Probably a repeat question...Sorry

General forum on engines, transmissions, gearing and modifications to each

Moderator: rztom

Post Reply
Message
Author
User avatar
1601pete
Posts: 470
Joined: Fri Mar 10, 2006 5:37 pm
Location: Bristol, UK

Probably a repeat question...Sorry

#1 Post by 1601pete » Sat Jun 10, 2017 7:16 am

Hi all.

Tried searching but didn't really get a definative answer.

My bike is completely standard and for piece of mind I'm considering running on premix. I've had a rear cylinder seize (upper right). I know there are many reasons why this could if happened.

If I was to run premix. What exactly do I need to do?

1. Remove pump, can I leave drive shaft from clutch side in place?
2. Isolate 4 reed intake points. Stop air leaks.
3. Increase main jet size? If so by how much.
4. What ratio premix? 32:1 or 40:1? Other?

Just want a straight forward list please

Thanks

RC45
- - - - -
- - - - -
Posts: 1713
Joined: Fri Aug 19, 2011 5:18 am
Location: Houston, Texas.

Re: Probably a repeat question...Sorry

#2 Post by RC45 » Sat Jun 10, 2017 4:57 pm

I use AMSoil Dominator 2T oil with Sunoco 110 leaded fuel mixed 40:1.

I could probably go even higher on the ratio, AMSoil recommend 50:1 - modern 2T oils are very good.

*edit* and my bike is stock internals & barrels, flat-slide carbs, Jolly Moto pipes.

Image
CBR1000RR SP2 HRC WSBK
TZ500V/OW53 Track bike
YZR500 OW81 Clone
OW69 Daytona 200 Replica - 784cc Monster
NS400 Track Bike
RS250R NF5
TZ250T 2KM
TZ250B 3YL
TZR250 3MA Track Bike
427ci C5 Z07

2002tiil
Posts: 140
Joined: Mon Jun 01, 2015 5:49 pm
Location: Veendam, the Netherlands

Re: Probably a repeat question...Sorry

#3 Post by 2002tiil » Sun Jun 11, 2017 3:56 am

Are you sure that it was lean on oil? Are there marks all over that piston? Why is only 1 cilinder seized when it was a mixture failure? Is the oil line blocked?
It would be a shame if it's lean on fuel, so you could have the same problem after setting on premix.
I'd recommend a leak test on that cilinder to be surer.
My 2 cents

User avatar
1601pete
Posts: 470
Joined: Fri Mar 10, 2006 5:37 pm
Location: Bristol, UK

Re: Probably a repeat question...Sorry

#4 Post by 1601pete » Sun Jun 11, 2017 4:28 am

Thanks. Bit late for a leak down test

Image

Nipped up for split second then carried on running

User avatar
phildu31
Posts: 430
Joined: Tue Jul 19, 2011 7:49 pm
Location: Toulouse France

Re: Probably a repeat question...Sorry

#5 Post by phildu31 » Sun Jun 11, 2017 12:23 pm

Hi.
Since seizure is on right hand side, there's a good probability that the crank seal failed, specially if bike was stored not running during winter.
Also take a look at your check valves in oil lines if one is blocked.

Post Reply