Can I use Dynojet needles with standard main jets?

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Harveyz
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Re: Can I use Dynojet needles with standard main jets?

Post by Harveyz »

Hi folk's

Another morning wasted drained tank checked breather ( not 100% on filler cap but seal look OK) - both overflow and tank breather work - managed to find a 175 jet - other than a 45 pilot jet it's a back to stock as you can get - but still runs like a pig under 3,000 rpm - surging and stuttering - - after yesterday tried it with 5l fuel in the tank - another miserable ride.

If anyone has any wise words I'd appreciate it - I've been messing with it for 6 months - pity as it is a great handling bike. I'm at the point now where unless I have an epiphany it's going to get binned as I'll end up wasting whole summer messing with it instead of riding


New fuel tap repair kit
Standard Airfliter
TPS set to 490K
Fr 175 R 178
Pilot 48
F 2 turns. R 2 1/4 turns
Delkovic cans
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xeris
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Re: Can I use Dynojet needles with standard main jets?

Post by xeris »

Have you examined the enrichment control linkage and fittings (aka choke)?
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tony.mon
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Re: Can I use Dynojet needles with standard main jets?

Post by tony.mon »

I think I'd try a replacement set of carbs before anything else.
You can always sell them on if they don't help, to get your money back.
It's not falling off, it's an upgrade opportunity.
Harveyz
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Re: Can I use Dynojet needles with standard main jets?

Post by Harveyz »

After a few pints of thinking juice last night - could it be a fault TPS sensor - I've checked it with the multi meter previously and appeared to work (set near 500k ohms as recommended on the forum) - all the symptoms I'm getting could be ignition related rather than fuel - has anyone had a faulty TPS?
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sirch345
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Re: Can I use Dynojet needles with standard main jets?

Post by sirch345 »

Harveyz wrote: Mon May 08, 2023 10:50 am After a few pints of thinking juice last night - could it be a fault TPS sensor - I've checked it with the multi meter previously and appeared to work (set near 500k ohms as recommended on the forum) - all the symptoms I'm getting could be ignition related rather than fuel - has anyone had a faulty TPS?
I can't say I recall anyone having that happen, that's not to say it has not happened though.

My 2p worth, try cutting 1/2" (13mm) off the HT leads at the sparkplug ends, then re-fit the sparkplug caps,

Chris.
sisumi
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Re: Can I use Dynojet needles with standard main jets?

Post by sisumi »

I had considered purchasing some used carbs on ebay previously - just to rule out carb settings as the issue. No guarantee you'd be buying a standard set though. As Tony said, you could sell on to recover some cost if they don't fix the problem. But with your problem being intermittent, it seems less likely to be carb setup related and more electrical. Another set of carbs would come with a TPS though.

Rooting for you on tracking down this issue! I know how frustrating it can be, but I did learn a lot about the bike on the journey. The first time taking the carbs off seemed like opening pandora's box, but now I see it as a 10 minute job.
Harveyz
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Re: Can I use Dynojet needles with standard main jets?

Post by Harveyz »

Thanks for the support - this is definitely a challenging bike - I'm going to rule out fuelling - checked all the tank vents, going to replace the inlet rubbers (rule of leaks), reached the fuel petcock - go a new fuel cap coming as can't rule out vapour locking.

Plan then is to move onto the ignition circuit - got new plugs, check ICU (not getting any fault codes but need to rule it out ), TPS seems to work OK on a multimeter, check the ignition pulse generator.

Left field as it had a dull Dynojet kit fitted wondering if it had had an ignition advance fitted - say a thread on this forum "Ignition Advancer" - this may be an issue as I've reset the TPS to 500ohms

Busy weekend ahead

sisumi - is yours still going storm after the changes ?
tony.mon
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Re: Can I use Dynojet needles with standard main jets?

Post by tony.mon »

If you have a Factory Pro ignition advancer fitted it will have the advance degrees- either 2 or 4 - stamped on it.
The original is grey/silver but FP ones are gold-coloured.
It's not falling off, it's an upgrade opportunity.
Harveyz
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Re: Can I use Dynojet needles with standard main jets?

Post by Harveyz »

Thank for the tip - I wondering how I’d identify if it had been changed
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fabiostar
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Re: Can I use Dynojet needles with standard main jets?

Post by fabiostar »

ok my 2p.. the tps? over the years iv forgot to re connect mine a few times on test rides and the bikes ran fine, hooked them back up and it ran? just the same as before so they dont make a huge difference, at least not causing the problems you have..

now you say the carbs had a dynojet kit fitted? what slide springs are you using? the reason i ask is i know some after market kit use softer/different springs from standard ,, which to me would make the slides open faster giving the engine a gulp of fuel it might not want in your case,,

iv had an engine that had ignition problems stamped all over it with missing and spluttering and even a dyno didnt pick it up because it wasnt out on the road with real load on the bike :eek2 ...

and the probem was? it was running rich...
the older i get,the faster i was :lol:
Harveyz
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Re: Can I use Dynojet needles with standard main jets?

Post by Harveyz »

Latest - I changed the plug and got a new fuel tank cap - as I suspected it had vapour lock issue - took it ou today for a run it ran fine outer than a slight pop on the over run when it got hot
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sirch345
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Re: Can I use Dynojet needles with standard main jets?

Post by sirch345 »

Harveyz wrote: Sun May 14, 2023 1:39 am Latest - I changed the plug and got a new fuel tank cap - as I suspected it had vapour lock issue - took it ou today for a run it ran fine outer than a slight pop on the over run when it got hot
I'm glad to hear that, well done :thumbup: :thumbup:

Chris.
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fabiostar
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Re: Can I use Dynojet needles with standard main jets?

Post by fabiostar »

Harveyz wrote: Sun May 14, 2023 1:39 am Latest - I changed the plug and got a new fuel tank cap - as I suspected it had vapour lock issue - took it ou today for a run it ran fine outer than a slight pop on the over run when it got hot

you can call that a result as they mostly do a little popping and banging at times :clap:
the older i get,the faster i was :lol:
sisumi
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Re: Can I use Dynojet needles with standard main jets?

Post by sisumi »

Harveyz wrote: Sun May 14, 2023 1:39 am Latest - I changed the plug and got a new fuel tank cap - as I suspected it had vapour lock issue - took it ou today for a run it ran fine outer than a slight pop on the over run when it got hot
Great news.

Mine also has a few pops on the Delkevics, nothing like before, and I haven't had one misfire or carb fart since returning to standard. I've adjusted my riding style now too and realised I don't need to constantly swap cogs in the curves and can just ride the torque. It picks up cleanly from low revs. Trying to keep it above 4000 rpm was driving me nuts, reminded me of my ex girlfriend's badly tuned 350LC :lol:
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sirch345
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Re: Can I use Dynojet needles with standard main jets?

Post by sirch345 »

sisumi wrote: Tue May 16, 2023 6:53 pm
Harveyz wrote: Sun May 14, 2023 1:39 am Latest - I changed the plug and got a new fuel tank cap - as I suspected it had vapour lock issue - took it ou today for a run it ran fine outer than a slight pop on the over run when it got hot
Great news.

Mine also has a few pops on the Delkevics, nothing like before, and I haven't had one misfire or carb fart since returning to standard. I've adjusted my riding style now too and realised I don't need to constantly swap cogs in the curves and can just ride the torque. It picks up cleanly from low revs. Trying to keep it above 4000 rpm was driving me nuts, reminded me of my ex girlfriend's badly tuned 350LC :lol:
That's it you're getting the VTR now by making use of the torque, it's definitely no narrow band two stroke that needs revving hard in every gear to get the most from it :lol: :thumbup:

Chris.
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