Camshaft issues

[Guest]

My Gsx1100 katana (Gs1100 to you guys) has just gone & trashed it's cams & followers. Don't know quite why yet but it could be a combination of things. Anyhow I am after some suggestions as to what to replace them with. The motor is 1290cc with a decent head on it with big valves & the cams were G3's.
I would like something a little less top endy as it was forever banging off the rev limiter previously. The bike is used purely on the road these days.
I have looked at many options & the price seems to be about $450 for the cams & similar for the rockers but I am in the UK so the cost of shipping is huge from most of the obvious suppliers. Also there is the added pain of maybe having to pay 25% import duty if customs catch them on their way to me.
Any info would be great.
Nick

[Nessism]

A top end oiler kit and high flow oil pump gears are recommended when aftermarket cams/valve springs are used. Hardened rockers are also recommended for high lift applications, but shouldn't be necessary with mild street cams.

Good luck

[coombehouse]

A top end oiler kit and high flow oil pump gears are recommended when aftermarket cams/valve springs are used. Hardened rockers are also recommended for high lift applications, but shouldn't be necessary with mild street cams.

Good luck

The bike has external oil lines already, gsx750 gears & a new oil pump so it can't be that. I am going to change the lines to dash 6 from dash 4 though just to sure when its back together. The only difference post my rebuild last year was APE valve springs & an oil cooler. Maybe 25 year old cams don't like the springs though they should have been fine.
Nick

[blowerbike]

to much spring seat pressure will eat the cams and followers weather you have a top end oiler or not.
i recall around 42lbs being a safe number.

[coombehouse]

to much spring seat pressure will eat the cams and followers weather you have a top end oiler or not.
i recall around 42lbs being a safe number.

Yes I think you are correct with the figure. I made myself a valve spring checker last week & they measure 40 pounds on the seat. They are still a lot stiffer than original springs though which I always used in the past. Have bent a few valves in my time though!
Nick

[Nessism]

The bike has external oil lines already, gsx750 gears & a new oil pump so it can't be that. I am going to change the lines to dash 6 from dash 4 though just to sure when its back together. The only difference post my rebuild last year was APE valve springs & an oil cooler. Maybe 25 year old cams don't like the springs though they should have been fine.
Nick

Hey Nick,

This info would have been nice to know before I posted. You holding out any other critical info?

Sorry about the problem.

I'm not very knowledgeable about matters such as this, but I know that hardened rockers are more durable than the stockers.

Good luck

[coombehouse]

Hey Nick,

This info would have been nice to know before I posted. You holding out any other critical info?

Sorry about the problem.

I'm not very knowledgeable about matters such as this, but I know that hardened rockers are more durable than the stockers.

Good luck

Sorry about that. I am doing this on my phone whilst working on a bike & typing is a pain. Also really long posts are hard to read don't you think. Nothing relevant has been left out about the build spec. It has all the usual stuff like a welded crank, HD clutch, straight cut gears & runs Gsxr fuel injection & programmable ignition.
Nick

[blowerbike]

very good parts and a nice build.
maybe it was just the cam(s) time to die.
cam's flakes/pit's/wears and rockers follow suit...snow ball effect...
40lbs is a good number for a street bike.
good luck and make sure you dissemble and flush the bugger out!

[coombehouse]

very good parts and a nice build.
maybe it was just the cam(s) time to die.
cam's flakes/pit's/wears and rockers follow suit...snow ball effect...
40lbs is a good number for a street bike.
good luck and make sure you dissemble and flush the bugger out!

I am thinking the same as you. A combination of mostly old parts with a few random new bits thrown in is never a good idea. We all live & learn. I haven't pulled the motor completely apart yet but I expecting a lot of iron filings. Might be time to use the dishwasher again when my wife is at work.
Nick

[quexpress]

I am going to change the lines to dash 6 from dash 4 though just to sure when its back together.
Nick

Hi Nick,

I was under the impression that dash 4 lines are "normally" used for top end oilers and that dash 6 lines are used for the front oil cooler.
I'm not challenging .... just wondering why bigger lines would be better or required.

Normand

[coombehouse]

Hi Nick,

I was under the impression that dash 4 lines are "normally" used for top end oilers and that dash 6 lines are used for the front oil cooler.
I'm not challenging .... just wondering why bigger lines would be better or required.

Normand

Hi Normand
Yes you are correct on the dash 4 for the oiler but the cooler lines should be dash 8 or even 10. I use dash 8. My reasoning is on using dash 6 is that each line is feeding 2 shafts which are 5mm diameter into the rockers. The i/d of dash 4 is around 6mm so in theory the flow may be restricted. The dash 6 lines are around 8mm. The other reason is the cams had more wear on #2 & 3 cylinders & they get the oil after #1 & 4.
Might be just all rubbish but cant do any harm & i have some off a helicopter gearbox that i just happened to find in a bin at work. We throw loads of good stuff away.
Nick

[quexpress]

Hi Normans
Yes you are correct on the dash 4 for the oiler but the cooler lines should be dash 8 or even 10. I use dash 8. My reasoning is on using dash 6 is that each line is feeding 2 shafts which are 5mm diameter into the rockers. The i/d of dash 4 is around 6mm so in theory the flow may be restricted. The dash 6 lines are around 8mm. The other reason is the cams had more wear on #2 & 3 cylinders & they get the oil after #1 & 4.
Might be just all rubbish but cant do any harm & i have some off a helicopter gearbox that i just happened to find in a bin at work. We throw loads of good stuff away.
Nick

Thanks for the insight Nick!
Much appreciated!
Normand