Sluggish take off

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Stumpy 32
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Current Ride: Suzuki Burgman 400
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Sluggish take off

Post by Stumpy 32 » Mon Oct 29, 2018 2:24 pm

Evening all. I've replaced the belt and variator rollers on my recently bought K4 Burgman, smoother now on take off as some of the rollers were worn unevenly. But, (isn't there always a but?) the bike begins to move at about 1800rpm rather than the Suzuki recommended 2300-2900rpm. This makes the bike very sluggish on take off and it definitely struggles to pull away on hills. The Suzuki "lock up" test says this should happen at 3500-4500rpm, I seem to be getting nowhere near that speed.
The new rollers weigh 21 grammes (std. weight?), the old worn rollers weigh around 19 grammes each.
On the road, once moving the bike seems fine.
Prior to doing the work I could blip the throttle to over 2000rpm and the bike wouldn't move, can't do that now.
I'm thinking I've assembled something incorrectly, the variator?
Any ideas?
Thanks, John

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Ralph
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Re: Sluggish take off

Post by Ralph » Mon Oct 29, 2018 3:33 pm

Did you do anything to the rear pulley/clutch it’s more likely the clutch than the veriator.
Ralph
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Stumpy 32
Posts: 15
Joined: Thu Oct 11, 2018 12:45 pm
Current Ride: Suzuki Burgman 400
Location: North Wiltshire, UK
Great Britain
Re: Sluggish take off

Post by Stumpy 32 » Mon Oct 29, 2018 3:45 pm

I didn't dismantle the clutch but I used an airline to blow the dust out of it, not that there was much in there.
Iv'e now stripped the drive again, there is now a distinct "shiny" mark around the variator pulley sheaves, I think I could hear a squeal as if the belt was slipping, this could confirm that is happening. The marks are at about the midpoint on the sheaves. This might suggest that the variator is not working correctly, that is to say it is not dropping to a low enough "gear". hence the sluggish get away. Might also explain why the clutch locks up early?

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Ralph
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Re: Sluggish take off

Post by Ralph » Mon Oct 29, 2018 5:12 pm

If as you say it is not dropping low enough then would be like setting off in to high a gear so you could be on the right track
Ralph
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Normsthename
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Re: Sluggish take off

Post by Normsthename » Mon Oct 29, 2018 5:50 pm

Did you fit an original Suzuki Belt or an aftermarket one?
If the belt was a different width it would alter the gearing etc???

Andy
2018 Yamaha Xmax 300
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Stumpy 32
Posts: 15
Joined: Thu Oct 11, 2018 12:45 pm
Current Ride: Suzuki Burgman 400
Location: North Wiltshire, UK
Great Britain
Re: Sluggish take off

Post by Stumpy 32 » Tue Oct 30, 2018 4:15 am

The new belt is an after market item, slightly wider, ~1mm. I refitted the old belt, that is on the maximum width specified, made no difference. I am wondering if I have done something to the variator. I think that the rollers need to be positioned so the pulley sheaves are in the low gear position on assembly. They seem to find there own positions! Anyway of holding the variator in the low gear position for assembly? the Suzuki manual hints at this, careful assembly is required "so as not to allow the roller to dislocate" it says.

John

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Ralph
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Re: Sluggish take off

Post by Ralph » Tue Oct 30, 2018 5:01 am

It's a few years since I had a Burgman in bits but cant remember any thing to watch out for,
I fitted Doc Pulley weights on one and they could turn if you did not keep the bits pressed together
which was a bit finger trapping but the normal rollers just settle in the right place.
I used to turn the ventilator as I tightened the nut so the belt settled and never had any problems.
Ralph
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roadster
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Re: Sluggish take off

Post by roadster » Wed Oct 31, 2018 5:07 am

Stumpy 32 wrote:
Mon Oct 29, 2018 2:24 pm
The new rollers weigh 21 grammes (std. weight?), the old worn rollers weigh around 19 grammes each.
The change in roller weight alone would be noticeably slower on acceleration, especially if the old ones were worn enough to close the pulley halves less hence giving a smaller effective pulley diameter both on acceleration and when at the top of their travel. When, on previous Piaggios, I used Dr. Pulleys I found they outlasted standard rollers and gave better performance using the reduced weight recommended.
Located on UK South Coast
Rides Kymco AK550 previously Kymco Downtown 300i ABS and Triumph Street Twin.

XMax400Paul
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Re: Sluggish take off

Post by XMax400Paul » Wed Oct 31, 2018 7:18 am

After market belt may be a slightly different LENGTH as well a slightly different WIDTH...
My Recommendation would be OE Belt... and Dr Pulley Rollers / Sliders at OE weight... rather than dropping the 10%

I have fitted Dr Pulleys in my XMax 250, XMax 400, and SH125... and after going down the 10% (or slightly less) have re-ordered for OE weight...
The XMax 400 and SH125 was way to revvy for stop start commuting traffic... the drop of 10% may be more suitable for A road and M Way Cruising...

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Ralph
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Re: Sluggish take off

Post by Ralph » Wed Oct 31, 2018 10:16 am

I had a gates belt on my burger no problems but the 07 on model used a different more expensive belt just wounding if you have the right one . I also had doc pulley weights they were 21g but I found it a bit revvy so added a little weight they were just over 22g and seemed about right, still reved a bit higher below about 50 but lower when at speed.
Ralph
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