some really silly questions and answers :)

Any topic relating to the FZR/YZF (UK) or motorcycling in general.

Moderators: Site Director, FZR Forum Moderators

fzrowner1
50+ Posts
50+ Posts
Posts: 87
Joined: Wed Oct 03, 2012 4:17 pm
Location: uk

some really silly questions and answers :)

Post by fzrowner1 »

i cant see on here a page for some silly questions so i though id make a page :) could someone explain sprockets me to like what plus a tooth does and minus a tooth and so on and what would be the best combination for acceleration cheers and could anyone tell me what tyre upgrades and changes i could do for a 400 3en2 :) thankyou Sean.
S.J.Hunter

Yamaha FZR400R 3EN2 1989
SouthendChris
Level 2.0
Level 2.0
Posts: 224
Joined: Sat Oct 15, 2011 2:14 pm
Location: Essex, UK

Re: some really silly questions and answers :)

Post by SouthendChris »

Sean

For better acceleration you need to go smaller (less teeth) on the front sprocket and/or bigger on the rear sprocket.

There are limits though! You can't go too small on the front or the chain will rub on the swingarm where it pivots. A good ratio for the 400's is 15 on the front and 47 on the back.

There is a 520 chain conversion available for this setup (a more heavy duty version of the standard 428 chain). Definitely for the 3TJ model bike, and I'm sure Clanger now has it on his earlier FZR400.

Tyres are a very personal thing and you need to think about how (and how much) you will use the bike. Modern sports touring tyres are very good compared to 'sports' tyres of 5-10 years ago. But you have to see what's available in your sizes - you have an 18" rear wheel if I'm right????

Chris
1990 3LN3 FZR250 - back in safe hands :)
https://farm6.staticflickr.com/5782/227 ... 41e9_b.jpg
1994 3HE FZR600 - R.I.P. 10/01/12

3x RG80 Gamma :)
User avatar
reelrazor
Wrench
Wrench
Posts: 1658
Joined: Sun Oct 05, 2008 8:19 am

Re: some really silly questions and answers :)

Post by reelrazor »

Remember 'ratios' in math class?

Altering sprocket teeth numbers alters the ratio of turns...

Let's go with Chris' example of 15 front, 47 rear teeth.

47 divided by 15 is 3.1333333...that means the front sprocket will turn 3.133333 revolutions for every single revolution of the rear sprocket (ratio of front revs vs. rear revs is 3.1333333:1)

16f 47 r yields a ratio of 2.9375


Lower numerically means less torque...more top end speed (as long as the engine has the guts to 'pull' that gearing)

Higher numerically means better acceleration....at the expense of top speed....

Higher numerically sounds great doesn't it? It's a balance tho....higher engine speed for a given speed..less fuel economy....
http://www.michiganmobileservice.com/


Image

“A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.”-Douglas Adams

http://www.youtube.com/user/reelrazor
fzrowner1
50+ Posts
50+ Posts
Posts: 87
Joined: Wed Oct 03, 2012 4:17 pm
Location: uk

Re: some really silly questions and answers :)

Post by fzrowner1 »

rear tyre is 140 60 18 can only find a bridgestone battleaxe there 2 easy wearing! and ahhh i kinda get it now thankyou reelrazor.
S.J.Hunter

Yamaha FZR400R 3EN2 1989
fzrowner1
50+ Posts
50+ Posts
Posts: 87
Joined: Wed Oct 03, 2012 4:17 pm
Location: uk

Re: some really silly questions and answers :)

Post by fzrowner1 »

if i got 15f 47r what length chain will i need as im buying it off the roll :)
S.J.Hunter

Yamaha FZR400R 3EN2 1989
SouthendChris
Level 2.0
Level 2.0
Posts: 224
Joined: Sat Oct 15, 2011 2:14 pm
Location: Essex, UK

Re: some really silly questions and answers :)

Post by SouthendChris »

*If* a 140/70 18 will fit then you open up yourself to more tyre availability. If you want V-rated tyres then Avon do the AM26 Roadrider in that size. If H rated will do then you can get the BT45 from Bridgestone.

http://www.mytyres.co.uk/cgi-bin/rshop. ... hrzeugart=

As for chain length its a bit suck it and see. The std chain length for 19/55 sprockets is 130 links. For the 520 conversion 14/43 is 104 links on a 3TJ. I'm not sure if the 1WG has same length swingarm.

Chris
1990 3LN3 FZR250 - back in safe hands :)
https://farm6.staticflickr.com/5782/227 ... 41e9_b.jpg
1994 3HE FZR600 - R.I.P. 10/01/12

3x RG80 Gamma :)
User avatar
Clanky
100+ Posts
100+ Posts
Posts: 149
Joined: Thu Jul 21, 2011 11:11 am
Location: Portsmouth, UK

Re: some really silly questions and answers :)

Post by Clanky »

Hi Sean,

I've just gone from the stock 19/55 sprockets 428 chain to 15/47 sprockets 520 chain. I bought a 110 link chain and had to remove 2 or 3 links to fit it so a 108 might do you. Personally I'd go for the 110 link chain because you know it is going to be plenty long enough.

One thing to be aware of is that the Renthal front sprockets are only 6mm wide and the original sprocket is 9mm wide. You'll just need a 1.5mm washer each side to compensate for that. I bought a big bag so if you go ahead let me know and I'll post you some. The 47 tooth rear sprocket was only available in the UK in hardened anodised steel by Renthal. There are plain steel versions around but they're more readily available in the US than the UK I think.

I can't recommend this set up enough the bike is a real joy to ride now. Plenty of acceleration and so much better for riding round town if you do any commuting. In town traffic it was difficult to get a gear that it was happy in but now it deals with the 20 and 30 restrictions with no dramas. Hardly have to feather the clutch at all because it just responds so well in the low gears.

I had new tyres front and rear which were a Bridgestone Battlax BT23 front and BT92 rear. A huge improvement over the old ones.

If you need any parts try these people, they own FZRs and know what works best with each model:

http://www.projection-components.co.uk/
User avatar
Genesis
Level 8.0
Level 8.0
Posts: 828
Joined: Wed Jul 30, 2008 11:47 pm
Location: Washington, USA

Re: some really silly questions and answers :)

Post by Genesis »

I have the BT45, great tires.

Sent from my C771 using Tapatalk 2
1990 Yamaha FZR600 Genesis, Daily Driver
My FZR6 Rebuild

1985 GMC 4x4 T-15 X-Cab Sierra
1999 Chevy 4x4 Blazer (wifes car)

"If a man can build it, I can take it apart and sometimes even put it back together and fix it" --Unknown

"'I wish none of this had happened.' 'So do all who live to see such times. But that is not for them to decide. All we have to decide is what to do with the time that is given to us.....'" J.R.R. Tolkien
yamaha_george
5000+ Posts
5000+ Posts
Posts: 5853
Joined: Fri May 09, 2008 8:46 am
Location: west london UK

Re: some really silly questions and answers :)

Post by yamaha_george »

fzrowner1 wrote:i cant see on here a page for some silly questions so i though id make a page thank you Sean.
Sean,
As i always told my students"the only stupid question is the one you do not ask simply because it will never be answered and thus you will remain ignorant "

All of us started in the dark, just that in my case that was 53 years ago and although i consider my self none too bright I did manage to collect some useful information in that time and the guys here and else where have had the benefit of those "dumb questions " that I asked.
Have fun
fzrowner1
50+ Posts
50+ Posts
Posts: 87
Joined: Wed Oct 03, 2012 4:17 pm
Location: uk

Re: some really silly questions and answers :)

Post by fzrowner1 »

clanky thankyou very much il pm you my aderess via pm and send you some money via paypal if you like :)
genisis are your wheels 140 60 18 originally? cheers
yamaha george just some of the stuff feels silly to ask but genuine questions so i though id just open a post :) thankyou for all replys they do help :) cheers
sean.
S.J.Hunter

Yamaha FZR400R 3EN2 1989
yamaha_george
5000+ Posts
5000+ Posts
Posts: 5853
Joined: Fri May 09, 2008 8:46 am
Location: west london UK

Re: some really silly questions and answers :)

Post by yamaha_george »

fzrowner1 wrote:clanky thankyou very much il pm you my aderess via pm and send you some money via paypal if you like :)
genisis are your wheels 140 60 18 originally? cheers
yamaha george just some of the stuff feels silly to ask but genuine questions so i though id just open a post :) thankyou for all replys they do help :) cheers
sean.
Sean,
you would feel sillier if you did not ask as you would still be worrying over it, this site is by far away the best around for bikers helping bikers. Despite the fact i am no longer allowed to ride (spinal damage thro a walking accident) I still enjoy reading and where i can put down my 2c and help out those new to biking.
enjoy & ask what you like with this lot there is bound to be someone who has been there done that and skinned their knuckles, sworn loudly and learned what you are not sure of. Hopefully you will not skin your knuckles as well !
User avatar
Genesis
Level 8.0
Level 8.0
Posts: 828
Joined: Wed Jul 30, 2008 11:47 pm
Location: Washington, USA

Re: Re: some really silly questions and answers :)

Post by Genesis »

fzrowner1 wrote: genisis are your wheels 140 60 18 originally? cheers
No, I opted for I think 150, I will have to check when I get home

Sent from my C771 using Tapatalk 2
1990 Yamaha FZR600 Genesis, Daily Driver
My FZR6 Rebuild

1985 GMC 4x4 T-15 X-Cab Sierra
1999 Chevy 4x4 Blazer (wifes car)

"If a man can build it, I can take it apart and sometimes even put it back together and fix it" --Unknown

"'I wish none of this had happened.' 'So do all who live to see such times. But that is not for them to decide. All we have to decide is what to do with the time that is given to us.....'" J.R.R. Tolkien
fzrowner1
50+ Posts
50+ Posts
Posts: 87
Joined: Wed Oct 03, 2012 4:17 pm
Location: uk

Re: some really silly questions and answers :)

Post by fzrowner1 »

yamaha george i am sorry to hear that you can no longer ride :s thankyou for any advice you have given past and future:).

genesis ok mate thanks do you know any other tyres would fit do you know? cheers
S.J.Hunter

Yamaha FZR400R 3EN2 1989
fzrowner1
50+ Posts
50+ Posts
Posts: 87
Joined: Wed Oct 03, 2012 4:17 pm
Location: uk

Re: some really silly questions and answers :)

Post by fzrowner1 »

also whats the easiest way to balance carbs (running really rich) cheers
S.J.Hunter

Yamaha FZR400R 3EN2 1989
User avatar
Clanky
100+ Posts
100+ Posts
Posts: 149
Joined: Thu Jul 21, 2011 11:11 am
Location: Portsmouth, UK

Re: some really silly questions and answers :)

Post by Clanky »

Hello Sean,

I don't want anything for the washers just PM me or email your address and I'll post them to you asap. For synching the carbs you can do an initial bench synch with the carbs off the bike to get a good starting point and after that you can buy or make a gadget to do it once you have them on the bike and running. I've done the bench synch and bought one of these to fine tune it http://www.carbtune.co.uk/ . I found the bench synch really was very close to the final set up.

The wiki has lots of info and some videos to help guide you through it http://fzronline.com/wiki/doku.php?id=carburetor_page

Part of the fun (sometimes agony) is just having a go. So much info here that you're hardly ever in the dark or stuck for long.
Post Reply