yoshimura cams/ cam chain length

[jellywrestler]

i've recently bought a gsx1100 race bike with yoshi cams and the idler sprocket set up fitted between the cams too. this set up obviuosly requires a longer cam chain but still when all is set up the standard cam chain tensioner is at full length and theres still 7degrees of backlash at the crank as the chain is still loose.

the motor was rebuilt and hasn't really been run much since so i wouldn't hink it was worn out.
can anyone tell me how many teeth a cam chain for this set up should have please?

cheers
from new zealand--hence me calling it a gsx

 

[RacingJake]

I'd mark the cam chain with white out or some paint and then count the pins.
Maybe the wrong cam chain was used. Are you using a manual adjuster??

Not 100% sure but a GS has 120, GSXR has 122 and Kawi has 124 ??? count the pins and check the book.

Good luck

 

[Nessism]

The factory manual also has a measurement standard, between a set number of pins, to measure chain stretch.

 

[jellywrestler]

I'd mark the cam chain with white out or some paint and then count the pins.
Maybe the wrong cam chain was used. Are you using a manual adjuster??

Not 100% sure but a GS has 120, GSXR has 122 and Kawi has 124 ??? count the pins and check the book.

thanks for your answer although i'm still a little confused. you mention the gs and gsxr mine is in american terms a gs1100 although we call it a gsx here. 4 valvles per cylinder. where does this fit in? remembering it has yoshimura cams with a jockey wheel between the two which is differnet from standard set up.
thanks

 

[Suzuki mad]

Standard service limit for the GSX1100E is 157.80mm (6.123inches) from the 1st to 20th pitch as per setting the engine timing. The workshop manual doesn't tell you how many pitches the chain length should be!!

Yes, the USA is confusing with the use of the GS for all models of Suzuki especially when looking for parts. It's just there way. We only had 1100's supplied with 16 valves here in the UK so when posting here I have to guess that any GS1100 is a 16 valver. Its a little harder on the smaller ones.

Suzuki mad

 

[RacingJake]

All GS1100 and GS1150 in the states don't have the idle gear between the camshafts.

When I installed a newer Katana head or GSXR head on a GS bottom end I just removed the idle gear assy and used the 120 pin cam chain and GS sprockets on the newer head and adjust the cam tensioner at the rear of the cylinder block.

Maybe the head has been swapped too, can you post a pic of the head and bike. Also what year is your bike.

I'd also double check your cam tensioner to make sure it working, also how's the condition of the rear cam guide cause they can break in two at the top and cause excess chain play.

 

[jellywrestler]

the bike was built for the world formula one champs in the early 80's with the monocoque chassis made entirely from carbon fibre, a world first. its a hot rod engine and with the yoshi cam set up needs the idler between the cams built into the rocker cover.
this however leaves the cam chain real tight with a standard 120 link one and therefore someones fitted a 122. this has led the cam chain to be real loose and out of touch really with the standard tensioner, or too tight with 120 links.

what i'm looking for is anyone who has this set up and what they found with their cam chain


how does one post a photo?

 

[Guest]

Manual tensioner, you should run one anyway

 

[Guest]

Some of the pro stocks had that set up installed when they used the 16 valve heads. Don't know what the chain length was. Std is 120.

Jay

 

[focus frenzy]

ok if 120 is to tight and 122 is to loose run one with 121! simple!!LOL

 

[RacingJake]

ok if 120 is to tight and 122 is to loose run one with 121! simple!!LOL

Yeah Right :lol: :lol:

That's a good one for the new guy behind the parts counter to figure out :lol:

 

[jellywrestler]

what a great idea and so obvious! problem is you can't buy a 121 link chain they are made up in bits of two!!

 

[RacingJake]

All I can think of since a 120 chain is too short and a 122 chain is too long and that's using a idle gear between the cams, is that there must be and issue with the rear cam chain adjuster or maybe the rear cam guide is hitting something in the cam tunnel. Like the mounting bolt for the rear cam guide is loose causing the guide to turn inside the cam tunnel??

I've never seen that type of head so I can't be much help. Does it even have a rear tenioner on the back side of the cylinder block or does the idle gear on top of the head do all the adjusting???

 

[Guest]

its a hot rod engine and with the yoshi cam set up needs the idler between the cams built into the rocker cover.
this however leaves the cam chain real tight with a standard 120 link one and therefore someones fitted a 122. this has led the cam chain to be real loose and out of touch really with the standard tensioner, or too tight with 120 links.

what i'm looking for is anyone who has this set up and what they found with their cam chain


how does one post a photo?

Problem solved

See my signature

 

[jellywrestler]

121 teeth is not an option, the chains come in segments of two. thanks anyway

 

[Steveb64]

the bike was built for the world formula one champs in the early 80's with the monocoque chassis made entirely from carbon fibre, a world first. its a hot rod engine and with the yoshi cam set up needs the idler between the cams built into the rocker cover.
this however leaves the cam chain real tight with a standard 120 link one and therefore someones fitted a 122. this has led the cam chain to be real loose and out of touch really with the standard tensioner, or too tight with 120 links.

what i'm looking for is anyone who has this set up and what they found with their cam chain


how does one post a photo?

Is that one of the Steve Roberts ones? ... I've got a single shock McIntosh - waiting for a new workshop before I start the rebuild....

The cams are a little weird! Are they Stage 2 Yoshi's? If so, there shouldn't be any idler gear! Mine never had any (with Stage 2 cams), and did 10's of 1000's of km's - no probs. Well, no probs until the centers of the cam lobes started to disintegrate, due to the bozo's who originally fitted them not grinding down the little oil nipple on the underside of the rocker arms. Left little grooves in the middle of all the lobes - but still lasted a long time. I then switched the cams out, and put the ones in from the McIntosh (even more lift, and a LOT more duration than the Yoshi's) - still with no idler gear... and still no problems. The GSX used to get a good thrashing too - Vic club road races (err rides), track days, Carterton and Lyall Bay sprints (best SS1/4 11.1 sec, best flying 1/4 - 143mph, and still accelerating!).

My recommendation is to go into Wellington Motorcycles, and try and speak with Steve Dundon, as he was the GSX tuning guru for the time...

 

[Big T]

how does one post a photo?

You need a photo hosting site. Most people use Photobucket, since it's free.

Go to Photobucket.com and set up an account. Upload your photos into the account. Then, left click once on the IMG Code line below the photo. A small box saying "Copy" will pop up. Now, go to the GSR posting you're writing, right click and paste it into your post.

It will come out like this

I'd really like to see some photos of your bike. It will take you 15 minutes or so to set up your Photobucket and load up a few pics.