagree with you fontyyy on this one. A competent dyno operator will jet your bike according to what conditions you will be riding in. Whether this is all year round road riding, track day, race etc, so you will have a safety margin that caters for each setup.

If you've no idea where to start, you could potentially seize your bike during your plug chop. Jo at Apex advised a mate to run 'C' needles on his mc28 after it felt a bit woolly on B's. It promptly ate itself 4 days later after only having been just run in. No blame being made, but it's the settings they were using on their bikes, which have no relation in my opinion to his.

It's not chasing top end numbers either, if you're conscious of your engines reliablity, as the figure you get will again depend on what kind of setup you require...

The strong point of using a dyno is that if jetted conservatively, although the load on the dyno is minimal, less than even on a longish race track straight, you could stay WOT on your favourite A road sound in the knowledge that it ain't going to pop.

I'm sure you'll dig out some 3 year old post where I've said you should only use plug chops and where you've worked for Erv Kanemoto or something, but it's my opinion and you've got yours obviously!
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NSR300R - Why did i ever have a 250...

maxim wrote: Jo at Apex advised a mate to run 'C' needles on his mc28 after it felt a bit woolly on B's.

Errrr, excuse me, but I have NEVER advised ANYONE to run C needles, so unless I have a sister I never knew about I believe you are mistaken.

I am also more than happy to stand up and swear that not a single customer's NSR that has left our workshop has left wiith C needles in as fitted by ourselves.

maxim wrote:No blame being made, but it's the settings they were using on their bikes, which have no relation in my opinion to his.

Given that you've never stripped the carbs down on my own NSR I'd love to know how you would have any idea what settings I use on my bike. For your information though "our" bikes certainly don't use C needles.

This isn't the first time you've suggested on this forum that we've sent out bikes with C needles fitted, but have no proof of. The last time was with fontyy's bike which did not leave here with C needles and which was verified by him.

I would therefore be interested to know who this "mate" is that we are supposedly meant to have advised to fit C needles as he's certainly never come forward to us with any issues over work we have done.
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Jo
www.apexleisure.co.uk

Jo... I made it clear that there was no apportion of blame, simply infering that it is unwise to take advice on settings as they can be of little use unless everything is identical. I gave Apex as an example as you claim to be an authority on the NSR, in the same way that fontyyy referred to TYGA and their base settings. This was purely meant to illustrate my original point and I apologise if you have taken this the wrong way.

The reason he's not come forward as you say is purely because he had taken your advice, and as it was his decision to do so, why should he expect any recourse...

Check your PM for details of who seized...
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NSR300R - Why did i ever have a 250...

I ran my 300 once on C needles, it seized lol, then again it seized a A needles the next time... so ho hum to that theory!
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If I have to take the carbs off once more...