Newbie With Running Problem

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Linx
Posts: 169
Joined: Fri Jul 28, 2017 4:23 pm
Location: Stratford Upon Avon UK

Newbie With Running Problem

#1 Post by Linx » Sat Jul 29, 2017 8:59 am

Hi all,
Just joined. Finally got myself a 1984 RD500LC.
The bike has some history. Imported from France by it's original owner. Moved on to Peter who seized it and got a full engine rebuild done by Stan Stephens just before he sold it to Gavin. Apparently it seized because the airfilter and fuel filer had disintegrated. Bits of both in the carbs. Gavin just bought it as an investment but got the carbs striped and cleaned by V Twin Motorcycle Engineering in Co Durham. I see they fitted 47X Keyster carb kits. He only did 30 miles in 18 months.
I've now serviced it and checked powervalve adjustment, oil pump and carb sync. However on my first ride all was not good. It seemed fine at first but when it was up to normal temperature there was a terrible mid range lag. I only did 3 miles before turning round and nursing it home hoping it did seize. When I got home I found one carb over flowing and one exhaust only luke warm. The bike idles fine and is completely standard.
So any ideas what could be wrong with it please?
I've scanned the posts of course and see Keyster kits get a mixed reception. Is there a better kit I can buy?
Any advice much appreciated.
I'm not unaccustomed to 2-strokes and I raced a 350 Powervalve in 350 Production 1994 to 1998.
Cheers
Linx
:smt006 Current Bikes
1984 47X RD500LC, 2018 Triumph Speed Triple RS, 1999 Honda CB600F Hornet
Past Bikes Include
RD250LC, RD350YPVS LC2 Race Bike, RD350F2, 1976 CB400F

Motolli
Posts: 73
Joined: Tue Apr 18, 2017 7:10 am

Re: Newbie With Running Problem

#2 Post by Motolli » Mon Jul 31, 2017 4:11 am

Hi Linx,

overflowing carbs will cause a bad stumbling when driving, sure. I had this issue also. I replaced the float valves with new original parts from Topham. After changing them, there was also some flooding. But I found then some rubber parts inside the valve, coming from the petcock and blocking the valve. After cleaning it, everything runs perfect. After all, I am not sure if replacing the valves was really nessecary.

Olli

Timspu
Posts: 52
Joined: Fri Nov 18, 2005 10:59 pm
Location: Devon, UK

Re: Newbie With Running Problem

#3 Post by Timspu » Thu Aug 03, 2017 3:16 pm

Hi Linx,
Hope you have got to the bottom of your issue. I have just got mine back on the road after 10 years. It is a Stan Stephens stage 3 on a 540 cc. Had it own in some heavy rain last week and it totally died, no spark at all. Found water in the CDI connector. All dried out and runs better. I started of by having the left lower carb over flowing also found crudd in the float valve. Now fitted an inline filter and all is good.
I am still tuning as I think the bike is not giving true performance for the tune. My compression is only around 90 psi and has been that since tune and rebuild. Not sure what it should perfom like as my daily is a ZX10R. Keep us posted. Tim

Linx
Posts: 169
Joined: Fri Jul 28, 2017 4:23 pm
Location: Stratford Upon Avon UK

Re: Newbie With Running Problem

#4 Post by Linx » Thu Aug 03, 2017 6:25 pm

Thanks for the replies. I'm going to strip the carbs to see what I find at the weekend. I'll let you know.

Sent from my HTC Desire 530 using Tapatalk
:smt006 Current Bikes
1984 47X RD500LC, 2018 Triumph Speed Triple RS, 1999 Honda CB600F Hornet
Past Bikes Include
RD250LC, RD350YPVS LC2 Race Bike, RD350F2, 1976 CB400F

Linx
Posts: 169
Joined: Fri Jul 28, 2017 4:23 pm
Location: Stratford Upon Avon UK

Re: Newbie With Running Problem

#5 Post by Linx » Fri Aug 04, 2017 5:00 am

Rim. Your compression should be about 150 psi!

Sent from my HTC Desire 530 using Tapatalk
:smt006 Current Bikes
1984 47X RD500LC, 2018 Triumph Speed Triple RS, 1999 Honda CB600F Hornet
Past Bikes Include
RD250LC, RD350YPVS LC2 Race Bike, RD350F2, 1976 CB400F

Timspu
Posts: 52
Joined: Fri Nov 18, 2005 10:59 pm
Location: Devon, UK

Re: Newbie With Running Problem

#6 Post by Timspu » Fri Aug 04, 2017 9:18 am

Thanks, that what I thought. SS does not verify compression after tuning so he was not interested in my compression figures. Not sure how to get compression back if it's been over ported
Sorry to hi jack your thread.

Linx
Posts: 169
Joined: Fri Jul 28, 2017 4:23 pm
Location: Stratford Upon Avon UK

Re: Newbie With Running Problem

#7 Post by Linx » Sun Aug 20, 2017 11:50 am

A quick update just in case anyone is interested.
I cleaned out the carbs and checked jets. All looks standard and not Keyster as I was led to believe.
The bike is running much better now. I rode 400 miles last weekend. The only problem is, it doesn't like a neutral throttle. Accelerating and decelerating fine but chugs and shakes when cruising. Is this normal? I've also noticed the bottom two exhausts have quite a bit of oil coming out the back.
:smt006 Current Bikes
1984 47X RD500LC, 2018 Triumph Speed Triple RS, 1999 Honda CB600F Hornet
Past Bikes Include
RD250LC, RD350YPVS LC2 Race Bike, RD350F2, 1976 CB400F

Blobber
Posts: 186
Joined: Mon Jan 07, 2008 5:34 am
Location: Lancashire, England

Re: Newbie With Running Problem

#8 Post by Blobber » Thu Aug 24, 2017 10:28 am

Hi Linx,
I had the same problems.
Its better when at higher revs but at low to medium revs when cruising in traffic I found it a real pain.
Its took me years to sort out to my satisfaction but I am fussy.
My first step was to clean the carbs with correct needle and jets for your model and state of tune.
Make sure the carbs are in balance.
Make sure the oil pump is not too rich as this can cause bad running so reset correctly
This provides a reasonable level of smoothness but still in my view unacceptable.
Having played with many carb settings and jet changes I eventually fitted Ivans needles and as I had the restricted RZV emulsion tubes also fiited Ivans needle jets.
The bike is now much better and for me acceptable only showing a slight bit of lumpyness if cruised below 3000 rpm which is guess is probably a bit unfair to expect perfection at such low revs.

Hope that helps and good luck.
Attachments
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Bikes:
RZV500R FZR1000 forks wheels JL pipes
RD350LC N2

Blobber
Posts: 186
Joined: Mon Jan 07, 2008 5:34 am
Location: Lancashire, England

Re: Newbie With Running Problem

#9 Post by Blobber » Thu Aug 24, 2017 10:48 am

sorry wrong upside down photo lol
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Bikes:
RZV500R FZR1000 forks wheels JL pipes
RD350LC N2

Linx
Posts: 169
Joined: Fri Jul 28, 2017 4:23 pm
Location: Stratford Upon Avon UK

Re: Newbie With Running Problem

#10 Post by Linx » Thu Aug 24, 2017 11:23 am

Thanks Blobber. Have you heard of Sigma Jet Kits? My bike is an early one. Later ones had different jetting. I don't know if a straight forward jet change to the later specs will help. I'll check the oil pump.

Sent from my HTC Desire 530 using Tapatalk
:smt006 Current Bikes
1984 47X RD500LC, 2018 Triumph Speed Triple RS, 1999 Honda CB600F Hornet
Past Bikes Include
RD250LC, RD350YPVS LC2 Race Bike, RD350F2, 1976 CB400F

Blobber
Posts: 186
Joined: Mon Jan 07, 2008 5:34 am
Location: Lancashire, England

Re: Newbie With Running Problem

#11 Post by Blobber » Thu Aug 24, 2017 11:38 am

Hi, I have heard of them but no experience of how they perform. Sound like they are the perfect solution and would be interested to know how you get on if you go for them.
I dont think they have not been discussed on this forum and this would make me a bit cautious.
Bikes:
RZV500R FZR1000 forks wheels JL pipes
RD350LC N2

Linx
Posts: 169
Joined: Fri Jul 28, 2017 4:23 pm
Location: Stratford Upon Avon UK

Re: Newbie With Running Problem

#12 Post by Linx » Thu Aug 24, 2017 11:43 am

Nice bike BTW [emoji106].

Sent from my HTC Desire 530 using Tapatalk
:smt006 Current Bikes
1984 47X RD500LC, 2018 Triumph Speed Triple RS, 1999 Honda CB600F Hornet
Past Bikes Include
RD250LC, RD350YPVS LC2 Race Bike, RD350F2, 1976 CB400F

Linx
Posts: 169
Joined: Fri Jul 28, 2017 4:23 pm
Location: Stratford Upon Avon UK

Re: Newbie With Running Problem

#13 Post by Linx » Sun Oct 15, 2017 3:40 pm

A quick update. I have the bike running much better now. I've fitted Ivan B needles on 4th clip slot down and leaned off the oil pump a bit. float heights are at 22.5mm as stated by Ivan. It's nice to ride now but I think I will drill out the pilot path to 1.5mm over the winter as recommended by Ivan too. I did notice today between 8k rpm and 10k rpm there doesn't seem to be any increase in power. I might not have the best main jet and I'm thinking of getting it dynoed next year. I'll be restoring the frame and running gear over winter first.
:smt006 Current Bikes
1984 47X RD500LC, 2018 Triumph Speed Triple RS, 1999 Honda CB600F Hornet
Past Bikes Include
RD250LC, RD350YPVS LC2 Race Bike, RD350F2, 1976 CB400F

V4 Heaven
Posts: 182
Joined: Mon Nov 28, 2011 6:43 pm
Location: Wiltshire, UK

Re: Newbie With Running Problem

#14 Post by V4 Heaven » Thu Oct 19, 2017 9:19 am

Leaning off the oil pump sends shivers down my spine. I can't see how it should be any different to Yamaha who would have produced their settings after a great deal of development work? I've also read of forum members doing this, only to have the thing seize on them. For me, I'd leave the oil settings as per manufacturer's settings then look at jet sizes etc. Vin on this forum used Projex to dyno his and said that despite thinking his was well set up, it felt great afterwards. This is my plan for the spring too. Who were you thinking of doing your dyno-ing Linx?

(https://www.google.co.uk/url?sa=t&rct=j ... WTvRfJfZAA" onclick="window.open(this.href);return false;)
Gettin' kinda squirrely!

Linx
Posts: 169
Joined: Fri Jul 28, 2017 4:23 pm
Location: Stratford Upon Avon UK

Re: Newbie With Running Problem

#15 Post by Linx » Thu Oct 19, 2017 1:56 pm

Hi V4. I agree. It is a worry. A seizure is the last thing any of us want. I was going by the Autolube Adjustment thread a bit lower down the list. Also I have quite a bit of oil coming out the pipes. Anyway you've convinced me, I'll put it back to standard.
I haven't looked for a suitable dyno yet. Thanks for the link. A friend of mine recommended a place down near Crawley.

Thought I show off the bike!
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:smt006 Current Bikes
1984 47X RD500LC, 2018 Triumph Speed Triple RS, 1999 Honda CB600F Hornet
Past Bikes Include
RD250LC, RD350YPVS LC2 Race Bike, RD350F2, 1976 CB400F

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