Tight cam chain

As mentioned, those cam blocks look oem style but I can measure one tomorrow. It'll be a retired cnc type.

Since you have a vernier, can you measure and compare those cam sprockets? I saw one looked normal with induction hardened teeth.
The other one looked odd to me.
The root across the diameter.
 
The upper end of the intake side tensioner blade is fixed by a screw in the had and it is not touching the chain at this point. It is touching the chain at a lower point where the tension adjuster is. You cannot see it or maybe with some light and a mirror….
 
The adjusting screw isn't long enough to properly tension a 104 link chain. :rolleyes:

Find the source of the issue instead of attempting a bodge. How about actually measuring your chain length? Not all chains are the same, despite identical designation. Industrial and automotive chains can show significant differences, Andy the Chainman has told us all about that numerous times.

piet
 
The Regina chain I always fitted came in a red box which was marked C121HCS ...... ( 3/8" x 1/4" x102 links ) ........ and came with a spring clip connecting link ......

The IWIS version is marked G67WZ apparently , although I have never used that .......

From the info I can source on the web , there was once upon a time a batch of Regina C121HCS which were badly manufactured , being on the short side ........ and if fitted were very tight with no slack .........


I was going to suggest refitting the original chain , and rechecking the tension again , bearing in mind these chains can seem to be a tight fit anyway ...... but I see Bob has mentioned that this Regina he removed had a riveted connector link , not spring clip ..... but depending on how it was removed , may not be such an easy option now .

Does the replacement IWIS chain conform to G67WZ ? ........ or for that matter appear to be very similar , if not identical ..... ( which it will need to be ) ...... to the chain it`s intended to replace ?
 
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Side by side the IWIS that was impossible to join on that twin, beside the DID which easily joined, was about half a mm difference which I found very puzzling, so comparing lengths won't explain it. On this bike both the chain he replaced and the new one were way too tight.
 
Ok more information removed the head gasket measures 1mm thick so replaced the head replaced cam shafts made sure at rest not touching any of the tippet caps made sure chain on crank sprocket then connected the chain which was very hard to do with pointed pliers so no rear slipper fitted and still no slack in the chain should their be any play in this position IMG_2464.jpegIMG_2462.jpegIMG_2458.jpeg
 
Tippie said:
Side by side the IWIS that was impossible to join on that twin, beside the DID which easily joined, was about half a mm difference which I found very puzzling, so comparing lengths won't explain it. On this bike both the chain he replaced and the new one were way too tight.
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May not only be overall length Lee. A tiny difference in roller diametre could actually "shorten" the chain several mm when fitted.

As I've already said, try a new chain...

piet
 
Bob , I can`t help thinking it looks fine to me ........... are you sure there`s absolutely no play between the two sprockets , even if it`s only a couple of mm ?

Can you now insert the rear tensioner blade without it making any difference ?

I would have thought pressing down really hard should give some movement ....... there won`t be the sort of loose slack you get with say , a final drive chain ...... you have to apply a bit of pressure .

Personally , even if there was only a few mm of movement , I would accept it for what it is , and leave it at that ......

Just my own opinion mind ........ wish I could give it a wiggle myself , just to see .......... :) .............
 
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Thanks
If I put the back slipper in it goers even tighter
And if you look at the connecting link it has already stretched unable to fit the front link as it has stretched there is no up or down movement at all between the wheels
 
So does the cam chain tension remain tight, no matter when the motor is advanced any?
I had a similar problem when re-fitting the cam chain on my twin and advancing the motor slightly back and forth at TDC finally got the chain seated properly. And temporarily tightening the cylinder head might help ease the chain tension.
 
TeddyG said:
So does the cam chain tension remain tight, no matter when the motor is advanced any?
I had a similar problem when re-fitting the cam chain on my twin and advancing the motor slightly back and forth at TDC finally got the chain seated properly. And temporarily tightening the cylinder head might help ease the chain tension.
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With twins, Teddy, I always fit spacers and head stud nuts to get some compression into the gaskets - makes fitting the cam chain SO much easier. When adjusting the twin cam chain, you should always be rotating fwd, feel the plunger with your finger and tighten at the point where it has gone in the furthest (which means there's tension on the front part of the chain and the slack is at the back).
 
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