Triumph Rat Motorcycle Forums banner

1 - 13 of 13 Posts

·
Registered
Joined
·
372 Posts
Discussion Starter #1
hi all. i have a question related to installing new main jets on a T100. my bike currently has the dynojet kit installed with the DJ108 mains. My current bike setup is snorkel removed, k&n air filter, and epco pipes. when riding have noticed that there seems to be alot (to me) popping and backfiring on deceleration. before the dynojet kit i had 127 mains that had been installed my the dealer which were WAY rich. if i am deducing this all right i believe i could go to the DJ112 and probably be right on the money. jenks lists the possibilities as either a 115 or 120 main jet with my setup so the DJ112 (117 Keihin) would fall in between. first off, what do you all think about moving up 1 size and second i have never rejetted before so i need a little help. since this has been winterized and there is no gas in the carbs can i just loosen the screws to the float bowl and install the main jet? i am assuming this can be done with out removing the carbs? sorry to be so ignorant, i am still learning my way around these great bikes. -keith
 

·
Registered
Joined
·
666 Posts
If the float bowls are dry you can just drop the bowls and change the jet. Sounds like your heading in the right direction as far as jet size goes.
 

·
Registered
Joined
·
164 Posts
You do anything with your pilot jets? The popping on decel can be an indication of too lean pilots, I believe.

I like the "off-throttle" test for main jets--run at full throttle for a few seconds, then let off just a bit--like 1/8 throttle--if the bike surges, you're probably too lean. Likewise, when you're hitting it WOT you may seem to run out of oomph at the higher revs.

But it does sound like you're low on the mains anyway. So you have your airbox but just removed the snorkel, right? Seems like 120 would be about right, but I'm just a noob learning.
 

·
Registered
Joined
·
372 Posts
Discussion Starter #4
thanks for the replies. to answer your question, no i didn't do anything to the airbox short of removing the snorkel and installing the k&n filter. oh yea, didn't mention the ai has been removed. also, you asked about the pilot jets. i believe they are the stock jets. if i remember right the dynojet kits use the stock pilots and only change the needles and mains. i will stand corrected if i am wrong. thanks, keith
 

·
Registered
Joined
·
164 Posts
It could also be that your pipes just do that--pop and fart--lots of after market pipes will.

As to rejetting go to the dinqua.com site and follow his step by step. Removing the carbs is really simple, so don't be put off by that. But that being said, if your screws are good on the bowls it shouldn't be that hard to get them off with the carbs installed. get one of the replacement stainless bolt sets--will save you time and frustration later.
 

·
Premium Member
Joined
·
8,211 Posts
great info since this is next on my list after my bars. The last carb I mucked around with was a Rochester Q-Jet on my old Chevy 15 years ago.
 

·
Registered
Joined
·
22 Posts
When I changed my jets there were a few great tips I picked up along the way that really helped - first was to change over the float bowl chamber screws to allen heads - they chew up something rottem & are a right nuisance to access.

Secondly, the job is so much less fiddly if you disconnect the carbs & pull them through to one side of the bike before changing the jets. Takes ten minutes before you can set to work on making the change, but saves so much cursing it has been well worth the effort (for me at least).

Matt:D
 

·
Registered
Joined
·
3,537 Posts
Seems like guys either can easily get the jets out - carbs on - with a screwdriver or wind up taking the carbs off. I could not easily get the jets out with a screwdriver. With the carbs on, I simply used a wrench and took out the jet holder and collar and removed the jet from that, put in the new jet, and reinstalled, taking care the collar was in correctly. Quite simple - much more so than removing the carbs. I'll save that job for when it absolutely needs to be done.
 

·
Registered
Joined
·
35 Posts
Hi Keith,
I too have installed the Dynojet kit.
I am very happy with it.

My bike has the snorkel and restrictor removed, the inlet to the air filter opened up and Staintune pipes.
I am running the Dynojet 120 main jet, Dynojet springs and the New Bonneville adjustable air screws at 2and3/4 turns out.

With only the snorkel removed my thoughts are you could go either the Dynojet 112 or 116 main jets.

I am using the allenhead carb screws too, money well spent!
Cheers
Pete
 

·
Registered
Joined
·
372 Posts
Discussion Starter #11
thanks for the replies. i am going to go with the DJ112's and see how that goes. do you all think i should mess with the pilots and the needles or just see how it runs with the bigger mains. i am kind of thinking just changing the mains and going from there. my feeling is that the pilots and/or needles are probably pretty close as they are to the dynojet instructions. what do you all say? -keith
 

·
Registered
Joined
·
1,687 Posts
i am going to go with the DJ112's and see how that goes. do you all think i should mess with the pilots and the needles.
What do you all say? -keith
I'd hesitate in going any bigger than the 112 DJ's (117.5 K'hin) unless you're intending to further open the airbox.

Wouldn't mess with the pilots or needles for now.
Probably no need to anyway, but always best to do one thing at a time.
Then if anything changes (for better or worse) you know exactly whats caused it.
Change more than one thing then you dont!


V.
 

·
Registered
Joined
·
372 Posts
Discussion Starter #13
thanks ventura. i think you have hit the nail on the head. i plan to just go with the DJ112's and see how it runs in the spring. it ran pretty good with the 108's before. i just noticed backfiring and popping until it was good and warmed up. i am hoping this change will help the problem and i believe going to the 112's will get me closer to ideal jetting anyway. now i just need to get my butt to a dyno and really get it dialed in! -keith
 
1 - 13 of 13 Posts
Top