Change the valve seals?

[WMarshy]

Just woundering some thing about the final drive convert. Mine is stock and at 70mph I run about 4000 RPM, with the final drive converted and running at 70mph whats your RPM at? Thanks

~Wade

[bikerphil]

With the 750/850 FD mod, you'll be running about 750 RPM less while cruising.

[Crazcnuk]

heh, that would help if he knew 'less than what'.

At 110kph (68mph) I am pretty much bang on 4000rpm. 4500rpm at 120kph (74mph)


I have the 750 final drive on mine.

[Crazcnuk]

Actually, the cams can stay on, but you have to break the cam chain.

[DGXSER]

Stock final drive on my 81SH I run about 5k rpm at 70 MPH. So with the final drive mod you wuld be about 4300 RPM. A standard will drop a few RPM due to the larger rear wheel. I gotta think you already have the swapped FD.

Wish you could see the drive shaft to count revs, maybe if you peel back the rubber boot at the middle drive to drive shaft connection? Then you could count revs of shaft with one rev of rear wheel. The XS11 is about 3.3:1 IIRC and the 750/850 jumps it to 3:1

[trbig]

Actually, the cams can stay on, but you have to break the cam chain.

Just to clarify...

You can leave the chain alone and remove the cams, or leave the cams in place and cut and replace the chain.


Tod

[randy]

You're talking a ton of money for something when you could buy a really nice carb synching tool for under $100 and do that part yourself... and a very knowledgeable member (Randy) that is a fellow New Yorker that could probably be bribed with food and beer to help when he has the time. (Don't people like when they get volunteered and didn't even raise their stinkin' hand?!?)

Holy crap, gotta love your sense of humor, Tod. Sure I would help and I have ALL the tools. Changed my valve seals in less than a day. BUT, Rochester is quite a ways from NYC! I can offer to lend the valve compressor tool if you dive into it yourself, but I'm guessing the reason you went to a mechanic in the first place is because you don't have the experience/confidence to do engine work?

[Crazcnuk]

Heh, what TR said!

I should have put emphasis on the 'can'!

[Bigleo]

valve guides.

Hi there, 1200 miles per quart of oil? I would not bother trying to fix that until it gets much worse. Down to 200 miles per quart. It is a fairly involved job, for not a lot of gain, I mean 1200 miles per quart is not that bad. I second what someone else said, try one of the oil additives to soften the rubber in the valve seals. Also what oil are you running? I think most of us run 20/50 in the summer. A thicker oil will help with your consumtion as well.
Leo

[WMarshy]

I can offer to lend the valve compressor tool if you dive into it yourself, but I'm guessing the reason you went to a mechanic in the first place is because you don't have the experience/confidence to do engine work?

Randy, thanks for the offer but I don’t think I will be changing my valve seals anytime in the immediate future. You’re partially right, I don’t have that much experience working on engines but I do have the confidence & mechanical aptitude. Any job is intimidating when you don’t have as much as a work bench to work on...

I think TC was on the right path, rich mixture burning oil off the cylinder walls...? The bike's at the shop today, will have compression test numbers to post and an update on how well of a job he does. All fluids are getting changed, I think it wouldnt hurt to have him adjust valve clearance while he's got it.

Next time I drive it I will take better note of my RPM/MPH. Best MPG I ever got with it was about 32~33 on highway 60-65 mph. I hope that improves some, as far as I know the FD is stock although could it be possible to get a lower ratio as factory option for crusing? Anyone know? Thanks guys.

[WMarshy]

Well after reading Valve Adjustment thread by Mbarna I feel confident I could handle doing this myself, even without a work bench lol.

My question now is, if I have my carbs synced and tuned then I adjust my valve clearance how much will this affect the proformance/tune of the engine? It seems counterproductive to adjust the valves after I just spent money on carb tuning..? I dont hear much over head "chatter" or anything to be concerned with, but at the same time I dont know when the last time they were adjusted... Any thoughts?

[randy]

The proper sequence is valves, ignition timing, then carbs. Any changes you do to the valve clearances will affect the carbs. You don't do your own synch?

BTW, as the valves go out of adjustement they TIGHTEN, so you won't hear any 'chatter'

[trbig]

A simple cam chain adjustment won't mess with your carb synch noticeably.. but a valve adjustment will.


Tod

[WMarshy]

Well, stopped by the mechanics shop yesterday to get an update. Copmression with warm engine WOT: 140, 140, 135, 140
He put new plugs in and did throttle chop to get plug color, then took the bottom half of the air box off to see if it would lean out and run better. You can read about it in my new post: Needle Height Adjustment. Thanks for the advice guys. Looking forward to learing more from you guys.