Bonneville America Forums Forums Technical Forums Performance Mods 904 BB Kit - Got one? I need help (urgent)

The barrels are off at the shop having the new sleeves pushed in.. the bloke there reckons the barrels are NOT finnished and need work on them.

When I looked at them they looked like they were ready for the pistons.

So, can someone that KNOWS or has had the work done on the 904 kit tell me once the sleeves are pressed in do I need to have ANY work done as regards honing or boring?

Thanks for your help on this, there is no instructions with the kit to say anything, the only figure I could find was the sleeve outter diameter, nothing else came in the kit.

TrOjAn

need honing...if bloke knows his job then he should know what to do....measure them.....thats why I did this part of the job in Poland in real engine shop with over 40 years of expirience

Here are some comments from mag10 who posted some specs from memory some time ago regarding what has to be done to the sleeves once installed. A good engine shop should know this.

Guys your all STARS, thanks for the info, the bloke doing them has no specific knowledge of our bikes. The sleeves are in and he has the pistons and rings but asked me for some specs.

Ill pass on the interference the other info from the linked post above..

Terry,

I'd do what Mic suggested and phone/email Wiesco about the clearance needed between the piston skirt and cylinder wall. Also the ring end gap between the top and lower rings will be different. Get that also.

Pass the dimensions on to the group so we can add to the tech vault since I haven't seen them posted yet.

Here are the general Wiesco Ring End Gap instructions.

Here are the Piston fit instructions. According to this the piston/cylinder clearance is written on the label on the piston box they came in.

got a price for the complete job for a 904 conversion of $2000 is at a bit price.rudy

you should be able to get it done for $12-1500

Well here in the UK to buy JUST the kit is 1,053.10 USD at todays exchange rate but for them to actually do the work it is 1,261.75 USD FITTED

My cost so far is 642.195 USD which aint bad, nice having friends

that sounds about right, and you're getting a great deal!

Hi once again,

so heres the deal, the BB kit is on (big cheer) but I got a small niggle in the back o my head thats driving me mad.

If you look at the attached photos you will see that the top valve drive gear is slightly offset when the bike has the flywheel timing marks ligned up.

Now BEFORE any smart ****** says, "line them up", I am unable to get them exact, they are either behind of in front, NEVER spot on.

I have turned the bike over and tried lots of times to get them exact but no, its not possible..

The bike as it stands turns over (by hand) fine, nothing is hitting but its going to annoy the ****** outta me if I dont get some advice on it.. so, anyone care to chip in??

TrOjAn

I dont know if it'll affect your alignment inquiry but Im pretty sure that "I" cam needs to be tensioned. The hole in the cam gear should align or it'll cause a heck of a raucous.

Is the chain correctly tensioned?

Agree with Pieman. It doesn't look like it is really out looking at your pic. Tensioning the cam should address the issue.

I don't think it's cam chain tension. Looks to me like the
intake cam split gear is not preloaded. The holes don't line
up. I believe this is why "TOP" is not up. That's also why
it looks like it's all off by one or two teeth, even though the
lines and dots match up.

I had the exact same problem 2 yrs ago. The instructions say to pull the chain taught and then over the gear from the side that does not have the tensioner. This put the chain pin that's between the links directly over a tooth instead of between the teeth of the gear. I had to turn the gear one way or the other in order to get the chain to seat. I turned it away from the side that has the tensioner and have had no problems. This process is done before the tensioner is installed. The bike had 64,000 mi. on it and I assumed the chain had stretched. I often wonder how the bike would run if I had turned the gear the other direction.

OK, reading through the manual, here and various other information sites I dont think there is anything wrong with it.

The manual states to position the cam lobs as pictured, then nudge the flywheel forward to the timing mark, this actually moves the TOP of the cam drive gear to where mine is.

I spent a lot of time turning the engine over and over and trying the chain on the gear for ages and its always slightly off (half a tooth).

The pictures above are with BOTH cam tensioners in and zero slack at the front. The cams are still tensioned as they were taken off (I had pins in them) so theres no issue on those.

Assuming there might be SOME kind of give in the chain as it gets hot / worn then the gear will err slighty back so this should be ok.

I shall report back once she is running, hopefully with good news and not " I had to rebuild my head / valves " LOL

As a side note, does anyone know a supplier of the base gasket, head gasket for the big bore kit? or do I have to contact Wiseco?

Our very own Fast Eddy was able to procure a BB gasket kit for me at a fair savings over the Wiseco site.

http://www.wiseco.co.uk/ They should be able to help.

Hi all, just an update on this camshaft drive being half a tooth out,

the bad news: I got to take the cam cover, cams and tensioners out again

the good news: I now know what is wrong.

Laying in the bath not 10 minutes ago I had a EUREKA moment (no I didnt run down the street naked) and now have the solution.

Its so simple Im really annoyed I didnt work it out earlier but for those ionterested here it is.

During the rebuild the crankshaft was turned, that in its self is not an issue but the problem arises when the chain is OFF the crankshaft gear.

ONE tooth on the crankshaft equates to 1/2 a tooth at the top which is the error I have.

Still, hopefully this will help someone out, should have worked it out before I built the engine back up but hey, at least I had not run the engine.

Ill report back hopefully tomorrow if I get out there to do it, snow is forecast

I'm not sure that's it TrOjAn, unless I'm not understanding your Eureka moment.

You can't be one tooth off on the crank gear, only one tooth off on the cam drive gear. As long as the crank is in the correct position when you line up the cam drive gear, that should be that. It can only be wrong if the crank was slightly off the mark when the cam drive gear was lined up or the cam drive gear timing marks were not parallel with the head surface when fitted.

Looking at your second photo down, if the alternator rotor mark was lined up with the case joint when this photo was taken, then it looks like you are one tooth out on the cam drive gear not the crank.

I hope you have a nice warm garage to work in, tomorrow's gonna be bloody freezing. Good luck.

Hey Pieman..

I appreciate what your saying, I can only hope to prove my theory tomorrow (in the cold).

Just to clear things up.. and hopefully make it a bit simplistic, one turn of the crank = 1/2 a turn on the cams.

So therefore, 1 tooth on the crank = 1/2 a tooth on the cams.

I will get some photos as I do it and hopefully it will be clearer. While the chain was hooked up it hung below the crank gear, as I turned the crank to get the barrels on the chain was not on it, when I did pull it up it must have been one tooth round which has caused this issue..

Bear with me, Ill hopefully be happy tomorrow and have some good news.

Terry,

Pieman's right. It doesn't matter if the chain was removed from the crank and the crank rotated then the chain put back on. What matters is where the crank is in relation to the case reference. If it lines up, it is ok. Yes the cam turns at 1/2 the speed of the crank, that's why the cam sprocket is twice as big as the crank sprocket. The size of the teeth on the sprockets are the same though.

Looking at the 2nd picture again, I see that the reference marks aren't parallel with the head. It indeed looks like it is out a tooth. How did you tension the tensioner? Have you installed the cam chain guides properly?

Hold on a minute....I think I just spotted what you were trying to say. The cam sprocket does have twice the radius of the crank sprocket. Rather than trying to move the cam sprocket the 1/4 inch to fit the chain, move the chain the 1/8 inch on the crank sprocket to move the cam. Does that make sense? Now I'm second guessing myself. Wish I had my engine apart to check myself.

Being one link off, it shouldn't matter if you move the one link on the cam sprocket or on the crank sprocket. The link of the chain is still the same length, be it on the crank or cam sprocket. Yes the circumference is doubled on the cam sprocket vs. the crank,but the distance one link moves is the same... The angler distance is doubled on the crank vs. the cam...So you can move the CAM sprocket one link and get the same results as moving the crank sprocket one link.

Well I stipped it down, messed about for an hour, moved the chain about on the crank gear, not sure if it helped, didnt look like it did, so it looks like Pieman and Two Wheel n are right... a links a links a link.

Of course thats NOT the end of this story, lol.... for some reason my shims were wrong, maybe my maths were wrong, wrong gauges who knows.. so I called Triumph to make sure they had the ones I wanted and off I went.

Got there, North City Triumph in Romford, in I go and had a chat with one of their mechanics, Danny, only a young bloke but Triumph trained.

He was doing a Bonny shims so we had a look and a chat about my one tooth issue.. he said it may well be cam chain wear and that I should line the marks up slightly behind the timing mark so as NOT to advance the valve timing.

Picked my shims up and went home.. re shimmed valves, put cams back in an bugger me.... the lines are now SPOT ON, timing is perfect.

Was it the chain? was it a tooth on the bottom gear.. well I will never know, what I do know is its back together correct and Im looking forward to firing it up and hearing it

Glad it's all right now!! Happy to hear!!

Hope it all works out for you. I recently reset my valves after 28,000 miles. I had four out of eight that were to loose. The right exaust was the looses. I swear it is quieter now even though my hearing is not the best. Made me feel good,that one valve has been bugging me for some time.Just had not had the time to do it.

Nice one TrOjAn.

A tip on setting valve gaps. Set a micrometer to say 0.025mm and slide an oiled 0.025 feeler gauge in there, move it backwards and forwards. This will give you the feel of how the feeler gauge feels when a gap is dead on. From this you can judge when a gap is slightly under or over from correct.

Excellent tip Mike. Much appreciated.

Far cannel,glad to hear its all come together.

So bloody cold out there atm, Im hoping to put some more back together this weekend.

Engines ready to fire up but the body work is scattered all over Essex atm

Thanks to all my mates....

Crikey, has it been that long!!!

Started the bike up yesterday and it runs smoked like hell and the wife ran out LOL you gotta love em, anyway, first ride today and it sucks big time. the 150 main jets are WAY too big.

So just pulled the carbs and jetted down to 135`s and took it for a run.. running better but still not right.

Next drop will be down to 128`s and another test run, once its running sorta like a bike should it will be up to the dyno man to find out where its lacking and hopefully she will be done pretty soon.

The BB kit seems ok, no leaks or issues so thats a result.

I am reserving judgement on the "bang for bucks" until its running right.. took her up to 70mph and in my "seat of pants" opinion not a lot of difference.. time will tell.

TrOjAn

u will see when bike will be broken in and properly tuned ..there is a difference in torque when u overteaking hope u can find good dyno operator who can give u good advice and u will tune the bike ,mine does and is really good