4 bent valves and more!

[petejw]

Hey all,
Yesterday I adjusted my cam chain, took the4 bike out for a ride for a good hour no problems, Last nite I went to start the bike, its been a bugger to start lately, after cranking it over a cpl of times, the last time the motor cranked, it cranked a lot faster, also i could hear the odd clunking sound, which isnt a good sign, the motor still didnt start, but it didnt sound any good either, after taking a plug out, i found no compression, after taking all plugs out, no compression in any cylinders. the motor still cranked over with the starter, but i couldnt turn the motor over with a spanner, it litterally jammed.
off came the rocker cover, the inlet cam had jumped a tooth while i was trying to start the bike initially, i now have 4 bent inlet valves, the valves are sitting about a quart inch from its seat.

Has anyone else ever had this sort of problem.


Pete

[John]

Can you tell us how you adjusted the cam chain? It sounds to me like either you forgot to retighten the bolt/locknut that holds the plunger in place, which I doubt you did, or you may have tightened the bolt too tight, and the aluminum threads stripped. Once the bike was running, the plunger was allowed to move, creating some slack in the chain, and that caused the chain to skip on a cam sprocket. I hate to be the bearer of bad news, but there is a strong possibility that you may have damaged a piston, or four, if the valves hit the piston crown. You'll be able to inspect them when you pull the head off to replace the valves. Good luck. Keep us informed.

[prometheus578]

Been there... bent that.

Though unfortunate... what a great opportunity to learn. (don't you hate when people say crap like that?)
As John eluded to... first thing would be to figger' out what went wrong. That cam chain tensioner does seem suspect.
As far as repairs go, if you can adjust a cam chain, you can tear down the head and rebuild. Just takes time, a little effort and a manual.
As for parts: unless you have a spare head lying around, obviously you'll need 4 new valves. Vesrah makes a good gasket set... think it's around $94. Depending on the bike's mileage, you may want to put in a new cam chain, too. I can't recall the price, but I just ordered two from K+L Supply. Think they were around $25, with a master link for $2.50. There's several articles in the tech section on how to attach it to the old chain and slink it around the crank gear. Also several tips on how to install the master link without using a chain tool. Cam chain riveter tool can be gotten from Mike's XS for $39, which is the cheapest price around. (Just bought one, and is the same product that the MAC toolman sells for $120)
As for replacing the valves, Mike's also has the tool for compressing the spring($37), again, lowest price around.
Not trying to spend your money... just giving options and prices.

[skids]

Re: 4 bent valves

Yes, Pete. I overtightened the adjusted to the point of the bolt "feeling like it was easier to turn." A stripped tensioner not only allowed the plunger to looses, but it held it in a slack position. Yamaha should have made those tensioner out of STEEL!

Originally posted by petejw
Hey all,

Has anyone else ever had this sort of problem.


Pete

[skids]

Re: Re: 4 bent valves

Sorry about the typos. adjusted > adjuster and looses > loosen

Originally posted by skids
Yes, Pete. I overtightened the adjusted to the point of the bolt "feeling like it was easier to turn." A stripped tensioner not only allowed the plunger to looses, but it held it in a slack position. Yamaha should have made those tensioner out of STEEL!

[2fast]

Sorry to hear about this problem, I know how I would hate it. If you want to keep and fix the bike, this would be a good time to do the big bore kit. Do a search for past threads and links.

[Winterhawk]

Same thing happened to my adjuster. I threaded it for a 1/4-28 Cadmium plated aircraft Allen head bolt with the nylon locknut on back wards. Seams to be working good but I like Bob Jones at Merriam Cycle's idea better. He uses 6mm Helicoil's to repair the adjuster.

[petejw]

Thanx john for the reply, u r a genious,
As a result of your reply, i went out and checked the
cam chain tensioner, I know I tightened it, what i didnt
realize was I did overtighten it, before i loosened the tensioner
bolt, i tried to push the plunger in with my hand, I was able to move it, then I checked the tightness of the bolt, the bolt was tight, but when i tightened it further it began slipping, the thread
WAS stripped. I wouldnt have thought to check that, I was racking my brain out figuring why the chain wouldve slipped, thought mayby worn cogs, but there fine.
The chain skipped a cog whilst trying to start the bike, luckily the motor hadnt fired when it did skip a cog, considering Id been riding it 4 a cpl of hrs after i retightened the chain, Ive taken the head off already, the pistons appear fine, tho i guess I wont really know till its all back together, $300.00 later 4 a second hand head, $130.00 for a gasket kit, a further $300 for the service to the head, the 2nd hand head weaps fluid thru the valves, after a seapage test. It becomes a very
expensive cam chain adjustment.
so the moral of the story is, be very careful when adjusting the cam chain tension.
Thanx again John.

[petejw]

Thanx 4 all ur replys i didnt realize they were there, only saw johns reply.
I took the bolt all the way out of the alloy adjuster, along with half
the alluminium from the adjuster. If only they had
ill get a heli coil put in, and hopefully that
will fix that problem.
Also ordered a cam chain, the guides all appear in good nic.
once again Thanks for the replies.

pete

[RiskyBusiness]

Pete, you might call or email Steve at L . LLOYD Ltd: Benelli6@aol.com. I just got a gasket and o-ring set from him for under $80. He told me he has cam chains too.

He has a web site but it is sort of ugly and does not list all of his XS1100 stuff: http://www.biker.net/lloyd/

[petejw]

quick update

Hopefully ill get the head back tomorrow arvo,
and she'll be running by tomorrow nite.

Today i did the cam chain,
much easier with the head off thats 4 sure.

Ive read how others have changed there chains,
i didnt have the proper tool to remove the link,
so i got an angle grinder onto the old chain, cut the link in half,
then tied a piece of cord to the old chain and tied it to the new chain, length of cord doesnt matter, as long as its strong enough not to break. while turning motor over fed new chain thru, there were no snags fed thru very easily, once thru placed a new link onto the chain and with a punch burred the edges. done!

ive read where ppl have stated that they have joined the old chain to the new chain with a new link and fed it thru that way, i think from memory they stated the chain had a tendency to snag, i had no problems and found that it would b time consuming and a pain to do it that way especially with not having the correct tool to remove the link.

I hope the above makes sense.

pete

[petejw]

master link cam chain

hey prom, or any one else that have bought new cam chains.

when u got ur new chain with a master link,
was the master link like the 1 u would find on a bike chain,
with a clip, or was it like a normal link that u had to burr the edges over.


pete

[Ken Talbot]

The chain I replaced came with a master link that needed to be peened over to lock on the side plate - no clip. The inside of a crankcase is not a good place for a clip type master link.

[skids]

Re: master link cam chain

Mine came with the type that you center punch and peen the pins (or use a correct tool). No way would I use a retainer clip except to temporarily attach the new chain to the old, for feeding it through.

Originally posted by petejw
hey prom, or any one else that have bought new cam chains.

when u got ur new chain with a master link,
was the master link like the 1 u would find on a bike chain,
with a clip, or was it like a normal link that u had to burr the edges over.


pete

[petejw]

mine was the same was just curious if they sold the chain with the master link with a clip.

pete.