New owner

Bike running like a dog? This section might well answer your questions. Posting restricted to registered users.
Post Reply
kangaroo
Posts: 67
Joined: Fri May 30, 2014 10:15 pm
AntiSpam: No

New owner

Post by kangaroo »

Hey Guys,

I have just purchased a 1985 ns400r in rothmans colours, 5000miles from new, mostly stock except for a set of jolly moto pipes. The pipes were fitted without rejetting, so before I go any further, I would like to know what jetting changes you guys think may be necessary, if any.

Bike also came with original workshop manual and paddock stand, along with a single seat hump, mph clocks (the bike is an italian import) and a box of bits and bobs.

Any help on the jetting is greatly appreciated!!

P.S pictures to follow :D

fredie
Posts: 582
Joined: Thu Jun 28, 2007 1:32 pm
Location: sydney australia

Re: New owner

Post by fredie »

hello kangaroo . welcome :D

kangaroo
Posts: 67
Joined: Fri May 30, 2014 10:15 pm
AntiSpam: No

Re: New owner

Post by kangaroo »

Thanks :D

I've ridden the bike a few times, I'm currently running it on motul 710, which seems pretty good... Anyone else running it or would advise against it? Anyway... I've pulled the front 2 plugs and the bike looks to be running perfect... I can post a pic of a plug later on for you guys to judge but I think it's ok.

Straycat
Posts: 86
Joined: Sat Feb 18, 2012 7:37 pm
AntiSpam: No
Location: Canada

Re: New owner

Post by Straycat »

Hi there, Ill chime in with my opinion here and others with more expertise than me can add.

Firsly on the Oil, I only run Amsoil Interceptor now in all my 2 stroke bikes it burns clean and doesnt gum up power valves. Never used motul so cant say anything about it

On Jetting, id be concerend if your running stock jetting with aftermarket performance pipes. Im sure the folks at Jolly moto (or folks here can give you a good starting point for jetting). Unless your doing plug chop tests at different rpm, you may not see the adverse effects of a lean condition after you get back from a ride, until you squeak it or melt it while on the road. Trouble with checking the plugs after you get home is, if you've ridden it gently for the last little bit, your not seeing the true plug colour while under mid or full throttle. you'll want to do a plug chop a different throttle positions to see where the Jetting is. Some folks are surprised at how many lean seizures occur at mid throttle (vs full).

Never modded my 2 stroke bikes (My RZ was modded by someone else and my RG250, NS400 are stock) but Im pretty familiar with snowmobile 2 strokes, and plug chop is one way to test the jetting and the preferred is if you have acces to a set EGT's (Exhaust Gas Temperature Sensors). In my world of sled mod's no one is without EGT's when piping and jetting a 2 stroke sled, way too easy to burn a motor down before you know it. But thats not always practical for someone who's not going to be doing it regularly.

lots of instructions out there on doing a plug chop.
1986 Honda NS400r
1985 Yam RZ500
1990 Yam RZ350 YPVS
1987 Suzuki RG250
1988 Suzuki RGV250 VJ21
1989 Yam FZR400
1986 Honda TLR 200 Relfex
1986 Honda VF500F Interceptor
1985 Honda VF500F Rothmans
1985 Hond VF1000R (x4)
2014 Honda VFR800

Post Reply