Thumper Club Forum
Technical => Bike Problems/Questions => Topic started by: Simons...XBR500 on July 08, 2017, 12:42:27 PM
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Hi fellas
I've got a slr 650 that's new to me and when it's under load in low rpm I get a rattle or clattering noise until rpms take it away
Quiet at idle hot or cold
Any adeas ?
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There's quite a lot of backlash in the transmission and they can be quite lumpy at low revs. How low are we talking?
I tried to ride mine like a G80 and it didn't like it.......
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Aye Simons...XBR500,
From your description, I would tend to agree with Ian's diagnosis, "Give it some revs!". Over-square Japanese singles don't like being 'lugged' in high gears and will make horrible rattling noises that can lead to broken gearboxes and a knocking big-end! :( Long stroke singles e.g. Norton, BSA, AJS/Matchless and Arial will "thump" quite happily in a high gear, with a touch of retarded ignition and a slight throttle; they also often have a ruddy great big spring shock absorber on the drive side end of the crankshaft to absorb some of this torque reaction and smooth out the thumps! ;) As well as a rubber shock absorber in the rear hub. ;)
If as your 'handle' suggests that you are already familiar with Japanese singles, then maybe the alternator rotor is starting to chatter on the crankshaft taper due to the 'lugging' and or a fretted woodruff key and an insufficiently torqued rotor nut.
Usually, these motors require 2,000rpm to get them off the mark without stalling and to be doing at least 55 - 60mph afore selecting 5th gear, unlees you have altered the sprockets to provide alternative gearing.
I hope this helps and you can get to enjoy the bike, rather than worry about it.
My regards, Bill
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Hi Simon. I'm no expert, but these SLRs/Vigors/Dommies don't like to be below three and a half thousand revs, in my experience. Hope it is something as simple as this ;)
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Aye Simons...XBR500,
From your description, I would tend to agree with Ian's diagnosis, "Give it some revs!". Over-square Japanese singles don't like being 'lugged' in high gears and will make horrible rattling noises that can lead to broken gearboxes and a knocking big-end! :( Long stroke singles e.g. Norton, BSA, AJS/Matchless and Arial will "thump" quite happily in a high gear, with a touch of retarded ignition and a slight throttle; they also often have a ruddy great big spring shock absorber on the drive side end of the crankshaft to absorb some of this torque reaction and smooth out the thumps! ;) As well as a rubber shock absorber in the rear hub. ;)
Hi bill
It does help thanks very much for the info
The bike is new to me so just learning
Cheers 👍
If as your 'handle' suggests that you are already familiar with Japanese singles, then maybe the alternator rotor is starting to chatter on the crankshaft taper due to the 'lugging' and or a fretted woodruff key and an insufficiently torqued rotor nut.
Usually, these motors require 2,000rpm to get them off the mark without stalling and to be doing at least 55 - 60mph afore selecting 5th gear, unlees you have altered the sprockets to provide alternative gearing.
I hope this helps and you can get to enjoy the bike, rather than worry about it.
My regards, Bill
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There's quite a lot of backlash in the transmission and they can be quite lumpy at low revs. How low are we talking?
I tried to ride mine like a G80 and it didn't like it....... not sure exactly as no rev counter but best way I can put it is it seems very sensitive to being the n right gear I thought these motors had lots of torque to pull
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Hi Simon. I'm no expert, but these SLRs/Vigors/Dommies don't like to be below three and a half thousand revs, in my experience. Hope it is something as simple as this ;)
thanks mate so do I 👍
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Aye Simons...XBR500,
From your description, I would tend to agree with Ian's diagnosis, "Give it some revs!". Over-square Japanese singles don't like being 'lugged' in high gears and will make horrible rattling noises that can lead to broken gearboxes and a knocking big-end! :( Long stroke singles e.g. Norton, BSA, AJS/Matchless and Arial will "thump" quite happily in a high gear, with a touch of retarded ignition and a slight throttle; they also often have a ruddy great big spring shock absorber on the drive side end of the crankshaft to absorb some of this torque reaction and smooth out the thumps! ;) As well as a rubber shock absorber in the rear hub. ;)
Yes this helps a lot thanks for the info 💪
If as your 'handle' suggests that you are already familiar with Japanese singles, then maybe the alternator rotor is starting to chatter on the crankshaft taper due to the 'lugging' and or a fretted woodruff key and an insufficiently torqued rotor nut.
Usually, these motors require 2,000rpm to get them off the mark without stalling and to be doing at least 55 - 60mph afore selecting 5th gear, unlees you have altered the sprockets to provide alternative gearing.
I hope this helps and you can get to enjoy the bike, rather than worry about it.
My regards, Bill
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Simon,
Wouldn't be a slack drive chain, would it? Have you checked the chain tension?
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Simon,
Wouldn't be a slack drive chain, would it? Have you checked the chain tension?
it has 20 mm slack !
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Aye Simon,
15mm - 20mm slack with your full weight sitting on the bike. Be aware that the chain may have lengths which appear tighter or slacker than others and you need to check the tension on a tighter section if you have one. If the chain has become very stiff or slack then consider a new chain and sprockets. I have a measure of allowable wear/stretch for a drive chain from a Yamaha SRX manual, but this might cause unjustifide alarm! :o If your sprockets are looking hooked, this is another indication of potential problems.
Finally, if you enter "chain" into the search window in the top right of the 'Bike Problems/Questions' forum window, you will select 7 pages of messages about chain problems and there rectification discussed on this forum down the years and this could be of help.
My regards, Bill
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Aye Simon,
15mm - 20mm slack with your full weight sitting on the bike. Be aware that the chain may have lengths which appear tighter or slacker than others and you need to check the tension on a tighter section if you have one. If the chain has become very stiff or slack then consider a new chain and sprockets. I have a measure of allowable wear/stretch for a drive chain from a Yamaha SRX manual, but this might cause unjustifide alarm! :o If your sprockets are looking hooked, this is another indication of potential problems.
Finally, if you enter "chain" into the search window in the top right of the 'Bike Problems/Questions' forum window, you will select 7 pages of messages about chain problems and there rectification discussed on this forum down the years and this could be of help.
My regards, Bil
thanks again bill I think I'm going to put a 15t front sprocket on it anyway so motorway speeds a little calmer so will change the lot
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Aye Simon,
Be aware that this change of sprocket size is likely to alter (increase) the number of links in the chain you require. Be careful when purchasing a 'standard' chain for your model of bike, as this may not be long enough to accomodate your increase in size of the gearbox sprocket. If it isn't clear in the parts lists what is being offered and what might be required, enquire before placing your order and if no satisfactory answer is forthcoming, it might be prudent to take your custom elsewhere.
My regards, Bill
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It may also increase the hammering effect as the engine will be turning slower for the same road speed.
I must admit I found mine pretty exhausting at "motorway" speeds and felt 65 was about the maximum for any length of time. But then I'm old and decrepit.
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I loved mine, no where near as 'revvy' as the F650 but it was the stupidly small tank that drove me mad in the end...
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Aye Simon,
Be aware that this change of sprocket size is likely to alter (increase) the number of links in the chain you require. Be careful when purchasing a 'standard' chain for your model of bike, as this may not be long enough to accomodate your increase in size of the gearbox sprocket. If it isn't clear in the parts lists what is being offered and what might be required, enquire before placing your order and if no satisfactory answer is forthcoming, it might be prudent to take your custom elsewhere.
My regards, Bill
hi again bill
I took my front sprocket cover off and the last owner already put a 15t on so wondering about maybe dropping a couple of teeth on the back as it's very revvy even now
Simon
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I loved mine, no where near as 'revvy' as the F650 but it was the stupidly small tank that drove me mad in the end...
yes I've had a few days and liking it a lot quite pokey as well
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Simon,
Wouldn't be a slack drive chain, would it? Have you checked the chain tension?
it has 20 mm slack !
I don't know the specification for an slr, but it doesn't sound bad. 20mm on an xbr would be fine.
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I wasn't sure if you meant 20mm in addition to the slack which you should have or just a total of 20mm movement. If its the former, then its too slack, if its the latter, then its about right. But as Bill says, check the chain play at different points along the chain, and set at the tightest spot :)
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Aye Simon,
Be aware that this change of sprocket size is likely to alter (increase) the number of links in the chain you require. Be careful when purchasing a 'standard' chain for your model of bike, as this may not be long enough to accomodate your increase in size of the gearbox sprocket. If it isn't clear in the parts lists what is being offered and what might be required, enquire before placing your order and if no satisfactory answer is forthcoming, it might be prudent to take your custom elsewhere.
My regards, Bill
hi again bill
I took my front sprocket cover off and the last owner already put a 15t on so wondering about maybe dropping a couple of teeth on the back as it's very revvy even now
Simon
Aye Simon, "Very revvy"!
What is very revvy to you, for a 650cc 4 stroke single, is an inherent design a characteristic of short stroke large bore 4 stroke single engines. My SRX 600 has a final gear ratio of 1:2.437 (16 teeth:39 teeth), this equates to 55 mph at 3000 rpm in top (lowest rpm at which I select 5th gear). On this same gearing 70 - 75 mph comes up at 4,000 - 4,250 rpm in 5th gear. This is with the engine in a 'standard' state of tune, probably giving 40BHP at the rear wheel at best.
My understanding is that the SLR650 motor is in a soft state of tune and produces probably less BHP at the rear wheel than my SRX, when in a standard state of tuning.
I have attached as jpg images the comparable gear ratios for the 2 models of motorcycle. You should also be aware that the SLR uses a 17" diameter wheel, whilst the SRX 600 1JL model has an 18" diameter wheel that alters the final ratio, as may do the tyre type fitted.
Make your calculations and modify as you see fit, but be aware that as I have previously said, despite their colloquial name of "Thumpers", compared with long stroke 4 stroke singles, short stroke 4 stroke singles are in fact "Revvers" and if you really want a "Thumper" then a Big Pussy 120 (Panther 120, 650cc) might be more your machine. :)
Here is a link to a copy of the Honda_SLR_Workshop_Manual: Honda_SLR_Workshop_Manual (http://www.dominator-club.ru/manuals/Honda_SLR650_Servis_manual.pdf)
My regards, Bill
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