CB350 Cam chain tensioner

crazypj

Split personality, I fake being smart
I was going to make Delrin rollers for Marc but he got a Ka at a good price, thats how I have an idea how long they last racing.
The stock rubber rollers are know to break up at sustained 10k plus rpm
 

MotorbikeBruno

Over 1,000 Posts
crazypj said:
I was going to make Delrin rollers for Marc but he got a Ka at a good price, thats how I have an idea how long they last racing.
The stock rubber rollers are know to break up at sustained 10k plus rpm


I'll take a look into that poland guy, I think I found a set of those while searching for hours yesterday. The SL350 was running fine, but it made some chain slapping noises and I found bits of aluminum in the oil "filter" (that centrifugal thing) so I gave her a check and sure enough that roller that I can see when you pull the tensioner off is in bits. Already cleaned out the oil pump and such. I was more worried that a NOS roller would be brittle from sitting so long. Is this something I shouldn't worry about? I've found the lower roller for cheap, but the top one attached to the metal bracket is harder to source. Thanks gents!

This one looked sketchy at best, and isn't an "original" Honda part it looks like... http://www.ebay.com/itm/Honda-CB350-CB250-CL350-CL250-SL350-NEW-TENSIONER-CAM-CHAIN-/360498599140?pt=Motorcycles_Parts_Accessories&hash=item53ef6414e4&vxp=mtr
 

gregajo

wrenching in the bad oil garage
Hi All, I am at this point in my motor rebuild of needing the cam chain tensioner. I thought about getting those rollers from the guy in Poland (Pawel). However he has had trouble finding the time to produce more of them. l wondered about the KA slipper model from Bore Tech but saw in their add that there may be some machining needed to make it fit? So, other choices? I hate the idea of putting in the OEM rollers that were historically the Achilles heal of these motors. Thanks Greg
 

MotorbikeBruno

Over 1,000 Posts
gregajo said:
Hi All, I am at this point in my motor rebuild of needing the cam chain tensioner. I thought about getting those rollers from the guy in Poland (Pawel). However he has had trouble finding the time to produce more of them. l wondered about the KA slipper model from Bore Tech but saw in their add that there may be some machining needed to make it fit? So, other choices? I hate the idea of putting in the OEM rollers that were historically the Achilles heal of these motors. Thanks Greg

I heard the Achilles heel part of it was sustained speeds that it wasn't "designed" to do, and when they sit, they get brittle. If they were used regularly, there wasn't a problem. Can anybody confirm that? PJ, how lucrative is it for you to make some out of delrin at this point. I'd rather give someone like you my money vs someone in Thailand...which seems to have a bunch of these things..haha
 

crazypj

Split personality, I fake being smart
NOS should be fine, it's the heat cycling that screws them up.
I think I have a lower roller here somewhere but I know I don't have the upper one
I was going to look for a needle bearing to fit into them but never got any further after Marc got the Ka
I have some Delrin but not needle bearings or something for pattern
 

MotorbikeBruno

Over 1,000 Posts
crazypj said:
NOS should be fine, it's the heat cycling that screws them up.
I think I have a lower roller here somewhere but I know I don't have the upper one
I was going to look for a needle bearing to fit into them but never got any further after Marc got the Ka
I have some Delrin but not needle bearings or something for pattern

Ah, I guess the heat cycling makes sense. The lower roller is pretty easy to find as it's used on the CB750 assembly as well. The upper one is more of a pain in the arse. I guess I'll look for another NOS one. Thanks for the info PJ. If I do get one, I'll take some good measurements and throw them up in here.

EDIT: Found upper assembly and lower roller here:
http://www.cyclepartsoutlet.com/ecbasket.asp?fveh=131026&section=2448579&year=1970&make=Honda&model=SL350&category=Motorcycles&sid=01380579X4K16K2013J12I58I30JPMQ7189R0

87.47 + shipping. Doesn't seem TOO bad. Thoughts?
 

DrJ

Over 1,000 Posts
MotorbikeBruno said:
I heard the Achilles heel part of it was sustained speeds that it wasn't "designed" to do, and when they sit, they get brittle. If they were used regularly, there wasn't a problem. Can anybody confirm that?

I'd say yes, the hot engine oil keeps the rubber supple making the rollers more absorbent to the stress. When sitting for a long time, the rollers get dry and brittle.
 

MotorbikeBruno

Over 1,000 Posts
DrJ said:
I'd say yes, the hot engine oil keeps the rubber supple making the rollers more absorbent to the stress. When sitting for a long time, the rollers get dry and brittle.

Yeah, and PJ pointed out the heat cycles too. I suppose it wasn't designed to last 40 years either... ::)
 

liam

1970 cb350/1980 xs250/2004 klx400/BMW E30 323I
gregajo said:
l wondered about the KA slipper model from Bore Tech but saw in their add that there may be some machining needed to make it fit?

the machining is not really machining,so much as checking the clearance of the slipper in the case, and maybe filing some of the cast lines flat inside the slot so it can move freely without the rivets in the slipper catching the wall. it should take about 10mins with a hand file at least in my experience...
 

legendary_rider

Jump in with both feet.
I took an angle grinder without the guard to the inside of my case! lol. There is some material that needs to be removed from in between but it's not a huge deal. Just don't slip and hit a gasket surface or worse yet your hands/face. lol. You could also probably use a dremel but it takes a lot longer! I tried using sanding drums on dremel but took too long. Power grinder is the way to go.
 

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legendary_rider

Jump in with both feet.
No man, I'm just refunding everyone's money and cutting my loses. Done bleeding money on that project. The other places I found wanted over 2 grand just to cut all the guides out and would have been a lot of material waste. Someone else can empty their wallets. I am tempted to figure out different ways of doing it but it'll be after I've paid everyone back and low budget stuff without CNC machines and $3000 sheets of plastic.

The cnc machine and sheet of plastic is up for sale if you want to take a crack at it! Be my guest. lol.
 

Wee Todd

Coast to Coast
hmmmmmm,,,I built 2 engines with stock cam chain roller setup for road racing and have had no problems,,,,would I opt to have a slipper or poly sprocket,,,,,,yes, but after 10 yrs on both engines the rollers are fine,,,,,,,,,,,,,so far!!!!!!!!!!!!
 

crazypj

Split personality, I fake being smart
I think if you keep them below 11,500 the rollers don't have a problem
I have seem them starting to shred on 12,000 rpm motors but changed them out before things got too bad
 

alzcbz

Been Around the Block
I am in need of the tensioner assembly. The dealer says they are no longer available.
Are the rollers the same for the CB750K0-K8 and CB350? I know the brackets are different. My intent would be to remove the small roller from the 750 bracket and fit it to the 350.
 

rcl5011

New Member
For those of you still looking for these rollers and has come across this thread, I have brand new chromolly versions of both the upper and lower rollers.

They will fit CB/CL/SL motorcycles. Upper roller is a sprocket, lower is a smooth roller. Each have high quality needle roller bearings pressed into them. Upper roller comes with a deformable rivet. Material is chromolly steel. See the following links for purchase.

Set:
http://www.ebay.com/itm/Honda-CB250-CB350-CL350-SL350-CB750-Cam-Chain-Tensioner-Roller-Wheel-Set-/231576401099?hash=item35eb0774cb:g:GKIAAOSwstxVZygr&vxp=mtr

Upper:
http://www.ebay.com/itm/Honda-CB350-CL-SL-Cam-Chain-Tensioner-Upper-Roller-Sprocket-Wheel-CNC-Machined-/231560299062?hash=item35ea11c236&vxp=mtr

Lower:
http://www.ebay.com/itm/Honda-CB250-CB350-CL350-SL350-CB750-Cam-Chain-Tensioner-Lower-Roller-Wheel-/231560304770?hash=item35ea11d882:g:NNUAAOSwPhdVUrAn&vxp=mtr

Link to Instructions:
https://drive.google.com/file/d/0B31LrzzamA7UbHBFY1E2a2JnMFU/view?usp=docslist_api


Thanks
 

crazypj

Split personality, I fake being smart
That's nice looking stuff and indestructible. 8)
Needle bearings a great addition
How much heavier than stock?
Wouldn’t Delrin be 'better'?
 

DrJ

Over 1,000 Posts
rcl5011 said:
For those of you still looking for these rollers and has come across this thread, I have brand new chromolly versions of both the upper and lower rollers.

Do you only sell through ebay? Would you ship to Canada?
 

rcl5011

New Member
I can ship to Canada no problem. Send me a PM if you are interested in an order. Payments can be made through PayPal.

Delrin is not recommended for temperatures above 180°F. I would be concerned with wear at high temperatures, as well as the press fit holding together on the bearings. These are heavier than stock, but at these small diameters, the added rotating inertia is minimal. I can get you exact numbers if interested.

Thanks

-Ryan
 

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